// 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.Input.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;}
        }

        #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 InputManager manager;
        private Rectangle[] keymapPos;
        private KeyState[] keymapState;
        private int keymapSize;
        private KeyboardDefinition keyboard;
        private Texture2D image;
        private Vector2 position;
        private Texture2D overlay;
        private bool subscribed;

        #endregion

        #region Private members

        /// <summary>
        /// Updates the keyboard.
        /// </summary>
        public void TouchScreenHandler(object sender, InputManager.TouchLocationEventArgs e)
        {
            int x = (int)e.Location.Position.X;
            int y = (int)e.Location.Position.Y;
            int f = 0;
            KeyState key = null;


            if (e.Location.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 = e.Location.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 (e.Location.State == TouchLocationState.Released)
            {
                for(f = 0; f < keymapSize && key == null; f++)
                {
                    if (keymapState[f].TouchId == e.Location.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});
                        }
                    }
                }
            }

            // Check if input was used.
            //
            if (key != null || keymapState.Where(r => r.TouchId == e.Location.Id).Count() > 0)
            {
                e.Handled = true;
            }
        }

        #endregion

        #region Public members

        /// <summary>
        /// Stops consuming inputs and releases all keys.
        /// </summary>
        /// <param name="generateEvents">Generates events for cleared keys.</param>
        public void StopKeyboardUpdates(bool generateEvents)
        {
            if (subscribed)
            {
                manager.TouchEvent -= TouchScreenHandler;
                subscribed = false;

                foreach (KeyState key in keymapState)
                {
                    if (key.IsPressed)
                    {
                        key.IsPressed = false;

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

        /// <summary>
        /// Stops consuming inputs and releases all keys.  Generates events for released keys.
        /// </summary>
        public void StopKeyboardUpdates()
        {
            StopKeyboardUpdates(true);
        }

        /// <summary>
        /// Starts consuming inputs.
        /// </summary>
        public void StartKeyboardUpdates()
        {
            if (!subscribed)
            {
                manager.TouchEvent += TouchScreenHandler;
                subscribed = true;
            }
        }

        /// <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;

        #endregion

        #region Constructors

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="manager">The input manager to attached to.</param>
        /// <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(InputManager manager, GraphicsDevice graphics, Texture2D image, Vector2 position, KeyboardDefinition keyboard)
        {
            this.manager = manager;
            this.keyboard = keyboard;
            this.image = image;
            this.position = position;
            this.subscribed = false;

            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((int)position.X + k.X, (int)position.Y + 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});

            StartKeyboardUpdates();
        }

        #endregion
    }
}