At the highest level, PS is split into three parts:
All three communicate directly with each other.
The game server is written in TypeScript and runs on Node.js.
Its entry point is server/index.ts, which launches several major components:
server/sockets.ts sets up a SockJS (abstracted WebSocket) server to accept connections from clients
server/users.ts sets up Users, which wraps the SockJS connections in a system that handles users
server/rooms.ts sets up Rooms, which handles the individual chat rooms and battle rooms
server/chat.ts sets up Chat, which handles chat commands and messages coming in from users (all client-to-server commands are routed through there)
Rooms also includes support for battle rooms, which is where the server connects to the game simulator itself. Game simulation code is in sim/.
The client is built in a mix of TypeScript and JavaScript, with a mostly hand-rolled framework built on Backbone. There’s a rewrite to migrate it to Preact but it’s very stalled.
Its entry point is index.template.html
It was written long ago, so instead of a single JS entry point, it includes a lot of JS files. Everything important is launched from js/client.js
The client’s login server, which handles logins and most database interaction, is written in TypeScript in progress. The backend is split between a MySQL InnoDB database (for most things) and a Postgres database (for Replays).
Its entry point is server.ts.