/**
 * Copyright 2021 Johannes Marbach
 *
 * This file is part of unl0kr, hereafter referred to as the program.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */


#include "config.h"

#include "log.h"

#include "lvgl/lvgl.h"

#include <dirent.h>
#include <ini.h>
#include <stdlib.h>

#include "squeek2lvgl/sq2lv.h"


/**
 * Static prototypes
 */

/**
 * Compares two strings from opaque types.
 *
 * @param a first string as void pointer
 * @param b second string as void pointer
 * @return a positive integer if a > b, a negative integer if a < b and 0 otherwise
 */
static int compare_strings(const void* a, const void* b);

/**
 * Checks whether a string ends with a suffix
 *
 * @param string string to check
 * @param suffix suffix to compare to
 * @return true if the suffix matches at the end of the string, false otherwise
 */
static bool string_ends_with(const char *string, const char *suffix);

/**
 * Non-recursively searches a directory for configuration files.
 * 
 * @param path folder to search in
 * @param found pointer to write found configuration file names into (to be freed by the caller)
 * @param num_found pointer to write number of found files into
 */
static void find_files(const char *path, char ***found, int *num_found);

/**
 * Handle parsing events from INIH.
 *
 * @param user_data pointer to user data
 * @param section current section name
 * @param key option key
 * @param value option value
 * @return 0 on error, non-0 otherwise
 */
static int parsing_handler(void* user_data, const char* section, const char* key, const char* value);

/**
 * Attempt to parse a boolean value.
 *
 * @param value string to parse
 * @param result pointer to write result into if parsing is successful
 * @return true on success, false otherwise
 */
static bool parse_bool(const char *value, bool *result);


/**
 * Static functions
 */

static int compare_strings(const void* a, const void* b) {
    return strcmp(*(const char**)a, *(const char**)b);
}

static bool string_ends_with(const char *string, const char *suffix) {
    if (!string || !suffix || strlen(suffix) > strlen(string)) {
        return false;
    }
    return strncmp(string + strlen(string) - strlen(suffix), suffix, strlen(suffix)) == 0;
}

static void find_files(const char *path, char ***found, int *num_found) {
    /* Initialise output variables */
    *found = NULL;
    *num_found = 0;

    /* Count length of directory path */
    const int path_length = strlen(path);

    /* Open directory */
    DIR *d = opendir(path);
    if (!d) {
        ul_log(UL_LOG_LEVEL_WARNING, "Could not read contents of folder %s", path);
        return;
    }

    /* Loop over directory contents */
    struct dirent *dir;
    while ((dir = readdir(d)) != NULL) {
        /* Ignore anything except for .conf files */
        if (dir->d_type != DT_REG || !string_ends_with(dir->d_name, ".conf")) {
            continue;
        }

        /* Grow output array */
        char **tmp = realloc(*found, (*num_found + 1) * sizeof(char *));
        if (!tmp) {
            ul_log(UL_LOG_LEVEL_ERROR, "Could not reallocate memory for configuration file paths");
            break;
        }
        *found = tmp;

        /* Extract file name and length */
        char *name = dir->d_name;
        int name_length = strlen(name);

        /* Allocate memory for full path */
        char *found_path = malloc(path_length + name_length + 2); /* +1 for path separator and null terminator, respectively */
        if (!found_path) {
            ul_log(UL_LOG_LEVEL_ERROR, "Could not allocate memory for configuration file path");
            break;
        }

        /* Build full path */
        memcpy(found_path, path, path_length);
        found_path[path_length] = '/';
        memcpy(found_path + path_length + 1, dir->d_name, name_length + 1); /* +1 for path separator and null terminator, respectively */

        /* Store file path */
        (*found)[*num_found] = found_path;
        *num_found += 1;
    }

    /* Close directory */
    closedir(d);
}

static int parsing_handler(void* user_data, const char* section, const char* key, const char* value) {
    ul_config_opts *opts = (ul_config_opts *)user_data;

    if (strcmp(section, "general") == 0) {
        if (strcmp(key, "animations") == 0) {
            if (parse_bool(value, &(opts->general.animations))) {
                return 1;
            }
        } else if (strcmp(key, "backend") == 0) {
            ul_backends_backend_id_t id = ul_backends_find_backend_with_name(value);
            if (id != UL_BACKENDS_BACKEND_NONE) {
                opts->general.backend = id;
                return 1;
            }
        } else if (strcmp(key, "timeout") == 0) {
            /* Use a max ceiling of 60 minutes (3600 secs) */
            opts->general.timeout = (uint16_t)LV_MIN(strtoul(value, (char **)NULL, 10), 3600);
            return 1;
        }
    } else if (strcmp(section, "keyboard") == 0) {
        if (strcmp(key, "autohide") == 0) {
            if (parse_bool(value, &(opts->keyboard.autohide))) {
                return 1;
            }
        } else if (strcmp(key, "layout") == 0) {
            sq2lv_layout_id_t id = sq2lv_find_layout_with_short_name(value);
            if (id != SQ2LV_LAYOUT_NONE) {
                opts->keyboard.layout_id = id;
                return 1;
            }
        } else if (strcmp(key, "popovers") == 0) {
            if (parse_bool(value, &(opts->keyboard.popovers))) {
                return 1;
            }
        }
    } else if (strcmp(section, "textarea") == 0) {
        if (strcmp(key, "obscured") == 0) {
            if (parse_bool(value, &(opts->textarea.obscured))) {
                return 1;
            }
        } else if (strcmp(key, "bullet") == 0) {
            char *bullet = strdup(value);
            if (bullet) {
                opts->textarea.bullet = bullet;
                return 1;
            }
        }
    } else if (strcmp(section, "theme") == 0) {
        if (strcmp(key, "default") == 0) {
            ul_themes_theme_id_t id = ul_themes_find_theme_with_name(value);
            if (id != UL_THEMES_THEME_NONE) {
                opts->theme.default_id = id;
                return 1;
            }
        } else if (strcmp(key, "alternate") == 0) {
            ul_themes_theme_id_t id = ul_themes_find_theme_with_name(value);
            if (id != UL_THEMES_THEME_NONE) {
                opts->theme.alternate_id = id;
                return 1;
            }
        }
    } else if (strcmp(section, "input") == 0) {
        if (strcmp(key, "keyboard") == 0) {
            if (parse_bool(value, &(opts->input.keyboard))) {
                return 1;
            }
        } else if (strcmp(key, "pointer") == 0) {
            if (parse_bool(value, &(opts->input.pointer))) {
                return 1;
            }
        } else if (strcmp(key, "touchscreen") == 0) {
            if (parse_bool(value, &(opts->input.touchscreen))) {
                return 1;
            }
        }
    } else if (strcmp(section, "quirks") == 0) {
        if (strcmp(key, "fbdev_force_refresh") == 0) {
            if (parse_bool(value, &(opts->quirks.fbdev_force_refresh))) {
                return 1;
            }
        } else if (strcmp(key, "terminal_prevent_graphics_mode") == 0) {
            if (parse_bool(value, &(opts->quirks.terminal_prevent_graphics_mode))) {
                return 1;
            }
        } else if (strcmp(key, "terminal_allow_keyboard_input") == 0) {
            if (parse_bool(value, &(opts->quirks.terminal_allow_keyboard_input))) {
                return 1;
            }
        }
    }

    ul_log(UL_LOG_LEVEL_ERROR, "Ignoring invalid config value \"%s\" for key \"%s\" in section \"%s\"", value, key, section);
    return 1; /* Return 1 (true) so that we can use the return value of ini_parse exclusively for file-level errors (e.g. file not found) */
}

static bool parse_bool(const char *value, bool *result) {
    if (strcmp(value, "true") == 0) {
        *result = true;
        return true;
    }

    if (strcmp(value, "false") == 0) {
        *result = false;
        return true;
    }

    return false;
}


/**
 * Public functions
 */

void ul_config_init_opts(ul_config_opts *opts) {
    opts->general.animations = false;
    opts->general.backend = ul_backends_backends[0] == NULL ? UL_BACKENDS_BACKEND_NONE : 0;
    opts->general.timeout = 0;
    opts->keyboard.autohide = true;
    opts->keyboard.layout_id = SQ2LV_LAYOUT_US;
    opts->keyboard.popovers = true;
    opts->textarea.obscured = true;
    opts->textarea.bullet = LV_SYMBOL_BULLET;
    opts->theme.default_id = UL_THEMES_THEME_BREEZY_DARK;
    opts->theme.alternate_id = UL_THEMES_THEME_BREEZY_LIGHT;
    opts->input.keyboard = true;
    opts->input.pointer = true;
    opts->input.touchscreen = true;
    opts->quirks.fbdev_force_refresh = false;
    opts->quirks.terminal_prevent_graphics_mode = false;
    opts->quirks.terminal_allow_keyboard_input = false;
}

void ul_config_parse_directory(const char *path, ul_config_opts *opts) {
    /* Find files in directory */
    char **found = NULL;
    int num_found = 0;
    find_files(path, &found, &num_found);

    /* Sort and parse files */
    qsort(found, num_found, sizeof(char *), compare_strings);
    ul_config_parse_files((const char **)found, num_found, opts);

    /* Free memory */
    for (int i = 0; i < num_found; ++i) {
        free(found[i]);
    }
    free(found);
}

void ul_config_parse_files(const char **files, int num_files, ul_config_opts *opts) {
    for (int i = 0; i < num_files; ++i) {
        ul_config_parse_file(files[i], opts);
    }
}

void ul_config_parse_file(const char *path, ul_config_opts *opts) {
    ul_log(UL_LOG_LEVEL_VERBOSE, "Parsing config file %s", path);
    if (ini_parse(path, parsing_handler, opts) != 0) {
        ul_log(UL_LOG_LEVEL_ERROR, "Ignoring invalid config file %s", path);
    }
}