@author mr.doob / http://mrdoob.com/

Ported to Dart from JS by: @author rob silverton / http://www.unwrong.com/

class Rectangle {
 num _left, _top, _right, _bottom, _width, _height;
 bool _isEmpty;

 Rectangle()
     : _left = 0,
       _top = 0,
       _right = 0,
       _bottom = 0,
       _width = 0,
       _height = 0,
       _isEmpty = true;

 resize() {
   _width = _right - _left;
   _height = _bottom - _top;
 }

 num getX() => _left;
 num getY() => _top;
 num getWidth() => _width;
 num getHeight() => _height;
 num getLeft() => _left;
 num getTop() => _top;
 num getRight() => _right;
 num getBottom() => _bottom;

 setValues( num left, num top, num right, num bottom ) {
   _isEmpty = false;

   _left = left; _top = top;
   _right = right; _bottom = bottom;

   resize();
 }

 addPoint( num x, num y ) {
   if ( _isEmpty ) {
     _isEmpty = false;
     _left = x; _top = y;
     _right = x; _bottom = y;

     resize();
   } else {
     _left = _left < x ? _left : x; // Math.min( _left, x );
     _top = _top < y ? _top : y; // Math.min( _top, y );
     _right = _right > x ? _right : x; // Math.max( _right, x );
     _bottom = _bottom > y ? _bottom : y; // Math.max( _bottom, y );

     resize();
   }
 }

 add3Points( num x1, num y1, num x2, num y2, num x3, num y3 ) {
   if (_isEmpty) {
     _isEmpty = false;
     _left = x1 < x2 ? ( x1 < x3 ? x1 : x3 ) : ( x2 < x3 ? x2 : x3 );
     _top = y1 < y2 ? ( y1 < y3 ? y1 : y3 ) : ( y2 < y3 ? y2 : y3 );
     _right = x1 > x2 ? ( x1 > x3 ? x1 : x3 ) : ( x2 > x3 ? x2 : x3 );
     _bottom = y1 > y2 ? ( y1 > y3 ? y1 : y3 ) : ( y2 > y3 ? y2 : y3 );

     resize();
   } else {
     _left = x1 < x2 ? ( x1 < x3 ? ( x1 < _left ? x1 : _left ) : ( x3 < _left ? x3 : _left ) ) : ( x2 < x3 ? ( x2 < _left ? x2 : _left ) : ( x3 < _left ? x3 : _left ) );
     _top = y1 < y2 ? ( y1 < y3 ? ( y1 < _top ? y1 : _top ) : ( y3 < _top ? y3 : _top ) ) : ( y2 < y3 ? ( y2 < _top ? y2 : _top ) : ( y3 < _top ? y3 : _top ) );
     _right = x1 > x2 ? ( x1 > x3 ? ( x1 > _right ? x1 : _right ) : ( x3 > _right ? x3 : _right ) ) : ( x2 > x3 ? ( x2 > _right ? x2 : _right ) : ( x3 > _right ? x3 : _right ) );
     _bottom = y1 > y2 ? ( y1 > y3 ? ( y1 > _bottom ? y1 : _bottom ) : ( y3 > _bottom ? y3 : _bottom ) ) : ( y2 > y3 ? ( y2 > _bottom ? y2 : _bottom ) : ( y3 > _bottom ? y3 : _bottom ) );

     resize();
   }
 }

 addRectangle( Rectangle r ) {
   if ( _isEmpty )
   {
     _isEmpty = false;
     _left = r.getLeft(); _top = r.getTop();
     _right = r.getRight(); _bottom = r.getBottom();

     resize();
   } else {
     _left = _left < r.getLeft() ? _left : r.getLeft(); // Math.min(_left, r.getLeft() );
     _top = _top < r.getTop() ? _top : r.getTop(); // Math.min(_top, r.getTop() );
     _right = _right > r.getRight() ? _right : r.getRight(); // Math.max(_right, r.getRight() );
     _bottom = _bottom > r.getBottom() ? _bottom : r.getBottom(); // Math.max(_bottom, r.getBottom() );

     resize();
   }
 }

 inflate( num v ) {
   _left -= v; _top -= v;
   _right += v; _bottom += v;

   resize();
 }

 minSelf( Rectangle r ) {
   _left = _left > r.getLeft() ? _left : r.getLeft(); // Math.max( _left, r.getLeft() );
   _top = _top > r.getTop() ? _top : r.getTop(); // Math.max( _top, r.getTop() );
   _right = _right < r.getRight() ? _right : r.getRight(); // Math.min( _right, r.getRight() );
   _bottom = _bottom < r.getBottom() ? _bottom : r.getBottom(); // Math.min( _bottom, r.getBottom() );

   resize();
 }

 bool intersects ( Rectangle r ) {
   // http://gamemath.com/2011/09/detecting-whether-two-boxes-overlap/

   if ( _right < r.getLeft() ) return false;
   if ( _left > r.getRight() ) return false;
   if ( _bottom < r.getTop() ) return false;
   if ( _top > r.getBottom() ) return false;

   return true;
 }

 empty() {
   _isEmpty = true;

   _left = 0; _top = 0;
   _right = 0; _bottom = 0;

   resize();
 }

 bool get isEmpty => _isEmpty;

}