/*
 * LuaConsoleScreen.cs
 * Authors: Adam Nabinger
 *	based on code by August Zinsser
 * Copyright (c) 2007-2008 Cornell University

 This program 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 2
 of the License, or (at your option) any later version.

 This program 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 this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using LuaInterface;
using Microsoft.Xna.Framework;
using Util;

public class LuaConsoleScreen : GameScreen
{
	private struct HistoryItem
	{
		internal enum Code { Command, Output, Error };

		internal string Text;
		internal Code CodeType;

		internal HistoryItem(string text, Code codeType)
		{
			Text = text;
			CodeType = codeType;
		}
	}

	private const int mLeft = 5;
	private const int mBottom = 40;
	private const int mSpacing = 40;
	private const float mScreenPercentage = .333f;
	private const int mHistoryCount = 25;

	private static readonly string mCursor = "> ";

	private static List<HistoryItem> mHistory = new List<HistoryItem>();
	private static int mHistoryIndex = 0;

	private SpriteBatch mSpriteBatch;
	private SpriteFont font;
	private InputHandler inputHandler;
	private Lua LuaVM;

	private string commandString = string.Empty;

	private Texture2D lineTex;

	public LuaConsoleScreen(Lua VM)
	{
		LuaVM = VM;
	}

	protected override void Dispose(bool disposing)
	{
		if (disposing)
		{
			mSpriteBatch.Dispose();
		}
		base.Dispose(disposing);
	}

	public override void Initialize()
	{
		inputHandler = GetInputHandler();

		inputHandler.Initialize();
		inputHandler.ReportAllEvents = true;
		inputHandler.ReportCase = true;

		base.Initialize();
	}

	protected override void LoadContent()
	{
		mSpriteBatch = new SpriteBatch(GraphicsDevice);
		font = Content.Load<SpriteFont>(@"Fonts\menufont");
		lineTex = Content.Load<Texture2D>(@"blank");

		base.LoadContent();
	}

	public override void Reinitialize()
	{
		throw new Exception("The method or operation is not implemented.");
	}

	public override void Update(Microsoft.Xna.Framework.GameTime gameTime)
	{

		while (inputHandler.HasEvent())
		{
			InputEvent e = inputHandler.GetNextEvent();

			KeyInputEvent key = e as KeyInputEvent;
			if (key != null && e.Trigger == Trigger.Activated)
			{
				switch (key.Key)
				{
					case Keys.Back:
						commandString = commandString.Substring(0, Math.Max(commandString.Length - 1, 0));
						break;
					case Keys.Up:
						int newIndexUp = mHistoryIndex;
						do
						{
							if (newIndexUp < mHistory.Count - 1)
							{
								++newIndexUp;
							}
							else
							{
								return;
							}
						} while (mHistory[newIndexUp].CodeType != HistoryItem.Code.Command);
						mHistoryIndex = newIndexUp;
						commandString = mHistory[mHistoryIndex].Text;
						break;
					case Keys.Down:
						int newIndexDown = mHistoryIndex;
						do
						{
							if (newIndexDown > 0)
							{
								--newIndexDown;
							}
							else
							{
								return;
							}
						} while (mHistory[newIndexDown].CodeType != HistoryItem.Code.Command);
						mHistoryIndex = newIndexDown;
						commandString = mHistory[mHistoryIndex].Text;
						break;
					case Keys.Enter:
						if (commandString != string.Empty)
						{
							mHistory.Insert(0, new HistoryItem(commandString, HistoryItem.Code.Command));

							// Send the command the Lua Virtual Machine
							try
							{
								LuaVM.DoString(commandString);
							}
							catch (Exception ex)
							{
								mHistory.Insert(0, new HistoryItem(ex.Message, HistoryItem.Code.Error));
							}

							// Update console commands
							commandString = string.Empty;
							mHistoryIndex = -1;
						}
						break;
					case Keys.Escape:
					case Keys.OemTilde:
						Done();
						break;
					default:
						commandString += key.ToCodeString();
						break;
				}

			}

		}

		// Update history lines
		while (mHistory.Count > mHistoryCount)
		{
			mHistory.RemoveAt(mHistory.Count - 1);
		}

		base.Update(gameTime);
	}

	// TODO: Cleanup
	public override void Draw(Microsoft.Xna.Framework.GameTime gameTime)
	{
		mSpriteBatch.Begin(SpriteBlendMode.Additive, SpriteSortMode.Immediate, SaveStateMode.None);

		int lineY = (int)(GraphicsDevice.Viewport.Height * mScreenPercentage);

		mSpriteBatch.Draw(
			lineTex,
			new Rectangle(0, 0, GraphicsDevice.Viewport.Width, (int)(GraphicsDevice.Viewport.Height * mScreenPercentage)),
			null,
			new Color(75, 75, 155, 180),
			0f,
			Vector2.Zero,
			SpriteEffects.None,
			0f);
		mSpriteBatch.Draw(
			lineTex,
			new Rectangle(0, (int)(lineY - 2), GraphicsDevice.Viewport.Width, 4),
			null,
			new Color(200, 200, 200, 200),
			0f,
			Vector2.Zero,
			SpriteEffects.None,
			0f);

		// Draw the command line
		Vector2 cursorSize = font.MeasureString(mCursor);

		mSpriteBatch.DrawString(font,
			mCursor,
			new Vector2(mLeft, lineY - mBottom),
			new Color(255, 150, 0, 255));
		mSpriteBatch.DrawString(font,
			commandString,
			new Vector2(mLeft + (int)cursorSize.X, lineY - mBottom),
			new Color(255, 255, 175, 255));

		// Draw the history lines
		Color color;
		for (int i = 0; i < mHistory.Count; i++)
		{
			int y = lineY - (mSpacing) * (i + 2);

			if (mHistoryIndex == i)
				mSpriteBatch.DrawString(font,
					mCursor,
					new Vector2(mLeft, y),
					new Color(200, 150, 0, 200));

			if (mHistory[i].CodeType == HistoryItem.Code.Command)
				color = new Color(200, 200, 150, 255);
			else if (mHistory[i].CodeType == HistoryItem.Code.Output)
				color = new Color(155, 255, 255, 255);
			else
				color = new Color(255, 0, 0, 255);

			mSpriteBatch.DrawString(font,
				mHistory[i].Text,
				new Vector2(mLeft + (int)cursorSize.X, y),
				color);
		}

		mSpriteBatch.End();

		base.Draw(gameTime);
	}

}