// Copyright (c) the JPEG XL Project 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 "tools/cmdline.h"

#include <memory>
#include <string>

namespace jpegxl {
namespace tools {

void CommandLineParser::PrintHelp() const {
  // Use stdout, not stderr, so help can easily be grepped.
  FILE* out = stdout;
  fprintf(out, "Usage: %s", program_name_ ? program_name_ : "command");

  for (const auto& option : options_) {
    if (option->positional()) {
      if (option->verbosity_level() > verbosity) continue;
      if (option->required()) {
        fprintf(out, " %s", option->help_flags().c_str());
      } else {
        fprintf(out, " [%s]", option->help_flags().c_str());
      }
    }
  }
  fprintf(out, " [OPTIONS...]\n");

  bool showed_all = true;
  for (const auto& option : options_) {
    if (option->verbosity_level() > verbosity) {
      showed_all = false;
      continue;
    }
    fprintf(out, " %s\n", option->help_flags().c_str());
    const char* help_text = option->help_text();
    if (help_text) {
      fprintf(out, "    %s\n", help_text);
    }
  }
  fprintf(out, " -h, --help\n    Prints this help message%s.\n",
          (showed_all ? "" : " (use -v to see more options)"));
}

bool CommandLineParser::Parse(int argc, const char* argv[]) {
  if (argc) program_name_ = argv[0];
  int i = 1;  // argv[0] is the program name.
  // if false, stop matching options and take only positional arguments
  bool parse_options = true;
  while (i < argc) {
    if (!strcmp("-h", argv[i]) || !strcmp("--help", argv[i])) {
      help_ = true;
      i++;
      continue;
    }
    if (!strcmp("-v", argv[i]) || !strcmp("--verbose", argv[i])) {
      verbosity++;
    }
    // after "--", filenames starting with "-" can be used
    if (!strcmp("--", argv[i])) {
      parse_options = false;
      i++;
      continue;
    }
    // special case: "-" is a filename denoting stdin or stdout
    bool parse_this_option = true;
    if (!strcmp("-", argv[i])) {
      parse_this_option = false;
    }
    bool found = false;
    for (const auto& option : options_) {
      if (option->Match(argv[i], parse_options && parse_this_option)) {
        // Parsing advances the value i on success.
        const char* arg = argv[i];
        if (!option->Parse(argc, argv, &i)) {
          fprintf(stderr, "Error parsing flag %s\n", arg);
          return false;
        }
        found = true;
        break;
      }
    }
    if (!found) {
      // No option matched argv[i].
      fprintf(stderr, "Unknown argument: %s\n", argv[i]);
      return false;
    }
  }
  return true;
}

}  // namespace tools
}  // namespace jpegxl