using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using OpenRa.Game.Traits;
using System.IO;

namespace OpenRa.Game
{
	sealed class Order
	{
		public readonly Player Player;
		public readonly string OrderString;
		public readonly Actor Subject;
		public readonly Actor TargetActor;
		public readonly int2 TargetLocation;
		public readonly string TargetString;

		private Order( Player player, string orderString, Actor subject, Actor targetActor, int2 targetLocation, string targetString )
		{
			this.Player = player;
			this.OrderString = orderString;
			this.Subject = subject;
			this.TargetActor = targetActor;
			this.TargetLocation = targetLocation;
			this.TargetString = targetString;
		}

		public byte[] Serialize()
		{
			switch( OrderString )
			{
			// Format:
			//		u32   : player, with msb set. (if msb is clear, not an order)
			//		u8    : orderID.
			//		            0xFF: Full serialized order.
			//		varies: rest of order.
			default:
				// TODO: specific serializers for specific orders.
				{
					var ret = new MemoryStream();
					var w = new BinaryWriter(ret);
					w.Write( (uint)Player.Palette | 0x80000000u );
					w.Write( (byte)0xFF ); // 
					w.Write( OrderString );
					w.Write( Subject == null ? 0xFFFFFFFF : Subject.ActorID );
					w.Write( TargetActor == null ? 0xFFFFFFFF : TargetActor.ActorID );
					w.Write( TargetLocation.X );
					w.Write( TargetLocation.Y );
					w.Write( TargetString != null );
					if( TargetString != null )
						w.Write( TargetString );
					return ret.ToArray();
				}
			}
		}

		public static Order Deserialize( BinaryReader r, uint first )
		{
			if( ( first >> 31 ) == 0 ) return null;

			var player = Game.players.Where( x => x.Value.Palette == (first & 0x7FFFFFFF) ).First().Value;
			switch( r.ReadByte() )
			{
			case 0xFF:
				{
					var order = r.ReadString();
					var subject = ActorFromUInt( r.ReadUInt32() );
					var targetActor = ActorFromUInt( r.ReadUInt32() );
					var targetLocation = new int2( r.ReadInt32(), 0 );
					targetLocation.Y = r.ReadInt32();
					var targetString = null as string;
					if( r.ReadBoolean() )
						targetString = r.ReadString();
					return new Order( player, order, subject, targetActor, targetLocation, targetString );
				}
			default:
				throw new NotImplementedException();
			}
		}

		static Actor ActorFromUInt( uint aID )
		{
			if( aID == 0xFFFFFFFF ) return null;
			return Game.world.Actors.Where( x => x.ActorID == aID ).First();
		}

		public static Order Attack( Actor subject, Actor target )
		{
			return new Order( subject.Owner, "Attack", subject, target, int2.Zero, null );
		}

		public static Order Move( Actor subject, int2 target )
		{
			return new Order( subject.Owner, "Move", subject, null, target, null );
		}

		public static Order DeployMcv( Actor subject )
		{
			return new Order( subject.Owner, "DeployMcv", subject, null, int2.Zero, null );
		}

		public static Order PlaceBuilding( Player subject, int2 target, string buildingName )
		{
			return new Order( subject, "PlaceBuilding", null, null, target, buildingName );
		}
	}
}