using System;
using System.Collections.Specialized;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using MatterHackers.VectorMath;
using MatterHackers.MatterControl;
using MatterHackers.Agg.VertexSource;

namespace MatterHackers.Agg.UI
{
    public class DropDownMenu : Menu
    {        
        public event EventHandler SelectionChanged;
        TextWidget mainControlText;

        public bool MenuAsWideAsItems { get; set; }

        int borderWidth = 1;
        public int BorderWidth
        {
            get { return borderWidth; }
            set { borderWidth = value; }
        }

        RGBA_Bytes borderColor;
        public RGBA_Bytes BorderColor
        {
            get { return borderColor; }
            set { borderColor = value; }
        }

        RGBA_Bytes arrowColor;
        public RGBA_Bytes ArrowColor
        {
            get { return arrowColor; }
            set { arrowColor = value; }
        }

        RGBA_Bytes normalColor;
        public RGBA_Bytes NormalColor
        {
            get { return normalColor; }
            set { normalColor = value; }
        }

        RGBA_Bytes hoverColor;
        public RGBA_Bytes HoverColor
        {
            get { return hoverColor; }
            set { hoverColor = value; }
        }

        RGBA_Bytes textColor = RGBA_Bytes.Black;
        public RGBA_Bytes TextColor
        {
            get { return textColor; }
            set
            {
                textColor = value;
                //mainControlText.TextColor = TextColor;
            }
        }

        int selectedIndex = -1;
        public int SelectedIndex
        {
            get { return selectedIndex; }
            set
            {
                selectedIndex = value;
                OnSelectionChanged(null);
                Invalidate();
            }
        }

        public String SelectedValue
        {
            get { return GetValue(SelectedIndex); }
        }

        public string GetValue(int itemIndex)
        {
            return MenuItems[SelectedIndex].Value;
        }

        public DropDownMenu(GuiWidget topMenuWidget, Direction direction = Direction.Down)
            : base(direction)
        {
        }

        public DropDownMenu(string topMenuText, Direction direction = Direction.Down, double pointSize = 12)
            : base(direction)
        {
            MenuAsWideAsItems = true;
            SetDisplayAttributes();

            MenuItems.CollectionChanged += new NotifyCollectionChangedEventHandler(MenuItems_CollectionChanged);
            
            mainControlText = new TextWidget(topMenuText, pointSize: pointSize);
            mainControlText.TextColor = this.TextColor;
            mainControlText.AutoExpandBoundsToText = true;
            mainControlText.VAnchor = UI.VAnchor.ParentCenter;
            mainControlText.HAnchor = UI.HAnchor.ParentLeft;
            AddChild(mainControlText);
            HAnchor = HAnchor.FitToChildren;
            VAnchor = VAnchor.FitToChildren;

            MouseEnter += new EventHandler(DropDownList_MouseEnter);
            MouseLeave += new EventHandler(DropDownList_MouseLeave);

            NormalColor = normalColor;
            HoverColor = hoverColor;
            BackgroundColor = normalColor;
            BorderColor = normalColor;

            //IE Don't show arrow unless color is set explicitly
            ArrowColor = new RGBA_Bytes(255, 255, 255, 0);
            
        }

        void DropDownList_MouseLeave(object sender, EventArgs e)
        {
            if (!this.IsOpen)
            {
                BackgroundColor = NormalColor;
                ArrowColor = new RGBA_Bytes(255, 255, 255, 0);
            }
        }

        void DropDownList_MouseEnter(object sender, EventArgs e)
        {
            BackgroundColor = HoverColor;
            ArrowColor = TextColor;
        }

        void OnSelectionChanged(EventArgs e)
        {
            if (SelectionChanged != null)
            {
                SelectionChanged(this, e);
            }
        }

        void MenuItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            Vector2 minSize = new Vector2(LocalBounds.Width, LocalBounds.Height);

            string startText = mainControlText.Text;
            foreach (MenuItem item in MenuItems)
            {
                mainControlText.Text = item.Text;

                minSize.x = Math.Max(minSize.x, LocalBounds.Width);
                minSize.y = Math.Max(minSize.y, LocalBounds.Height);
            }
            mainControlText.Text = startText;

            if (MenuAsWideAsItems)
            {
                this.MinimumSize = minSize;
            }

            foreach (MenuItem item in e.NewItems)
            {
                item.MinimumSize = minSize;
                // remove it if it is there so we don't have two. It is ok to remove a delagate that is not present.
                item.Selected -= new EventHandler(item_Selected);
                item.Selected += new EventHandler(item_Selected);
            }
        }

        void item_Selected(object sender, EventArgs e)
        {
            int newSelectedIndex = 0;
            foreach (MenuItem item in MenuItems)
            {
                if (item == sender)
                {
                    break;
                }
                newSelectedIndex++;
            }

            SelectedIndex = newSelectedIndex;
            BackgroundColor = NormalColor;
        }

        private void SetDisplayAttributes()
        {
            this.TextColor = RGBA_Bytes.White;
            this.NormalColor = ActiveTheme.Instance.PrimaryBackgroundColor;
            this.HoverColor = RGBA_Bytes.Gray;
            this.MenuItemsBorderWidth = 1;
            this.MenuItemsBackgroundColor = RGBA_Bytes.White;
            this.MenuItemsBorderColor = RGBA_Bytes.Gray;
            this.MenuItemsPadding = new BorderDouble(10, 10, 10, 10);
        }

        public override void OnDraw(Graphics2D graphics2D)
        {            
            base.OnDraw(graphics2D);
            this.DrawBorder(graphics2D);
            this.DrawDirectionalArrow(graphics2D);
        }

        private void DrawDirectionalArrow(Graphics2D graphics2D)
        {
            PathStorage littleArrow = new PathStorage();
            if (this.MenuDirection == Direction.Down)
            {
                littleArrow.MoveTo(-4, 0);
                littleArrow.LineTo(4, 0);
                littleArrow.LineTo(0, -5);
            }
            else if (this.MenuDirection == Direction.Up)
            {
                littleArrow.MoveTo(-4, -5);
                littleArrow.LineTo(4, -5);
                littleArrow.LineTo(0, 0);
            }
            else
            {
                throw new NotImplementedException("Pulldown direction has not been implemented");
            }
            graphics2D.Render(littleArrow, LocalBounds.Right - 10, LocalBounds.Bottom + Height - 4, arrowColor);
        }

        private void DrawBorder(Graphics2D graphics2D)
        {
            RectangleDouble Bounds = LocalBounds;
            RoundedRect borderRect = new RoundedRect(this.LocalBounds, 0);
            Stroke strokeRect = new Stroke(borderRect, borderWidth);
            graphics2D.Render(strokeRect, borderColor);
        }

        public void AddItem(string name, string value = null, double pointSize = 12)
        {
            if (value == null)
            {
                value = name;
            }

            mainControlText.Margin = MenuItemsPadding;

            GuiWidget normalTextWithMargin = new GuiWidget();
            normalTextWithMargin.HAnchor = UI.HAnchor.ParentLeft;
            normalTextWithMargin.BackgroundColor = MenuItemsBackgroundColor;
            TextWidget normal = new TextWidget(name, pointSize: pointSize);
            normal.Margin = MenuItemsPadding;
            normal.TextColor = MenuItemsTextColor;
            normalTextWithMargin.AddChild(normal);
            normalTextWithMargin.HAnchor = HAnchor.FitToChildren;
            normalTextWithMargin.VAnchor = VAnchor.FitToChildren;

            GuiWidget hoverTextWithMargin = new GuiWidget();
            hoverTextWithMargin.HAnchor = UI.HAnchor.ParentLeft;
            hoverTextWithMargin.BackgroundColor = MenuItemsBackgroundHoverColor;
            TextWidget hover = new TextWidget(name, pointSize: pointSize);
            hover.Margin = MenuItemsPadding;
            hover.TextColor = mainControlText.TextColor;
            hoverTextWithMargin.AddChild(hover);
            hoverTextWithMargin.HAnchor = HAnchor.FitToChildren;
            hoverTextWithMargin.VAnchor = VAnchor.FitToChildren;

            MenuItem menuItem = new MenuItem(new MenuItemStatesView(normalTextWithMargin, hoverTextWithMargin), value);
            menuItem.Text = name;
            MenuItems.Add(menuItem);
        }
    }
}