import { Application, Router } from "@oak/oak";
import { Packet } from "./proto.ts";
import { CausalTree } from "./sync/ordt/causal-tree.ts";
import { PlainTextORDT } from "./sync/ordt/plain-text.ts";

const app = new Application();
const router = new Router();

const pt = new PlainTextORDT();
const sockets = new Set<WebSocket>();

// simple websocket broadcast
router.get("/api/connect", ctx => {
  const socket = ctx.upgrade();
  sockets.add(socket);
  socket.addEventListener("message", event => {
    if (typeof event.data !== "string") return;

    const op = JSON.parse(event.data);
    pt.apply(op); // mutates op to strong
    const weakOp = CausalTree.toWeakOp(op);

    for (const other of sockets) {
      if (other === socket) continue;
      other.send(JSON.stringify({ t: "op", op: weakOp }));
    }
  });
  socket.addEventListener("close", () => {
    sockets.delete(socket);
  });

  const onReady = () => {
    socket.send(
      JSON.stringify({
        t: "init",
        ops: pt.operations.map(it => CausalTree.toWeakOp(it)),
        you: crypto.randomUUID(),
      } satisfies Packet),
    );
  };
  if (socket.readyState === WebSocket.OPEN) {
    onReady();
  } else {
    socket.addEventListener("open", () => onReady());
  }
});

router.get("/:path*", async ctx => {
  try {
    await ctx.send({ root: "./client", index: "index.html" });
  } catch {
    // ignore
  }
});

app.use(router.routes());
app.use(router.allowedMethods());

console.log("Listening at: http://127.0.0.1:3000/ ...");
app.listen({ port: 3000 });