frosty/lib/models/irc.dart

import 'package:flutter/foundation.dart';
import 'package:frosty/api/irc_api.dart';

/// The object representation of a Twitch IRC message.
class IRCMessage {
  final Map<String, String> tags;
  final String? user;
  Command command;
  String? message;

  IRCMessage({required this.tags, required this.command, required this.user, required this.message});

  /// Parses an IRC string and returns its corresponding [IRCMessage] object.
  factory IRCMessage.fromString(String whole) {
    // We have three parts:
    // 1. The tags of the IRC message
    // 2. The metadata (user, command, and channel)
    // 3. The message itself

    // First, slice the message tags (1) and set aside the rest for later.
    // Each part is separated by a space, so we'll start off by breaking off the tags and parsing them.

    // Obtain the index to break off the tags.
    final tagAndIrcMessageDivider = whole.indexOf(' ');

    // Get the tags substring and escape characters.
    // IRC messages escape spaces with \s.
    final tags = whole.substring(1, tagAndIrcMessageDivider).replaceAll('\\s', ' ');

    // Next, parse and map the tags.
    final mappedTags = <String, String>{};

    // Loop through each tag and store their key value pairs into the map.
    for (final tag in tags.split(';')) {
      // Skip if the tag has no value.
      if (tag.endsWith('=')) continue;

      final tagSplit = tag.split('=');
      mappedTags[tagSplit[0]] = tagSplit[1];
    }

    // Now we'll parse the message itself.
    // Obtain the entire substring after the tags and excluding the first : (colon)
    final ircMessage = whole.substring(tagAndIrcMessageDivider + 2);

    // Split each section of the message (part 2 and its subparts and part 3).
    // Index 0 contains the username of sender (user) or tmi.twitch.tv depending on the command
    // Index 1 is command type
    // Index 2 is #channel name that we are currently connected to
    // Index 3 and beyond is the :message (word by word) that is sent by the user or empty depending on the command
    final splitMessage = ircMessage.split(' ');

    // If the username exists, set it.
    // tmi.twitch.tv means the message was sent by Twitch rather than a user, so will be irrelevant.
    final String? user = splitMessage[0] == 'tmi.twitch.tv' ? null : splitMessage[0].substring(0, splitMessage[0].indexOf('!'));

    // If there is an associated message, set it.
    final String? message = splitMessage.length > 3 ? splitMessage.sublist(3).join(' ').substring(1) : null;

    // Check and parse the command.
    // The majority of messages will be PRIVMSG, so check that first.
    final Command messageCommand;
    switch (splitMessage[1]) {
      case 'PRIVMSG':
        messageCommand = Command.privateMessage;
        break;
      case 'CLEARCHAT':
        messageCommand = Command.clearChat;
        break;
      case 'CLEARMSG':
        messageCommand = Command.clearMessage;
        break;
      case 'USERNOTICE':
        messageCommand = Command.userNotice;
        break;
      case 'ROOMSTATE':
        messageCommand = Command.roomState;
        break;
      case 'USERSTATE':
        messageCommand = Command.userState;
        break;
      case 'GLOBALUSERSTATE':
        messageCommand = Command.globalUserState;
        break;
      default:
        debugPrint('Unknown command: $splitMessage[1]');
        messageCommand = Command.none;
    }

    return IRCMessage(
      tags: mappedTags,
      command: messageCommand,
      user: user,
      message: message,
    );
  }
}

/// The object representation of the IRC ROOMSTATE message.
class ROOMSTATE {
  final String emoteOnly;
  final String followersOnly;
  final String r9k;
  final String slowMode;
  final String subMode;

  ROOMSTATE({
    this.emoteOnly = "0",
    this.followersOnly = "0",
    this.r9k = "0",
    this.slowMode = "0",
    this.subMode = "0",
  });

  /// Create a new copy with the paremeters from the provided [IRCMessage]
  ROOMSTATE copyWith(IRCMessage ircMessage) {
    return ROOMSTATE(
      emoteOnly: ircMessage.tags['emote-only'] ?? emoteOnly,
      followersOnly: ircMessage.tags['followers-only'] ?? followersOnly,
      r9k: ircMessage.tags['r9k'] ?? r9k,
      slowMode: ircMessage.tags['slow'] ?? slowMode,
      subMode: ircMessage.tags['subs-only'] ?? subMode,
    );
  }
}