/* 
 * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; version 2 of the
 * License.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */

// Layout contained views vertically. Width of subviews will be adjusted to the same as parent
// Height will be taken from the subviews themselves. Will resize to fit the height of all subviews.

#import "MVerticalLayoutView.h"

@interface NSView(NSView_Extras)
@property (readonly) NSSize minimumSize;
- (BOOL)expandsOnLayoutVertically:(BOOL)vertically;
@end

@implementation MVerticalLayoutView

- (instancetype)initWithFrame:(NSRect)frameRect
{
  self = [super initWithFrame: frameRect];
  if (self)
  {
    expandsByDefault = YES;
    minimumHeight = 100;
  }
  return self;
}

- (void)dealloc
{
  [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)setSpacing:(float)spc
{
  spacing= spc;
  [self tile];
}

- (void)setPaddingLeft:(float)lpad right:(float)rpad top:(float)tpad bottom:(float)bpad
{
  leftPadding = lpad;
  rightPadding = rpad;
  topPadding = tpad;
  bottomPadding = bpad;
  [self tile];
}

- (void)setExpandSubviewsByDefault:(BOOL)flag
{
  expandsByDefault = flag;
  [self tile];
}

- (BOOL)_subviewShouldExpand:(NSView*)view
{
  if ([view respondsToSelector: @selector(expandsOnLayoutVertically:)])
    return [view expandsOnLayoutVertically: YES];
  else
    return expandsByDefault;
}

- (void)tile
{
  float width = NSWidth([self frame]) - leftPadding - rightPadding;
  float availableHeight;
  float y;
  int expandable = 0;
  float extraSpacePerItem = 0;
  
  if (relayouting)
    return;
  relayouting= YES;
  
  if ([[self subviews] count] > 0)
    minimumHeight = spacing * ([[self subviews] count]-1) + topPadding + bottomPadding;
  else
    minimumHeight = 0;

  for (id view in [self subviews])
  {
    float minHeight;
    if (![view isHidden])
    {
      BOOL expands = [self _subviewShouldExpand: view];
      
      if ([view respondsToSelector: @selector(tile)])
          [view tile];
      
      if ([view respondsToSelector: @selector(minimumSize)])
        minHeight = [view minimumSize].height;
      else
        minHeight = 1;
      
      if (!expands)
        minimumHeight += MAX(NSHeight([view frame]), minHeight);
      else
      {
        minimumHeight += minHeight;
        expandable++;
      }
    }
  }

  availableHeight= NSHeight([self frame]);
  if (!expandsByDefault)
    [self setFrameSize:NSMakeSize(NSWidth([self frame]), MAX(minimumHeight, availableHeight))];

  if (availableHeight > minimumHeight && expandable > 0)
    extraSpacePerItem = (availableHeight - minimumHeight) / expandable;
  else
    extraSpacePerItem = 0;
  y= NSHeight([self frame]) - topPadding;
  for (id view in [self subviews])
  {
    if (![view isHidden])
    {
      float height = NSHeight([view frame]);
      
      if ([self _subviewShouldExpand: view])
      {
        if ([view respondsToSelector: @selector(minimumSize)])
          height = MAX(extraSpacePerItem, [view minimumSize].height);
        else
          height = extraSpacePerItem;
      }

      height = MAX(1, height);

      y-= height;
      [view setFrame: NSMakeRect(leftPadding, y, width, height)];
      y -= spacing;
    }
  }
  [self setNeedsDisplay:YES];
  
  relayouting= NO;
}


- (void)resizeWithOldSuperviewSize:(NSSize)oldBoundsSize
{
  NSRect superBounds = [[self superview] bounds];
  NSRect frame = [self frame];
  float leftMargin = NSMinX(frame);
  float bottomMargin = NSMinY(frame);
  float rightMargin = oldBoundsSize.width - NSMaxX(frame);
  float topMargin = oldBoundsSize.height - NSMaxY(frame);
  
  frame = NSMakeRect(leftMargin, bottomMargin, 
                     NSWidth(superBounds) - (leftMargin + rightMargin), 
                     NSHeight(superBounds) - (topMargin + bottomMargin));
  [self setFrame: frame];
  [self tile];
}


- (void)resizeSubviewsWithOldSize:(NSSize)oldSize
{
  NSRect frame= [self frame];
  if (minimumHeight > frame.size.height)
  {
    frame.size.height= minimumHeight;
    [self setFrame: frame];
  }
  [self tile];
}


- (void)childFrameChanged:(NSNotification*)notif
{
  [self tile];
}


- (void)didAddSubview:(NSView*)subview
{
  [subview setPostsFrameChangedNotifications:YES];
  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(childFrameChanged:)
                                               name:NSViewFrameDidChangeNotification
                                             object:subview];
  
  [super didAddSubview:subview];
  
  [self tile];
}

- (void)setBackgroundColor: (NSColor*)color
{
  backColor= color;
}

- (void)drawRect:(NSRect)rect
{
  if (backColor)
  {
    [backColor set];
    NSRectFill(rect);
  }
}


- (BOOL)expandsOnLayoutVertically:(BOOL)vertically
{
  if (vertically)
    return expandsByDefault;
  return YES;
}

@end
