/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "shell/jsoptparse.h"

#include <algorithm>
#include <stdarg.h>
#include <string_view>

#include "util/Unicode.h"

using namespace js;
using namespace js::cli;
using namespace js::cli::detail;

#define OPTION_CONVERT_IMPL(__cls)                                             \
  bool Option::is##__cls##Option() const { return kind == OptionKind##__cls; } \
  __cls##Option* Option::as##__cls##Option() {                                 \
    MOZ_ASSERT(is##__cls##Option());                                           \
    return static_cast<__cls##Option*>(this);                                  \
  }                                                                            \
  const __cls##Option* Option::as##__cls##Option() const {                     \
    return const_cast<Option*>(this)->as##__cls##Option();                     \
  }

ValuedOption* Option::asValued() {
  MOZ_ASSERT(isValued());
  return static_cast<ValuedOption*>(this);
}

const ValuedOption* Option::asValued() const {
  return const_cast<Option*>(this)->asValued();
}

OPTION_CONVERT_IMPL(Bool)
OPTION_CONVERT_IMPL(String)
OPTION_CONVERT_IMPL(Int)
OPTION_CONVERT_IMPL(MultiString)

void OptionParser::setArgTerminatesOptions(const char* name, bool enabled) {
  findArgument(name)->setTerminatesOptions(enabled);
}

void OptionParser::setIgnoresUnknownOptions(const char* name, bool enabled) {
  auto* opt = findOption(name);
  MOZ_ASSERT(opt);
  opt->setIgnoresUnknownOptions(enabled);
}

void OptionParser::setArgCapturesRest(const char* name) {
  MOZ_ASSERT(restArgument == -1,
             "only one argument may be set to capture the rest");
  restArgument = findArgumentIndex(name);
  MOZ_ASSERT(restArgument != -1,
             "unknown argument name passed to setArgCapturesRest");
}

OptionParser::Result OptionParser::error(const char* fmt, ...) {
  va_list args;
  va_start(args, fmt);
  fprintf(stderr, "Error: ");
  vfprintf(stderr, fmt, args);
  va_end(args);
  fputs("\n\n", stderr);
  return ParseError;
}

/* Quick and dirty paragraph printer. */
static void PrintParagraph(const char* text, unsigned startColno,
                           const unsigned limitColno, bool padFirstLine) {
  unsigned colno = startColno;
  unsigned indent = 0;
  const char* it = text;

  if (padFirstLine) {
    printf("%*s", int(startColno), "");
  }

  /* Skip any leading spaces. */
  while (*it != '\0' && unicode::IsSpace(*it)) {
    ++it;
  }

  while (*it != '\0') {
    MOZ_ASSERT(!unicode::IsSpace(*it) || *it == '\n');

    /* Delimit the current token. */
    const char* limit = it;
    while (!unicode::IsSpace(*limit) && *limit != '\0') {
      ++limit;
    }

    /*
     * If the current token is longer than the available number of columns,
     * then make a line break before printing the token.
     */
    size_t tokLen = limit - it;
    if (tokLen + colno >= limitColno) {
      printf("\n%*s%.*s", int(startColno + indent), "", int(tokLen), it);
      colno = startColno + tokLen;
    } else {
      printf("%.*s", int(tokLen), it);
      colno += tokLen;
    }

    switch (*limit) {
      case '\0':
        return;
      case ' ':
        putchar(' ');
        colno += 1;
        it = limit;
        while (*it == ' ') {
          ++it;
        }
        break;
      case '\n':
        /* |text| wants to force a newline here. */
        printf("\n%*s", int(startColno), "");
        colno = startColno;
        it = limit + 1;
        /* Could also have line-leading spaces. */
        indent = 0;
        while (*it == ' ') {
          putchar(' ');
          ++colno;
          ++indent;
          ++it;
        }
        break;
      default:
        MOZ_CRASH("unhandled token splitting character in text");
    }
  }
}

static const char* OptionFlagsToFormatInfo(char shortflag, bool isValued,
                                           size_t* length) {
  static const char* const fmt[4] = {"  -%c --%s ", "  --%s ", "  -%c --%s=%s ",
                                     "  --%s=%s "};

  /* How mny chars w/o longflag? */
  size_t lengths[4] = {strlen(fmt[0]) - 3, strlen(fmt[1]) - 3,
                       strlen(fmt[2]) - 5, strlen(fmt[3]) - 5};
  int index = isValued ? 2 : 0;
  if (!shortflag) {
    index++;
  }

  *length = lengths[index];
  return fmt[index];
}

OptionParser::Result OptionParser::printHelp(const char* progname) {
  constexpr std::string_view prognameMeta = "{progname}";

  const char* prefixEnd = strstr(usage, prognameMeta.data());
  if (prefixEnd) {
    printf("%.*s%s%s\n", int(prefixEnd - usage), usage, progname,
           prefixEnd + prognameMeta.length());
  } else {
    puts(usage);
  }

  if (descr) {
    putchar('\n');
    PrintParagraph(descr, 2, descrWidth, true);
    putchar('\n');
  }

  if (version) {
    printf("\nVersion: %s\n\n", version);
  }

  if (!arguments.empty()) {
    printf("Arguments:\n");

    static const char fmt[] = "  %s ";
    size_t fmtChars = sizeof(fmt) - 2;
    size_t lhsLen = 0;
    for (Option* arg : arguments) {
      lhsLen = std::max(lhsLen, strlen(arg->longflag) + fmtChars);
    }

    for (Option* arg : arguments) {
      size_t chars = printf(fmt, arg->longflag);
      for (; chars < lhsLen; ++chars) {
        putchar(' ');
      }
      PrintParagraph(arg->help, lhsLen, helpWidth, false);
      putchar('\n');
    }
    putchar('\n');
  }

  if (!options.empty()) {
    printf("Options:\n");

    /* Calculate sizes for column alignment. */
    size_t lhsLen = 0;
    for (Option* opt : options) {
      size_t longflagLen = strlen(opt->longflag);

      size_t fmtLen;
      OptionFlagsToFormatInfo(opt->shortflag, opt->isValued(), &fmtLen);

      size_t len = fmtLen + longflagLen;
      if (opt->isValued()) {
        len += strlen(opt->asValued()->metavar);
      }
      lhsLen = std::max(lhsLen, len);
    }

    /* Print option help text. */
    for (Option* opt : options) {
      size_t fmtLen;
      const char* fmt =
          OptionFlagsToFormatInfo(opt->shortflag, opt->isValued(), &fmtLen);
      size_t chars;
      if (opt->isValued()) {
        if (opt->shortflag) {
          chars = printf(fmt, opt->shortflag, opt->longflag,
                         opt->asValued()->metavar);
        } else {
          chars = printf(fmt, opt->longflag, opt->asValued()->metavar);
        }
      } else {
        if (opt->shortflag) {
          chars = printf(fmt, opt->shortflag, opt->longflag);
        } else {
          chars = printf(fmt, opt->longflag);
        }
      }
      for (; chars < lhsLen; ++chars) {
        putchar(' ');
      }
      PrintParagraph(opt->help, lhsLen, helpWidth, false);
      putchar('\n');
    }
  }

  return EarlyExit;
}

OptionParser::Result OptionParser::printVersion() {
  MOZ_ASSERT(version);
  printf("%s\n", version);
  return EarlyExit;
}

OptionParser::Result OptionParser::extractValue(size_t argc, char** argv,
                                                size_t* i, char** value) {
  MOZ_ASSERT(*i < argc);
  char* eq = strchr(argv[*i], '=');
  if (eq) {
    *value = eq + 1;
    if (*value[0] == '\0') {
      return error("A value is required for option %.*s", (int)(eq - argv[*i]),
                   argv[*i]);
    }
    return Okay;
  }

  if (argc == *i + 1) {
    return error("Expected a value for option %s", argv[*i]);
  }

  *i += 1;
  *value = argv[*i];
  return Okay;
}

OptionParser::Result OptionParser::handleOption(Option* opt, size_t argc,
                                                char** argv, size_t* i,
                                                bool* optionsAllowed) {
  if (opt->getTerminatesOptions()) {
    *optionsAllowed = false;
  }

  switch (opt->kind) {
    case OptionKindBool: {
      if (opt == &helpOption) {
        return printHelp(argv[0]);
      }
      if (opt == &versionOption) {
        return printVersion();
      }
      opt->asBoolOption()->value = true;
      return Okay;
    }
    /*
     * Valued options are allowed to specify their values either via
     * successive arguments or a single --longflag=value argument.
     */
    case OptionKindString: {
      char* value = nullptr;
      if (Result r = extractValue(argc, argv, i, &value)) {
        return r;
      }
      opt->asStringOption()->value = value;
      return Okay;
    }
    case OptionKindInt: {
      char* value = nullptr;
      if (Result r = extractValue(argc, argv, i, &value)) {
        return r;
      }
      opt->asIntOption()->value = atoi(value);
      return Okay;
    }
    case OptionKindMultiString: {
      char* value = nullptr;
      if (Result r = extractValue(argc, argv, i, &value)) {
        return r;
      }
      StringArg arg(value, *i);
      return opt->asMultiStringOption()->strings.append(arg) ? Okay : Fail;
    }
    default:
      MOZ_CRASH("unhandled option kind");
  }
}

OptionParser::Result OptionParser::handleArg(size_t argc, char** argv,
                                             size_t* i, bool* optionsAllowed) {
  if (nextArgument >= arguments.length()) {
    return error("Too many arguments provided");
  }

  Option* arg = arguments[nextArgument];

  if (arg->getTerminatesOptions()) {
    *optionsAllowed = false;
  }

  switch (arg->kind) {
    case OptionKindString:
      arg->asStringOption()->value = argv[*i];
      nextArgument += 1;
      return Okay;
    case OptionKindMultiString: {
      // Don't advance the next argument -- there can only be one (final)
      // variadic argument.
      StringArg value(argv[*i], *i);
      return arg->asMultiStringOption()->strings.append(value) ? Okay : Fail;
    }
    default:
      MOZ_CRASH("unhandled argument kind");
  }
}

OptionParser::Result OptionParser::parseArgs(int inputArgc, char** argv) {
  MOZ_ASSERT(inputArgc >= 0);
  size_t argc = inputArgc;

  // Permit a "no more options" capability, like |--| offers in many shell
  // interfaces.
  bool optionsAllowed = true;

  // Whether unknown options should report a warning instead of an error. This
  // is enabled by setIgnoresUnknownOptions and used for --fuzzing-safe.
  bool ignoreUnknownOptions = false;

  for (size_t i = 1; i < argc; ++i) {
    char* arg = argv[i];
    Result r;
    /* Note: solo dash option is actually a 'stdin' argument. */
    if (arg[0] == '-' && arg[1] != '\0' && optionsAllowed) {
      /* Option. */
      Option* opt;
      if (arg[1] == '-') {
        if (arg[2] == '\0') {
          /* End of options */
          optionsAllowed = false;
          nextArgument = restArgument;
          continue;
        } else {
          /* Long option. */
          opt = findOption(arg + 2);
          if (!opt) {
            if (ignoreUnknownOptions) {
              fprintf(stderr, "Warning: Ignoring unknown shell flag: %s\n",
                      arg);
              continue;
            }
            return error("Invalid long option: %s", arg);
          }
        }
      } else {
        /* Short option */
        if (arg[2] != '\0') {
          return error("Short option followed by junk: %s", arg);
        }
        opt = findOption(arg[1]);
        if (!opt) {
          return error("Invalid short option: %s", arg);
        }
      }

      if (opt->getIgnoresUnknownOptions()) {
        ignoreUnknownOptions = true;
      }

      r = handleOption(opt, argc, argv, &i, &optionsAllowed);
    } else {
      /* Argument. */
      r = handleArg(argc, argv, &i, &optionsAllowed);
    }

    if (r != Okay) {
      return r;
    }
  }
  return Okay;
}

void OptionParser::setHelpOption(char shortflag, const char* longflag,
                                 const char* help) {
  helpOption.setFlagInfo(shortflag, longflag, help);
}

bool OptionParser::getHelpOption() const { return helpOption.value; }

bool OptionParser::getBoolOption(char shortflag) const {
  return tryFindOption(shortflag)->asBoolOption()->value;
}

int OptionParser::getIntOption(char shortflag) const {
  return tryFindOption(shortflag)->asIntOption()->value;
}

const char* OptionParser::getStringOption(char shortflag) const {
  return tryFindOption(shortflag)->asStringOption()->value;
}

MultiStringRange OptionParser::getMultiStringOption(char shortflag) const {
  const MultiStringOption* mso =
      tryFindOption(shortflag)->asMultiStringOption();
  return MultiStringRange(mso->strings.begin(), mso->strings.end());
}

bool OptionParser::getBoolOption(const char* longflag) const {
  return tryFindOption(longflag)->asBoolOption()->value;
}

int OptionParser::getIntOption(const char* longflag) const {
  return tryFindOption(longflag)->asIntOption()->value;
}

const char* OptionParser::getStringOption(const char* longflag) const {
  return tryFindOption(longflag)->asStringOption()->value;
}

MultiStringRange OptionParser::getMultiStringOption(
    const char* longflag) const {
  const MultiStringOption* mso = tryFindOption(longflag)->asMultiStringOption();
  return MultiStringRange(mso->strings.begin(), mso->strings.end());
}

OptionParser::~OptionParser() {
  for (Option* opt : options) {
    js_delete<Option>(opt);
  }
  for (Option* arg : arguments) {
    js_delete<Option>(arg);
  }
}

Option* OptionParser::findOption(char shortflag) {
  for (Option* opt : options) {
    if (opt->shortflag == shortflag) {
      return opt;
    }
  }

  if (versionOption.shortflag == shortflag) {
    return &versionOption;
  }

  return helpOption.shortflag == shortflag ? &helpOption : nullptr;
}

const Option* OptionParser::findOption(char shortflag) const {
  return const_cast<OptionParser*>(this)->findOption(shortflag);
}

const Option* OptionParser::tryFindOption(char shortflag) const {
  const Option* maybeOption = findOption(shortflag);
  if (!maybeOption) {
    fprintf(stderr, "Failed to find short option %c\n", shortflag);
    MOZ_CRASH();
  }
  return maybeOption;
}

Option* OptionParser::findOption(const char* longflag) {
  for (Option* opt : options) {
    const char* target = opt->longflag;
    if (opt->isValued()) {
      size_t targetLen = strlen(target);
      /* Permit a trailing equals sign on the longflag argument. */
      for (size_t i = 0; i < targetLen; ++i) {
        if (longflag[i] == '\0' || longflag[i] != target[i]) {
          goto no_match;
        }
      }
      if (longflag[targetLen] == '\0' || longflag[targetLen] == '=') {
        return opt;
      }
    } else {
      if (strcmp(target, longflag) == 0) {
        return opt;
      }
    }
  no_match:;
  }

  if (strcmp(versionOption.longflag, longflag) == 0) {
    return &versionOption;
  }

  return strcmp(helpOption.longflag, longflag) ? nullptr : &helpOption;
}

const Option* OptionParser::findOption(const char* longflag) const {
  return const_cast<OptionParser*>(this)->findOption(longflag);
}

const Option* OptionParser::tryFindOption(const char* longflag) const {
  const Option* maybeOption = findOption(longflag);
  if (!maybeOption) {
    fprintf(stderr, "Failed to find long option %s\n", longflag);
    MOZ_CRASH();
  }
  return maybeOption;
}

/* Argument accessors */

int OptionParser::findArgumentIndex(const char* name) const {
  for (Option* const* it = arguments.begin(); it != arguments.end(); ++it) {
    const char* target = (*it)->longflag;
    if (strcmp(target, name) == 0) {
      return it - arguments.begin();
    }
  }
  return -1;
}

Option* OptionParser::findArgument(const char* name) {
  int index = findArgumentIndex(name);
  return (index == -1) ? nullptr : arguments[index];
}

const Option* OptionParser::findArgument(const char* name) const {
  int index = findArgumentIndex(name);
  return (index == -1) ? nullptr : arguments[index];
}

const char* OptionParser::getStringArg(const char* name) const {
  return findArgument(name)->asStringOption()->value;
}

MultiStringRange OptionParser::getMultiStringArg(const char* name) const {
  const MultiStringOption* mso = findArgument(name)->asMultiStringOption();
  return MultiStringRange(mso->strings.begin(), mso->strings.end());
}

/* Option builders */

// Use vanilla malloc for allocations. See OptionAllocPolicy.
JS_DECLARE_NEW_METHODS(opt_new, malloc, static MOZ_ALWAYS_INLINE)

bool OptionParser::addIntOption(char shortflag, const char* longflag,
                                const char* metavar, const char* help,
                                int defaultValue) {
  if (!options.reserve(options.length() + 1)) {
    return false;
  }
  IntOption* io =
      opt_new<IntOption>(shortflag, longflag, help, metavar, defaultValue);
  if (!io) {
    return false;
  }
  options.infallibleAppend(io);
  return true;
}

bool OptionParser::addBoolOption(char shortflag, const char* longflag,
                                 const char* help) {
  if (!options.reserve(options.length() + 1)) {
    return false;
  }
  BoolOption* bo = opt_new<BoolOption>(shortflag, longflag, help);
  if (!bo) {
    return false;
  }
  options.infallibleAppend(bo);
  return true;
}

bool OptionParser::addStringOption(char shortflag, const char* longflag,
                                   const char* metavar, const char* help) {
  if (!options.reserve(options.length() + 1)) {
    return false;
  }
  StringOption* so = opt_new<StringOption>(shortflag, longflag, help, metavar);
  if (!so) {
    return false;
  }
  options.infallibleAppend(so);
  return true;
}

bool OptionParser::addMultiStringOption(char shortflag, const char* longflag,
                                        const char* metavar, const char* help) {
  if (!options.reserve(options.length() + 1)) {
    return false;
  }
  MultiStringOption* mso =
      opt_new<MultiStringOption>(shortflag, longflag, help, metavar);
  if (!mso) {
    return false;
  }
  options.infallibleAppend(mso);
  return true;
}

/* Argument builders */

bool OptionParser::addOptionalStringArg(const char* name, const char* help) {
  if (!arguments.reserve(arguments.length() + 1)) {
    return false;
  }
  StringOption* so = opt_new<StringOption>(1, name, help, (const char*)nullptr);
  if (!so) {
    return false;
  }
  arguments.infallibleAppend(so);
  return true;
}

bool OptionParser::addOptionalMultiStringArg(const char* name,
                                             const char* help) {
  MOZ_ASSERT_IF(!arguments.empty(), !arguments.back()->isVariadic());
  if (!arguments.reserve(arguments.length() + 1)) {
    return false;
  }
  MultiStringOption* mso =
      opt_new<MultiStringOption>(1, name, help, (const char*)nullptr);
  if (!mso) {
    return false;
  }
  arguments.infallibleAppend(mso);
  return true;
}