// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/spellcheck/renderer/custom_dictionary_engine.h"

#include <stddef.h>

#include "base/functional/bind.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/task_traits.h"
#include "base/task/thread_pool.h"

namespace {

std::set<std::u16string> BuildDictionary(
    const std::vector<std::string>& custom_words) {
  std::set<std::u16string> dictionary;
  for (const std::string& word : custom_words) {
    dictionary.insert(base::UTF8ToUTF16(word));
  }
  return dictionary;
}

}  // namespace

CustomDictionaryEngine::CustomDictionaryEngine() {
}

CustomDictionaryEngine::~CustomDictionaryEngine() {
}

void CustomDictionaryEngine::Init(const std::set<std::string>& custom_words) {
  dictionary_.clear();

  // SpellingMenuOberver calls UTF16ToUTF8(word) to convert words for storage,
  // synchronization, and use in the custom dictionary engine. Since
  // (UTF8ToUTF16(UTF16ToUTF8(word)) == word) holds, the engine does not need to
  // normalize the strings.
  for (const std::string& word : custom_words)
    dictionary_.insert(base::UTF8ToUTF16(word));
}

void CustomDictionaryEngine::InitAsync(
    const std::vector<std::string>& custom_words) {
  weak_ptr_factory_.InvalidateWeakPtrs();

  base::ThreadPool::PostTaskAndReplyWithResult(
      FROM_HERE, {base::TaskPriority::USER_VISIBLE},
      base::BindOnce(&BuildDictionary, custom_words),
      base::BindOnce(&CustomDictionaryEngine::OnDictionaryBuilt,
                     weak_ptr_factory_.GetWeakPtr()));
}

void CustomDictionaryEngine::OnDictionaryBuilt(
    std::set<std::u16string> dictionary) {
  dictionary_ = std::move(dictionary);
}

void CustomDictionaryEngine::OnCustomDictionaryChanged(
    const std::set<std::string>& words_added,
    const std::set<std::string>& words_removed) {
  for (const std::string& word : words_added)
    dictionary_.insert(base::UTF8ToUTF16(word));

  for (const std::string& word : words_removed)
    dictionary_.erase(base::UTF8ToUTF16(word));
}

bool CustomDictionaryEngine::SpellCheckWord(const std::u16string& text,
                                            size_t misspelling_start,
                                            size_t misspelling_len) {
  // The text to be checked is empty on OSX(async) right now.
  // TODO(groby): Fix as part of async hook-up. (http://crbug.com/178241)
  return misspelling_len > 0 &&
         misspelling_start + misspelling_len <= text.length() &&
         dictionary_.count(text.substr(misspelling_start, misspelling_len)) > 0;
}