// Copyright (c) 2026 Microsoft GmbH.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.

#include "shell/common/command_line_util_win.h"

#include <string>

namespace electron {

std::wstring AddQuoteForArg(const std::wstring& arg) {
  // We follow the quoting rules of CommandLineToArgvW.
  // http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
  constexpr wchar_t kQuotableChars[] = L" \\\"";
  if (arg.find_first_of(kQuotableChars) == std::wstring::npos) {
    // No quoting necessary.
    return arg;
  }

  std::wstring out;
  out.push_back(L'"');
  for (size_t i = 0; i < arg.size(); ++i) {
    if (arg[i] == '\\') {
      // Find the extent of this run of backslashes.
      size_t start = i, end = start + 1;
      for (; end < arg.size() && arg[end] == '\\'; ++end) {
      }
      size_t backslash_count = end - start;

      // Backslashes are escapes only if the run is followed by a double quote.
      // Since we also will end the string with a double quote, we escape for
      // either a double quote or the end of the string.
      if (end == arg.size() || arg[end] == '"') {
        // To quote, we need to output 2x as many backslashes.
        backslash_count *= 2;
      }
      for (size_t j = 0; j < backslash_count; ++j)
        out.push_back('\\');

      // Advance i to one before the end to balance i++ in loop.
      i = end - 1;
    } else if (arg[i] == '"') {
      out.push_back('\\');
      out.push_back('"');
    } else {
      out.push_back(arg[i]);
    }
  }
  out.push_back('"');

  return out;
}

}  // namespace electron
