package snapfit.shape 
{
	/**
	* ...
	* @author nutsu
	*/
	public class PathLine implements IPath
	{
		//start point
		private var _x0:Number;
		private var _y0:Number;
		
		//end point
		private var _x1:Number;
		private var _y1:Number;
		
		//length
		private var _length:Number;
		
		
		public function PathLine( x0:Number, y0:Number, x1:Number, y1:Number ) 
		{
			_x0 = x0;
			_y0 = y0;
			_x1 = x1;
			_y1 = y1;
			_length = -1;
		}
		
		public function clone():PathLine
		{
			return new PathLine( _x0, _y0, _x1, _y1 );
		}
		
		public function f( t:Number ):PathPoint
		{
			return new PathPoint( _x0 + ( _x1 - _x0 ) * t, _y0 + ( _y1 - _y0 ) * t );
		}
		
		public function diff( t:Number ):PathPoint
		{
			return new PathPoint( ( _x1 - _x0 ), ( _y1 - _y0 ) );
		}
		
		public function vector( t:Number ):PathVector
		{
			return new PathVector( _x0 + ( _x1 - _x0 ) * t, _y0 + ( _y1 - _y0 ) * t, ( _x1 - _x0 ), ( _y1 - _y0 ) );
		}
		
		public function lengthToPoint( len:Number ):PathPoint
		{
			return f( lengthToValue( len ) );
		}
		
		public function lengthToValue( len:Number ):Number
		{
			return len/length;
		}
		
		public function get length():Number
		{
			return Math.sqrt( ( _x1 - _x0 ) * ( _x1 - _x0 ) + ( _y1 - _y0 ) * ( _y1 - _y0 ) );
		}
		
		public function get x0():Number{ return _x0; }
		public function set x0(v:Number):void
		{
			_x0 = v; _length = -1;
		}
		
		public function get y0():Number{ return _y0; }
		public function set y0(v:Number):void
		{
			_y0 = v; _length = -1;
		}
		public function get x1():Number{ return _x1; }
		public function set x1(v:Number):void
		{
			_x1 = v; _length = -1;
		}
		
		public function get y1():Number{ return _y1; }
		public function set y1(v:Number):void
		{
			_y1 = v; _length = -1;
		}
	}
	
}