Okay, here's how this sucker's going to work.
General utility functions and objects. For instance...
Initializes and sets up logging using winston
Handles oAuth handshakes, for TMI login details and the like. Maybe - currently handled by twitch.js
Handles communication with twitch. Has functions for each twitch API call, which return promises.
Plugins extend functionality. They can be enabled or disabled on a per-channel basis, they may raise websockets events and API values, and can be configured via the web interface for the owner (and mods? - Can't get from the API, would have to log from chat, which has issues of its own) of a channel. Should be monolithic, one plugin per file, so index.js can load them all and they do their own setup with DB definitions and the like.
Holds basic database initializers. Stores channels, users, and settings. Also loads/initializes DB extensions from plugins... somehow. Using sequelize, with their ES6 constructor syntax (which appears not to be documented outside tickets, as it's not in the current stable release yet)
Opens a connection to Twitch Chat through TMI.js, maintains that connection, handles global events, creates/destroys channel objects and passes channel events through to them. Uses /lib/Twitch.js to get chat username and the like.
Handles events for channels, uses settings to attach plugins.
The web interface.
Provides top-level control.
Shows currently live channels.
Handles oAuth for Twitch, stores Twitch user ID in DB and in session, to keep user authorized for items that require it. Like...
REQUIRES oAUTH
Allows user to control leg_bot in their channel, enabling and disabling plugins and configuring them as necessary.
Shows public pages from plugins, like statistics, quotes and the like. If user is logged in, allows them to make/change votes and the like, but login is not required to view.
Receives oAuth codes from twitch, and passes them off to /lib/Twitch.js, which should be waiting for them.
Various API endpoints for overlays and the like.
Websockets endpoints. Hopefully working ones.
At startup, fetch our follow list (and store it), to get a list of current channel names to join.
Every so often (Every hour?), re-fetch the list of users we are following and compare it to the previously fetched list. If there are any differences, someone we're following has changed their username. Tear down that channel connection and rebuild using the new name.