//-----------------------------------------------------------------------------
// InputState.cs
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------

using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;

namespace CatapultGame
{
	/// <summary>
	/// Helper for reading input from keyboard, gamepad, and touch input. This class 
	/// tracks both the current and previous state of the input devices, and implements 
	/// query methods for high level input actions such as "move up through the menu"
	/// or "pause the game".
	/// </summary>
	public class InputState
	{
		public const int MaxInputs = 4;
		public readonly KeyboardState[] CurrentKeyboardStates;
		public readonly GamePadState[] CurrentGamePadStates;
		public readonly KeyboardState[] LastKeyboardStates;
		public readonly GamePadState[] LastGamePadStates;
		public readonly bool[] GamePadWasConnected;
		public TouchCollection TouchState;
		public MouseState CurrentMouseState;
		public MouseState LastMouseState;
		public readonly List<GestureSample> Gestures = new List<GestureSample>();

		Matrix inputTransformation;
		readonly float baseBufferWidth;
		readonly float baseBufferHeight;

		/// <summary>
		/// Constructs a new input state.
		/// </summary>
		public InputState(float baseBufferWidth, float baseBufferHeight)
		{
			this.baseBufferWidth = baseBufferWidth;
			this.baseBufferHeight = baseBufferHeight;

			CurrentKeyboardStates = new KeyboardState[MaxInputs];
			CurrentGamePadStates = new GamePadState[MaxInputs];

			LastKeyboardStates = new KeyboardState[MaxInputs];
			LastGamePadStates = new GamePadState[MaxInputs];

			GamePadWasConnected = new bool[MaxInputs];
		}

		/// <summary>
		/// Reads the latest state of the keyboard and gamepad.
		/// </summary>
		public void Update()
		{
			for (int i = 0; i < MaxInputs; i++)
			{
				LastKeyboardStates[i] = CurrentKeyboardStates[i];
				LastGamePadStates[i] = CurrentGamePadStates[i];

				CurrentKeyboardStates[i] = Keyboard.GetState();
				CurrentGamePadStates[i] = GamePad.GetState((PlayerIndex)i);

				// Keep track of whether a gamepad has ever been
				// connected, so we can detect if it is unplugged.
				if (CurrentGamePadStates[i].IsConnected)
				{
					GamePadWasConnected[i] = true;
				}
			}

			TouchState = TouchPanel.GetState();

			LastMouseState = CurrentMouseState;
			CurrentMouseState = Mouse.GetState();

			UpdateMouseStates();

			Gestures.Clear();
			while (TouchPanel.IsGestureAvailable)
			{
				Gestures.Add(TouchPanel.ReadGesture());
			}
		}

		bool dragging = false;
		bool dragComplete = false;
		bool leftMouseDown = false;
		int dragThreshold = 3;
		MouseGestureType mouseGestureType;
		Vector2 currentMousePosition = Vector2.Zero;
		Vector2 prevMousePosition = Vector2.Zero;
		Vector2 dragMouseStart = Vector2.Zero;
		Vector2 dragMouseEnd = Vector2.Zero;

		public MouseGestureType MouseGesture
		{
			get
			{
				return mouseGestureType;
			}
		}

		public Vector2 CurrentMousePosition
		{
			get
			{
				return currentMousePosition;
			}
		}

		public Vector2 PrevMousePosition
		{
			get
			{
				return prevMousePosition;
			}
		}

		public Vector2 MouseDelta
		{
			get
			{
				return prevMousePosition - currentMousePosition;
			}
		}

		public Vector2 MouseDragDelta
		{
			get
			{
				return dragMouseStart - dragMouseEnd;
			}
		}

		public Vector2 MouseDragStartPosition
		{
			get
			{
				return dragMouseStart;
			}
		}

		public Vector2 MouseDragEndPosition
		{
			get
			{
				return dragMouseEnd;
			}
		}

		void UpdateMouseStates()
		{
			currentMousePosition.X = CurrentMouseState.X;
			currentMousePosition.Y = CurrentMouseState.Y;

			prevMousePosition.X = LastMouseState.X;
			prevMousePosition.Y = LastMouseState.Y;

			if (mouseGestureType.HasFlag(MouseGestureType.LeftClick))
				mouseGestureType = mouseGestureType ^ MouseGestureType.LeftClick;

			if (mouseGestureType.HasFlag(MouseGestureType.Move))
				mouseGestureType = mouseGestureType ^ MouseGestureType.Move;

			if (MouseDelta.Length() != 0)
				mouseGestureType = mouseGestureType | MouseGestureType.Move;

			// If we were dragging and the left mouse button was released
			// then we are no longer dragging and need to throw the banana.
			if (CurrentMouseState.LeftButton == ButtonState.Released &&
					dragging)
			{

				leftMouseDown = false;
				dragging = false;
				dragComplete = true;
				dragMouseEnd = currentMousePosition;
				mouseGestureType |= MouseGestureType.DragComplete;
				mouseGestureType = mouseGestureType ^ MouseGestureType.FreeDrag;
				//Console.WriteLine ("Dragging: " + mouseGestureType);

			}

			// Let's set the left mouse down and the mouse origin
			if (!leftMouseDown && CurrentMouseState.LeftButton == ButtonState.Pressed &&
					!CurrentMouseState.Equals(LastMouseState))
			{
				//Console.WriteLine ("left down");
				leftMouseDown = true;
				dragComplete = false;
				dragMouseStart = currentMousePosition;
			}

			if (leftMouseDown && CurrentMouseState.LeftButton == ButtonState.Released &&
					!CurrentMouseState.Equals(LastMouseState))
			{
				leftMouseDown = false;
				mouseGestureType |= MouseGestureType.LeftClick;
			}

			// Here we test the distance and if over the threshold then we set the dragging to true
			//  Current threshold is 5 pixels.
			if (leftMouseDown && !dragging)
			{

				Vector2 delta = dragMouseStart - currentMousePosition;

				if (delta.Length() > dragThreshold)
				{
					dragging = true;
					dragMouseStart = currentMousePosition;
					mouseGestureType = mouseGestureType | MouseGestureType.FreeDrag;
					//Console.WriteLine ("Dragging: " + mouseGestureType);
				}
			}

			//Console.WriteLine(mouseGestureType);
		}

		/// <summary>
		/// Helper for checking if a key was newly pressed during this update. The
		/// controllingPlayer parameter specifies which player to read input for.
		/// If this is null, it will accept input from any player. When a keypress
		/// is detected, the output playerIndex reports which player pressed it.
		/// </summary>
		public bool IsNewKeyPress(Keys key, PlayerIndex? controllingPlayer, out PlayerIndex playerIndex)
		{
			if (controllingPlayer.HasValue)
			{
				// Read input from the specified player.
				playerIndex = controllingPlayer.Value;

				int i = (int)playerIndex;

				return (CurrentKeyboardStates[i].IsKeyDown(key) && LastKeyboardStates[i].IsKeyUp(key));
			}
			else
			{
				// Accept input from any player.
				return (IsNewKeyPress(key, PlayerIndex.One, out playerIndex) ||
					IsNewKeyPress(key, PlayerIndex.Two, out playerIndex) ||
					IsNewKeyPress(key, PlayerIndex.Three, out playerIndex) ||
					IsNewKeyPress(key, PlayerIndex.Four, out playerIndex));
			}
		}

		/// <summary>
		/// Helper for checking if a button was newly pressed during this update.
		/// The controllingPlayer parameter specifies which player to read input for.
		/// If this is null, it will accept input from any player. When a button press
		/// is detected, the output playerIndex reports which player pressed it.
		/// </summary>
		public bool IsNewButtonPress(Buttons button, PlayerIndex? controllingPlayer, out PlayerIndex playerIndex)
		{
			if (controllingPlayer.HasValue)
			{
				// Read input from the specified player.
				playerIndex = controllingPlayer.Value;

				int i = (int)playerIndex;

				return (CurrentGamePadStates[i].IsButtonDown(button) && LastGamePadStates[i].IsButtonUp(button));
			}
			else
			{
				// Accept input from any player.
				return (IsNewButtonPress(button, PlayerIndex.One, out playerIndex) ||
					IsNewButtonPress(button, PlayerIndex.Two, out playerIndex) ||
					IsNewButtonPress(button, PlayerIndex.Three, out playerIndex) ||
					IsNewButtonPress(button, PlayerIndex.Four, out playerIndex));
			}
		}

		/// <summary>
		/// Checks for a "menu select" input action.
		/// The controllingPlayer parameter specifies which player to read input for.
		/// If this is null, it will accept input from any player. When the action
		/// is detected, the output playerIndex reports which player pressed it.
		/// </summary>
		public bool IsMenuSelect(PlayerIndex? controllingPlayer, out PlayerIndex playerIndex)
		{
			return IsNewKeyPress(Keys.Space, controllingPlayer, out playerIndex) ||
						IsNewKeyPress(Keys.Enter, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.A, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.Start, controllingPlayer, out playerIndex);
		}

		/// <summary>
		/// Checks for a "menu cancel" input action.
		/// The controllingPlayer parameter specifies which player to read input for.
		/// If this is null, it will accept input from any player. When the action
		/// is detected, the output playerIndex reports which player pressed it.
		/// </summary>
		public bool IsMenuCancel(PlayerIndex? controllingPlayer, out PlayerIndex playerIndex)
		{
			return IsNewKeyPress(Keys.Escape, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.B, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.Back, controllingPlayer, out playerIndex);
		}

		/// <summary>
		/// Checks for a "menu up" input action.
		/// The controllingPlayer parameter specifies which player to read
		/// input for. If this is null, it will accept input from any player.
		/// </summary>
		public bool IsMenuUp(PlayerIndex? controllingPlayer)
		{
			PlayerIndex playerIndex;

			return IsNewKeyPress(Keys.Up, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.DPadUp, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.LeftThumbstickUp, controllingPlayer, out playerIndex);
		}

		/// <summary>
		/// Checks for a "menu down" input action.
		/// The controllingPlayer parameter specifies which player to read
		/// input for. If this is null, it will accept input from any player.
		/// </summary>
		public bool IsMenuDown(PlayerIndex? controllingPlayer)
		{
			PlayerIndex playerIndex;

			return IsNewKeyPress(Keys.Down, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.DPadDown, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.LeftThumbstickDown, controllingPlayer, out playerIndex);
		}

		/// <summary>
		/// Checks for a "pause the game" input action.
		/// The controllingPlayer parameter specifies which player to read
		/// input for. If this is null, it will accept input from any player.
		/// </summary>
		public bool IsPauseGame(PlayerIndex? controllingPlayer)
		{
			PlayerIndex playerIndex;

			return IsNewKeyPress(Keys.Escape, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.Back, controllingPlayer, out playerIndex) ||
						IsNewButtonPress(Buttons.Start, controllingPlayer, out playerIndex);
		}

		/// <summary>
		/// Updates the matrix used to transform input coordinates.
		/// </summary>
		/// <param name="inputTransformation">The transformation matrix to apply.</param>
		public void UpdateInputTransformation(Matrix inputTransformation)
		{
			this.inputTransformation = inputTransformation;
		}
	}
}