// Copyright 2018 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.

#include "third_party/blink/renderer/core/layout/ng/inline/ng_caret_position.h"

#include "third_party/blink/renderer/core/editing/text_affinity.h"
#include "third_party/blink/renderer/core/layout/layout_block_flow.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_cursor.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_offset_mapping.h"
#include "third_party/blink/renderer/core/layout/ng/ng_layout_test.h"

namespace blink {

class NGCaretPositionTest : public NGLayoutTest {
 public:
  NGCaretPositionTest() : NGLayoutTest() {}

  void SetUp() override {
    NGLayoutTest::SetUp();
    LoadAhem();
  }

 protected:
  void SetInlineFormattingContext(const char* id,
                                  const char* html,
                                  unsigned width,
                                  TextDirection dir = TextDirection::kLtr,
                                  const char* style = nullptr) {
    InsertStyleElement(
        "body { font: 10px/10px Ahem;  }"
        "bdo { display:block; }");
    const char* pattern =
        dir == TextDirection::kLtr
            ? "<div id='%s' style='width: %u0px; %s'>%s</div>"
            : "<bdo dir=rtl id='%s' style='width: %u0px; %s'>%s</bdo>";
    SetBodyInnerHTML(String::Format(
        pattern, id, width, style ? style : "word-break: break-all", html));
    container_ = GetElementById(id);
    DCHECK(container_);
    context_ = To<LayoutBlockFlow>(container_->GetLayoutObject());
    DCHECK(context_);
    DCHECK(context_->IsLayoutNGMixin());
  }

  NGCaretPosition ComputeNGCaretPosition(unsigned offset,
                                         TextAffinity affinity) const {
    return blink::ComputeNGCaretPosition(*context_, offset, affinity);
  }

  NGInlineCursor FragmentOf(const Node* node) const {
    NGInlineCursor cursor;
    cursor.MoveTo(*node->GetLayoutObject());
    return cursor;
  }

  Persistent<Element> container_;
  const LayoutBlockFlow* context_;
};

#define TEST_CARET(caret, fragment_, type_, offset_)                         \
  {                                                                          \
    EXPECT_EQ(caret.cursor, fragment_);                                      \
    EXPECT_EQ(caret.position_type, NGCaretPositionType::type_);              \
    EXPECT_EQ(caret.text_offset, offset_) << caret.text_offset.value_or(-1); \
  }

TEST_F(NGCaretPositionTest, CaretPositionInOneLineOfText) {
  SetInlineFormattingContext("t", "foo", 3);
  const Node* text = container_->firstChild();
  const NGInlineCursor& text_fragment = FragmentOf(text);

  // Beginning of line
  TEST_CARET(ComputeNGCaretPosition(0, TextAffinity::kDownstream),
             text_fragment, kAtTextOffset, base::Optional<unsigned>(0));
  TEST_CARET(ComputeNGCaretPosition(0, TextAffinity::kUpstream), text_fragment,
             kAtTextOffset, base::Optional<unsigned>(0));

  // Middle in the line
  TEST_CARET(ComputeNGCaretPosition(1, TextAffinity::kDownstream),
             text_fragment, kAtTextOffset, base::Optional<unsigned>(1));
  TEST_CARET(ComputeNGCaretPosition(1, TextAffinity::kUpstream), text_fragment,
             kAtTextOffset, base::Optional<unsigned>(1));

  // End of line
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kDownstream),
             text_fragment, kAtTextOffset, base::Optional<unsigned>(3));
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kUpstream), text_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));
}

// For http://crbug.com/1021993
// We should not call |NGInlineCursor::CurrentBidiLevel()| for soft hyphen
TEST_F(NGCaretPositionTest, CaretPositionAtSoftHyphen) {
  // We have three fragment "foo\u00AD", "\u2010", "bar"
  SetInlineFormattingContext("t", "foo&shy;bar", 3, TextDirection::kLtr, "");
  const LayoutText& text =
      *To<Text>(container_->firstChild())->GetLayoutObject();
  NGInlineCursor cursor;
  cursor.MoveTo(text);
  const NGInlineCursor foo_fragment = cursor;

  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kDownstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kUpstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
}

TEST_F(NGCaretPositionTest, CaretPositionAtSoftLineWrap) {
  SetInlineFormattingContext("t", "foobar", 3);
  const LayoutText& text =
      *To<Text>(container_->firstChild())->GetLayoutObject();
  NGInlineCursor cursor;
  cursor.MoveTo(text);
  const NGInlineCursor foo_fragment = cursor;
  cursor.MoveToNextForSameLayoutObject();
  const NGInlineCursor bar_fragment = cursor;

  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kDownstream), bar_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kUpstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));
}

TEST_F(NGCaretPositionTest, CaretPositionAtSoftLineWrapWithSpace) {
  SetInlineFormattingContext("t", "foo bar", 3);
  const LayoutText& text =
      *To<Text>(container_->firstChild())->GetLayoutObject();
  NGInlineCursor cursor;
  cursor.MoveTo(text);
  const NGInlineCursor foo_fragment = cursor;
  cursor.MoveToNextForSameLayoutObject();
  const NGInlineCursor bar_fragment = cursor;

  // Before the space
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kDownstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kUpstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));

  // After the space
  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kDownstream), bar_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kUpstream), bar_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
}

TEST_F(NGCaretPositionTest, CaretPositionAtForcedLineBreak) {
  SetInlineFormattingContext("t", "foo<br>bar", 3);
  const Node* foo = container_->firstChild();
  const Node* br = foo->nextSibling();
  const Node* bar = br->nextSibling();
  const NGInlineCursor& foo_fragment = FragmentOf(foo);
  const NGInlineCursor& bar_fragment = FragmentOf(bar);

  // Before the BR
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kDownstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));
  TEST_CARET(ComputeNGCaretPosition(3, TextAffinity::kUpstream), foo_fragment,
             kAtTextOffset, base::Optional<unsigned>(3));

  // After the BR
  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kDownstream), bar_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kUpstream), bar_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
}

TEST_F(NGCaretPositionTest, CaretPositionAtEmptyLine) {
  SetInlineFormattingContext("f", "foo<br><br>bar", 3);
  const Node* foo = container_->firstChild();
  const Node* br1 = foo->nextSibling();
  const Node* br2 = br1->nextSibling();
  const NGInlineCursor& br2_fragment = FragmentOf(br2);

  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kDownstream), br2_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
  TEST_CARET(ComputeNGCaretPosition(4, TextAffinity::kUpstream), br2_fragment,
             kAtTextOffset, base::Optional<unsigned>(4));
}

TEST_F(NGCaretPositionTest, CaretPositionInOneLineOfImage) {
  SetInlineFormattingContext("t", "<img>", 3);
  const Node* img = container_->firstChild();
  const NGInlineCursor& img_fragment = FragmentOf(img);

  // Before the image
  TEST_CARET(ComputeNGCaretPosition(0, TextAffinity::kDownstream), img_fragment,
             kBeforeBox, base::nullopt);
  TEST_CARET(ComputeNGCaretPosition(0, TextAffinity::kUpstream), img_fragment,
             kBeforeBox, base::nullopt);

  // After the image
  TEST_CARET(ComputeNGCaretPosition(1, TextAffinity::kDownstream), img_fragment,
             kAfterBox, base::nullopt);
  TEST_CARET(ComputeNGCaretPosition(1, TextAffinity::kUpstream), img_fragment,
             kAfterBox, base::nullopt);
}

TEST_F(NGCaretPositionTest, CaretPositionAtSoftLineWrapBetweenImages) {
  SetInlineFormattingContext("t",
                             "<img id=img1><img id=img2>"
                             "<style>img{width: 1em; height: 1em}</style>",
                             1);
  const Node* img1 = container_->firstChild();
  const Node* img2 = img1->nextSibling();
  const NGInlineCursor& img1_fragment = FragmentOf(img1);
  const NGInlineCursor& img2_fragment = FragmentOf(img2);

  TEST_CARET(ComputeNGCaretPosition(1, TextAffinity::kDownstream),
             img2_fragment, kBeforeBox, base::nullopt);
  TEST_CARET(ComputeNGCaretPosition(1, TextAffinity::kUpstream), img1_fragment,
             kAfterBox, base::nullopt);
}

TEST_F(NGCaretPositionTest,
       CaretPositionAtSoftLineWrapBetweenMultipleTextNodes) {
  SetInlineFormattingContext("t",
                             "<span>A</span>"
                             "<span>B</span>"
                             "<span id=span-c>C</span>"
                             "<span id=span-d>D</span>"
                             "<span>E</span>"
                             "<span>F</span>",
                             3);
  const Node* text_c = GetElementById("span-c")->firstChild();
  const Node* text_d = GetElementById("span-d")->firstChild();
  const NGInlineCursor& fragment_c = FragmentOf(text_c);
  const NGInlineCursor& fragment_d = FragmentOf(text_d);

  const Position wrap_position(text_c, 1);
  const NGOffsetMapping& mapping = *NGOffsetMapping::GetFor(wrap_position);
  const unsigned wrap_offset = *mapping.GetTextContentOffset(wrap_position);

  TEST_CARET(ComputeNGCaretPosition(wrap_offset, TextAffinity::kUpstream),
             fragment_c, kAtTextOffset, base::Optional<unsigned>(wrap_offset));
  TEST_CARET(ComputeNGCaretPosition(wrap_offset, TextAffinity::kDownstream),
             fragment_d, kAtTextOffset, base::Optional<unsigned>(wrap_offset));
}

TEST_F(NGCaretPositionTest,
       CaretPositionAtSoftLineWrapBetweenMultipleTextNodesRtl) {
  SetInlineFormattingContext("t",
                             "<span>A</span>"
                             "<span>B</span>"
                             "<span id=span-c>C</span>"
                             "<span id=span-d>D</span>"
                             "<span>E</span>"
                             "<span>F</span>",
                             3, TextDirection::kRtl);
  const Node* text_c = GetElementById("span-c")->firstChild();
  const Node* text_d = GetElementById("span-d")->firstChild();
  const NGInlineCursor& fragment_c = FragmentOf(text_c);
  const NGInlineCursor& fragment_d = FragmentOf(text_d);

  const Position wrap_position(text_c, 1);
  const NGOffsetMapping& mapping = *NGOffsetMapping::GetFor(wrap_position);
  const unsigned wrap_offset = *mapping.GetTextContentOffset(wrap_position);

  TEST_CARET(ComputeNGCaretPosition(wrap_offset, TextAffinity::kUpstream),
             fragment_c, kAtTextOffset, base::Optional<unsigned>(wrap_offset));
  TEST_CARET(ComputeNGCaretPosition(wrap_offset, TextAffinity::kDownstream),
             fragment_d, kAtTextOffset, base::Optional<unsigned>(wrap_offset));
}

TEST_F(NGCaretPositionTest, CaretPositionAtSoftLineWrapBetweenDeepTextNodes) {
  SetInlineFormattingContext(
      "t",
      "<style>span {border: 1px solid black}</style>"
      "<span>A</span>"
      "<span>B</span>"
      "<span id=span-c>C</span>"
      "<span id=span-d>D</span>"
      "<span>E</span>"
      "<span>F</span>",
      4);  // Wider space to allow border and 3 characters
  const Node* text_c = GetElementById("span-c")->firstChild();
  const Node* text_d = GetElementById("span-d")->firstChild();
  const NGInlineCursor& fragment_c = FragmentOf(text_c);
  const NGInlineCursor& fragment_d = FragmentOf(text_d);

  const Position wrap_position(text_c, 1);
  const NGOffsetMapping& mapping = *NGOffsetMapping::GetFor(wrap_position);
  const unsigned wrap_offset = *mapping.GetTextContentOffset(wrap_position);

  TEST_CARET(ComputeNGCaretPosition(wrap_offset, TextAffinity::kUpstream),
             fragment_c, kAtTextOffset, base::Optional<unsigned>(wrap_offset));
  TEST_CARET(ComputeNGCaretPosition(wrap_offset, TextAffinity::kDownstream),
             fragment_d, kAtTextOffset, base::Optional<unsigned>(wrap_offset));
}

TEST_F(NGCaretPositionTest, GeneratedZeroWidthSpace) {
  LoadAhem();
  InsertStyleElement(
      "p { font: 10px/1 Ahem; }"
      "p { width: 4ch; white-space: pre-wrap;");
  // We have ZWS before "abc" due by "pre-wrap".
  // text content is
  //    [0..3] "   "
  //    [4] ZWS
  //    [5..8] "abcd"
  SetBodyInnerHTML("<p id=t>    abcd</p>");
  const Text& text = To<Text>(*GetElementById("t")->firstChild());
  const Position after_zws(text, 4);  // before "a".

  NGInlineCursor cursor;
  cursor.MoveTo(*text.GetLayoutObject());

  ASSERT_EQ(NGTextOffset(0, 4), cursor.Current().TextOffset());
  TEST_CARET(blink::ComputeNGCaretPosition(
                 PositionWithAffinity(after_zws, TextAffinity::kUpstream)),
             cursor, kAtTextOffset, base::Optional<unsigned>(4));

  cursor.MoveToNextForSameLayoutObject();
  ASSERT_EQ(NGTextOffset(5, 9), cursor.Current().TextOffset());
  TEST_CARET(blink::ComputeNGCaretPosition(
                 PositionWithAffinity(after_zws, TextAffinity::kDownstream)),
             cursor, kAtTextOffset, base::Optional<unsigned>(5));
}

// http://crbug.com/1183269
// See also NGCaretPositionTest.CaretPositionAtSoftLineWrap
TEST_F(NGCaretPositionTest, SoftLineWrap) {
  LoadAhem();
  InsertStyleElement(
      "p { font: 10px/1 Ahem; }"
      "p { width: 4ch;");
  // Note: "contenteditable" adds
  //    line-break: after-white-space;
  //    overflow-wrap: break-word;
  SetBodyInnerHTML("<p id=t contenteditable>abc xyz</p>");
  const Text& text = To<Text>(*GetElementById("t")->firstChild());
  const Position before_xyz(text, 4);  // before "w".

  NGInlineCursor cursor;
  cursor.MoveTo(*text.GetLayoutObject());

  // Note: upstream/downstream before "xyz" are in different line.

  ASSERT_EQ(NGTextOffset(0, 3), cursor.Current().TextOffset());
  TEST_CARET(blink::ComputeNGCaretPosition(
                 PositionWithAffinity(before_xyz, TextAffinity::kUpstream)),
             cursor, kAtTextOffset, base::Optional<unsigned>(3));

  cursor.MoveToNextForSameLayoutObject();
  ASSERT_EQ(NGTextOffset(4, 7), cursor.Current().TextOffset());
  TEST_CARET(blink::ComputeNGCaretPosition(
                 PositionWithAffinity(before_xyz, TextAffinity::kDownstream)),
             cursor, kAtTextOffset, base::Optional<unsigned>(4));
}

TEST_F(NGCaretPositionTest, ZeroWidthSpace) {
  LoadAhem();
  InsertStyleElement(
      "p { font: 10px/1 Ahem; }"
      "p { width: 4ch;");
  // dom and text content is
  //    [0..3] "abcd"
  //    [4] ZWS
  //    [5..8] "wxyz"
  SetBodyInnerHTML("<p id=t>abcd&#x200B;wxyz</p>");
  const Text& text = To<Text>(*GetElementById("t")->firstChild());
  const Position after_zws(text, 5);  // before "w".

  NGInlineCursor cursor;
  cursor.MoveTo(*text.GetLayoutObject());

  ASSERT_EQ(NGTextOffset(0, 5), cursor.Current().TextOffset());
  TEST_CARET(blink::ComputeNGCaretPosition(
                 PositionWithAffinity(after_zws, TextAffinity::kUpstream)),
             cursor, kAtTextOffset, base::Optional<unsigned>(4));

  cursor.MoveToNextForSameLayoutObject();
  ASSERT_EQ(NGTextOffset(5, 9), cursor.Current().TextOffset());
  TEST_CARET(blink::ComputeNGCaretPosition(
                 PositionWithAffinity(after_zws, TextAffinity::kDownstream)),
             cursor, kAtTextOffset, base::Optional<unsigned>(5));
}

TEST_F(NGCaretPositionTest, InlineBlockBeforeContent) {
  SetInlineFormattingContext(
      "t",
      "<style>span::before{display:inline-block; content:'foo'}</style>"
      "<span id=span>bar</span>",
      100);  // Line width doesn't matter here.
  const Node* text = GetElementById("span")->firstChild();
  const NGInlineCursor& text_fragment = FragmentOf(text);

  // Test caret position of "|bar", which shouldn't be affected by ::before
  const Position position(text, 0);
  const NGOffsetMapping& mapping = *NGOffsetMapping::GetFor(position);
  const unsigned text_offset = *mapping.GetTextContentOffset(position);

  TEST_CARET(ComputeNGCaretPosition(text_offset, TextAffinity::kDownstream),
             text_fragment, kAtTextOffset,
             base::Optional<unsigned>(text_offset));
}

TEST_F(NGCaretPositionTest, InlineBoxesLTR) {
  SetBodyInnerHTML(
      "<div dir=ltr>"
      "<bdo id=box1 dir=ltr>ABCD</bdo>"
      "<bdo id=box2 dir=ltr style='font-size: 150%'>EFG</bdo></div>");

  // text_content:
  //    [0] U+202D LEFT-TO_RIGHT_OVERRIDE
  //    [1:4] "ABCD"
  //    [5] U+202C POP DIRECTIONAL FORMATTING
  //    [6] U+202D LEFT-TO_RIGHT_OVERRIDE
  //    [7:8] "EF"
  //    [9] U+202C POP DIRECTIONAL FORMATTING
  const Node& box1 = *GetElementById("box1")->firstChild();
  const Node& box2 = *GetElementById("box1")->firstChild();

  TEST_CARET(
      blink::ComputeNGCaretPosition(PositionWithAffinity(Position(box1, 4))),
      FragmentOf(&box1), kAtTextOffset, base::Optional<unsigned>(5));

  TEST_CARET(
      blink::ComputeNGCaretPosition(PositionWithAffinity(Position(box2, 0))),
      FragmentOf(&box2), kAtTextOffset, base::Optional<unsigned>(1));
}

TEST_F(NGCaretPositionTest, InlineBoxesRTL) {
  SetBodyInnerHTML(
      "<div dir=rtl>"
      "<bdo id=box1 dir=rtl>ABCD</bdo>"
      "<bdo id=box2 dir=rtl style='font-size: 150%'>EFG</bdo></div>");

  // text_content:
  //    [0] U+202E RIGHT-TO_LEFT _OVERRIDE
  //    [1:4] "ABCD"
  //    [5] U+202C POP DIRECTIONAL FORMATTING
  //    [6] U+202E RIGHT-TO_LEFT _OVERRIDE
  //    [7:8] "EF"
  //    [9] U+202C POP DIRECTIONAL FORMATTING
  const Node& box1 = *GetElementById("box1")->firstChild();
  const Node& box2 = *GetElementById("box1")->firstChild();

  TEST_CARET(
      blink::ComputeNGCaretPosition(PositionWithAffinity(Position(box1, 4))),
      FragmentOf(&box1), kAtTextOffset, base::Optional<unsigned>(5));

  TEST_CARET(
      blink::ComputeNGCaretPosition(PositionWithAffinity(Position(box2, 0))),
      FragmentOf(&box2), kAtTextOffset, base::Optional<unsigned>(1));
}

}  // namespace blink