#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.Reflection;

namespace OpenRA.FileFormats
{
	public static class FieldLoader
	{
		public static void Load(object self, IniSection ini)
		{
			foreach (var x in ini)
				LoadField(self, x.Key, x.Value);
		}

		public static void Load(object self, MiniYaml my)
		{
			foreach (var x in my.Nodes)
				if (!x.Key.StartsWith("-"))
					LoadField( self, x.Key, x.Value.Value );
		}

		public static T Load<T>(MiniYaml y) where T : new()
		{
			var t = new T();
			Load(t, y);
			return t;
		}
		
		public static void LoadFields( object self, Dictionary<string,MiniYaml> my, IEnumerable<string> fields )
		{
			foreach (var field in fields)
			{
				if (!my.ContainsKey(field)) continue;
				FieldLoader.LoadField(self,field,my[field].Value);
			}
		}

		public static void LoadField( object self, string key, string value )
		{
			var field = self.GetType().GetField( key.Trim() );
			if( field == null )
				throw new NotImplementedException( "Missing field `{0}` on `{1}`".F( key.Trim(), self.GetType().Name ) );
			field.SetValue( self, GetValue( field.FieldType, value ) );
		}

		public static object GetValue( Type fieldType, string x )
		{
			if (x != null) x = x.Trim();
			if( fieldType == typeof( int ) )
				return int.Parse( x );
			
			else if( fieldType == typeof( ushort ) )
				return ushort.Parse( x );

			else if (fieldType == typeof(float))
				return float.Parse(x.Replace("%","")) * (x.Contains( '%' ) ? 0.01f : 1f);

			else if (fieldType == typeof(string))
				return x;
			
			else if (fieldType == typeof(System.Drawing.Color))
			{
				var parts = x.Split(',');
				return System.Drawing.Color.FromArgb(int.Parse(parts[0]), int.Parse(parts[1]), int.Parse(parts[2]));
			}
			
			else if (fieldType.IsEnum)
				return Enum.Parse(fieldType, x, true);

			else if (fieldType == typeof(bool))
				return ParseYesNo(x);

			else if (fieldType.IsArray)
			{
				if (x == null)
					return Array.CreateInstance(fieldType.GetElementType(), 0);

				var parts = x.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);

				var ret = Array.CreateInstance(fieldType.GetElementType(), parts.Length);
				for (int i = 0; i < parts.Length; i++)
					ret.SetValue(GetValue(fieldType.GetElementType(), parts[i].Trim()), i);
				return ret;
			}
			else if (fieldType == typeof(int2))
			{
				var parts = x.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
				return new int2(int.Parse(parts[0]), int.Parse(parts[1]));
			}
			else
				throw new InvalidOperationException("FieldLoader: don't know how to load field of type " + fieldType.ToString());
		}

		static bool ParseYesNo( string p )
		{
			p = p.ToLowerInvariant();
			if( p == "yes" ) return true;
			if( p == "true" ) return true;
			if( p == "no" ) return false;
			if( p == "false" ) return false;
			throw new InvalidOperationException();
		}
	}

	public static class FieldSaver
	{
		public static MiniYaml Save(object o)
		{
			return new MiniYaml(null, o.GetType().GetFields(BindingFlags.Public | BindingFlags.Instance)
				.ToDictionary(
					f => f.Name,
					f => new MiniYaml(FormatValue(o, f))));
		}
		
		public static MiniYaml SaveDifferences(object o, object from)
		{
			if (o.GetType() != from.GetType())
				throw new InvalidOperationException("FieldLoader: can't diff objects of different types");

			var fields = o.GetType().GetFields(BindingFlags.Public | BindingFlags.Instance)
				.Where(f => FormatValue(o,f) != FormatValue(from,f));
			
			return new MiniYaml(null, fields.ToDictionary(
					f => f.Name,
					f => new MiniYaml(FormatValue(o, f))));
		}

		public static string FormatValue(object o, FieldInfo f)
		{
			var v = f.GetValue(o);
			if (v == null)
				return "";

			return f.FieldType.IsArray
				? string.Join(",", ((Array)v).OfType<object>().Select(a => a.ToString()).ToArray())
				: v.ToString();
		}
	}
}