import type { IncomingMessage } from "node:http";
import type { WebSocket, WebSocketServer } from "ws";
import { verifyMeetingToken } from "./token";
import {
  broadcast,
  getParticipant,
  isKicked,
  joinRoom,
  kickFromRoom,
  leaveRoom,
  type Participant,
} from "./rooms";
import type { ClientToServerMessage, ParticipantSummary } from "./protocol";

function participantSummary(p: Participant): ParticipantSummary {
  return { participantId: p.participantId, name: p.name, role: p.role };
}

export function attachSignalingServer(wss: WebSocketServer) {
  wss.on("connection", (ws: WebSocket, req: IncomingMessage) => {
    const url = new URL(req.url ?? "", "http://internal");
    const token = url.searchParams.get("token") ?? "";
    const payload = verifyMeetingToken(token);

    if (!payload) {
      ws.close(4000, "invalid-token");
      return;
    }
    if (isKicked(payload.eventSlug, payload.participantId)) {
      ws.close(4001, "removed-by-host");
      return;
    }

    const self: Participant = {
      ws,
      participantId: payload.participantId,
      name: payload.name,
      role: payload.role,
    };

    const existing = joinRoom(payload.eventSlug, self);

    ws.send(
      JSON.stringify({
        type: "welcome",
        participantId: self.participantId,
        role: self.role,
        participants: existing.map(participantSummary),
      }),
    );

    broadcast(payload.eventSlug, { type: "peer-joined", ...participantSummary(self) }, {
      exclude: self.participantId,
    });

    ws.on("message", (raw) => {
      let message: ClientToServerMessage;
      try {
        message = JSON.parse(raw.toString());
      } catch {
        return;
      }

      if (message.type === "offer" || message.type === "answer" || message.type === "ice-candidate") {
        const target = getParticipant(payload.eventSlug, message.to);
        if (target && target.ws.readyState === target.ws.OPEN) {
          target.ws.send(
            JSON.stringify({ type: message.type, from: self.participantId, payload: message.payload }),
          );
        }
        return;
      }

      if (message.type === "kick") {
        if (self.role !== "host") return; // server-side authority, not client-claimed
        const target = getParticipant(payload.eventSlug, message.targetParticipantId);
        if (!target) return;
        kickFromRoom(payload.eventSlug, target.participantId);
        target.ws.send(JSON.stringify({ type: "kicked" }));
        target.ws.close(4001, "removed-by-host");
        broadcast(payload.eventSlug, { type: "peer-left", participantId: target.participantId });
      }
    });

    ws.on("close", () => {
      leaveRoom(payload.eventSlug, self.participantId);
      broadcast(payload.eventSlug, { type: "peer-left", participantId: self.participantId });
    });
  });
}