package com.atlassian.selenium.visualcomparison.utils;
   
   import com.atlassian.annotations.Internal;
   
   import java.util.ArrayList;
   import java.util.List;
   
   @Internal
   public class BoundingBox
  {
      private int left;
      private int top;
      private int right;
      private int bottom;
  
      private int leftMargin;
      private int topMargin;
      private int rightMargin;
      private int bottomMargin;
      private static final int MARGIN = 25;
  
      public BoundingBox(int x, int y)
      {
          this(x, y, x, y);
      }
  
      public BoundingBox(int left, int top, int right, int bottom)
      {
          setLeft(left);
          setTop(top);
          setRight(right);
          setBottom(bottom);
      }
  
      // Although the margin values are derived values, let's cache them because we'll be using them
      // far more often than we set them.
      private void setLeft(int left)
      {
          this.left = left;
          this.leftMargin = left - MARGIN;
      }
  
      private void setRight(int right)
      {
          this.right = right;
          this.rightMargin = right + MARGIN;
      }
  
      private void setTop(int top)
      {
          this.top = top;
          this.topMargin = top - MARGIN;
      }
  
      private void setBottom(int bottom)
      {
          this.bottom = bottom;
          this.bottomMargin = bottom + MARGIN;
      }
  
      public int getLeft()
      {
          return left;
      }
  
      public int getTop()
      {
          return top;
      }
  
      public int getRight()
      {
          return right;
      }
  
      public int getBottom()
      {
          return bottom;
      }
  
      public int getWidth()
      {
          return right - left + 1;
      }
  
      public int getHeight()
      {
          return bottom - top + 1;
      }
  
      // Accessor functions for the box's margins that restrict them to fit within the image.
      public int getMarginLeft()
      {
          return Math.max(left - MARGIN, 0);
      }
  
      public int getMarginTop()
      {
          return Math.max(top - MARGIN, 0);
     }
 
     public int getMarginRight(int maxX)
     {
         return Math.min(right + MARGIN, maxX);
     }
 
     public int getMarginBottom(int maxY)
     {
         return Math.min(bottom + MARGIN, maxY);
     }
 
     public int getMarginWidth(int maxX)
     {
         return getMarginRight(maxX) - getMarginLeft() + 1;
     }
 
     public int getMarginHeight(int maxY)
     {
         return getMarginBottom(maxY) - getMarginTop() + 1;
     }
 
     public boolean contains (int x, int y)
     {
         // Return true if the given co-ords are within this box.
         return ((x >= left) && (x <= right) &&
                 (y >= top) && (y <= bottom));
     }
 
     public boolean isNear(int x, int y)
     {
         // Return true if the given co-ords are within this box, or within the given margin of it.
         return ((x >= leftMargin) && (x <= rightMargin) &&
                 (y >= topMargin) && (y <= bottomMargin));
     }
 
     public boolean isNear(BoundingBox box)
     {
         // If any of this box's corners are near the other box, or any of the other box's corners are
         // near this box, then the boxes overlap or are very close.
         return (box.isNear(left, top) || box.isNear(right, top) ||
                 box.isNear(left, bottom) || box.isNear(right, bottom) ||
                 isNear(box.left, box.top) || isNear(box.right, box.top) ||
                 isNear(box.left, box.bottom) || isNear(box.right, box.bottom));
     }
 
     public void merge(int x, int y)
     {
         // Expand this box to contain the given co-ords.
         if (x < left)
         {
             setLeft(x);
         }
         if (x > right)
         {
             setRight(x);
         }
         if (y < top)
         {
             setTop(y);
         }
         if (y > bottom)
         {
             setBottom(y);
         }
     }
 
     public void merge(BoundingBox box)
     {
         // Expand this box to contain the given box.
         merge(box.left, box.top);
         merge(box.right, box.bottom);
     }
 
     public static void mergeOverlappingBoxes(ArrayList<BoundingBox> boxes)
     {
         // This is very messy. The basic idea is to merge all boxes that overlap.
         // The current approach (until I think of a better one) is to compare every box
         // in the array with every box after it, and keep iterating over the whole
         // array until there are no longer any overlaps. The outer loop is needed because
         // merging two boxes could bring the combined box into conflict with a box we've
         // already checked.
         boolean mergePerformedThisLoop;
         do
         {
             mergePerformedThisLoop = false;
             for (int iCurrent = 0; iCurrent < boxes.size(); iCurrent++)
             {
                 BoundingBox current = boxes.get(iCurrent);
                 for (int iOther = iCurrent + 1; iOther < boxes.size();)
                 {
                     if (current.isNear(boxes.get(iOther)))
                     {
                         current.merge(boxes.get(iOther));
                         boxes.remove(iOther);
                         mergePerformedThisLoop = true;
                     }
                     else
                     {
                         iOther++;
                     }
                 }
             }
         }
         while (mergePerformedThisLoop);
     }
 
     public static void deleteSingleLineBoxes(List<BoundingBox> boxes)
     {
         // Remove any changes that are only one pixel wide or high
         for (int i = 0; i < boxes.size(); )
         {
             BoundingBox box = boxes.get(i);
             if (box.getWidth() == 1 || box.getHeight() == 1)
             {
                 boxes.remove(i);
             }
             else
             {
                 i++;
             }
         }
     }
 }