Source: commands.js

/**
 * Represents a bot command.
 */
class BotCommand {
  /**
   * Creates a new command.
   * You must register it with Core.commands.register(command) to make it work.
   * @param {string} name - Command name. MUST be in lowercase and contain no spaces
   * @param {object} options - Command options
   * @param {string[]} options.aliases - Command aliases
   * @param {boolean} options.adminOnly - Restrict this command to administrators
   * @param {boolean} options.djOnly - Restrict this command to DJs
   * @param {boolean} options.ownerOnly - Restrict this command to the owner
   * @param {boolean} options.argSeparator - The argument delimiter
   * @param {boolean} options.includeCommandNameInArgs - Useful for aliases
   * @param {boolean} options.allowDM - Allow this command to be executed in DMs
   * @param {boolean} options.everyone - For SelfBots, allow this command to be executed by others.
   * @param {function} func - Command handler
   */
  constructor(name, options, func) {
    /** Command name */
    this.name = name;
    if (!name) throw new Error('You must specify a command name!');
    if (typeof options === 'function') {
      // Function as 2nd argument
      this.func = options;
    } else if (typeof options === 'object') {
      Object.assign(this, options);
      this.func = func;
    }
  }

  /**
   * Calls the command handler.
   * @param {object} msg - Message object
   * @param {string|string[]} args - Arguments
   */
  exec(msg, args) {
    Core.guilds.getGuild(msg.guild).then(data => this.func(msg, args, data, Core.bot, Core))
    .catch(err => Core.log(err, 2));
  }
}

/**
 * Manages the commands.
 */
class CommandManager {
  /**
   * Instantiates a new command manager.
   */
  constructor() {
    /** Registered commands */
    this.registered = {};
    /** Registered commands including aliases */
    this.plain = {};
  }

  /**
   * Registers command(s).
   * First parameter can be either a name, or a {BotCommand} instance or array.
   * Second parameter can be an object containg settings, or the handler function.
   * Third parameter is the handler function when settings are the second.
   *
   * If a command with the same name exists, it will be overwritten.
   *
   * @return {BotCommand|BotCommand[]} The registered command instance(s).
   */
  register(name, options, func) {
    // Arrays can be used as first parameters
    if (name.forEach && !options && !func) {
      const r = [];
      name.forEach(command => r.push(this.register(command)));
      return r;
    }
    // Command instances can be used as first parameters
    const command = (name instanceof BotCommand) ? name : new BotCommand(name, options, func);
    this.registered[command.name] = command;
    this.plain[command.name] = command;
    // :D
    if (command.aliases && command.aliases.forEach) {
      command.aliases.forEach((alias) => {
        this.plain[alias] = command;
      });
    }
    return command;
  }

  /**
   * Unregisters command(s)
   * First parameter can be either a name, a {BotCommand} instance or an array of both.
   */
  unregister(c) {
    // Arrays
    if (c.forEach) {
      const r = [];
      c.forEach(command => r.push(this.unregister(command)));
      return r;
    }
    const command = (c instanceof BotCommand) ? c : this.commands[c];
    if (command && command.name && this.registered[command.name]) {
      if (command.aliases && command.aliases.forEach) {
        command.aliases.forEach((alias) => {
          delete this.plain[alias];
        });
      }
      delete this.registered[command.name];
      delete this.plain[command.name];
      return true;
    }
    return false;
  }

  /**
   * Gets the current prefix.
   * @return {Promise<string>}
   */
  getPrefix(msg) {
    if (Core.settings.selfBot && Core.settings.publicPrefix && msg.author.id !== Core.bot.User.id) {
      return Promise.resolve(Core.settings.publicPrefix);
    }
    return Promise.resolve(Core.settings.prefix);
  }

  /**
   * Processes a message.
   */
  processMessage(msg) {
    // Build a regex
    this.getPrefix(msg).then((prefix) => {
      const escapedPrefix = prefix.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&');
      const match = msg.content.match(new RegExp(`^${escapedPrefix}(\\S+)\\s?([\\S\\s]*)$`));
      if (!match) return;
      // Get the command
      const command = this.plain[match[1].toLowerCase()];
      if (!command) return;
      // Check if it can be executed
      if (!msg.guild && !command.allowDM) return;
      if (Core.settings.selfBot && !command.everyone && msg.author.id !== Core.bot.User.id) return;
      if (command.adminOnly && !Core.permissions.isAdmin(msg.author, msg.guild)) return;
      if (command.djOnly && !Core.permissions.isDJ(msg.author, msg.guild)) return;
      if (command.ownerOnly && !Core.permissions.isOwner(msg.author)) return;
      // Get arguments
      let args = [];
      if (command.includeCommandNameInArgs) args.push(match[1]);
      if (command.argSeparator) args = args.concat(match[2].split(command.argSeparator));
      else args.push(match[2]);
      if (args.length === 1 && !command.argSeparator) args = args[0];
      // Run the command!
      try {
        command.exec(msg, args);
      } catch (e) {
        Core.log(e, 2);
      }
    });
  }
}

module.exports = CommandManager;
global.BotCommand = BotCommand;