// This file is part of the Noddybox.Emulation C# suite.
//
// Noddybox.Emulation 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.
//
// Noddybox.Emulation 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 Noddybox.Emulation.  If not, see <http://www.gnu.org/licenses/>.
//
// Copyright (c) 2012 Ian Cowburn
//
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Noddybox.Emulation.Keyboard.Schema;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Input.Touch;

namespace Noddybox.Emulation.Xna.Keyboard
{
    /// <summary>
    /// Displays and drives the keyboard.
    /// </summary>
    /// <typeparam name="T">The enumerated type matching the symbols in the used keyboard definition.</typeparam>
    public class KeyboardDriver<T> where T: struct,IConvertible
    {
        #region Event arguments

        /// <summary>
        /// Event data when a key is pressed or released.
        /// </summary>
        public class KeyPressEventArgs : EventArgs
        {
            /// <summary>
            /// The key that was pressed.
            /// </summary>
            public T Key {get;set;}

            /// <summary>
            /// True if the key was pressed.  False if released.
            /// </summary>
            public bool Pressed {get; set;}
        }

        /// <summary>
        /// Event data when the screen is touched away from a key.
        /// </summary>
        public class TouchLocationEventArgs : EventArgs
        {
            /// <summary>
            /// The touch.
            /// </summary>
            public TouchLocation Location {get; set;}
        }

        #endregion

        #region Private data

        private class KeyState
        {
            public T Symbol {get;set;}
            public bool IsPressed {get; set;}
            public bool IsSticky {get; set;}
            public int TouchId {get; set;}
        }

        private Rectangle[] keymapPos;
        private KeyState[] keymapState;
        private int keymapSize;
        private KeyboardDefinition keyboard;
        private Texture2D image;
        private Vector2 position;
        private Texture2D overlay;

        #endregion

        #region Private members

        #endregion

        #region Public members

        /// <summary>
        /// Updates the keyboard.  Note that this will consume all the key press events.
        /// </summary>
        public void Update()
        {
            foreach (TouchLocation t in TouchPanel.GetState())
            {
                int x = (int)t.Position.X;
                int y = (int)t.Position.Y;
                int f = 0;
                KeyState key = null;


                if (t.State == TouchLocationState.Pressed)
                {
                    for(f = 0; f < keymapSize && key == null; f++)
                    {
                        if (keymapPos[f].Contains(x, y))
                        {
                            key = keymapState[f];
                        }
                    }

                    if (key != null)
                    {
                        key.TouchId = t.Id;

                        if (key.IsSticky)
                        {
                            key.IsPressed = !key.IsPressed;
                        }
                        else
                        {
                            key.IsPressed = true;
                        }

                        if (KeyEvent != null)
                        {
                            KeyEvent(this, new KeyPressEventArgs() {Key = key.Symbol, Pressed = key.IsPressed});
                        }
                    }
                }
                else if (t.State == TouchLocationState.Released)
                {
                    for(f = 0; f < keymapSize && key == null; f++)
                    {
                        if (keymapState[f].TouchId == t.Id)
                        {
                            key = keymapState[f];
                        }
                    }

                    if (key != null)
                    {
                        if (!key.IsSticky)
                        {
                            key.IsPressed = false;

                            if (KeyEvent != null)
                            {
                                KeyEvent(this, new KeyPressEventArgs() {Key = key.Symbol, Pressed = key.IsPressed});
                            }
                        }
                    }
                }

                // If no key handled, pass on the event
                //
                if (key == null && keymapState.Where(r => r.TouchId == t.Id).Count() == 0)
                {
                    if (TouchEvent != null)
                    {
                        TouchEvent(this, new TouchLocationEventArgs() {Location = t});
                    }
                }
            }
        }

        /// <summary>
        /// Draw the keyboard
        /// </summary>
        /// <param name="spriteBatch"></param>
        public void Draw(SpriteBatch spriteBatch)
        {
            spriteBatch.Draw(image, position, Color.White);

            for(int f = 0; f < keymapSize; f++)
            {
                if (keymapState[f].IsPressed)
                {
                    spriteBatch.Draw(overlay, keymapPos[f], new Color(200, 200, 0, 25));
                }
            }
        }

        #endregion

        #region Events

        public EventHandler<KeyPressEventArgs> KeyEvent;
        public EventHandler<TouchLocationEventArgs> TouchEvent;

        #endregion

        #region Constructors

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="graphics">The graphics device to associate textures with.</param>
        /// <param name="image">The image for the keyboard.</param>
        /// <param name="position">Where to draw and offset the keyboard to.</param>
        /// <param name="keyboard">The keyboard to drive this from.</param>
        public KeyboardDriver(GraphicsDevice graphics, Texture2D image, Vector2 position, KeyboardDefinition keyboard)
        {
            this.keyboard = keyboard;
            this.image = image;
            this.position = position;

            keymapSize = keyboard.Definitions.Count;
            keymapPos = new Rectangle[keymapSize];
            keymapState = new KeyState[keymapSize];

            for(int f = 0; f < keymapSize; f++)
            {
                KeyboardKey k = keyboard.Definitions[f];

                keymapPos[f] = new Rectangle(k.X, k.Y, k.Width, k.Height);

                keymapState[f] = new KeyState()
                {
                    Symbol = (T)Enum.Parse(typeof(T), k.KeySymbol, false),
                    IsPressed = false,
                    IsSticky = k.Sticky
                };
            }

            Color c = Color.White;
            overlay = new Texture2D(graphics, 2, 2, false, SurfaceFormat.Color);
            overlay.SetData<Color>(new Color[] {c, c, c, c});
        }

        #endregion
    }
}