geary/src/client/composer/composer-widget.vala

/*
 * Copyright 2016 Software Freedom Conservancy Inc.
 * Copyright 2017-2019 Michael Gratton <mike@vee.net>
 *
 * This software is licensed under the GNU Lesser General Public License
 * (version 2.1 or later). See the COPYING file in this distribution.
 */

private errordomain AttachmentError {
    FILE,
    DUPLICATE
}


/**
 * A widget for editing an email message.
 *
 * Composers must always be placed in an instance of {@link ComposerContainer}.
 */
[GtkTemplate (ui = "/org/gnome/Geary/composer-widget.ui")]
public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {


    /** The email fields the composer requires for referred email. */
    public const Geary.Email.Field REQUIRED_FIELDS = ENVELOPE | BODY;

    /// Translators: Title for an empty composer window
    private const string DEFAULT_TITLE = _("New Message");

    public enum ComposeType {
        NEW_MESSAGE,
        REPLY,
        REPLY_ALL,
        FORWARD
    }

    /**
     * Determines the result of prompting whether to close the composer.
     *
     * @see conditional_close
     */
    public enum CloseStatus {

        /** The composer is already closed. */
        CLOSED,

        /** The composer is ready to be closed, but is not yet. */
        READY,

        /** Closing the composer was not confirmed by a human. */
        CANCELLED;

    }

    /** Defines different supported user interface modes. */
    public enum PresentationMode {

        /** Composer has been closed. */
        CLOSED,

        /** Composer is not currently visible. */
        NONE,

        /**
         * Composer is in its own window, not in a main windows.
         *
         * @see Window
         */
        DETACHED,

        /**
         * Composer is in a full-height box in a main window.
         *
         * @see Box
         */
        PANED,

        /**
         * Composer is embedded inline in a conversation.
         *
         * @see Embed
         */
        INLINE,

        /**
         * Composer is embedded inline with header fields hidden.
         *
         * @see Embed
         */
        INLINE_COMPACT;

    }

    private enum AttachPending { ALL, INLINE_ONLY }

    private class FromAddressMap {
        public Geary.Account account;
        public Geary.RFC822.MailboxAddresses from;
        public FromAddressMap(Geary.Account a, Geary.RFC822.MailboxAddresses f) {
            account = a;
            from = f;
        }
    }

    // XXX need separate composer close action in addition to the
    // default window close action so we can bind Esc to it without
    // also binding the default window close action to Esc as
    // well. This could probably be fixed by pulling both the main
    // window's and composer's actions out of the 'win' action
    // namespace, leaving only common window actions there.
    private const string ACTION_CLOSE = "composer-close";
    private const string ACTION_CUT = "cut";
    private const string ACTION_COPY_LINK = "copy-link";
    private const string ACTION_PASTE = "paste";
    private const string ACTION_PASTE_WITHOUT_FORMATTING = "paste-without-formatting";
    private const string ACTION_SELECT_ALL = "select-all";
    private const string ACTION_BOLD = "bold";
    private const string ACTION_ITALIC = "italic";
    private const string ACTION_UNDERLINE = "underline";
    private const string ACTION_STRIKETHROUGH = "strikethrough";
    private const string ACTION_FONT_SIZE = "font-size";
    private const string ACTION_FONT_FAMILY = "font-family";
    private const string ACTION_REMOVE_FORMAT = "remove-format";
    private const string ACTION_INDENT = "indent";
    private const string ACTION_OUTDENT = "outdent";
    private const string ACTION_OLIST = "olist";
    private const string ACTION_ULIST = "ulist";
    private const string ACTION_JUSTIFY = "justify";
    private const string ACTION_COLOR = "color";
    private const string ACTION_INSERT_IMAGE = "insert-image";
    private const string ACTION_INSERT_LINK = "insert-link";
    private const string ACTION_COMPOSE_AS_HTML = "compose-as-html";
    private const string ACTION_SHOW_EXTENDED_HEADERS = "show-extended-headers";
    private const string ACTION_SHOW_FORMATTING = "show-formatting";
    private const string ACTION_DISCARD = "discard";
    private const string ACTION_DETACH = "detach";
    private const string ACTION_SEND = "send";
    private const string ACTION_ADD_ATTACHMENT = "add-attachment";
    private const string ACTION_ADD_ORIGINAL_ATTACHMENTS = "add-original-attachments";
    private const string ACTION_SELECT_DICTIONARY = "select-dictionary";
    private const string ACTION_OPEN_INSPECTOR = "open_inspector";

    // ACTION_INSERT_LINK and ACTION_REMOVE_FORMAT are missing from
    // here since they are handled in update_selection_actions
    private const string[] HTML_ACTIONS = {
        ACTION_BOLD, ACTION_ITALIC, ACTION_UNDERLINE, ACTION_STRIKETHROUGH,
        ACTION_FONT_SIZE, ACTION_FONT_FAMILY, ACTION_COLOR, ACTION_JUSTIFY,
        ACTION_INSERT_IMAGE, ACTION_COPY_LINK,
        ACTION_OLIST, ACTION_ULIST
    };

    private const ActionEntry[] EDITOR_ACTIONS = {
        { Action.Edit.COPY,                on_copy                            },
        { Action.Edit.REDO,                on_redo                            },
        { Action.Edit.UNDO,                on_undo                            },
        { ACTION_BOLD,                     on_action,        null, "false"    },
        { ACTION_COLOR,                    on_select_color                    },
        { ACTION_COPY_LINK,                on_copy_link                       },
        { ACTION_CUT,                      on_cut                             },
        { ACTION_FONT_FAMILY,              on_font_family,   "s",  "'sans'"   },
        { ACTION_FONT_SIZE,                on_font_size,     "s",  "'medium'" },
        { ACTION_INDENT,                   on_indent                          },
        { ACTION_INSERT_IMAGE,             on_insert_image                    },
        { ACTION_INSERT_LINK,              on_insert_link                     },
        { ACTION_ITALIC,                   on_action,        null, "false"    },
        { ACTION_JUSTIFY,                  on_justify,       "s",  "'left'"   },
        { ACTION_OLIST,                    on_olist                           },
        { ACTION_OUTDENT,                  on_action                          },
        { ACTION_PASTE,                    on_paste                           },
        { ACTION_PASTE_WITHOUT_FORMATTING, on_paste_without_formatting        },
        { ACTION_REMOVE_FORMAT,            on_remove_format, null, "false"    },
        { ACTION_SELECT_ALL,               on_select_all                      },
        { ACTION_STRIKETHROUGH,            on_action,        null, "false"    },
        { ACTION_ULIST,                    on_ulist                           },
        { ACTION_UNDERLINE,                on_action,        null, "false"    },
    };

    private const ActionEntry[] COMPOSER_ACTIONS = {
        { Action.Window.CLOSE,             on_close                                                   },
        { ACTION_ADD_ATTACHMENT,           on_add_attachment                                          },
        { ACTION_ADD_ORIGINAL_ATTACHMENTS, on_pending_attachments                                     },
        { ACTION_CLOSE,                    on_close                                                   },
        { ACTION_DISCARD,                  on_discard                                       },
        { ACTION_COMPOSE_AS_HTML,          on_toggle_action, null, "true", on_compose_as_html_toggled },
        { ACTION_DETACH,                   on_detach                                                  },
        { ACTION_OPEN_INSPECTOR,           on_open_inspector                  },
        { ACTION_SELECT_DICTIONARY,        on_select_dictionary                                       },
        { ACTION_SEND,                     on_send                                                    },
        { ACTION_SHOW_EXTENDED_HEADERS,    on_toggle_action, null, "false", on_show_extended_headers_toggled },
        { ACTION_SHOW_FORMATTING,          on_toggle_action, null, "false", on_show_formatting        },
    };

    public static void add_accelerators(Application.Client application) {
        application.add_window_accelerators(ACTION_DISCARD, { "Escape" } );
        application.add_window_accelerators(ACTION_ADD_ATTACHMENT, { "<Ctrl>t" } );
        application.add_window_accelerators(ACTION_DETACH, { "<Ctrl>d" } );

        application.add_edit_accelerators(ACTION_CUT, { "<Ctrl>x" } );
        application.add_edit_accelerators(ACTION_PASTE, { "<Ctrl>v" } );
        application.add_edit_accelerators(ACTION_PASTE_WITHOUT_FORMATTING, { "<Ctrl><Shift>v" } );
        application.add_edit_accelerators(ACTION_INSERT_IMAGE, { "<Ctrl>g" } );
        application.add_edit_accelerators(ACTION_INSERT_LINK, { "<Ctrl>l" } );
        application.add_edit_accelerators(ACTION_INDENT, { "<Ctrl>bracketright" } );
        application.add_edit_accelerators(ACTION_OUTDENT, { "<Ctrl>bracketleft" } );
        application.add_edit_accelerators(ACTION_REMOVE_FORMAT, { "<Ctrl>space" } );
        application.add_edit_accelerators(ACTION_BOLD, { "<Ctrl>b" } );
        application.add_edit_accelerators(ACTION_ITALIC, { "<Ctrl>i" } );
        application.add_edit_accelerators(ACTION_UNDERLINE, { "<Ctrl>u" } );
        application.add_edit_accelerators(ACTION_STRIKETHROUGH, { "<Ctrl>k" } );
    }

    private const string DRAFT_SAVED_TEXT = _("Saved");
    private const string DRAFT_SAVING_TEXT = _("Saving");
    private const string DRAFT_ERROR_TEXT = _("Error saving");
    private const string BACKSPACE_TEXT = _("Press Backspace to delete quote");

    private const string URI_LIST_MIME_TYPE = "text/uri-list";
    private const string FILE_URI_PREFIX = "file://";

    private const string MAILTO_URI_PREFIX = "mailto:";

    // Keep these in sync with the next const below.
    private const string ATTACHMENT_KEYWORDS =
        "attach|attaching|attaches|attachment|attachments|attached|enclose|enclosed|enclosing|encloses|enclosure|enclosures";
    // Translators: This is list of keywords, separated by pipe ("|")
    // characters, that suggest an attachment; since this is full-word
    // checking, include all variants of each word. No spaces are
    // allowed. The words will be converted to lower case based on
    // locale and English versions included automatically.
    private const string ATTACHMENT_KEYWORDS_LOCALISED =
        _("attach|attaching|attaches|attachment|attachments|attached|enclose|enclosed|enclosing|encloses|enclosure|enclosures");

    private const string PASTED_IMAGE_FILENAME_TEMPLATE = "geary-pasted-image-%u.png";


    /** The account the email is being sent from. */
    public Geary.Account account { get; private set; }

    /** The identifier of the draft this composer holds, if any. */
    public Geary.EmailIdentifier? current_draft_id {
        get; private set; default = null;
    }

    /** Determines the composer's current presentation mode. */
    public PresentationMode current_mode { get; set; default = NONE; }

    /** Determines the type of email being composed. */
    public ComposeType compose_type { get; private set; default = ComposeType.NEW_MESSAGE; }

    /** Determines if the composer is completely empty. */
    public bool is_blank {
        get {
            return this.to_entry.empty
                && this.cc_entry.empty
                && this.bcc_entry.empty
                && this.reply_to_entry.empty
                && this.subject_entry.buffer.length == 0
                && this.editor.is_empty
                && this.attached_files.size == 0;
        }
    }

    public WebView editor { get; private set; }

    internal Headerbar header { get; private set; }

    internal bool has_multiple_from_addresses {
        get {
            return (
                this.accounts.size > 1 ||
                this.account.information.has_sender_aliases
            );
        }
    }

    internal string subject {
        get { return this.subject_entry.get_text(); }
        private set { this.subject_entry.set_text(value); }
    }

    private Geary.RFC822.MailboxAddresses from { get; private set; }

    private string to {
        get { return this.to_entry.get_text(); }
        set { this.to_entry.set_text(value); }
    }

    private string cc {
        get { return this.cc_entry.get_text(); }
        set { this.cc_entry.set_text(value); }
    }

    private string bcc {
        get { return this.bcc_entry.get_text(); }
        set { this.bcc_entry.set_text(value); }
    }

    private string reply_to {
        get { return this.reply_to_entry.get_text(); }
        set { this.reply_to_entry.set_text(value); }
    }

    private Gee.Set<Geary.RFC822.MessageID> in_reply_to = new Gee.HashSet<Geary.RFC822.MessageID>();

    private string references { get; private set; }

    [GtkChild]
    private Gtk.Grid editor_container;

    [GtkChild]
    private Gtk.Grid body_container;

    [GtkChild]
    private Gtk.Label from_label;
    [GtkChild] private Gtk.Box from_row;
    [GtkChild]
    private Gtk.Label from_single;
    [GtkChild]
    private Gtk.ComboBoxText from_multiple;
    private Gee.ArrayList<FromAddressMap> from_list = new Gee.ArrayList<FromAddressMap>();

    [GtkChild]
    private Gtk.Box to_box;
    [GtkChild]
    private Gtk.Label to_label;
    private EmailEntry to_entry;
    private Components.EntryUndo to_undo;

    [GtkChild]
    private Gtk.Revealer extended_fields_revealer;

    [GtkChild]
    private Gtk.EventBox cc_box;
    [GtkChild]
    private Gtk.Label cc_label;
    private EmailEntry cc_entry;
    private Components.EntryUndo cc_undo;

    [GtkChild]
    private Gtk.EventBox bcc_box;
    [GtkChild]
    private Gtk.Label bcc_label;
    private EmailEntry bcc_entry;
    private Components.EntryUndo bcc_undo;

    [GtkChild]
    private Gtk.EventBox reply_to_box;
    [GtkChild]
    private Gtk.Label reply_to_label;
    private EmailEntry reply_to_entry;
    private Components.EntryUndo reply_to_undo;

    [GtkChild] private Gtk.Box subject_row;
    [GtkChild]
    private Gtk.Entry subject_entry;
    private Components.EntryUndo subject_undo;
    private Gspell.Checker subject_spell_checker = new Gspell.Checker(null);
    private Gspell.Entry subject_spell_entry;

    [GtkChild]
    private Gtk.Label message_overlay_label;
    [GtkChild]
    private Gtk.Box attachments_box;
    [GtkChild]
    private Gtk.Box hidden_on_attachment_drag_over;
    [GtkChild]
    private Gtk.Box visible_on_attachment_drag_over;
    [GtkChild]
    private Gtk.Widget hidden_on_attachment_drag_over_child;
    [GtkChild]
    private Gtk.Widget visible_on_attachment_drag_over_child;
    [GtkChild]
    private Gtk.Widget recipients;
    [GtkChild]
    private Gtk.Box header_area;
    [GtkChild] private Gtk.Revealer formatting;
    [GtkChild]
    private Gtk.Button insert_link_button;
    [GtkChild]
    private Gtk.Button select_dictionary_button;
    [GtkChild]
    private Gtk.MenuButton menu_button;
    [GtkChild]
    private Gtk.Label info_label;

    [GtkChild]
    private Gtk.ProgressBar background_progress;

    private GLib.SimpleActionGroup composer_actions = new GLib.SimpleActionGroup();
    private GLib.SimpleActionGroup editor_actions = new GLib.SimpleActionGroup();

    private Menu html_menu;
    private Menu plain_menu;

    private Menu context_menu_model;
    private Menu context_menu_rich_text;
    private Menu context_menu_plain_text;
    private Menu context_menu_webkit_spelling;
    private Menu context_menu_webkit_text_entry;
    private Menu context_menu_inspector;

    /** Determines if the composer can currently save a draft. */
    private bool can_save {
        get { return this.draft_manager != null; }
    }

    /** Determines if current message should be saved as draft. */
    private bool should_save {
        get {
            return this.can_save
                && !this.is_draft_saved
                && !this.is_blank;
        }
    }

    private Gee.Collection<Geary.Account> accounts;

    private string body_html = "";

    private SpellCheckPopover? spell_check_popover = null;
    private string? pointer_url = null;
    private string? cursor_url = null;
    private bool is_attachment_overlay_visible = false;
    private Geary.RFC822.MailboxAddresses reply_to_addresses;
    private Geary.RFC822.MailboxAddresses reply_cc_addresses;
    private string reply_subject = "";
    private string forward_subject = "";
    private bool top_posting = true;
    private string? last_quote = null;

    // The message(s) this email is in reply to/forwarded from
    private Gee.Set<Geary.EmailIdentifier> referred_ids =
        new Gee.HashSet<Geary.EmailIdentifier>();

    private Gee.List<Geary.Attachment>? pending_attachments = null;
    private AttachPending pending_include = AttachPending.INLINE_ONLY;
    private Gee.Set<File> attached_files = new Gee.HashSet<File>(Geary.Files.nullable_hash,
        Geary.Files.nullable_equal);
    private Gee.Map<string,Geary.Memory.Buffer> inline_files = new Gee.HashMap<string,Geary.Memory.Buffer>();
    private Gee.Map<string,Geary.Memory.Buffer> cid_files = new Gee.HashMap<string,Geary.Memory.Buffer>();

    private Geary.App.DraftManager? draft_manager = null;
    private GLib.Cancellable? draft_manager_opening = null;
    private Geary.EmailFlags draft_flags = new Geary.EmailFlags.with(Geary.EmailFlags.DRAFT);
    private Geary.TimeoutManager draft_timer;
    private bool is_draft_saved = false;
    private string draft_status_text {
        get { return this._draft_status_text; }
        set {
            this._draft_status_text = value;
            update_info_label();
        }
    }
    private string _draft_status_text = "";

    private bool can_delete_quote {
        get { return this._can_delete_quote; }
        set {
            this._can_delete_quote = value;
            update_info_label();
        }
    }
    private bool _can_delete_quote = false;

    private Container? container {
        get { return this.parent as Container; }
    }

    private Application.Client application;

    // Timeout for showing the slow image paste pulsing bar
    private Geary.TimeoutManager show_background_work_timeout = null;

    // Timer for pulsing progress bar
    private Geary.TimeoutManager background_work_pulse;


    public Widget(Application.Client application,
                          Geary.Account initial_account,
                          ComposeType compose_type) {
        base_ref();
        this.application = application;
        this.account = initial_account;

        try {
            this.accounts = this.application.engine.get_accounts();
        } catch (GLib.Error e) {
            warning("Could not fetch account info: %s", e.message);
        }

        this.compose_type = compose_type;

        this.header = new Headerbar(application.config);
        this.header.expand_composer.connect(on_expand_compact_headers);

        // Setup drag 'n drop
        const Gtk.TargetEntry[] target_entries = { { URI_LIST_MIME_TYPE, 0, 0 } };
        Gtk.drag_dest_set(this, Gtk.DestDefaults.MOTION | Gtk.DestDefaults.HIGHLIGHT,
            target_entries, Gdk.DragAction.COPY);

        add_events(Gdk.EventMask.KEY_PRESS_MASK | Gdk.EventMask.KEY_RELEASE_MASK);

        this.visible_on_attachment_drag_over.remove(
            this.visible_on_attachment_drag_over_child
        );

        this.to_entry = new EmailEntry(this);
        this.to_entry.changed.connect(on_envelope_changed);
        this.to_box.pack_start(to_entry, true, true);
        this.to_label.set_mnemonic_widget(this.to_entry);
        this.to_undo = new Components.EntryUndo(this.to_entry);

        this.cc_entry = new EmailEntry(this);
        this.cc_entry.changed.connect(on_envelope_changed);
        this.cc_box.add(cc_entry);
        this.cc_label.set_mnemonic_widget(this.cc_entry);
        this.cc_undo = new Components.EntryUndo(this.cc_entry);

        this.bcc_entry = new EmailEntry(this);
        this.bcc_entry.changed.connect(on_envelope_changed);
        this.bcc_box.add(bcc_entry);
        this.bcc_label.set_mnemonic_widget(this.bcc_entry);
        this.bcc_undo = new Components.EntryUndo(this.bcc_entry);

        this.reply_to_entry = new EmailEntry(this);
        this.reply_to_entry.changed.connect(on_envelope_changed);
        this.reply_to_box.add(reply_to_entry);
        this.reply_to_label.set_mnemonic_widget(this.reply_to_entry);
        this.reply_to_undo = new Components.EntryUndo(this.reply_to_entry);

        this.subject_undo = new Components.EntryUndo(this.subject_entry);
        this.subject_spell_entry = Gspell.Entry.get_from_gtk_entry(
            this.subject_entry
        );
        update_subject_spell_checker();

        this.editor = new WebView(application.config);
        this.editor.set_hexpand(true);
        this.editor.set_vexpand(true);
        this.editor.content_loaded.connect(on_editor_content_loaded);
        this.editor.show();

        this.body_container.add(this.editor);

        // Initialize menus
        Gtk.Builder builder = new Gtk.Builder.from_resource(
            "/org/gnome/Geary/composer-menus.ui"
        );
        this.html_menu = (Menu) builder.get_object("html_menu_model");
        this.plain_menu = (Menu) builder.get_object("plain_menu_model");
        this.context_menu_model = (Menu) builder.get_object("context_menu_model");
        this.context_menu_rich_text = (Menu) builder.get_object("context_menu_rich_text");
        this.context_menu_plain_text = (Menu) builder.get_object("context_menu_plain_text");
        this.context_menu_inspector = (Menu) builder.get_object("context_menu_inspector");
        this.context_menu_webkit_spelling = (Menu) builder.get_object("context_menu_webkit_spelling");
        this.context_menu_webkit_text_entry = (Menu) builder.get_object("context_menu_webkit_text_entry");

        // Listen to account signals to update from menu.
        this.application.engine.account_available.connect(
            on_account_available
        );
        this.application.engine.account_unavailable.connect(
            on_account_unavailable
        );

        // Listen for drag and dropped image file
        this.editor.image_file_dropped.connect(
            on_image_file_dropped
        );

        // TODO: also listen for account updates to allow adding identities while writing an email

        this.from = new Geary.RFC822.MailboxAddresses.single(account.information.primary_mailbox);

        this.draft_timer = new Geary.TimeoutManager.seconds(
            10, on_draft_timeout
        );

        // Add actions once every element has been initialized and added
        initialize_actions();
        validate_send_button();

        // Connect everything (can only happen after actions were added)
        this.to_entry.changed.connect(validate_send_button);
        this.cc_entry.changed.connect(validate_send_button);
        this.bcc_entry.changed.connect(validate_send_button);
        this.reply_to_entry.changed.connect(validate_send_button);

        this.editor.command_stack_changed.connect(on_command_state_changed);
        this.editor.button_release_event_done.connect(on_button_release);
        this.editor.context_menu.connect(on_context_menu);
        this.editor.cursor_context_changed.connect(on_cursor_context_changed);
        this.editor.document_modified.connect(() => { draft_changed(); });
        this.editor.get_editor_state().notify["typing-attributes"].connect(on_typing_attributes_changed);
        this.editor.key_press_event.connect(on_editor_key_press_event);
        this.editor.content_loaded.connect(on_content_loaded);
        this.editor.mouse_target_changed.connect(on_mouse_target_changed);
        this.editor.selection_changed.connect(on_selection_changed);

        this.show_background_work_timeout = new Geary.TimeoutManager.milliseconds(
            Util.Gtk.SHOW_PROGRESS_TIMEOUT_MSEC, this.on_background_work_timeout
        );
        this.background_work_pulse = new Geary.TimeoutManager.milliseconds(
            Util.Gtk.PROGRESS_PULSE_TIMEOUT_MSEC, this.background_progress.pulse
        );
        this.background_work_pulse.repetition = FOREVER;

        load_entry_completions();
    }

    public Widget.from_mailbox(Application.Client application,
                               Geary.Account initial_account,
                               Geary.RFC822.MailboxAddress to) {
        this(application, initial_account, ComposeType.NEW_MESSAGE);
        this.to = to.to_full_display();
    }

    public Widget.from_mailto(Application.Client application,
                              Geary.Account initial_account,
                              string mailto) {
        this(application, initial_account, ComposeType.NEW_MESSAGE);

        Gee.HashMultiMap<string, string> headers = new Gee.HashMultiMap<string, string>();
        if (mailto.has_prefix(MAILTO_URI_PREFIX)) {
            // Parse the mailto link.
            string[] parts = mailto.substring(MAILTO_URI_PREFIX.length).split("?", 2);
            string email = Uri.unescape_string(parts[0]);
            string[] params = parts.length == 2 ? parts[1].split("&") : new string[0];
            foreach (string param in params) {
                string[] param_parts = param.split("=", 2);
                if (param_parts.length == 2) {
                    headers.set(Uri.unescape_string(param_parts[0]).down(),
                        Uri.unescape_string(param_parts[1]));
                }
            }

            // Assemble the headers.
            if (email.length > 0 && headers.contains("to"))
                this.to = "%s,%s".printf(
                    email, Geary.Collection.first(headers.get("to"))
                );
            else if (email.length > 0)
                this.to = email;
            else if (headers.contains("to"))
                this.to = Geary.Collection.first(headers.get("to"));

            if (headers.contains("cc"))
                this.cc = Geary.Collection.first(headers.get("cc"));

            if (headers.contains("bcc"))
                this.bcc = Geary.Collection.first(headers.get("bcc"));

            if (headers.contains("subject"))
                this.subject = Geary.Collection.first(headers.get("subject"));

            if (headers.contains("body"))
                this.body_html = Geary.HTML.preserve_whitespace(Geary.HTML.escape_markup(
                    Geary.Collection.first(headers.get("body"))));

            Gee.List<string> attachments = new Gee.LinkedList<string>();
            attachments.add_all(headers.get("attach"));
            attachments.add_all(headers.get("attachment"));
            foreach (string attachment in attachments) {
                try {
                    add_attachment_part(File.new_for_commandline_arg(attachment));
                } catch (Error err) {
                    attachment_failed(err.message);
                }
            }
        }
    }

    ~Widget() {
        base_unref();
    }

    /**
     * Returns the emails referred to by the composed email.
     *
     * A referred email is the email this composer is a reply to, or
     * forwarded from. There may be multiple if a composer was already
     * open and another email was replied to.
     */
    public Gee.Set<Geary.EmailIdentifier> get_referred_ids() {
        return this.referred_ids.read_only_view;
    }

    /**
     * Loads the message into the composer editor.
     */
    public async void load(Geary.Email? referred = null,
                           bool is_draft,
                           string? quote = null,
                           GLib.Cancellable? cancellable)
        throws GLib.Error {
        if (referred != null &&
            !referred.fields.is_all_set(REQUIRED_FIELDS)) {
            throw new Geary.EngineError.INCOMPLETE_MESSAGE(
                "Required fields not met: %s", referred.fields.to_string()
            );
        }
        string referred_quote = "";
        this.last_quote = quote;
        if (referred != null) {
            referred_quote = fill_in_from_referred(referred, quote);
            if (is_draft ||
                compose_type == ComposeType.NEW_MESSAGE ||
                compose_type == ComposeType.FORWARD) {
                this.pending_include = AttachPending.ALL;
            }
            if (is_draft) {
                yield restore_reply_to_state();
            }
        }

        update_attachments_view();
        update_pending_attachments(this.pending_include, true);

        this.editor.load_html(
            this.body_html,
            referred_quote,
            this.top_posting,
            is_draft
        );

        try {
            yield open_draft_manager(is_draft ? referred.id : null, cancellable);
        } catch (Error e) {
            debug("Could not open draft manager: %s", e.message);
        }
    }

    /** Detaches the composer and opens it in a new window. */
    public void detach() {
        Gtk.Widget? focused_widget = null;
        if (this.container != null) {
            focused_widget = this.container.top_window.get_focus();
            this.container.close();
        }
        Window new_window = new Window(this, this.application);

        // Workaround a GTK+ crasher, Bug 771812. When the
        // composer is re-parented, its menu_button's popover
        // keeps a reference to the conversation window's
        // viewport, so when that is removed it has a null parent
        // and we crash. To reproduce: Reply inline, detach the
        // composer, then choose a different conversation back in
        // the main window. The workaround here sets a new menu
        // model and hence the menu_button constructs a new
        // popover.
        this.composer_actions.change_action_state(
            ACTION_COMPOSE_AS_HTML,
            this.application.config.compose_as_html
        );

        set_mode(DETACHED);

        // If the previously focused widget is in the new composer
        // window then focus that, else focus something useful.
        bool refocus = true;
        if (focused_widget != null) {
            Window? focused_window = focused_widget.get_toplevel() as Window;
            if (new_window == focused_window) {
                focused_widget.grab_focus();
                refocus = false;
            }
        }
        if (refocus) {
            set_focus();
        }
    }

    /**
     * Prompts to close the composer if needed, before closing it.
     *
     * If the composer is already closed no action is taken.  If the
     * composer is blank then this method will call {@link exit},
     * destroying the composer, else the composer will either be saved
     * or discarded as needed then closed.
     *
     * The return value specifies whether the composer is being closed
     * or if the prompt was cancelled by a human.
     */
    public CloseStatus conditional_close(bool should_prompt,
                                         bool is_shutdown = false) {
        CloseStatus status = CLOSED;
        switch (this.current_mode) {
        case PresentationMode.CLOSED:
            // no-op
            break;

        case PresentationMode.NONE:
            status = READY;
            break;

        default:
            if (this.is_blank) {
                this.close.begin();
                // This may be a bit of a lie but will very soon
                // become true.
                status = CLOSED;
            } else if (should_prompt) {
                present();
                if (this.can_save) {
                    var dialog = new TernaryConfirmationDialog(
                        this.container.top_window,
                        // Translators: This dialog text is displayed to the
                        // user when closing a composer where the options are
                        // Keep, Discard or Cancel.
                        _("Do you want to keep or discard this draft message?"),
                        null,
                        Stock._KEEP,
                        Stock._DISCARD, Gtk.ResponseType.CLOSE,
                        "",
                        is_shutdown ? "destructive-action" : "",
                        Gtk.ResponseType.OK // Default == Keep
                    );
                    Gtk.ResponseType response = dialog.run();
                    if (response == CANCEL ||
                        response == DELETE_EVENT) {
                        // Cancel
                        status = CANCELLED;
                    } else if (response == OK) {
                        // Keep
                        this.save_and_close.begin();
                    } else {
                        // Discard
                        this.discard_and_close.begin();
                    }
                } else {
                    AlertDialog dialog = new ConfirmationDialog(
                        container.top_window,
                        // Translators: This dialog text is displayed to the
                        // user when closing a composer where the options are
                        // only Discard or Cancel.
                        _("Do you want to discard this draft message?"),
                        null,
                        Stock._DISCARD,
                        ""
                    );
                    Gtk.ResponseType response = dialog.run();
                    if (response == OK) {
                        this.discard_and_close.begin();
                    } else {
                        status = CANCELLED;
                    }
                }
            } else if (this.can_save) {
                this.save_and_close.begin();
            } else {
                this.discard_and_close.begin();
            }
            break;
        }

        return status;
    }

    /**
     * Closes the composer and any drafts unconditionally.
     *
     * This method disables the composer, closes the draft manager,
     * then destroys the composer itself.
     */
    public async void close() {
        if (this.current_mode != CLOSED) {
            // this will set current_mode to NONE first
            set_enabled(false);
            this.current_mode = CLOSED;

            if (this.draft_manager_opening != null) {
                this.draft_manager_opening.cancel();
                this.draft_manager_opening = null;
            }

            if (this.draft_manager != null) {
                try {
                    yield close_draft_manager(null);
                } catch (Error err) {
                    debug("Error closing draft manager on composer close");
                }
            }

            destroy();
        }
    }

    public override void destroy() {
        if (this.draft_manager != null) {
            warning("Draft manager still open on composer destroy");
        }

        this.application.engine.account_available.disconnect(
            on_account_available
        );
        this.application.engine.account_unavailable.disconnect(
            on_account_unavailable
        );

        this.show_background_work_timeout.reset();
        this.background_work_pulse.reset();

        base.destroy();
    }

    /**
     * Sets whether the composer is able to be used.
     *
     * If disabled, the composer hidden, detached from its container
     * and will stop periodically saving drafts.
     */
    public void set_enabled(bool enabled) {
        this.current_mode = NONE;
        this.set_sensitive(enabled);

        // Need to update this separately since it may be detached
        // from the widget itself.
        this.header.set_sensitive(enabled);

        if (enabled) {
            this.open_draft_manager.begin(this.current_draft_id, null);
        } else {
            if (this.container != null) {
                this.container.close();
            }
            this.draft_timer.reset();
        }
    }

    /**
     * Loads and sets contact auto-complete data for the current account.
     */
    private void load_entry_completions() {
        Application.ContactStore contacts =
            this.application.controller.get_contact_store_for_account(
                this.account
            );
        this.to_entry.completion = new ContactEntryCompletion(contacts);
        this.cc_entry.completion = new ContactEntryCompletion(contacts);
        this.bcc_entry.completion = new ContactEntryCompletion(contacts);
        this.reply_to_entry.completion = new ContactEntryCompletion(contacts);
    }

    /**
     * Restores the composer's widget state from any replied to messages.
     */
    private async void restore_reply_to_state() {
        bool first_email = true;

        foreach (Geary.RFC822.MessageID mid in this.in_reply_to) {
            Gee.MultiMap<Geary.Email, Geary.FolderPath?>? email_map;
            try {
                email_map =
                    yield this.account.local_search_message_id_async(mid, Geary.Email.Field.ENVELOPE,
                    true, null, new Geary.EmailFlags.with(Geary.EmailFlags.DRAFT)); // TODO: Folder blacklist
            } catch (Error error) {
                continue;
            }
            if (email_map == null)
                continue;
            Gee.Set<Geary.Email> emails = email_map.get_keys();
            Geary.Email? email = null;
            foreach (Geary.Email candidate in emails) {
                if (candidate.message_id != null &&
                    mid.equal_to(candidate.message_id)) {
                    email = candidate;
                    break;
                }
            }
            if (email == null)
                continue;

            // XXX pretty sure we are calling this only to update the
            // composer's internal set of ids - we really shouldn't be
            // messing around with the draft's recipients since the
            // user may have already updated them.
            add_recipients_and_ids(this.compose_type, email, false);

            if (first_email) {
                this.reply_subject = Geary.RFC822.Utils.create_subject_for_reply(email);
                this.forward_subject = Geary.RFC822.Utils.create_subject_for_forward(email);
                first_email = false;
            }
        }
        if (first_email)  // Either no referenced emails, or we don't have them.  Treat as new.
            return;

        if (this.cc == "")
            this.compose_type = ComposeType.REPLY;
        else
            this.compose_type = ComposeType.REPLY_ALL;

        this.to_entry.modified = this.cc_entry.modified = this.bcc_entry.modified = false;
        if (!to_entry.addresses.equal_to(reply_to_addresses))
            this.to_entry.modified = true;
        if (cc != "" && !cc_entry.addresses.equal_to(reply_cc_addresses))
            this.cc_entry.modified = true;
        if (bcc != "")
            this.bcc_entry.modified = true;

        // We're in compact inline mode, but there are modified email
        // addresses, so set us to use plain inline mode instead so
        // the modified addresses can be seen. If there are CC
        if (this.current_mode == INLINE_COMPACT && (
                this.to_entry.modified ||
                this.cc_entry.modified ||
                this.bcc_entry.modified ||
                this.reply_to_entry.modified)) {
            set_mode(INLINE);
        }

        // If there's a modified header that would normally be hidden,
        // show full fields.
        if (this.bcc_entry.modified ||
            this.reply_to_entry.modified) {
            this.editor_actions.change_action_state(
                ACTION_SHOW_EXTENDED_HEADERS, true
            );
        }
    }

    // Copies the addresses (e.g. From/To/CC) and content from referred into this one
    private string fill_in_from_referred(Geary.Email referred, string? quote) {
        string referred_quote = "";
        if (this.compose_type != ComposeType.NEW_MESSAGE) {
            add_recipients_and_ids(this.compose_type, referred);
            this.reply_subject = Geary.RFC822.Utils.create_subject_for_reply(referred);
            this.forward_subject = Geary.RFC822.Utils.create_subject_for_forward(referred);
        }
        this.pending_attachments = referred.attachments;
        switch (this.compose_type) {
            // Restoring a draft
            case ComposeType.NEW_MESSAGE:
                bool show_extended = false;
                if (referred.from != null)
                    this.from = referred.from;
                if (referred.to != null)
                    this.to_entry.addresses = referred.to;
                if (referred.cc != null)
                    this.cc_entry.addresses = referred.cc;
                if (referred.bcc != null) {
                    show_extended = true;
                    this.bcc_entry.addresses = referred.bcc;
                }
                if (referred.reply_to != null) {
                    show_extended = true;
                    this.reply_to_entry.addresses = referred.reply_to;
                }
                if (referred.in_reply_to != null)
                    this.in_reply_to.add_all(referred.in_reply_to.list);
                if (referred.references != null)
                    this.references = referred.references.to_rfc822_string();
                if (referred.subject != null)
                    this.subject = referred.subject.value ?? "";
                try {
                    Geary.RFC822.Message message = referred.get_message();
                    if (message.has_html_body()) {
                        referred_quote = message.get_html_body(null);
                    } else {
                        referred_quote = message.get_plain_body(true, null);
                    }
                } catch (Error error) {
                    debug("Error getting draft message body: %s", error.message);
                }
                if (show_extended) {
                    this.editor_actions.change_action_state(
                        ACTION_SHOW_EXTENDED_HEADERS, true
                    );
                    this.composer_actions.change_action_state(
                        ACTION_SHOW_EXTENDED_HEADERS, true
                    );
                }
            break;

            case ComposeType.REPLY:
            case ComposeType.REPLY_ALL:
                this.subject = reply_subject;
                this.references = Geary.RFC822.Utils.reply_references(referred);
                referred_quote = Util.Email.quote_email_for_reply(referred, quote,
                    this.application.config.clock_format,
                    Geary.RFC822.TextFormat.HTML);
                if (!Geary.String.is_empty(quote)) {
                    this.top_posting = false;
                } else {
                    this.can_delete_quote = true;
                }
            break;

            case ComposeType.FORWARD:
                this.subject = forward_subject;
                referred_quote = Util.Email.quote_email_for_forward(referred, quote,
                    Geary.RFC822.TextFormat.HTML);
            break;
        }
        return referred_quote;
    }

    public void present() {
        this.container.present();
        set_focus();
    }

    public void set_focus() {
        bool not_compact = this.current_mode != INLINE_COMPACT;
        if (not_compact && Geary.String.is_empty(to))
            this.to_entry.grab_focus();
        else if (not_compact && Geary.String.is_empty(subject))
            this.subject_entry.grab_focus();
        else {
            // Need to grab the focus after the content has finished
            // loading otherwise the text caret will not be visible.
            if (this.editor.is_content_loaded) {
                this.editor.grab_focus();
            } else {
                this.editor.content_loaded.connect(() => { this.editor.grab_focus(); });
            }
        }
    }

    // Initializes all actions and adds them to the action group
    private void initialize_actions() {
        // Composer actions
        this.composer_actions.add_action_entries(COMPOSER_ACTIONS, this);
        // Main actions use the window prefix so they override main
        // window actions. But for some reason, we can't use the same
        // prefix for the headerbar.
        insert_action_group(Action.Window.GROUP_NAME, this.composer_actions);
        this.header.insert_action_group("cmh", this.composer_actions);

        // Editor actions - scoped to the editor only.
        this.editor_actions.add_action_entries(EDITOR_ACTIONS, this);
        this.editor_container.insert_action_group(
            Action.Edit.GROUP_NAME, this.editor_actions
        );

        GLib.SimpleActionGroup[] composer_action_entries_users = {
            this.editor_actions, this.composer_actions
        };
        foreach (var entries_users in composer_action_entries_users) {
            entries_users.change_action_state(
                ACTION_SHOW_EXTENDED_HEADERS, false
            );
            entries_users.change_action_state(
                ACTION_COMPOSE_AS_HTML, this.application.config.compose_as_html
            );
        }

        this.composer_actions.change_action_state(
            ACTION_SHOW_FORMATTING,
            this.application.config.formatting_toolbar_visible
        );

        get_action(Action.Edit.UNDO).set_enabled(false);
        get_action(Action.Edit.REDO).set_enabled(false);

        update_cursor_actions();
    }

    private void update_cursor_actions() {
        bool has_selection = this.editor.has_selection;
        get_action(ACTION_CUT).set_enabled(has_selection);
        get_action(Action.Edit.COPY).set_enabled(has_selection);

        get_action(ACTION_INSERT_LINK).set_enabled(
            this.editor.is_rich_text && (has_selection || this.cursor_url != null)
        );
        get_action(ACTION_REMOVE_FORMAT).set_enabled(
            this.editor.is_rich_text && has_selection
        );
    }

    private bool check_preferred_from_address(Gee.List<Geary.RFC822.MailboxAddress> account_addresses,
        Geary.RFC822.MailboxAddresses? referred_addresses) {
        if (referred_addresses != null) {
            foreach (Geary.RFC822.MailboxAddress address in account_addresses) {
                if (referred_addresses.get_all().contains(address)) {
                    this.from = new Geary.RFC822.MailboxAddresses.single(address);
                    return true;
                }
            }
        }
        return false;
    }

    private void on_content_loaded() {
        if (this.can_delete_quote) {
            this.editor.selection_changed.connect(
                () => {
                    this.can_delete_quote = false;
                }
            );
        }
    }

    private void show_attachment_overlay(bool visible) {
        if (this.is_attachment_overlay_visible == visible)
            return;

        this.is_attachment_overlay_visible = visible;

        // If we just make the widget invisible, it can still intercept drop signals. So we
        // completely remove it instead.
        if (visible) {
            int height = hidden_on_attachment_drag_over.get_allocated_height();
            this.hidden_on_attachment_drag_over.remove(this.hidden_on_attachment_drag_over_child);
            this.visible_on_attachment_drag_over.pack_start(this.visible_on_attachment_drag_over_child, true, true);
            this.visible_on_attachment_drag_over.set_size_request(-1, height);
        } else {
            this.hidden_on_attachment_drag_over.add(this.hidden_on_attachment_drag_over_child);
            this.visible_on_attachment_drag_over.remove(this.visible_on_attachment_drag_over_child);
            this.visible_on_attachment_drag_over.set_size_request(-1, -1);
        }
   }

    [GtkCallback]
    private bool on_drag_motion() {
        show_attachment_overlay(true);
        return false;
    }

    [GtkCallback]
    private void on_drag_leave() {
        show_attachment_overlay(false);
    }

    [GtkCallback]
    private void on_drag_data_received(Gtk.Widget sender, Gdk.DragContext context, int x, int y,
        Gtk.SelectionData selection_data, uint info, uint time_) {

        bool dnd_success = false;
        if (selection_data.get_length() >= 0) {
            dnd_success = true;

            string uri_list = (string) selection_data.get_data();
            string[] uris = uri_list.strip().split("\n");
            foreach (string uri in uris) {
                if (!uri.has_prefix(FILE_URI_PREFIX))
                    continue;

                try {
                    add_attachment_part(File.new_for_uri(uri.strip()));
                    draft_changed();
                } catch (Error err) {
                    attachment_failed(err.message);
                }
            }
        }

        Gtk.drag_finish(context, dnd_success, false, time_);
    }

    [GtkCallback]
    private bool on_drag_drop(Gtk.Widget sender, Gdk.DragContext context, int x, int y, uint time_) {
        if (context.list_targets() == null)
            return false;

        uint length = context.list_targets().length();
        Gdk.Atom? target_type = null;
        for (uint i = 0; i < length; i++) {
            Gdk.Atom target = context.list_targets().nth_data(i);
            if (target.name() == URI_LIST_MIME_TYPE)
                target_type = target;
        }

        if (target_type == null)
            return false;

        Gtk.drag_get_data(sender, context, target_type, time_);
        return true;
    }

    /** Returns a representation of the current message. */
    public async Geary.ComposedEmail get_composed_email(GLib.DateTime? date_override = null,
                                                        bool for_draft = false) {
        Geary.ComposedEmail email = new Geary.ComposedEmail(
            date_override ?? new DateTime.now_local(),
            from
        ).set_to(
            this.to_entry.addresses
        ).set_cc(
            this.cc_entry.addresses
        ).set_bcc(
            this.bcc_entry.addresses
        ).set_reply_to(
            this.reply_to_entry.addresses
        ).set_subject(
            this.subject
        );

        if ((this.compose_type == ComposeType.REPLY || this.compose_type == ComposeType.REPLY_ALL) &&
            !this.in_reply_to.is_empty)
            email.set_in_reply_to(
                new Geary.RFC822.MessageIDList.from_collection(this.in_reply_to)
            );

        if (!Geary.String.is_empty(this.references)) {
            email.set_references(
                new Geary.RFC822.MessageIDList.from_rfc822_string(this.references)
            );
        }

        email.attached_files.add_all(this.attached_files);
        email.inline_files.set_all(this.inline_files);
        email.cid_files.set_all(this.cid_files);

        email.img_src_prefix = Components.WebView.INTERNAL_URL_PREFIX;

        try {
            if (!for_draft) {
                if (this.editor.is_rich_text) {
                    email.body_html = yield this.editor.get_html();
                }
                email.body_text = yield this.editor.get_text();
            } else {
                email.body_html = yield this.editor.get_html_for_draft();
            }
        } catch (Error error) {
            debug("Error getting composer message body: %s", error.message);
        }

        // User-Agent
        email.mailer = Environment.get_prgname() + "/" + Application.Client.VERSION;

        return email;
    }

    /** Appends an email or fragment quoted into the composer. */
    public void append_to_email(Geary.Email referred,
                                string? to_quote,
                                ComposeType type)
        throws Geary.EngineError {
        if (!referred.fields.is_all_set(REQUIRED_FIELDS)) {
            throw new Geary.EngineError.INCOMPLETE_MESSAGE(
                "Required fields not met: %s", referred.fields.to_string()
            );
        }

        if (!this.referred_ids.contains(referred.id)) {
            add_recipients_and_ids(type, referred);
        }

        if (this.last_quote != to_quote) {
            this.last_quote = to_quote;
            // Always use reply styling, since forward styling doesn't
            // work for inline quotes
            this.editor.insert_html(
                Util.Email.quote_email_for_reply(
                    referred,
                    to_quote,
                    this.application.config.clock_format,
                    Geary.RFC822.TextFormat.HTML
                )
            );
        }
    }

    private void add_recipients_and_ids(ComposeType type, Geary.Email referred,
        bool modify_headers = true) {
        Gee.List<Geary.RFC822.MailboxAddress> sender_addresses =
            account.information.sender_mailboxes;

        // Set the preferred from address. New messages should retain
        // the account default and drafts should retain the draft's
        // from addresses, so don't update them here
        if (this.compose_type != ComposeType.NEW_MESSAGE) {
            if (!check_preferred_from_address(sender_addresses, referred.to)) {
                if (!check_preferred_from_address(sender_addresses, referred.cc))
                    if (!check_preferred_from_address(sender_addresses, referred.bcc))
                        check_preferred_from_address(sender_addresses, referred.from);
            }
        }

        // Update the recipient addresses
        Geary.RFC822.MailboxAddresses to_addresses =
            Geary.RFC822.Utils.create_to_addresses_for_reply(referred, sender_addresses);
        Geary.RFC822.MailboxAddresses cc_addresses =
            Geary.RFC822.Utils.create_cc_addresses_for_reply_all(referred, sender_addresses);
        reply_to_addresses = Geary.RFC822.Utils.merge_addresses(reply_to_addresses, to_addresses);
        reply_cc_addresses = Geary.RFC822.Utils.remove_addresses(
            Geary.RFC822.Utils.merge_addresses(reply_cc_addresses, cc_addresses),
            reply_to_addresses);

        if (!modify_headers)
            return;

        bool recipients_modified = this.to_entry.modified || this.cc_entry.modified || this.bcc_entry.modified;
        if (!recipients_modified) {
            if (type == ComposeType.REPLY || type == ComposeType.REPLY_ALL)
                this.to_entry.addresses = Geary.RFC822.Utils.merge_addresses(to_entry.addresses,
                    to_addresses);
            if (type == ComposeType.REPLY_ALL)
                this.cc_entry.addresses = Geary.RFC822.Utils.remove_addresses(
                    Geary.RFC822.Utils.merge_addresses(this.cc_entry.addresses, cc_addresses),
                    this.to_entry.addresses);
            else
                this.cc_entry.addresses = Geary.RFC822.Utils.remove_addresses(this.cc_entry.addresses,
                    this.to_entry.addresses);
            this.to_entry.modified = this.cc_entry.modified = false;
        }

        if (referred.message_id != null) {
            this.in_reply_to.add(referred.message_id);
        }
        this.referred_ids.add(referred.id);
    }

    public override bool key_press_event(Gdk.EventKey event) {
        // Override the method since key-press-event is run last, and
        // we want this behaviour to take precedence over the default
        // key handling
        return check_send_on_return(event) && base.key_press_event(event);
    }

    /** Updates the composer's top level window and headerbar title. */
    public void update_window_title() {
        string subject = this.subject.strip();
        if (Geary.String.is_empty(subject)) {
            subject = DEFAULT_TITLE;
        }

        if (this.container != null) {
            this.container.top_window.title = subject;
        }

        if (this.application.config.desktop_environment != UNITY) {
            this.header.title = subject;
        }
    }

    internal void set_mode(PresentationMode new_mode) {
        this.current_mode = new_mode;
        this.header.set_mode(new_mode);

        switch (new_mode) {
        case PresentationMode.DETACHED:
        case PresentationMode.PANED:
            this.recipients.set_visible(true);
            this.subject_row.visible = true;
            break;

        case PresentationMode.INLINE:
            this.recipients.set_visible(true);
            this.subject_row.visible = false;
            break;

        case PresentationMode.INLINE_COMPACT:
            this.recipients.set_visible(false);
            this.subject_row.visible = false;
            set_compact_header_recipients();
            break;
        }

        update_from_field();
    }

    internal void embed_header() {
        if (this.header.parent == null) {
            this.header_area.add(this.header);
            this.header.hexpand = true;
        }
    }

    internal void free_header() {
        if (this.header.parent != null) {
            this.header.parent.remove(this.header);
        }
    }

    private async bool should_send() {
        bool has_subject = !Geary.String.is_empty(subject.strip());
        bool has_attachment = this.attached_files.size > 0;
        bool has_body = true;

        try {
            has_body = !Geary.String.is_empty(yield this.editor.get_html());
        } catch (Error err) {
            debug("Failed to get message body: %s", err.message);
        }

        string? confirmation = null;
        if (!has_subject && !has_body && !has_attachment) {
            confirmation = _("Send message with an empty subject and body?");
        } else if (!has_subject) {
            confirmation = _("Send message with an empty subject?");
        } else if (!has_body && !has_attachment) {
            confirmation = _("Send message with an empty body?");
        } else if (!has_attachment &&
                   yield this.editor.contains_attachment_keywords(
                       string.join(
                           "|",
                           ATTACHMENT_KEYWORDS,
                           ATTACHMENT_KEYWORDS_LOCALISED
                       ),
                       this.subject)) {
            confirmation = _("Send message without an attachment?");
        }
        if (confirmation != null) {
            ConfirmationDialog dialog = new ConfirmationDialog(container.top_window,
                confirmation, null, Stock._OK, "suggested-action");
            return (dialog.run() == Gtk.ResponseType.OK);
        }
        return true;
    }

    // Sends the current message.
    private void on_send() {
        this.should_send.begin((obj, res) => {
                if (this.should_send.end(res)) {
                    this.on_send_async.begin();
                }
            });
    }

    // Used internally by on_send()
    private async void on_send_async() {
        set_enabled(false);

        try {
            yield this.editor.clean_content();
            yield this.application.controller.send_composed_email(this);

            if (this.draft_manager != null) {
                yield discard_draft();
                yield close_draft_manager(null);
            }

            if (this.container != null) {
                this.container.close();
            }
        } catch (GLib.Error error) {
            this.application.controller.report_problem(
                new Geary.AccountProblemReport(
                    this.account.information, error
                )
            );
        }
    }

    /**
     * Creates and opens the composer's draft manager.
     */
    private async void open_draft_manager(Geary.EmailIdentifier? editing_draft_id,
                                          GLib.Cancellable? cancellable)
        throws GLib.Error {
        if (!this.account.information.save_drafts) {
            this.header.show_save_and_close = false;
            return;
        }

        // Cancel any existing opening first
        if (this.draft_manager_opening != null) {
            this.draft_manager_opening.cancel();
        }

        GLib.Cancellable internal_cancellable = new GLib.Cancellable();
        if (cancellable != null) {
            cancellable.cancelled.connect(
                () => { internal_cancellable.cancel(); }
            );
        }
        this.draft_manager_opening = internal_cancellable;

        Geary.App.DraftManager new_manager = new Geary.App.DraftManager(account);
        try {
            yield new_manager.open_async(editing_draft_id, internal_cancellable);
            debug("Draft manager opened");
        } catch (GLib.Error err) {
            this.header.show_save_and_close = false;
            throw err;
        } finally {
            this.draft_manager_opening = null;
        }

        new_manager.notify[Geary.App.DraftManager.PROP_DRAFT_STATE]
            .connect(on_draft_state_changed);
        new_manager.notify[Geary.App.DraftManager.PROP_CURRENT_DRAFT_ID]
            .connect(on_draft_id_changed);
        new_manager.fatal.connect(on_draft_manager_fatal);

        this.draft_manager = new_manager;

        update_draft_state();
        this.header.show_save_and_close = true;
    }

    /**
     * Closes current draft manager, if any, then opens a new one.
     */
    private async void reopen_draft_manager(GLib.Cancellable? cancellable)
        throws GLib.Error {
        if (this.draft_manager != null) {
            // Discard the draft, if any, since it may be on a
            // different account
            yield discard_draft();
            yield close_draft_manager(cancellable);
        }
        yield open_draft_manager(null, cancellable);
        yield save_draft();
    }

    private async void close_draft_manager(GLib.Cancellable? cancellable)
        throws GLib.Error {
        Geary.App.DraftManager old_manager = this.draft_manager;
        this.draft_manager = null;
        this.draft_status_text = "";

        old_manager.notify[Geary.App.DraftManager.PROP_DRAFT_STATE]
            .disconnect(on_draft_state_changed);
        old_manager.notify[Geary.App.DraftManager.PROP_CURRENT_DRAFT_ID]
            .disconnect(on_draft_id_changed);
        old_manager.fatal.disconnect(on_draft_manager_fatal);

        yield old_manager.close_async(cancellable);
        debug("Draft manager closed");
    }

    private void update_draft_state() {
        switch (this.draft_manager.draft_state) {
            case Geary.App.DraftManager.DraftState.STORED:
                this.draft_status_text = DRAFT_SAVED_TEXT;
                this.is_draft_saved = true;
            break;

            case Geary.App.DraftManager.DraftState.STORING:
                this.draft_status_text = DRAFT_SAVING_TEXT;
                this.is_draft_saved = true;
            break;

            case Geary.App.DraftManager.DraftState.NOT_STORED:
                this.draft_status_text = "";
                this.is_draft_saved = false;
            break;

            case Geary.App.DraftManager.DraftState.ERROR:
                this.draft_status_text = DRAFT_ERROR_TEXT;
                this.is_draft_saved = false;
            break;

            default:
                assert_not_reached();
        }
    }

    private inline void draft_changed() {
        if (this.should_save) {
            this.draft_timer.start();
        }
        this.draft_status_text = "";
        // can_save depends on the value of this, so reset it after
        // the if test above
        this.is_draft_saved = false;
    }

    // Note that drafts are NOT "linkified."
    private async void save_draft() throws GLib.Error {
        debug("Saving draft");

        // cancel timer in favor of just doing it now
        this.draft_timer.reset();

        if (this.draft_manager != null) {
            Geary.ComposedEmail draft = yield get_composed_email(null, true);
            yield this.draft_manager.update(
                yield draft.to_rfc822_message(null, null),
                this.draft_flags,
                null,
                null
            );
        }
    }

    private async void discard_draft() throws GLib.Error {
        debug("Discarding draft");

        // cancel timer in favor of this operation
        this.draft_timer.reset();

        yield this.draft_manager.discard(null);
        this.current_draft_id = null;
    }

    private async void save_and_close() {
        set_enabled(false);

        if (this.should_save) {
            try {
                yield save_draft();
            } catch (GLib.Error error) {
                this.application.controller.report_problem(
                    new Geary.AccountProblemReport(
                        this.account.information, error
                    )
                );
            }
        }

        // Pass on to the controller so the draft can be re-opened
        // on undo
        if (this.container != null) {
            this.container.close();
        }
        yield this.application.controller.save_composed_email(this);
    }

    private async void discard_and_close() {
        set_enabled(false);

        if (this.draft_manager != null) {
            try {
                yield discard_draft();
                yield close_draft_manager(null);
            } catch (GLib.Error error) {
                this.application.controller.report_problem(
                    new Geary.AccountProblemReport(
                        this.account.information, error
                    )
                );
            }
        }

        // Pass on to the controller so the discarded email can be
        // re-opened on undo
        if (this.container != null) {
            this.container.close();
        }
        yield this.application.controller.discard_composed_email(this);
    }

    private void update_attachments_view() {
        if (this.attached_files.size > 0 )
            attachments_box.show_all();
        else
            attachments_box.hide();
    }

    // Both adds pending attachments and updates the UI if there are
    // any that were left out, that could have been added manually.
    private bool update_pending_attachments(AttachPending include, bool do_add) {
        bool have_added = false;
        bool manual_enabled = false;
        if (this.pending_attachments != null) {
            foreach(Geary.Attachment part in this.pending_attachments) {
                try {
                    string? content_id = part.content_id;
                    Geary.Mime.DispositionType? type =
                        part.content_disposition.disposition_type;
                    File file = part.file;
                    if (type == Geary.Mime.DispositionType.INLINE) {
                        // We only care about the Content Ids of
                        // inline parts, since we need to display them
                        // in the editor web view. However if an
                        // inline part does not have a CID, it is not
                        // possible to be referenced from an IMG SRC
                        // using a cid: URL anyway, so treat it as an
                        // attachment instead.
                        if (content_id != null) {
                            Geary.Memory.FileBuffer file_buffer = new Geary.Memory.FileBuffer(file, true);
                            this.cid_files[content_id] = file_buffer;
                            this.editor.add_internal_resource(
                                content_id, file_buffer
                            );
                        } else {
                            type = Geary.Mime.DispositionType.ATTACHMENT;
                        }
                    }

                    if (type == Geary.Mime.DispositionType.INLINE ||
                        include == AttachPending.ALL) {
                        // The pending attachment should be added
                        // automatically, so add it if asked to and it
                        // hasn't already been added
                        if (do_add &&
                            !this.attached_files.contains(file) &&
                            !this.inline_files.has_key(content_id)) {
                            if (type == Geary.Mime.DispositionType.INLINE) {
                                check_attachment_file(file);
                                Geary.Memory.FileBuffer file_buffer = new Geary.Memory.FileBuffer(file, true);
                                string unused;
                                add_inline_part(file_buffer, content_id, out unused);
                            } else {
                                add_attachment_part(file);
                            }
                            have_added = true;
                        }
                    } else {
                        // The pending attachment should only be added
                        // manually
                        manual_enabled = true;
                    }
                } catch (Error err) {
                    attachment_failed(err.message);
                }
            }
        }
        this.header.set_show_pending_attachments(manual_enabled);
        return have_added;
    }

    private void add_attachment_part(File target)
        throws AttachmentError {
        FileInfo target_info = check_attachment_file(target);

        if (!this.attached_files.add(target)) {
            throw new AttachmentError.DUPLICATE(
                _("“%s” already attached for delivery.").printf(target.get_path())
                );
        }

        Gtk.Box box = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 6);
        this.attachments_box.pack_start(box);

        /// In the composer, the filename followed by its filesize, i.e. "notes.txt (1.12KB)"
        string label_text = _("%s (%s)").printf(target.get_basename(),
                                                Files.get_filesize_as_string(target_info.get_size()));
        Gtk.Label label = new Gtk.Label(label_text);
        box.pack_start(label);
        label.halign = Gtk.Align.START;
        label.margin_start = 4;
        label.margin_end = 4;

        Gtk.Button remove_button = new Gtk.Button.with_mnemonic(Stock._REMOVE);
        box.pack_start(remove_button, false, false);
        remove_button.clicked.connect(() => remove_attachment(target, box));

        update_attachments_view();
    }

    private void add_inline_part(Geary.Memory.Buffer target, string content_id, out string unique_contentid)
        throws AttachmentError {

        const string UNIQUE_RENAME_TEMPLATE = "%s_%02u";

        if (target.size == 0)
            throw new AttachmentError.FILE(
                _("“%s” is an empty file.").printf(content_id)
            );

        // Avoid filename conflicts
        unique_contentid = content_id;
        int suffix_index = 0;
        string unsuffixed_filename = "";
        while (this.inline_files.has_key(unique_contentid)) {
            string[] filename_parts = unique_contentid.split(".");

            // Handle no file extension
            int partindex;
            if (filename_parts.length > 1) {
                partindex = filename_parts.length-2;
            } else {
                partindex = 0;
            }
            if (unsuffixed_filename == "")
                unsuffixed_filename = filename_parts[partindex];
            filename_parts[partindex] = UNIQUE_RENAME_TEMPLATE.printf(unsuffixed_filename, suffix_index++);

            unique_contentid = string.joinv(".", filename_parts);
        }

        this.inline_files[unique_contentid] = target;
        this.editor.add_internal_resource(
            unique_contentid, target
        );
    }

    private FileInfo check_attachment_file(File target)
        throws AttachmentError {
        FileInfo target_info;
        try {
            target_info = target.query_info("standard::size,standard::type",
                FileQueryInfoFlags.NONE);
        } catch (Error e) {
            throw new AttachmentError.FILE(
                _("“%s” could not be found.").printf(target.get_path())
            );
        }

        if (target_info.get_file_type() == FileType.DIRECTORY) {
            throw new AttachmentError.FILE(
                _("“%s” is a folder.").printf(target.get_path())
            );
        }

        if (target_info.get_size() == 0){
            throw new AttachmentError.FILE(
                _("“%s” is an empty file.").printf(target.get_path())
            );
        }

        try {
            FileInputStream? stream = target.read();
            if (stream != null)
                stream.close();
        } catch(Error e) {
            debug("File '%s' could not be opened for reading. Error: %s", target.get_path(),
                e.message);

            throw new AttachmentError.FILE(
                _("“%s” could not be opened for reading.").printf(target.get_path())
            );
        }

        return target_info;
    }

    private void attachment_failed(string msg) {
        ErrorDialog dialog = new ErrorDialog(this.container.top_window, _("Cannot add attachment"), msg);
        dialog.run();
    }

    private void remove_attachment(File file, Gtk.Box box) {
        if (!this.attached_files.remove(file))
            return;

        foreach (weak Gtk.Widget child in this.attachments_box.get_children()) {
            if (child == box) {
                this.attachments_box.remove(box);
                break;
            }
        }

        update_attachments_view();
        update_pending_attachments(this.pending_include, false);
        draft_changed();
    }

    private bool check_send_on_return(Gdk.EventKey event) {
        bool ret = Gdk.EVENT_PROPAGATE;
        switch (Gdk.keyval_name(event.keyval)) {
            case "Return":
            case "KP_Enter":
                // always trap Ctrl+Enter/Ctrl+KeypadEnter to prevent
                // the Enter leaking through to the controls, but only
                // send if send is available
                if ((event.state & Gdk.ModifierType.CONTROL_MASK) != 0) {
                    this.composer_actions.activate_action(ACTION_SEND, null);
                    ret = Gdk.EVENT_STOP;
                }
            break;
        }
        return ret;
    }

    private void validate_send_button() {
        // To must be valid (and hence non-empty), the other email
        // fields must be either empty or valid.
        get_action(ACTION_SEND).set_enabled(
            this.to_entry.valid &&
            (this.cc_entry.empty || this.cc_entry.valid) &&
            (this.bcc_entry.empty || this.bcc_entry.valid) &&
            (this.reply_to_entry.empty || this.reply_to_entry.valid)
        );
    }

    private void set_compact_header_recipients() {
        bool tocc = !this.to_entry.empty && !this.cc_entry.empty,
            ccbcc = !(this.to_entry.empty && this.cc_entry.empty) && !this.bcc_entry.empty;
        string label = this.to_entry.buffer.text + (tocc ? ", " : "")
            + this.cc_entry.buffer.text + (ccbcc ? ", " : "") + this.bcc_entry.buffer.text;
        StringBuilder tooltip = new StringBuilder();
        if (to_entry.addresses != null) {
            foreach(Geary.RFC822.MailboxAddress addr in this.to_entry.addresses) {
                // Translators: Human-readable version of the RFC 822 To header
                tooltip.append("%s %s\n".printf(_("To:"), addr.to_full_display()));
            }
        }
        if (cc_entry.addresses != null) {
            foreach(Geary.RFC822.MailboxAddress addr in this.cc_entry.addresses) {
                // Translators: Human-readable version of the RFC 822 CC header
                tooltip.append("%s %s\n".printf(_("Cc:"), addr.to_full_display()));
            }
        }
        if (bcc_entry.addresses != null) {
            foreach(Geary.RFC822.MailboxAddress addr in this.bcc_entry.addresses) {
                // Translators: Human-readable version of the RFC 822 BCC header
                tooltip.append("%s %s\n".printf(_("Bcc:"), addr.to_full_display()));
            }
        }
        if (reply_to_entry.addresses != null) {
            foreach(Geary.RFC822.MailboxAddress addr in this.reply_to_entry.addresses) {
                // Translators: Human-readable version of the RFC 822 Reply-To header
                tooltip.append("%s%s\n".printf(_("Reply-To: "), addr.to_full_display()));
            }
        }
        this.header.set_recipients(label, tooltip.str.slice(0, -1));  // Remove trailing \n
    }

    private void on_justify(SimpleAction action, Variant? param) {
        this.editor.execute_editing_command("justify" + param.get_string());
    }

    private void on_action(SimpleAction action, Variant? param) {
        if (!action.enabled)
            return;

        // We need the unprefixed name to send as a command to the editor
        string[] prefixed_action_name = action.get_name().split(".");
        string action_name = prefixed_action_name[prefixed_action_name.length - 1];
        this.editor.execute_editing_command(action_name);
    }

    private void on_undo(SimpleAction action, Variant? param) {
        this.editor.undo();
    }

    private void on_redo(SimpleAction action, Variant? param) {
        this.editor.redo();
    }

    private void on_cut(SimpleAction action, Variant? param) {
        if (this.container.get_focus() == this.editor)
            this.editor.cut_clipboard();
        else if (this.container.get_focus() is Gtk.Editable)
            ((Gtk.Editable) this.container.get_focus()).cut_clipboard();
    }

    private void on_copy(SimpleAction action, Variant? param) {
        if (this.container.get_focus() == this.editor)
            this.editor.copy_clipboard();
        else if (this.container.get_focus() is Gtk.Editable)
            ((Gtk.Editable) this.container.get_focus()).copy_clipboard();
    }

    private void on_copy_link(SimpleAction action, Variant? param) {
        Gtk.Clipboard c = Gtk.Clipboard.get(Gdk.SELECTION_CLIPBOARD);
        // XXX could this also be the cursor URL? We should be getting
        // the target URL as from the action param
        c.set_text(this.pointer_url, -1);
        c.store();
    }

    private void on_paste(SimpleAction action, Variant? param) {
        if (this.container.get_focus() == this.editor) {
            if (this.editor.is_rich_text) {
                // Check for pasted image in clipboard
                Gtk.Clipboard clipboard = Gtk.Clipboard.get(Gdk.SELECTION_CLIPBOARD);
                bool has_image = clipboard.wait_is_image_available();
                if (has_image) {
                    paste_image();
                } else {
                    this.editor.paste_rich_text();
                }
            } else {
                this.editor.paste_plain_text();
            }
        } else if (this.container.get_focus() is Gtk.Editable) {
            ((Gtk.Editable) this.container.get_focus()).paste_clipboard();
        }
    }

    /**
     * Handle a pasted image, adding it as an inline attachment
     */
    private void paste_image() {
        // The slow operations here are creating the PNG and, to a lesser extent,
        // requesting the image from the clipboard
        this.show_background_work_timeout.start();

        get_clipboard(Gdk.SELECTION_CLIPBOARD).request_image((clipboard, pixbuf) => {
            if (pixbuf != null) {
                MemoryOutputStream os = new MemoryOutputStream(null);
                pixbuf.save_to_stream_async.begin(os, "png", null, (obj, res) => {
                    try {
                        pixbuf.save_to_stream_async.end(res);
                        os.close();

                        Geary.Memory.ByteBuffer byte_buffer = new Geary.Memory.ByteBuffer.from_memory_output_stream(os);

                        GLib.DateTime time_now = new GLib.DateTime.now();
                        string filename = PASTED_IMAGE_FILENAME_TEMPLATE.printf(time_now.hash());

                        string unique_filename;
                        add_inline_part(byte_buffer, filename, out unique_filename);
                        this.editor.insert_image(
                            Components.WebView.INTERNAL_URL_PREFIX + unique_filename
                        );
                        throw new Geary.EngineError.UNSUPPORTED("Mock method");
                    } catch (Error error) {
                        this.application.controller.report_problem(
                            new Geary.ProblemReport(error)
                        );
                    }

                    stop_background_work_pulse();
                });
            } else {
                warning("Failed to get image from clipboard");
                stop_background_work_pulse();
            }
        });
    }

    private void on_paste_without_formatting(SimpleAction action, Variant? param) {
        if (this.container.get_focus() == this.editor)
            this.editor.paste_plain_text();
    }

    private void on_select_all(SimpleAction action, Variant? param) {
        this.editor.select_all();
    }

    private void on_remove_format(SimpleAction action, Variant? param) {
        this.editor.execute_editing_command("removeformat");
        this.editor.execute_editing_command("removeparaformat");
        this.editor.execute_editing_command("unlink");
        this.editor.execute_editing_command_with_argument("backcolor", "#ffffff");
        this.editor.execute_editing_command_with_argument("forecolor", "#000000");
    }

    // Use this for toggle actions, and use the change-state signal to respond to these state changes
    private void on_toggle_action(SimpleAction? action, Variant? param) {
        action.change_state(!action.state.get_boolean());
    }

    private void on_compose_as_html_toggled(SimpleAction? action, Variant? new_state) {
        bool compose_as_html = new_state.get_boolean();
        action.set_state(compose_as_html);

        foreach (string html_action in HTML_ACTIONS)
            get_action(html_action).set_enabled(compose_as_html);

        update_cursor_actions();

        var show_formatting = (SimpleAction) this.composer_actions.lookup_action(ACTION_SHOW_FORMATTING);
        show_formatting.set_enabled(compose_as_html);
        update_formatting_toolbar();

        this.menu_button.menu_model = (compose_as_html) ? this.html_menu : this.plain_menu;

        this.editor.set_rich_text(compose_as_html);

        this.application.config.compose_as_html = compose_as_html;
    }

    private void on_show_extended_headers_toggled(GLib.SimpleAction? action,
                                                  GLib.Variant? new_state) {
        bool show_extended = new_state.get_boolean();
        action.set_state(show_extended);
        this.extended_fields_revealer.reveal_child = show_extended;

        if (show_extended && this.current_mode == INLINE_COMPACT) {
            set_mode(INLINE);
        }
    }

    private void update_formatting_toolbar() {
        var show_formatting = (SimpleAction) this.composer_actions.lookup_action(ACTION_SHOW_FORMATTING);
        var text_format = (SimpleAction) this.composer_actions.lookup_action(ACTION_TEXT_FORMAT);
        this.formatting.reveal_child = text_format.get_state().get_string() == "html" && show_formatting.get_state().get_boolean();
    }

    private void on_show_formatting(SimpleAction? action, Variant? new_state) {
        bool show_formatting = new_state.get_boolean();
        this.application.config.formatting_toolbar_visible = show_formatting;
        action.set_state(new_state);

        update_formatting_toolbar();
    }

    private void on_font_family(SimpleAction action, Variant? param) {
        this.editor.execute_editing_command_with_argument(
            "fontname", param.get_string()
        );
        action.set_state(param.get_string());
    }

    private void on_font_size(SimpleAction action, Variant? param) {
        string size = "";
        if (param.get_string() == "small")
            size = "1";
        else if (param.get_string() == "medium")
            size = "3";
        else // Large
            size = "7";

        this.editor.execute_editing_command_with_argument("fontsize", size);
        action.set_state(param.get_string());
    }

    private void on_select_color() {
        Gtk.ColorChooserDialog dialog = new Gtk.ColorChooserDialog(_("Select Color"),
            this.container.top_window);
        if (dialog.run() == Gtk.ResponseType.OK) {
            this.editor.execute_editing_command_with_argument(
                "forecolor", dialog.get_rgba().to_string()
            );
        }
        dialog.destroy();
    }

    private void on_indent(SimpleAction action, Variant? param) {
        this.editor.indent_line();
    }

    private void on_olist(SimpleAction action, Variant? param) {
        this.editor.insert_olist();
    }

    private void on_ulist(SimpleAction action, Variant? param) {
        this.editor.insert_ulist();
    }

    private void on_mouse_target_changed(WebKit.WebView web_view,
                                         WebKit.HitTestResult hit_test,
                                         uint modifiers) {
        bool copy_link_enabled = hit_test.context_is_link();
        this.pointer_url = copy_link_enabled ? hit_test.get_link_uri() : null;
        this.message_overlay_label.label = this.pointer_url ?? "";
        this.message_overlay_label.set_visible(copy_link_enabled);
        get_action(ACTION_COPY_LINK).set_enabled(copy_link_enabled);
    }

    private bool on_context_menu(WebKit.WebView view,
                                 WebKit.ContextMenu context_menu,
                                 Gdk.Event event,
                                 WebKit.HitTestResult hit_test_result) {
        // This is a three step process:
        // 1. Work out what existing menu items exist that we want to keep
        // 2. Clear the existing menu
        // 3. Rebuild it based on our GMenu specification

        // Step 1.

        const WebKit.ContextMenuAction[] SPELLING_ACTIONS = {
            WebKit.ContextMenuAction.SPELLING_GUESS,
            WebKit.ContextMenuAction.NO_GUESSES_FOUND,
            WebKit.ContextMenuAction.IGNORE_SPELLING,
            WebKit.ContextMenuAction.IGNORE_GRAMMAR,
            WebKit.ContextMenuAction.LEARN_SPELLING,
        };
        const WebKit.ContextMenuAction[] TEXT_INPUT_ACTIONS = {
            WebKit.ContextMenuAction.INPUT_METHODS,
            WebKit.ContextMenuAction.UNICODE,
        };

        Gee.List<WebKit.ContextMenuItem> existing_spelling =
            new Gee.LinkedList<WebKit.ContextMenuItem>();
        Gee.List<WebKit.ContextMenuItem> existing_text_entry =
            new Gee.LinkedList<WebKit.ContextMenuItem>();

        foreach (WebKit.ContextMenuItem item in context_menu.get_items()) {
            if (item.get_stock_action() in SPELLING_ACTIONS) {
                existing_spelling.add(item);
            } else if (item.get_stock_action() in TEXT_INPUT_ACTIONS) {
                existing_text_entry.add(item);
            }
        }

        // Step 2.

        context_menu.remove_all();

        // Step 3.

        Util.Gtk.menu_foreach(context_menu_model, (label, name, target, section) => {
                if (context_menu.last() != null) {
                    context_menu.append(new WebKit.ContextMenuItem.separator());
                }

                if (section == this.context_menu_webkit_spelling) {
                    foreach (WebKit.ContextMenuItem item in existing_spelling)
                        context_menu.append(item);
                } else if (section == this.context_menu_webkit_text_entry) {
                    foreach (WebKit.ContextMenuItem item in existing_text_entry)
                        context_menu.append(item);
                } else if (section == this.context_menu_rich_text) {
                    if (this.editor.is_rich_text)
                        append_menu_section(context_menu, section);
                } else if (section == this.context_menu_plain_text) {
                    if (!this.editor.is_rich_text)
                        append_menu_section(context_menu, section);
                } else if (section == this.context_menu_inspector) {
                    if (this.application.config.enable_inspector)
                        append_menu_section(context_menu, section);
                } else {
                    append_menu_section(context_menu, section);
                }
            });

        // 4. Update the clipboard
        // get_clipboard(Gdk.SELECTION_CLIPBOARD).request_targets(
        //     (_, targets) => {
        //         foreach (Gdk.Atom atom in targets) {
        //             debug("atom name: %s", atom.name());
        //         }
        //     });

        return Gdk.EVENT_PROPAGATE;
    }

    private inline void append_menu_section(WebKit.ContextMenu context_menu,
                                            Menu section) {
        Util.Gtk.menu_foreach(section, (label, name, target, section) => {
                string simple_name = name;
                if ("." in simple_name) {
                    simple_name = simple_name.split(".")[1];
                }

                GLib.SimpleAction? action = get_action(simple_name);
                if (action != null) {
                    context_menu.append(
                        new WebKit.ContextMenuItem.from_gaction(
                            action, label, target
                        )
                    );
                } else {
                    warning("Unknown action: %s/%s", name, label);
                }
            });
    }

    private void on_select_dictionary(SimpleAction action, Variant? param) {
        if (this.spell_check_popover == null) {
            Application.Configuration config = this.application.config;
            this.spell_check_popover = new SpellCheckPopover(
                this.select_dictionary_button, config
            );
            this.spell_check_popover.selection_changed.connect((active_langs) => {
                    config.set_spell_check_languages(active_langs);
                    update_subject_spell_checker();
                });
        }
        this.spell_check_popover.toggle();
    }

    private bool on_editor_key_press_event(Gdk.EventKey event) {
        // Widget's keypress override doesn't receive non-modifier
        // keys when the editor processes them, regardless if true or
        // false is called; this deals with that issue (specifically
        // so Ctrl+Enter will send the message)
        if (event.is_modifier == 0) {
            if (check_send_on_return(event) == Gdk.EVENT_STOP)
                return Gdk.EVENT_STOP;
        }

        if (this.can_delete_quote) {
            this.can_delete_quote = false;
            if (event.is_modifier == 0 && event.keyval == Gdk.Key.BackSpace) {
                this.editor.delete_quoted_message();
                return Gdk.EVENT_STOP;
            }
        }

        return Gdk.EVENT_PROPAGATE;
    }

    /**
     * Helper method, returns a composer action.
     * @param action_name - The name of the action (as found in action_entries)
     */
    public GLib.SimpleAction? get_action(string action_name) {
        GLib.Action? action = this.composer_actions.lookup_action(action_name);
        if (action == null) {
            action = this.editor_actions.lookup_action(action_name);
        }
        return action as SimpleAction;
    }

    private bool add_account_emails_to_from_list(Geary.Account other_account, bool set_active = false) {
        bool is_primary = true;
        foreach (Geary.RFC822.MailboxAddress mailbox in
                 other_account.information.sender_mailboxes) {
            Geary.RFC822.MailboxAddresses addresses =
                new Geary.RFC822.MailboxAddresses.single(mailbox);

            string display = mailbox.to_full_display();
            if (!is_primary) {
                // Displayed in the From dropdown to indicate an
                // "alternate email address" for an account.  The first
                // printf argument will be the alternate email address,
                // and the second will be the account's primary email
                // address.
                display = _("%1$s via %2$s").printf(
                    display, other_account.information.display_name
                );
            }
            is_primary = false;

            this.from_multiple.append_text(display);
            this.from_list.add(new FromAddressMap(other_account, addresses));

            if (!set_active && this.from.equal_to(addresses)) {
                this.from_multiple.set_active(this.from_list.size - 1);
                set_active = true;
            }
        }
        return set_active;
    }

    private void update_info_label() {
        string text = "";
        if (this.can_delete_quote) {
            text = BACKSPACE_TEXT;
        } else {
            text = this.draft_status_text;
        }

        this.info_label.set_text(text);
        this.info_label.set_tooltip_text(text);
    }

    // Updates from combobox contents and visibility, returns true if
    // the from address had to be set
    private bool update_from_field() {
        this.from_multiple.changed.disconnect(on_from_changed);
        this.from_single.visible = this.from_multiple.visible = this.from_row.visible = false;

        // Don't show in inline unless the current account has
        // multiple email accounts or aliases, since these will be replies to a
        // conversation
        if ((this.current_mode == INLINE ||
             this.current_mode == INLINE_COMPACT) &&
            !this.has_multiple_from_addresses) {
            return false;
        }

        // If there's only one account and it not have any aliases,
        // show nothing.
        if (this.accounts.size < 1 ||
            (this.accounts.size == 1 &&
            !Geary.traverse<Geary.Account>(this.accounts).first().information.has_sender_aliases)) {
            return false;
        }

        this.from_row.visible = true;
        this.from_label.set_mnemonic_widget(this.from_multiple);
        // Composer label (with mnemonic underscore) for the account selector
        // when choosing what address to send a message from.
        this.from_label.set_text_with_mnemonic(_("_From:"));

        this.from_multiple.visible = true;
        this.from_multiple.remove_all();
        this.from_list = new Gee.ArrayList<FromAddressMap>();

        // Always add at least the current account. The var set_active
        // is set to true if the current message's from address has
        // been set in the ComboBox.
        bool set_active = add_account_emails_to_from_list(this.account);
        foreach (var account in this.accounts) {
            if (account != this.account) {
                set_active = add_account_emails_to_from_list(
                    account, set_active
                );
            }
        }

        if (!set_active) {
            // The identity or account that was active before has been
            // removed use the best we can get now (primary address of
            // the account or any other)
            this.from_multiple.set_active(0);
        }

        this.from_multiple.changed.connect(on_from_changed);
        return !set_active;
    }

    private void update_from() throws Error {
        int index = this.from_multiple.get_active();
        if (index >= 0) {
            FromAddressMap selected = this.from_list.get(index);
            this.from = selected.from;

            if (selected.account != this.account) {
                this.account = selected.account;
                this.update_signature.begin(null);
                load_entry_completions();

                var current_account = this.account;
                this.reopen_draft_manager.begin(
                    null,
                    (obj, res) => {
                        try {
                            this.reopen_draft_manager.end(res);
                        } catch (GLib.Error error) {
                            this.application.controller.report_problem(
                                new Geary.AccountProblemReport(
                                    current_account.information, error
                                )
                            );
                        }
                    }
                );
            }
        }
    }

    private async void update_signature(Cancellable? cancellable = null) {
        string sig = "";
        if (this.account.information.use_signature) {
            sig = account.information.signature;
            if (Geary.String.is_empty_or_whitespace(sig)) {
                // No signature is specified in the settings, so use
                // ~/.signature
                File signature_file = File.new_for_path(Environment.get_home_dir()).get_child(".signature");
                try {
                    uint8[] data;
                    yield signature_file.load_contents_async(cancellable, out data, null);
                    sig = (string) data;
                } catch (Error error) {
                    if (!(error is IOError.NOT_FOUND)) {
                        debug("Error reading signature file %s: %s", signature_file.get_path(), error.message);
                    }
                }
            }
        }

        // Still want to update the signature even if it is empty,
        // since when changing the selected from account, if the
        // previously selected account had a sig but the newly
        // selected account does not, the old sig gets cleared out.
        if (Geary.String.is_empty_or_whitespace(sig)) {
            // Clear out multiple spaces etc so smart_escape
            // doesn't create &nbsp;'s
            sig = "";
        }
        this.editor.update_signature(Geary.HTML.smart_escape(sig));
    }

    private void update_subject_spell_checker() {
        Gspell.Language? lang = null;
        string[] langs = this.application.config.get_spell_check_languages();
        if (langs.length == 1) {
            lang = Gspell.Language.lookup(langs[0]);
        } else {
            // Since GSpell doesn't support multiple languages (see
            // <https://gitlab.gnome.org/GNOME/gspell/issues/5>) and
            // we don't support spell checker language priority, use
            // the first matching most preferred language, if any.
            foreach (string pref in
                     Util.International.get_user_preferred_languages()) {
                if (pref in langs) {
                    lang = Gspell.Language.lookup(pref);
                    if (lang != null) {
                        break;
                    }
                }
            }

            if (lang == null) {
                // No preferred lang found, so just use first
                // supported matching langauge
                foreach (string pref in langs) {
                    lang = Gspell.Language.lookup(pref);
                    if (lang != null) {
                        break;
                    }
                }
            }
        }

        Gspell.EntryBuffer buffer =
            Gspell.EntryBuffer.get_from_gtk_entry_buffer(
                this.subject_entry.buffer
            );
        Gspell.Checker checker = null;
        if (lang != null) {
            checker = this.subject_spell_checker;
            checker.language = lang;
        }
        this.subject_spell_entry.inline_spell_checking = (checker != null);
        buffer.spell_checker = checker;
    }

    private async LinkPopover new_link_popover(LinkPopover.Type type,
                                               string url) {
        var selection_id = "";
        try {
            selection_id = yield this.editor.save_selection();
        } catch (Error err) {
            debug("Error saving selection: %s", err.message);
        }
        LinkPopover popover = new LinkPopover(type);
        popover.set_link_url(url);
        popover.closed.connect(() => {
                this.editor.free_selection(selection_id);
                Idle.add(() => { popover.destroy(); return Source.REMOVE; });
            });
        popover.link_activate.connect((link_uri) => {
                this.editor.insert_link(popover.link_uri, selection_id);
            });
        popover.link_delete.connect(() => {
                this.editor.delete_link(selection_id);
            });
        popover.link_open.connect(() => {
                this.application.show_uri.begin(popover.link_uri);
            });
        return popover;
    }

    private void on_command_state_changed(bool can_undo, bool can_redo) {
        get_action(Action.Edit.UNDO).set_enabled(can_undo);
        get_action(Action.Edit.REDO).set_enabled(can_redo);
    }

    private void on_editor_content_loaded() {
        this.update_signature.begin(null);
    }

    private void on_draft_id_changed() {
        this.current_draft_id = this.draft_manager.current_draft_id;
    }

    private void on_draft_manager_fatal(Error err) {
        this.draft_status_text = DRAFT_ERROR_TEXT;
    }

    private void on_draft_state_changed() {
        update_draft_state();
    }

    [GtkCallback]
    private void on_subject_changed() {
        draft_changed();
        update_window_title();
    }

    [GtkCallback]
    private void on_envelope_changed() {
        draft_changed();
    }

    private void on_from_changed() {
        try {
            update_from();
        } catch (Error err) {
            debug("Error updating from address: %s", err.message);
        }
    }

    private void on_expand_compact_headers() {
        set_mode(INLINE);
    }

    private void on_detach() {
        detach();
    }

    private bool on_button_release(Gdk.Event event) {
        // Show the link popover on mouse release (instead of press)
        // so the user can still select text with a link in it,
        // without the popover immediately appearing and raining on
        // their text selection parade.
        if (this.pointer_url != null &&
            this.application.config.compose_as_html) {
            Gdk.EventButton? button = (Gdk.EventButton) event;
            Gdk.Rectangle location = Gdk.Rectangle();
            location.x = (int) button.x;
            location.y = (int) button.y;

            this.new_link_popover.begin(
                LinkPopover.Type.EXISTING_LINK, this.pointer_url,
                (obj, res) => {
                    LinkPopover popover = this.new_link_popover.end(res);
                    popover.set_relative_to(this.editor);
                    popover.set_pointing_to(location);
                    popover.show();
                });
        }
        return Gdk.EVENT_PROPAGATE;
    }

    private void on_cursor_context_changed(WebView.EditContext context) {
        this.cursor_url = context.is_link ? context.link_url : null;
        update_cursor_actions();

        this.editor_actions.change_action_state(
            ACTION_FONT_FAMILY, context.font_family
        );

        if (context.font_size < 11)
            this.editor_actions.change_action_state(ACTION_FONT_SIZE, "small");
        else if (context.font_size > 20)
            this.editor_actions.change_action_state(ACTION_FONT_SIZE, "large");
        else
            this.editor_actions.change_action_state(ACTION_FONT_SIZE, "medium");
    }

    private void on_typing_attributes_changed() {
        uint mask = this.editor.get_editor_state().get_typing_attributes();
        this.editor_actions.change_action_state(
            ACTION_BOLD,
            (mask & WebKit.EditorTypingAttributes.BOLD) == WebKit.EditorTypingAttributes.BOLD
        );
        this.editor_actions.change_action_state(
            ACTION_ITALIC,
            (mask & WebKit.EditorTypingAttributes.ITALIC) == WebKit.EditorTypingAttributes.ITALIC
        );
        this.editor_actions.change_action_state(
            ACTION_UNDERLINE,
            (mask & WebKit.EditorTypingAttributes.UNDERLINE) == WebKit.EditorTypingAttributes.UNDERLINE
        );
        this.editor_actions.change_action_state(
            ACTION_STRIKETHROUGH,
            (mask & WebKit.EditorTypingAttributes.STRIKETHROUGH) == WebKit.EditorTypingAttributes.STRIKETHROUGH
        );
    }

    private void on_add_attachment() {
        AttachmentDialog dialog = new AttachmentDialog(
            this.container.top_window, this.application.config
        );
        if (dialog.run() == Gtk.ResponseType.ACCEPT) {
            dialog.hide();
            foreach (File file in dialog.get_files()) {
                try {
                    add_attachment_part(file);
                    draft_changed();
                } catch (Error err) {
                    attachment_failed(err.message);
                    break;
                }
            }

        }
        dialog.destroy();
    }

    private void on_pending_attachments() {
        if (update_pending_attachments(AttachPending.ALL, true)) {
            draft_changed();
        }
    }

    private void on_insert_image(SimpleAction action, Variant? param) {
        AttachmentDialog dialog = new AttachmentDialog(
            this.container.top_window, this.application.config
        );
        Gtk.FileFilter filter = new Gtk.FileFilter();
        // Translators: This is the name of the file chooser filter
        // when inserting an image in the composer.
        filter.set_name(_("Images"));
        filter.add_mime_type("image/*");
        dialog.add_filter(filter);
        if (dialog.run() == Gtk.ResponseType.ACCEPT) {
            dialog.hide();
            foreach (File file in dialog.get_files()) {
                try {
                    check_attachment_file(file);
                    Geary.Memory.FileBuffer file_buffer = new Geary.Memory.FileBuffer(file, true);
                    string path = file.get_path();
                    string unique_filename;
                    add_inline_part(file_buffer, path, out unique_filename);
                    this.editor.insert_image(
                        Components.WebView.INTERNAL_URL_PREFIX + unique_filename
                    );
                } catch (Error err) {
                    attachment_failed(err.message);
                    break;
                }
            }
        }
        dialog.destroy();
    }

    private void on_insert_link(SimpleAction action, Variant? param) {
        LinkPopover.Type type = LinkPopover.Type.NEW_LINK;
        string url = "https://";
        if (this.cursor_url != null) {
            type = LinkPopover.Type.EXISTING_LINK;
            url = this.cursor_url;
        }

        this.new_link_popover.begin(type, url, (obj, res) => {
                LinkPopover popover = this.new_link_popover.end(res);

                // We have to disconnect then reconnect the selection
                // changed signal for the duration of the popover
                // being active since if the user selects the text in
                // the URL entry, then the editor will lose its
                // selection, the inset link action will become
                // disabled, and the popover will disappear
                this.editor.selection_changed.disconnect(on_selection_changed);
                popover.closed.connect(() => {
                        this.editor.selection_changed.connect(on_selection_changed);
                    });

                popover.set_relative_to(this.insert_link_button);
                popover.show();
            });
    }

    private void on_open_inspector(SimpleAction action, Variant? param) {
        this.editor.get_inspector().show();
    }

    private void on_selection_changed(bool has_selection) {
        update_cursor_actions();
    }

    private void on_close() {
        conditional_close(this.container is Window);
    }

    private void on_discard() {
        if (this.container is Window) {
            conditional_close(true);
        } else {
            this.discard_and_close.begin();
        }
    }

    private void on_draft_timeout() {
        var current_account = this.account;
        this.save_draft.begin(
            (obj, res) => {
                try {
                    this.save_draft.end(res);
                } catch (GLib.Error error) {
                    this.application.controller.report_problem(
                        new Geary.AccountProblemReport(
                            current_account.information, error
                        )
                    );
                }
            }
        );
    }

    private void on_account_available() {
        update_from_field();
    }

    private void on_account_unavailable() {
        if (update_from_field()) {
            on_from_changed();
        }
    }

    /**
     * Handle a dropped image file, adding it as an inline attachment
     */
    private void on_image_file_dropped(string filename, string file_type, uint8[] contents) {
        Geary.Memory.ByteBuffer buffer = new Geary.Memory.ByteBuffer(contents, contents.length);
        string unique_filename;
        try {
            add_inline_part(buffer, filename, out unique_filename);
        } catch (AttachmentError err) {
            warning("Couldn't attach dropped empty file %s", filename);
            return;
        }

        this.editor.insert_image(
            Components.WebView.INTERNAL_URL_PREFIX + unique_filename
        );
    }

    /** Shows and starts pulsing the progress meter. */
    private void on_background_work_timeout() {
        this.background_progress.fraction = 0.0;
        this.background_work_pulse.start();
        this.background_progress.show();
    }

    /** Hides and stops pulsing the progress meter. */
    private void stop_background_work_pulse() {
        this.background_progress.hide();
        this.background_work_pulse.reset();
        this.show_background_work_timeout.reset();
    }
}