import { IndexeddbPersistence } from "y-indexeddb";
import { WebrtcProvider } from "y-webrtc";
import * as Y from "yjs";

import type { ConnectionStatus, OptionRecord } from "./state";

export interface AppSync {
  doc: Y.Doc;
  yTitle: Y.Text;
  options: Y.Map<OptionRecord>;
  votes: Y.Map<string>;
  deadlineMap: Y.Map<unknown>;
  provider: WebrtcProvider;
  persistence: IndexeddbPersistence;
  getConnectionStatus: () => ConnectionStatus;
  getPeerCount: () => number;
  destroy: () => void;
}

export function initSync(roomId: string): AppSync {
  const doc = new Y.Doc();
  const yTitle = doc.getText("poll-title");
  const options = doc.getMap<OptionRecord>("poll-options");
  const votes = doc.getMap<string>("poll-votes");
  const deadlineMap = doc.getMap<unknown>("poll-deadline");

  let connectionStatus: ConnectionStatus = navigator.onLine
    ? "connecting"
    : "offline";

  const provider = new WebrtcProvider(roomId, doc,{
                signaling: ["ws://localhost:4444", "ws://lynxpi.ddns.net:4444"]
            });
  const persistence = new IndexeddbPersistence(roomId, doc);

  const syncConnectionStatus = (status: ConnectionStatus) => {
    connectionStatus = navigator.onLine ? status : "offline";
  };

  const handleOnline = () => {
    syncConnectionStatus(provider.connected ? "connected" : "connecting");
  };
  const handleOffline = () => {
    connectionStatus = "offline";
  };

  provider.on("status", (event: { connected: boolean }) => {
    syncConnectionStatus(event.connected ? "connected" : "connecting");
  });

  provider.on("synced", ({ synced }: { synced: boolean }) => {
    if (synced) syncConnectionStatus("connected");
  });

  window.addEventListener("online", handleOnline);
  window.addEventListener("offline", handleOffline);

  return {
    doc,
    yTitle,
    options,
    votes,
    deadlineMap,
    provider,
    persistence,
    getConnectionStatus: () => connectionStatus,
    getPeerCount: () => {
      const total = provider.awareness.getStates().size;
      return Math.max(0, total - 1);
    },
    destroy: () => {
      window.removeEventListener("online", handleOnline);
      window.removeEventListener("offline", handleOffline);
      persistence.destroy();
      provider.destroy();
      doc.destroy();
    },
  };
}