using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using ShiftOS.Engine;
using ShiftOS.Frontend.Desktop;
using ShiftOS.Frontend.GUI;

namespace ShiftOS.Frontend.GraphicsSubsystem
{
    public static class UIManager
    {
        private static List<GUI.Control> topLevels = new List<GUI.Control>();
        public static System.Drawing.Size Viewport { get; set; }
        public static GUI.Control FocusedControl = null;
        private static ShiftOS _game = null;

        public static void Init(ShiftOS sentience)
        {
            _game = sentience;
        }

        public static bool Fullscreen
        {
            get
            {
                return _game.graphicsDevice.IsFullScreen;
            }
            set
            {
                var uconf = Objects.UserConfig.Get();
                uconf.Fullscreen = value;
                System.IO.File.WriteAllText("config.json", Newtonsoft.Json.JsonConvert.SerializeObject(uconf, Newtonsoft.Json.Formatting.Indented));
                _game.graphicsDevice.IsFullScreen = value;
                _game.graphicsDevice.ApplyChanges();
            }
        }

        public static void BringToFront(GUI.Control ctrl)
        {
            topLevels.Remove(ctrl);
            topLevels.Add(ctrl);
        }

        public static void LayoutUpdate(GameTime gameTime)
        {
            foreach (var toplevel in topLevels.ToArray())
                toplevel.Layout(gameTime);
        }

        public static void Animate(object owner, System.Reflection.PropertyInfo prop, double from, double to, int timeMs)
        {
            var t = new System.Threading.Thread(() =>
            {
                for(int i = 0; i < timeMs; i++)
                {
                    double value = ProgressBar.linear(i, 0, timeMs, from, to);
                    prop.SetValue(owner, value);
                    System.Threading.Thread.Sleep(1);
                }
            });
            t.IsBackground = true;
            t.Start();
        }

        public static Dictionary<int, RenderTarget2D> TextureCaches = new Dictionary<int, RenderTarget2D>();

        public static void DrawTArgets(SpriteBatch batch)
        {
            foreach(var ctrl in topLevels.ToArray())
            {
                if (ctrl.Visible == true)
                {
                    int hc = ctrl.GetHashCode();
                    if (!TextureCaches.ContainsKey(hc))
                    {
                        ctrl.Invalidate();
                        continue;
                    }
                    var _target = TextureCaches[hc];
                    if (ExperimentalEffects)
                    {
                        for (int i = 5; i > 0; i--)
                        {
                            batch.Draw(_target, new Rectangle(ctrl.X - i, ctrl.Y - i, ctrl.Width+(i*2), ctrl.Height+(i*2)), new Color(Color.Black, 255 / (i * 2)));
                        }
                    }

                    batch.Draw(_target, new Rectangle(ctrl.X, ctrl.Y, ctrl.Width, ctrl.Height), Color.White);
                }
            }
        }

        public static void SendToBack(Control ctrl)
       { 
            topLevels.Remove(ctrl);
            topLevels.Insert(0, ctrl);
        }

        public static void DrawControlsToTargets(GraphicsDevice graphics, SpriteBatch batch, int width, int height)
        {
            foreach (var ctrl in topLevels.ToArray().Where(x=>x.Visible==true))
            {
                RenderTarget2D _target;
                int hc = ctrl.GetHashCode();
                if (!TextureCaches.ContainsKey(hc))
                {
                    _target = new RenderTarget2D(
                                    graphics,
                                    Math.Max(1,ctrl.Width),
                                    Math.Max(1,ctrl.Height),
                                    false,
                                    graphics.PresentationParameters.BackBufferFormat,
                                    DepthFormat.Depth24);
                    TextureCaches.Add(hc, _target);
                }
                else
                {
                    _target = TextureCaches[hc];
                    if(_target.Width != ctrl.Width || _target.Height != ctrl.Height)
                    {
                        _target = new RenderTarget2D(
                graphics,
                Math.Max(1,ctrl.Width),
                Math.Max(1,ctrl.Height),
                false,
                graphics.PresentationParameters.BackBufferFormat,
                DepthFormat.Depth24);
                        TextureCaches[hc] = _target;

                    }
                }
                if (ctrl.RequiresPaint)
                {
                    graphics.SetRenderTarget(_target);
                    graphics.DepthStencilState = new DepthStencilState() { DepthBufferEnable = true };
                    batch.Begin(SpriteSortMode.Immediate, BlendState.NonPremultiplied,
                                    SamplerState.LinearClamp, DepthStencilState.Default,
                                    RasterizerState.CullNone);
                    graphics.Clear(Color.Transparent);
                    var gfxContext = new GraphicsContext(graphics, batch, 0, 0, _target.Width, _target.Height);
                    ctrl.Paint(gfxContext);
                    
                    graphics.SetRenderTarget(null);
                    TextureCaches[hc] = _target;
                    batch.End();
                }
            }
        }

        public static void AddTopLevel(GUI.Control ctrl)
        {
            if (!topLevels.Contains(ctrl))
                topLevels.Add(ctrl);
            FocusedControl = ctrl;
        }

        public static void InvalidateAll()
        {
            foreach(var ctrl in topLevels)
            {
                ctrl.Invalidate();
            }
        }

        public static void ProcessMouseState(MouseState state, double lastLeftClickMS)
        {
            foreach(var ctrl in topLevels.ToArray())
            {
                ctrl.ProcessMouseState(state, lastLeftClickMS);
                
            }
        }

        public static void ProcessKeyEvent(KeyEvent e)
        {
            if (e.ControlDown && e.Key == Keys.T)
            {
                AppearanceManager.SetupWindow(new Apps.Terminal());
                return;
            }
            FocusedControl?.ProcessKeyEvent(e);
        }

        private static Texture2D DesktopBackground = null;

        public static Dictionary<string, Texture2D> SkinTextures = new Dictionary<string, Texture2D>();

        public static void ResetSkinTextures(GraphicsDevice graphics)
        {
            SkinTextures.Clear();
            foreach(var byteArray in SkinEngine.LoadedSkin.GetType().GetFields(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).Where(x=>x.FieldType == typeof(byte[])))
            {
                var imgAttrib = byteArray.GetCustomAttributes(false).FirstOrDefault(x => x is ImageAttribute) as ImageAttribute;
                if(imgAttrib != null)
                {
                    var img = SkinEngine.GetImage(imgAttrib.Name);
                    if(img != null)
                    {
                        var bmp = (System.Drawing.Bitmap)img;
                        var lck = bmp.LockBits(new System.Drawing.Rectangle(0, 0, bmp.Width, bmp.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
                        var data = new byte[Math.Abs(lck.Stride) * lck.Height];
                        Marshal.Copy(lck.Scan0, data, 0, data.Length);
                        bmp.UnlockBits(lck);
                        var tex2 = new Texture2D(graphics, bmp.Width, bmp.Height);
                        for(int i = 0; i < data.Length; i += 4)
                        {
                            byte r = data[i];
                            byte b = data[i + 2];
                            if (r == 1 && b == 1 && data[i + 1] == 1)
                            {
                                data[i + 3] = 0;
                            }
                            data[i] = b;
                            data[i + 2] = r;
                        }
                        tex2.SetData<byte>(data);
                        SkinTextures.Add(imgAttrib.Name, tex2);
                    }
                }
            }

            foreach(var colorfield in SkinEngine.LoadedSkin.GetType().GetFields(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).Where(x=>x.FieldType == typeof(System.Drawing.Color)))
            {
                var color = (System.Drawing.Color)colorfield.GetValue(SkinEngine.LoadedSkin);
                var tex2 = new Texture2D(graphics, 1, 1);
                tex2.SetData<byte>(new[] { color.R, color.G, color.B, color.A });
                SkinTextures.Add(colorfield.Name, tex2);
            }

            var pureWhite = new Texture2D(graphics, 1, 1);
            pureWhite.SetData<byte>(new byte[] { 255, 255, 255, 255 });
            SkinTextures.Add("PureWhite", pureWhite);

        }


        public static bool ExperimentalEffects = true;

        public static Queue<Action> CrossThreadOperations = new Queue<Action>();
        internal static GraphicsDevice GraphicsDevice;

        public static void DrawBackgroundLayer(GraphicsDevice graphics, SpriteBatch batch, int width, int height)
        {
            if (SkinEngine.LoadedSkin == null)
                SkinEngine.Init();
            graphics.Clear(SkinEngine.LoadedSkin.DesktopColor.ToMonoColor());
            if (SkinTextures.ContainsKey("desktopbackground"))
            {
                batch.Draw(SkinTextures["desktopbackground"], new Rectangle(0, 0, Viewport.Width, Viewport.Height), Color.White);
            }
        }

        public static Color ToMonoColor(this System.Drawing.Color color)
        {
            return new Color(color.R, color.G, color.B, color.A);
        }

        internal static void StopHandling(GUI.Control ctrl)
        {
            if (topLevels.Contains(ctrl))
                topLevels.Remove(ctrl);

            int hc = ctrl.GetHashCode();
            if (TextureCaches.ContainsKey(hc))
            {
                TextureCaches[hc].Dispose();
                TextureCaches.Remove(hc);
            }

            ctrl = null;
        }
    }

    public class KeyEvent
    {
        public KeyEvent(bool control, bool alt, bool shift, Keys key)
        {
            ControlDown = control;
            AltDown = alt;
            ShiftDown = shift;
            Key = key;
            KeyChar = key.ToCharacter(shift);
        }

        public bool ControlDown { get; private set; }
        public bool AltDown { get; private set; }
        public bool ShiftDown { get; set; }
        public Keys Key { get; private set; }

        public char KeyChar { get; private set; }
    }

    public static class KeysExtensions
    {
        /*
         * Notice: The following keymapping does <i>not</i> take into account the user's keyboard
         * layout. This is written under the assumption the keyboard is en_US. 
         * 
         * @MichaelTheShifter I'm leaving you to figure out how to make this work with other layouts.
         * 
         * My suggestion would be to simply do what you are doing with strings, define a JSON file
         * mapping each character to its associated character.
         */

        private static Dictionary<Keys, char> keymapDefault = new Dictionary<Keys, char>() {
            { Keys.Space, ' ' },
            { Keys.Tab, '\t' },
            { Keys.Enter, '\n' },
            { Keys.Back, '\b' },
            { Keys.A, 'a'},
            { Keys.B, 'b'},
            { Keys.C, 'c' },
            { Keys.D, 'd' },
            { Keys.E, 'e' },
            { Keys.F, 'f' },
            { Keys.G, 'g' },
            { Keys.H, 'h' },
            { Keys.I, 'i' },
            { Keys.J, 'j' },
            { Keys.K, 'k' },
            { Keys.L, 'l' },
            { Keys.M, 'm' },
            { Keys.N, 'n' },
            { Keys.O, 'o' },
            { Keys.P, 'p' },
            { Keys.Q, 'q' },
            { Keys.R, 'r' },
            { Keys.S, 's' },
            { Keys.T, 't' },
            { Keys.U, 'u' },
            { Keys.V, 'v' },
            { Keys.W, 'w' },
            { Keys.X, 'x' },
            { Keys.Y, 'y' },
            { Keys.Z, 'z' },
            { Keys.D0, '0' },
            { Keys.D1, '1' },
            { Keys.D2, '2' },
            { Keys.D3, '3' },
            { Keys.D4, '4' },
            { Keys.D5, '5' },
            { Keys.D6, '6' },
            { Keys.D7, '7' },
            { Keys.D8, '8' },
            { Keys.D9, '9' },
            { Keys.OemTilde, '`' },
            { Keys.OemMinus, '-' },
            { Keys.OemPlus, '+' },
            { Keys.OemOpenBrackets, '[' },
            { Keys.OemCloseBrackets, ']'},
            { Keys.OemBackslash, '\\'},
            { Keys.OemPipe, '\\' },
            { Keys.OemSemicolon, ';' },
            { Keys.OemQuotes, '\'' },
            { Keys.OemComma, ',' },
            { Keys.OemPeriod, '.' },
            { Keys.OemQuestion, '/' },
        };

        private static Dictionary<Keys, char> keymapShift = new Dictionary<Keys, char> () {
            { Keys.Space, ' ' },
            { Keys.Tab, '\t' },
            { Keys.Enter, '\n' },
            { Keys.Back, '\b' },
            { Keys.A, 'A'},
            { Keys.B, 'B'},
            { Keys.C, 'C' },
            { Keys.D, 'D' },
            { Keys.E, 'E' },
            { Keys.F, 'F' },
            { Keys.G, 'G' },
            { Keys.H, 'H' },
            { Keys.I, 'I' },
            { Keys.J, 'J' },
            { Keys.K, 'K' },
            { Keys.L, 'L' },
            { Keys.M, 'M' },
            { Keys.N, 'N' },
            { Keys.O, 'O' },
            { Keys.P, 'P' },
            { Keys.Q, 'Q' },
            { Keys.R, 'R' },
            { Keys.S, 'S' },
            { Keys.T, 'T' },
            { Keys.U, 'U' },
            { Keys.V, 'V' },
            { Keys.W, 'W' },
            { Keys.X, 'X' },
            { Keys.Y, 'Y' },
            { Keys.Z, 'Z' },
            { Keys.D0, ')' },
            { Keys.D1, '!' },
            { Keys.D2, '@' },
            { Keys.D3, '#' },
            { Keys.D4, '$' },
            { Keys.D5, '%' },
            { Keys.D6, '^' },
            { Keys.D7, '&' },
            { Keys.D8, '*' },
            { Keys.D9, '(' },
            { Keys.OemTilde, '~' },
            { Keys.OemMinus, '_' },
            { Keys.OemPlus, '+' },
            { Keys.OemOpenBrackets, '{' },
            { Keys.OemCloseBrackets, '}'},
            { Keys.OemBackslash, '|'},
            { Keys.OemPipe, '|' },
            { Keys.OemSemicolon, ':' },
            { Keys.OemQuotes, '\'' },
            { Keys.OemComma, '<' },
            { Keys.OemPeriod, '>' },
            { Keys.OemQuestion, '?' },
        };

        public static char ToCharacter(this Keys key, bool shift)
        {
            if (shift && keymapShift.ContainsKey(key))
            {
                return keymapShift[key];
            }

            if (!shift && keymapDefault.ContainsKey(key))
            {
                return keymapDefault[key];
            }

            return '\0'; // Ideally all keys should be included in this map
        }
    }
}