using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using IjwFramework.Types;
using System.Drawing;
using OpenRa.Game.Traits;

namespace OpenRa.Game
{
	class Controller
	{
		public IOrderGenerator orderGenerator;

		void ApplyOrders(float2 xy, bool left)
		{
			var doVoice = true;
			if (orderGenerator != null)
				foreach (var order in orderGenerator.Order(xy.ToInt2(), left))
				{
					order.Apply(doVoice);
					doVoice = false;
				}
		}

        float2 dragStart, dragEnd;
		public void HandleMouseInput(MouseInput mi)
		{
            var xy = Game.viewport.ViewToWorld(mi);

            if (mi.Button == MouseButtons.Left && mi.Event == MouseInputEvent.Down)
            {
				if (!(orderGenerator is PlaceBuilding))
					dragStart = dragEnd = xy;
				ApplyOrders(xy, true);
            }

            if (mi.Button == MouseButtons.Left && mi.Event == MouseInputEvent.Move)
				dragEnd = xy;

            if (mi.Button == MouseButtons.Left && mi.Event == MouseInputEvent.Up)
            {
				if (!(orderGenerator is PlaceBuilding))
				{
					if (dragStart != xy)
						orderGenerator = new UnitOrderGenerator( 
							Game.SelectUnitsInBox( Game.CellSize * dragStart, Game.CellSize * xy ) );
					else
						orderGenerator = new UnitOrderGenerator( 
							Game.SelectUnitOrBuilding( Game.CellSize * xy ) );
				}

				dragStart = dragEnd = xy;
            }

            if (mi.Button == MouseButtons.None && mi.Event == MouseInputEvent.Move)
            {
                /* update the cursor to reflect the thing under us - note this 
                 * needs to also happen when the *thing* changes, so per-frame hook */
				dragStart = dragEnd = xy;
            }

			if (mi.Button == MouseButtons.Right && mi.Event == MouseInputEvent.Down)
				ApplyOrders(xy, false);
		}

        public Pair<float2, float2>? SelectionBox
        {
			get
			{
				if (dragStart == dragEnd) return null;
				return Pair.New(Game.CellSize * dragStart, Game.CellSize * dragEnd);
			}
        }

		public Cursor ChooseCursor()
		{
			var uog = orderGenerator as UnitOrderGenerator;

			if (uog != null)
				uog.selection.RemoveAll(a => a.IsDead);

			if (uog != null && uog.selection.Count > 0 
				&& uog.selection.Any(a => a.traits.Contains<Traits.Mobile>()) 
				&& uog.selection.All( a => a.Owner == Game.LocalPlayer ))
			{
				var umts = uog.selection.Select(a => a.traits.GetOrDefault<Mobile>())
					.Where(m => m != null)
					.Select(m => m.GetMovementType())
					.Distinct();

				if (!umts.Any( umt => Game.IsCellBuildable( dragEnd.ToInt2(), umt ) ))
					return Cursor.MoveBlocked;
				return Cursor.Move;
			}

			if (Game.SelectUnitOrBuilding(Game.CellSize * dragEnd).Any())
				return Cursor.Select;
			
			return Cursor.Default;
		}
	}
}