// @ts-check
import { WebSocketServer } from 'ws';
import { readFileSync, mkdirSync, writeFileSync } from "fs";

const PORT = 8080

const wss = new WebSocketServer({ port: PORT });

console.log(`WebSocket server running on ws://localhost:${PORT}`);

wss.on('connection', (ws) => {
  console.log('New client connected');

  ws.on('message', (message) => {
    const { name, ...payload } = JSON.parse(message.toString('utf-8'));
    console.log(name, payload)
    switch (name) {
      case 'download_q': {
        const { q } = payload;

        try {
          mkdirSync(`docs/${q}`);
        } catch (e) {}

        let outMd = "";

        const re = /^(?<min>\d{1,2}):(?<sec>\d{2})\s*$/;

        for (const line of readFileSync(`docs/${q}.md`, "utf-8").trimEnd().split("\n")) {
          const m = re.exec(line);
          if (m?.groups) {
            const { min, sec } = m.groups;
            const t = parseInt(min) * 60 + parseInt(sec);
            ws.send(JSON.stringify({ name: "seek_q", t }));
            outMd += `\n[${line}](./${q}/${t}.png)\n\n`;
          } else {
            outMd += `${line}\n`;
          }
        }

        writeFileSync(`docs/${q}.md`, outMd);
      } break;
      case 'timed_q' : {
        const { q, t, data } = payload;

        writeFileSync(
          `docs/${q}/${t}.png`,
          data.replace(/^data:image\/png;base64,/, ""),
          "base64",
        );
      } break;
    }
  });

  ws.on('close', () => {
    console.log('Client disconnected');
  });
});