// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_HYPHENATION_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_HYPHENATION_H_

#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/forward.h"
#include "third_party/blink/renderer/platform/wtf/ref_counted.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string_hash.h"
#include "third_party/blink/renderer/platform/wtf/text/string_hash.h"
#include "third_party/blink/renderer/platform/wtf/text/unicode.h"
#include "third_party/blink/renderer/platform/wtf/wtf_size_t.h"

namespace blink {

class PLATFORM_EXPORT Hyphenation : public RefCounted<Hyphenation> {
 public:
  virtual ~Hyphenation() = default;

  // Find the last hyphenation location before |before_index|.
  // Returns 0 if no hyphenation locations were found.
  virtual wtf_size_t LastHyphenLocation(const StringView&,
                                        wtf_size_t before_index) const = 0;

  // Find the first hyphenation location after |after_index|.
  // Returns 0 if no hyphenation locations were found.
  virtual wtf_size_t FirstHyphenLocation(const StringView&,
                                         wtf_size_t after_index) const;

  // Find all hyphenation locations in the reverse order.
  virtual Vector<wtf_size_t, 8> HyphenLocations(const StringView&) const;

  // The minimum number of characters in the word / before the hyphen / after
  // the hyphen. `0` means that the UA chooses a value.
  wtf_size_t MinPrefixLength() const { return min_prefix_length_; }
  wtf_size_t MinSuffixLength() const { return min_suffix_length_; }
  wtf_size_t MinWordLength() const { return min_word_length_; }
  void SetLimits(wtf_size_t min_prefix_length,
                 wtf_size_t min_suffix_length,
                 wtf_size_t min_word_length);
  void ResetLimits() { SetLimits(0, 0, 0); }

 protected:
  void Initialize(const AtomicString& locale);

  bool ShouldHyphenateWord(const StringView& word) const {
    DCHECK_GE(MinWordLength(), 1u);
    if (word.length() < MinWordLength())
      return false;
    // Avoid hyphenating capitalized words.
    // SAFETY: length check above ensures first element valid.
    return hyphenate_capitalized_word_ ||
           !unicode::IsUpper(UNSAFE_BUFFERS(word[0]));
  }

 private:
  friend class LayoutLocale;
  FRIEND_TEST_ALL_PREFIXES(HyphenationTest, SetLimits);

  static scoped_refptr<Hyphenation> PlatformGetHyphenation(
      const AtomicString& locale);

  // The default values suggested by the spec:
  // https://drafts.csswg.org/css-text-4/#propdef-hyphenate-limit-chars
  static constexpr unsigned kDefaultMinPrefixLength = 2;
  static constexpr unsigned kDefaultMinSuffixLength = 2;
  static constexpr unsigned kDefaultMinWordLength = 5;
  static_assert(kDefaultMinWordLength >=
                kDefaultMinPrefixLength + kDefaultMinSuffixLength);
  wtf_size_t min_word_length_ = kDefaultMinWordLength;
  wtf_size_t min_prefix_length_ = kDefaultMinPrefixLength;
  wtf_size_t min_suffix_length_ = kDefaultMinSuffixLength;

  bool hyphenate_capitalized_word_ = false;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_HYPHENATION_H_