// Copyright 2013 The Flutter 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 "string_utils.h"

#include <shobjidl.h>
#include <windows.h>

#include <string>

namespace file_selector_windows {

// Converts the given UTF-16 string to UTF-8.
std::string Utf8FromUtf16(const std::wstring& utf16_string) {
  if (utf16_string.empty()) {
    return std::string();
  }
  int target_length = ::WideCharToMultiByte(
      CP_UTF8, WC_ERR_INVALID_CHARS, utf16_string.data(),
      static_cast<int>(utf16_string.length()), nullptr, 0, nullptr, nullptr);
  if (target_length == 0) {
    return std::string();
  }
  std::string utf8_string;
  utf8_string.resize(target_length);
  int converted_length = ::WideCharToMultiByte(
      CP_UTF8, WC_ERR_INVALID_CHARS, utf16_string.data(),
      static_cast<int>(utf16_string.length()), utf8_string.data(),
      target_length, nullptr, nullptr);
  if (converted_length == 0) {
    return std::string();
  }
  return utf8_string;
}

// Converts the given UTF-8 string to UTF-16.
std::wstring Utf16FromUtf8(const std::string& utf8_string) {
  if (utf8_string.empty()) {
    return std::wstring();
  }
  int target_length =
      ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, utf8_string.data(),
                            static_cast<int>(utf8_string.length()), nullptr, 0);
  if (target_length == 0) {
    return std::wstring();
  }
  std::wstring utf16_string;
  utf16_string.resize(target_length);
  int converted_length =
      ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, utf8_string.data(),
                            static_cast<int>(utf8_string.length()),
                            utf16_string.data(), target_length);
  if (converted_length == 0) {
    return std::wstring();
  }
  return utf16_string;
}

}  // namespace file_selector_windows