using System;

namespace HRD.Core
{
	public class VChessman : Chessman
	{
		public VChessman(Position position):base(position)
		{
		}

		#region Private Functions

		private bool CanMoveUp(BlankPosition _blankPosition)
		{
			if(_blankPosition.IsBlank(_position.x , _position.y - 1))
			{
				// 設置棋子新位置
				_newPosition.x = _position.x;
				_newPosition.y = _position.y - 1;

				// 設置新的空白位置
				if(_blankPosition.Pos1.x == _position.x && _blankPosition.Pos1.y == _position.y - 1)
				{
					_newBlankPosition.Pos1.x = _position.x;
					_newBlankPosition.Pos1.y = _position.y + 1;
					_newBlankPosition.Pos2 = _blankPosition.Pos2;
				}
				else
				{
					_newBlankPosition.Pos1 = _blankPosition.Pos1;
					_newBlankPosition.Pos2.x = _position.x;
					_newBlankPosition.Pos2.y = _position.y + 1;
				}
				
				return true;
			}

			return false;
		}

		private bool CanMoveDown(BlankPosition _blankPosition)
		{
			if(_blankPosition.IsBlank(_position.x , _position.y + 2))
			{
				// 設置棋子新位置
				_newPosition.x = _position.x;
				_newPosition.y = _position.y + 1;

				// 設置新的空白位置
				if(_blankPosition.Pos1.x == _position.x && _blankPosition.Pos1.y == _position.y + 2)
				{
					_newBlankPosition.Pos1 = _position;
					_newBlankPosition.Pos2.x = _blankPosition.Pos2.x;
					_newBlankPosition.Pos2.y = _blankPosition.Pos2.y;
				}
				else
				{
					_newBlankPosition.Pos1.x = _blankPosition.Pos1.x;
					_newBlankPosition.Pos1.y = _blankPosition.Pos1.y;
					_newBlankPosition.Pos2 = _position;
				}
				
				return true;
			}

			return false;
		}

		private bool CanMoveLeft(BlankPosition _blankPosition)
		{
			if(_blankPosition.IsBlank(_position.x - 1 , _position.y) && _blankPosition.IsBlank(_position.x - 1, _position.y + 1))
			{
				// 設置棋子新位置
				_newPosition.x = _position.x - 1;
				_newPosition.y = _position.y;

				// 設置新的空白位置
				_newBlankPosition.Pos1 = _position;
				_newBlankPosition.Pos2.x = _position.x;
				_newBlankPosition.Pos2.y = _position.y + 1;
				
				return true;
			}

			return false;
		}

		private bool CanMoveRight(BlankPosition _blankPosition)
		{
			if(_blankPosition.IsBlank(_position.x + 1 , _position.y) && _blankPosition.IsBlank(_position.x + 1, _position.y + 1))
			{
				// 設置棋子新位置
				_newPosition.x = _position.x + 1;
				_newPosition.y = _position.y;

				// 設置新的空白位置
				_newBlankPosition.Pos1 = _position;
				_newBlankPosition.Pos2.x = _position.x;
				_newBlankPosition.Pos2.y = _position.y + 1;
				
				return true;
			}

			return false;
		}

		private bool CanMoveUp2(BlankPosition _blankPosition)
		{
			if(_blankPosition.IsBlank(_position.x , _position.y - 2) && _blankPosition.IsBlank(_position.x , _position.y - 1))
			{
				// 設置棋子新位置
				_newPosition.x = _position.x;
				_newPosition.y = _position.y - 2;

				// 設置新的空白位置
				_newBlankPosition.Pos1 = _position;
				_newBlankPosition.Pos2.x = _position.x;
				_newBlankPosition.Pos2.y = _position.y + 1;
				
				return true;
			}

			return false;
		}

		private bool CanMoveDown2(BlankPosition _blankPosition)
		{
			if(_blankPosition.IsBlank(_position.x , _position.y + 2) && _blankPosition.IsBlank(_position.x , _position.y + 3))
			{
				// 設置棋子新位置
				_newPosition.x = _position.x;
				_newPosition.y = _position.y + 2;

				// 設置新的空白位置
				_newBlankPosition.Pos1 = _position;
				_newBlankPosition.Pos2.x = _position.x;
				_newBlankPosition.Pos2.y = _position.y + 1;
				
				return true;
			}

			return false;
		}

		#endregion

		public override ChessmanType chessmanType
		{
			get 
			{
				return ChessmanType.VChessman;
			}
		}

		public override void CheckAvailableSteps(BlankPosition _blankPosition, CallBackDelegate _callback)
		{
			if(CanMoveLeft(_blankPosition))
				_callback(_newPosition, _newBlankPosition, MoveMethod.Left);

			if(CanMoveRight(_blankPosition))
				_callback(_newPosition, _newBlankPosition, MoveMethod.Right);

			if(CanMoveUp(_blankPosition))
				_callback(_newPosition, _newBlankPosition, MoveMethod.Up);

			if(CanMoveDown(_blankPosition))
				_callback(_newPosition, _newBlankPosition, MoveMethod.Down);

			if(CanMoveUp2(_blankPosition))
				_callback(_newPosition, _newBlankPosition, MoveMethod.Up2);

			if(CanMoveDown2(_blankPosition))
				_callback(_newPosition, _newBlankPosition, MoveMethod.Down2);

			return;
		}
	}
}