// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#import "chrome/browser/cocoa/tab_strip_view.h"

#include "base/logging.h"

@implementation TabStripView

@synthesize newTabButton = newTabButton_;
@synthesize dropArrowShown = dropArrowShown_;
@synthesize dropArrowPosition = dropArrowPosition_;

- (id)initWithFrame:(NSRect)frame {
  self = [super initWithFrame:frame];
  if (self) {
    // Set lastMouseUp_ = -1000.0 so that timestamp-lastMouseUp_ is big unless
    // lastMouseUp_ has been reset.
    lastMouseUp_ = -1000.0;

    // Register to be an URL drop target.
    dropHandler_.reset([[URLDropTargetHandler alloc] initWithView:self]);
  }
  return self;
}

- (void)drawRect:(NSRect)rect {
  NSRect boundsRect = [self bounds];
  NSRect borderRect, contentRect;
  NSDivideRect(boundsRect, &borderRect, &contentRect, 1, NSMinYEdge);
  [[NSColor colorWithCalibratedWhite:0.0 alpha:0.2] set];

  NSRectFillUsingOperation(borderRect, NSCompositeSourceOver);

  // Draw drop-indicator arrow (if appropriate).
  // TODO(viettrungluu): this is all a stop-gap measure.
  if ([self dropArrowShown]) {
    // Programmer art: an arrow parametrized by many knobs. Note that the arrow
    // points downwards (so understand "width" and "height" accordingly).

    // How many (pixels) to inset on the top/bottom.
    const CGFloat kArrowTopInset = 1.5;
    const CGFloat kArrowBottomInset = 1;

    // What proportion of the vertical space is dedicated to the arrow tip,
    // i.e., (arrow tip height)/(amount of vertical space).
    const CGFloat kArrowTipProportion = 0.5;

    // This is a slope, i.e., (arrow tip height)/(0.5 * arrow tip width).
    const CGFloat kArrowTipSlope = 1.2;

    // What proportion of the arrow tip width is the stem, i.e., (stem
    // width)/(arrow tip width).
    const CGFloat kArrowStemProportion = 0.33;

    NSPoint arrowTipPos = [self dropArrowPosition];
    arrowTipPos.y += kArrowBottomInset;  // Inset on the bottom.

    // Height we have to work with (insetting on the top).
    CGFloat availableHeight =
        NSMaxY([self bounds]) - arrowTipPos.y - kArrowTopInset;
    DCHECK(availableHeight >= 5);

    // Based on the knobs above, calculate actual dimensions which we'll need
    // for drawing.
    CGFloat arrowTipHeight = kArrowTipProportion * availableHeight;
    CGFloat arrowTipWidth = 2 * arrowTipHeight / kArrowTipSlope;
    CGFloat arrowStemHeight = availableHeight - arrowTipHeight;
    CGFloat arrowStemWidth = kArrowStemProportion * arrowTipWidth;
    CGFloat arrowStemInset = (arrowTipWidth - arrowStemWidth) / 2;

    // The line width is arbitrary, but our path really should be mitered.
    NSBezierPath* arrow = [NSBezierPath bezierPath];
    [arrow setLineJoinStyle:NSMiterLineJoinStyle];
    [arrow setLineWidth:1];

    // Define the arrow's shape! We start from the tip and go clockwise.
    [arrow moveToPoint:arrowTipPos];
    [arrow relativeLineToPoint:NSMakePoint(-arrowTipWidth / 2, arrowTipHeight)];
    [arrow relativeLineToPoint:NSMakePoint(arrowStemInset, 0)];
    [arrow relativeLineToPoint:NSMakePoint(0, arrowStemHeight)];
    [arrow relativeLineToPoint:NSMakePoint(arrowStemWidth, 0)];
    [arrow relativeLineToPoint:NSMakePoint(0, -arrowStemHeight)];
    [arrow relativeLineToPoint:NSMakePoint(arrowStemInset, 0)];
    [arrow closePath];

    // Draw and fill the arrow.
    [[NSColor colorWithCalibratedWhite:0 alpha:0.67] set];
    [arrow stroke];
    [[NSColor colorWithCalibratedWhite:1 alpha:0.67] setFill];
    [arrow fill];
  }
}

// We accept first mouse so clicks onto close/zoom/miniaturize buttons and
// title bar double-clicks are properly detected even when the window is in the
// background.
- (BOOL)acceptsFirstMouse:(NSEvent*)event {
  return YES;
}

// Trap double-clicks and make them miniaturize the browser window.
- (void)mouseUp:(NSEvent*)event {
  NSInteger clickCount = [event clickCount];
  NSTimeInterval timestamp = [event timestamp];

  // Double-clicks on Zoom/Close/Mininiaturize buttons shouldn't cause
  // miniaturization. For those, we miss the first click but get the second
  // (with clickCount == 2!). We thus check that we got a first click shortly
  // before (measured up-to-up) a double-click. Cocoa doesn't have a documented
  // way of getting the proper interval (= (double-click-threshold) +
  // (drag-threshold); the former is Carbon GetDblTime()/60.0 or
  // com.apple.mouse.doubleClickThreshold [undocumented]). So we hard-code
  // "short" as 0.8 seconds. (Measuring up-to-up isn't enough to properly
  // detect double-clicks, but we're actually using Cocoa for that.)
  if (clickCount == 2 && (timestamp - lastMouseUp_) < 0.8) {
    // We use an undocumented method in Cocoa; if it doesn't exist, default to
    // YES. If it ever goes away, we can do (using an undocumented pref. key):
    //   NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
    //   if (![defaults objectForKey:@"AppleMiniaturizeOnDoubleClick"]
    //       || [defaults boolForKey:@"AppleMiniaturizeOnDoubleClick"])
    //     [[self window] performMiniaturize:self];
    DCHECK([NSWindow
        respondsToSelector:@selector(_shouldMiniaturizeOnDoubleClick)]);
    if (![NSWindow
            respondsToSelector:@selector(_shouldMiniaturizeOnDoubleClick)]
        || [NSWindow
            performSelector:@selector(_shouldMiniaturizeOnDoubleClick)])
      [[self window] performMiniaturize:self];
  } else {
    [super mouseUp:event];
  }

  // If clickCount is 0, the drag threshold was passed.
  lastMouseUp_ = (clickCount == 1) ? timestamp : -1000.0;
}

// Required by |URLDropTargetHandler|.
- (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender {
  return [dropHandler_ draggingEntered:sender];
}

// Required by |URLDropTargetHandler|.
- (NSDragOperation)draggingUpdated:(id<NSDraggingInfo>)sender {
  return [dropHandler_ draggingUpdated:sender];
}

// Required by |URLDropTargetHandler|.
- (void)draggingExited:(id<NSDraggingInfo>)sender {
  return [dropHandler_ draggingExited:sender];
}

// Required by |URLDropTargetHandler|.
- (BOOL)performDragOperation:(id<NSDraggingInfo>)sender {
  return [dropHandler_ performDragOperation:sender];
}

@end