// 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 "extensions/browser/api/i18n/i18n_api.h"

#include <algorithm>
#include <string>
#include <vector>

#include "base/strings/string_split.h"
#include "components/language/core/browser/pref_names.h"
#include "components/prefs/pref_service.h"
#include "components/user_prefs/user_prefs.h"
#include "content/public/browser/browser_context.h"
#include "extensions/browser/extensions_browser_client.h"
#include "extensions/common/api/i18n.h"

namespace GetAcceptLanguages = extensions::api::i18n::GetAcceptLanguages;

namespace extensions {

namespace {

// Errors.
static const char kEmptyAcceptLanguagesError[] = "accept-languages is empty.";

}  // namespace

ExtensionFunction::ResponseAction I18nGetAcceptLanguagesFunction::Run() {
  PrefService* pref_service = user_prefs::UserPrefs::Get(browser_context());
  std::string accept_languages =
      pref_service->GetString(language::prefs::kAcceptLanguages);
  // Currently, there are 2 ways to set browser's accept-languages: through UI
  // or directly modify the preference file. The accept-languages set through
  // UI is guaranteed to be valid, and the accept-languages string returned from
  // pref_service->GetString(language::prefs::kAcceptLanguages) is guaranteed
  // to be valid and well-formed, which means each accept-language is a valid
  // code, and accept-languages are separated by "," without surrrounding
  // spaces. But we do not do any validation (either the format or the validity
  // of the language code) on accept-languages set through editing preference
  // file directly. So, here, we're adding extra checks to be resistant to
  // crashes caused by data corruption.
  if (accept_languages.empty())
    return RespondNow(Error(kEmptyAcceptLanguagesError));

  std::vector<std::string> languages = base::SplitString(
      accept_languages, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
  std::erase(languages, "");

  if (languages.empty())
    return RespondNow(Error(kEmptyAcceptLanguagesError));

  return RespondNow(
      ArgumentList(GetAcceptLanguages::Results::Create(languages)));
}

}  // namespace extensions