/*
 * Copyright (C) 2005, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "third_party/blink/renderer/core/editing/substring_util.h"

#import <Cocoa/Cocoa.h>

#include "base/mac/foundation_util.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/dom/element.h"
#include "third_party/blink/renderer/core/dom/node.h"
#include "third_party/blink/renderer/core/editing/editor.h"
#include "third_party/blink/renderer/core/editing/ephemeral_range.h"
#include "third_party/blink/renderer/core/editing/frame_selection.h"
#include "third_party/blink/renderer/core/editing/iterators/text_iterator.h"
#include "third_party/blink/renderer/core/editing/plain_text_range.h"
#include "third_party/blink/renderer/core/editing/selection_template.h"
#include "third_party/blink/renderer/core/editing/visible_selection.h"
#include "third_party/blink/renderer/core/editing/visible_units.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/frame/visual_viewport.h"
#include "third_party/blink/renderer/core/frame/web_frame_widget_impl.h"
#include "third_party/blink/renderer/core/html/html_element.h"
#include "third_party/blink/renderer/core/layout/hit_test_result.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/core/style/computed_style.h"
#include "third_party/blink/renderer/platform/fonts/font.h"
#include "third_party/blink/renderer/platform/mac/color_mac.h"

namespace blink {

namespace {

NSAttributedString* AttributedSubstringFromRange(const EphemeralRange& range,
                                                 float font_scale) {
  NSMutableAttributedString* string = [[NSMutableAttributedString alloc] init];
  NSMutableDictionary* attrs = [NSMutableDictionary dictionary];
  size_t length = range.EndPosition().ComputeOffsetInContainerNode() -
                  range.StartPosition().ComputeOffsetInContainerNode();

  unsigned position = 0;

  // TODO(editing-dev): The use of updateStyleAndLayout
  // needs to be audited.  see http://crbug.com/590369 for more details.
  range.StartPosition().GetDocument()->UpdateStyleAndLayout(
      DocumentUpdateReason::kEditing);

  for (TextIterator it(range.StartPosition(), range.EndPosition());
       !it.AtEnd() && [string length] < length; it.Advance()) {
    unsigned num_characters = it.length();
    if (!num_characters)
      continue;

    const Node& container = it.CurrentContainer();
    LayoutObject* layout_object = container.GetLayoutObject();
    DCHECK(layout_object);
    if (!layout_object)
      continue;

    const ComputedStyle* style = layout_object->Style();
    FontPlatformData font_platform_data =
        style->GetFont().PrimaryFont()->PlatformData();
    font_platform_data.text_size_ *= font_scale;
    NSFont* font = base::mac::CFToNSCast(font_platform_data.CtFont());
    // If the platform font can't be loaded, or the size is incorrect comparing
    // to the computed style, it's likely that the site is using a web font.
    // For now, just use the default font instead.
    // TODO(rsesek): Change the font activation flags to allow other processes
    // to use the font.
    // TODO(shuchen): Support scaling the font as necessary according to CSS
    // transforms, not just pinch-zoom.
    if (!font || floor(font_platform_data.size()) !=
                     floor([[font fontDescriptor] pointSize])) {
      font = [NSFont systemFontOfSize:style->GetFont()
                                          .GetFontDescription()
                                          .ComputedSize() *
                                      font_scale];
    }
    [attrs setObject:font forKey:NSFontAttributeName];

    if (style->VisitedDependentColor(GetCSSPropertyColor()).Alpha())
      [attrs
          setObject:NsColor(style->VisitedDependentColor(GetCSSPropertyColor()))
             forKey:NSForegroundColorAttributeName];
    else
      [attrs removeObjectForKey:NSForegroundColorAttributeName];
    if (style->VisitedDependentColor(GetCSSPropertyBackgroundColor()).Alpha())
      [attrs setObject:NsColor(style->VisitedDependentColor(
                           GetCSSPropertyBackgroundColor()))
                forKey:NSBackgroundColorAttributeName];
    else
      [attrs removeObjectForKey:NSBackgroundColorAttributeName];

    String characters = it.GetTextState().GetTextForTesting();
    characters.Ensure16Bit();
    NSString* substring =
        [[[NSString alloc] initWithCharacters:reinterpret_cast<const UniChar*>(
                                                  characters.Characters16())
                                       length:characters.length()] autorelease];
    [string replaceCharactersInRange:NSMakeRange(position, 0)
                          withString:substring];
    [string setAttributes:attrs range:NSMakeRange(position, num_characters)];
    position += num_characters;
  }
  return [string autorelease];
}

gfx::Point GetBaselinePoint(LocalFrameView* frame_view,
                            const EphemeralRange& range,
                            NSAttributedString* string) {
  IntRect string_rect = frame_view->FrameToViewport(FirstRectForRange(range));
  IntPoint string_point = string_rect.MinXMaxYCorner();

  // Adjust for the font's descender. AppKit wants the baseline point.
  if ([string length]) {
    NSDictionary* attributes = [string attributesAtIndex:0
                                          effectiveRange:nullptr];
    if (NSFont* font = [attributes objectForKey:NSFontAttributeName])
      string_point.Move(0, ceil([font descender]));
  }
  return string_point;
}

}  // namespace

NSAttributedString* SubstringUtil::AttributedWordAtPoint(
    WebFrameWidgetImpl* frame_widget,
    gfx::Point point,
    gfx::Point& baseline_point) {
  HitTestResult result =
      frame_widget->CoreHitTestResultAt(FloatPoint(IntPoint(point)));

  if (!result.InnerNode())
    return nil;
  LocalFrame* frame = result.InnerNode()->GetDocument().GetFrame();
  EphemeralRange range =
      frame->GetEditor().RangeForPoint(result.RoundedPointInInnerNodeFrame());
  if (range.IsNull())
    return nil;

  // Expand to word under point.
  const SelectionInDOMTree selection = ExpandWithGranularity(
      SelectionInDOMTree::Builder().SetBaseAndExtent(range).Build(),
      TextGranularity::kWord);
  const EphemeralRange word_range = NormalizeRange(selection);

  // Convert to NSAttributedString.
  NSAttributedString* string = AttributedSubstringFromRange(
      word_range, frame->GetPage()->GetVisualViewport().Scale());
  baseline_point = GetBaselinePoint(frame->View(), word_range, string);
  return string;
}

NSAttributedString* SubstringUtil::AttributedSubstringInRange(LocalFrame* frame,
                                                              size_t location,
                                                              size_t length) {
  return SubstringUtil::AttributedSubstringInRange(frame, location, length,
                                                   nil);
}

NSAttributedString* SubstringUtil::AttributedSubstringInRange(
    LocalFrame* frame,
    size_t location,
    size_t length,
    gfx::Point* baseline_point) {
  if (frame->View()->NeedsLayout())
    frame->View()->UpdateLayout();

  Element* editable = frame->Selection().RootEditableElementOrDocumentElement();
  if (!editable)
    return nil;
  const EphemeralRange ephemeral_range(
      PlainTextRange(location, location + length).CreateRange(*editable));
  if (ephemeral_range.IsNull())
    return nil;

  NSAttributedString* result = AttributedSubstringFromRange(
      ephemeral_range, frame->GetPage()->GetVisualViewport().Scale());
  if (baseline_point)
    *baseline_point = GetBaselinePoint(frame->View(), ephemeral_range, result);
  return result;
}

}  // namespace blink