"use strict";

const { WebSocketServer, WebSocket } = require("ws");
const { isSecureRequest, requestOrigin } = require("../../../src/services/proxy-security");
const { insecureDeviceAllowed } = require("../../lumi_transcription/backend/companion/device_store");
const { onOverlayChatMessage } = require("../../../src/services/overlay-chat");
const { onLumiEvent } = require("../../../src/services/lumi-events");
const { parseClientMessage, sanitizeChat, sanitizeEvent, MAX_MESSAGE_BYTES } = require("./protocol");
const { listSources, listStatuses, sourceIdForChat, sourceIdForEvent, listEventTypes } = require("./sources");

const MAX_QUEUE = 300;
const MAX_DEDUPE = 2000;

class OverlayFeed {
  constructor({ devices, logger }) {
    this.devices = devices;
    this.logger = logger || { info() {}, warn() {}, error() {} };
    this.wss = new WebSocketServer({ noServer: true, maxPayload: MAX_MESSAGE_BYTES, perMessageDeflate: false });
    this.sessions = new Set();
    this.publishedSeen = new Map();
    this.sequence = 0;
    this.stopChat = onOverlayChatMessage((message) => this.publishChat(message));
    this.stopEvent = onLumiEvent((event) => this.publishEvent(event));
    this.wss.on("connection", (socket, request, device) => this.connected(socket, request, device));
  }

  upgrade(request, socket, head) {
    const auth = this.devices.authenticate(request.headers.authorization, "overlay.read.v1");
    if (!auth.allowed) return reject(socket, auth.reason === "capability_revoked" ? 403 : 401, auth.reason);
    let origin;
    try { origin = requestOrigin(request); } catch { return reject(socket, 400, "invalid_host"); }
    if (!isSecureRequest(request) && !insecureDeviceAllowed(auth.device, origin, request.socket.remoteAddress))
      return reject(socket, 426, "tls_required");
    this.wss.handleUpgrade(request, socket, head, (ws) => this.wss.emit("connection", ws, request, auth.device));
  }

  connected(socket, _request, device) {
    const session = {
      socket, device, sources: new Set(), events: new Set(), subscribed: false,
      queue: [], draining: false, seen: new Map(), lastPong: Date.now()
    };
    this.sessions.add(session);
    this.send(session, "hello", {
      protocol_version: 1,
      capabilities: ["overlay.feed.v1", "sources.catalog.v1", "live-state.v1"],
      sources: listSources(),
      event_types: listEventTypes(),
      statuses: listStatuses(),
      heartbeat_ms: 15000
    });
    const heartbeat = setInterval(() => {
      if (Date.now() - session.lastPong > 45000) return socket.close(4408, "heartbeat_timeout");
      this.send(session, "ping", { at: Date.now() });
      this.send(session, "catalog", { sources: listSources(), statuses: listStatuses() });
    }, 15000);
    heartbeat.unref?.();
    socket.on("message", (raw, binary) => {
      if (binary) return socket.close(4400, "text_messages_only");
      try {
        const message = parseClientMessage(raw);
        if (message.type === "subscribe") {
          session.sources = new Set(message.sources);
          session.events = new Set(message.events);
          session.subscribed = true;
          this.send(session, "subscribed", { sources: [...session.sources], events: [...session.events] });
        } else if (message.type === "pong") session.lastPong = Date.now();
        else if (message.type === "ping") this.send(session, "pong", { at: Date.now() });
      } catch (error) {
        this.send(session, "error", { code: error.code || "INVALID_MESSAGE", message: error.message });
      }
    });
    socket.on("close", () => { clearInterval(heartbeat); this.sessions.delete(session); });
    socket.on("error", (error) => this.logger.warn?.("Native overlay feed connection failed", { device_id: device.id, error: error.message }, { event: "overlay_feed_socket_error" }));
  }

  publishChat(message) {
    const sourceId = sourceIdForChat(message);
    if (!this.acceptPublished(`chat:${message.id}`)) return;
    for (const session of this.sessions) {
      if (!session.subscribed || !session.sources.has(sourceId)) continue;
      this.enqueue(session, "chat", { source_id: sourceId, message: sanitizeChat(message) }, `chat:${message.id}`);
    }
  }

  publishEvent(event) {
    const sourceId = sourceIdForEvent(event);
    if (!this.acceptPublished(`event:${event.id}`)) return;
    for (const session of this.sessions) {
      if (!session.subscribed || !session.events.has(event.type) || !matchesSelectedSource(session.sources, sourceId)) continue;
      this.enqueue(session, "event", { source_id: sourceId, event: sanitizeEvent(event) }, `event:${event.id}`);
    }
  }

  enqueue(session, type, payload, key) {
    const now = Date.now();
    if (session.seen.has(key)) return;
    session.seen.set(key, now);
    while (session.seen.size > MAX_DEDUPE) session.seen.delete(session.seen.keys().next().value);
    const envelope = { type, sequence: ++this.sequence, sent_at: now, ...payload };
    if (session.queue.length >= MAX_QUEUE) session.queue.shift();
    session.queue.push(envelope);
    this.drain(session);
  }

  acceptPublished(key) {
    this.publishedSeen ||= new Map();
    if (this.publishedSeen.has(key)) return false;
    this.publishedSeen.set(key, Date.now());
    while (this.publishedSeen.size > MAX_DEDUPE) this.publishedSeen.delete(this.publishedSeen.keys().next().value);
    return true;
  }

  drain(session) {
    if (session.draining) return;
    session.draining = true;
    try {
      while (session.queue.length && session.socket.readyState === WebSocket.OPEN) {
        session.socket.send(JSON.stringify(session.queue.shift()));
      }
    } finally { session.draining = false; }
  }

  send(session, type, payload) {
    if (session.socket.readyState === WebSocket.OPEN) session.socket.send(JSON.stringify({ type, sequence: ++this.sequence, sent_at: Date.now(), ...payload }));
  }

  async close() {
    this.stopChat();
    this.stopEvent();
    for (const session of this.sessions) session.socket.close(1001, "plugin_shutdown");
    await new Promise((resolve) => this.wss.close(resolve));
  }
}

function matchesSelectedSource(selected, sourceId) {
  if (selected.has(sourceId)) return true;
  if (sourceId.startsWith("discord:") && sourceId.endsWith(":*"))
    return [...selected].some((id) => id.startsWith(sourceId.slice(0, -1)));
  if (sourceId.endsWith(":current"))
    return [...selected].some((id) => id.startsWith(sourceId.split(":")[0] + ":"));
  return false;
}

function reject(socket, status, reason) {
  const labels = { 400: "Bad Request", 401: "Unauthorized", 403: "Forbidden", 426: "Upgrade Required" };
  socket.write(`HTTP/1.1 ${status} ${labels[status] || "Rejected"}\r\nConnection: close\r\nContent-Type: application/json\r\n\r\n${JSON.stringify({ error: reason })}`);
  socket.destroy();
}

module.exports = { OverlayFeed, MAX_QUEUE, matchesSelectedSource };