#region Copyright & License Information
/*
 * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
 * This file is part of OpenRA.
 * 
 *  OpenRA 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.
 * 
 *  OpenRA 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 OpenRA.  If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml;
using System.IO;
using OpenRA.FileFormats;

namespace OpenRA.Graphics
{
	static class SequenceProvider
	{
		static Dictionary<string, Dictionary<string, Sequence>> units;
		static Dictionary<string, CursorSequence> cursors;

		public static void Initialize(params string[] sequenceFiles)
		{
			units = new Dictionary<string, Dictionary<string, Sequence>>();
			cursors = new Dictionary<string, CursorSequence>();

			foreach (var f in sequenceFiles)
				LoadSequenceSource(f);
		}

		static void LoadSequenceSource(string filename)
		{
			XmlDocument document = new XmlDocument();
			document.Load(FileSystem.Open(filename));

			foreach (XmlElement eUnit in document.SelectNodes("/sequences/unit"))
				LoadSequencesForUnit(eUnit);

			foreach (XmlElement eCursor in document.SelectNodes("/sequences/cursor"))
				LoadSequencesForCursor(eCursor);
		}

		static void LoadSequencesForCursor(XmlElement eCursor)
		{
			string cursorSrc = eCursor.GetAttribute("src");

			foreach (XmlElement eSequence in eCursor.SelectNodes("./sequence"))
				cursors.Add(eSequence.GetAttribute("name"), new CursorSequence(cursorSrc, eSequence));

		}

		static void LoadSequencesForUnit(XmlElement eUnit)
		{
			string unitName = eUnit.GetAttribute("name");
			try {
				var sequences = eUnit.SelectNodes("./sequence").OfType<XmlElement>()
					.Select(e => new Sequence(unitName, e))
					.ToDictionary(s => s.Name);
				
				units.Add(unitName, sequences);
			} catch (FileNotFoundException) {} // Do nothing; we can crash later if we actually wanted art	
		}

		public static Sequence GetSequence(string unitName, string sequenceName)
		{
			try { return units[unitName][sequenceName]; }
			catch (KeyNotFoundException)
			{
				throw new InvalidOperationException(
					"Unit `{0}` does not have a sequence `{1}`".F(unitName, sequenceName));
			}
		}

		public static bool HasSequence(string unit, string seq)
		{
			return units[unit].ContainsKey(seq);
		}

		public static CursorSequence GetCursorSequence(string cursor)
		{
			try { return cursors[cursor]; }
			catch (KeyNotFoundException)
			{
				throw new InvalidOperationException(
					"Cursor does not have a sequence `{0}`".F(cursor));
			}
		}
	}
}
