import type {
  Comment,
  Dump,
  OnlineUser,
  Playlist,
  ServerToClientMessage,
  User,
} from "../model/interfaces.ts";

export interface WsClient {
  socket: WebSocket;
  userId?: string;
  username?: string;
  avatarMime?: string;
  avatarVersion?: number;
  pongReceived?: boolean;
}

const clients = new Set<WsClient>();

export function register(client: WsClient): void {
  clients.add(client);
}

export function unregister(client: WsClient): void {
  clients.delete(client);
}

export function updateClientAvatar(userId: string, avatarMime: string): void {
  const version = Date.now();
  for (const client of clients) {
    if (client.userId === userId) {
      client.avatarMime = avatarMime;
      client.avatarVersion = version;
    }
  }
  broadcastPresence();
}

export function getOnlineUsers(): OnlineUser[] {
  const seen = new Map<string, OnlineUser>();
  for (const client of clients) {
    if (client.userId && !seen.has(client.userId)) {
      seen.set(client.userId, {
        userId: client.userId,
        username: client.username!,
        hasAvatar: !!client.avatarMime,
        avatarVersion: client.avatarVersion,
      });
    }
  }
  return Array.from(seen.values());
}

function send(socket: WebSocket, data: ServerToClientMessage): void {
  if (socket.readyState === WebSocket.OPEN) {
    socket.send(JSON.stringify(data));
  }
}

export function sendToUser(userId: string, data: ServerToClientMessage): void {
  for (const client of clients) {
    if (client.userId === userId) {
      send(client.socket, data);
    }
  }
}

export function disconnectUser(userId: string): void {
  for (const client of clients) {
    if (client.userId === userId) {
      send(client.socket, { type: "force_logout" });
      client.socket.close(1000, "Account deleted");
    }
  }
}

export function broadcastPresence(): void {
  const users = getOnlineUsers();
  for (const client of clients) {
    send(client.socket, { type: "presence_update", users });
  }
}

export function broadcastNewDump(dump: Dump): void {
  for (const client of clients) {
    send(client.socket, { type: "dump_created", dump });
  }
}

export function broadcastDumpUpdated(dump: Dump): void {
  for (const client of clients) {
    send(client.socket, { type: "dump_updated", dump });
  }
}

export function broadcastDumpDeleted(dumpId: string): void {
  for (const client of clients) {
    send(client.socket, { type: "dump_deleted", dumpId });
  }
}

export function broadcastVoteUpdate(
  dumpId: string,
  voteCount: number,
  voterId: string,
  action: "cast" | "remove",
): void {
  for (const client of clients) {
    send(client.socket, {
      type: "votes_update",
      dumpId,
      voteCount,
      voterId,
      action,
    });
  }
}

function sendToPlaylistAudience(
  playlist: Pick<Playlist, "isPublic" | "userId">,
  data: ServerToClientMessage,
): void {
  for (const client of clients) {
    if (playlist.isPublic || client.userId === playlist.userId) {
      send(client.socket, data);
    }
  }
}

export function broadcastPlaylistCreated(playlist: Playlist): void {
  sendToPlaylistAudience(playlist, { type: "playlist_created", playlist });
}

export function broadcastPlaylistUpdated(playlist: Playlist): void {
  // Broadcast to ALL clients so non-owners can react to visibility changes
  // (e.g. remove a now-private playlist from their feed).
  for (const client of clients) {
    send(client.socket, { type: "playlist_updated", playlist });
  }
}

export function broadcastPlaylistDeleted(
  playlistId: string,
  userId: string,
  isPublic: boolean,
): void {
  sendToPlaylistAudience({ isPublic, userId }, {
    type: "playlist_deleted",
    playlistId,
    userId,
  });
}

export function broadcastPlaylistDumpsUpdated(
  playlist: Playlist,
  dumpIds: string[],
): void {
  sendToPlaylistAudience(playlist, {
    type: "playlist_dumps_updated",
    playlistId: playlist.id,
    dumpIds,
  });
}

export function broadcastUserUpdated(user: Omit<User, "passwordHash">): void {
  for (const client of clients) {
    send(client.socket, { type: "user_updated", user });
  }
}

export function broadcastCommentCreated(comment: Comment): void {
  for (const client of clients) {
    send(client.socket, { type: "comment_created", comment });
  }
}

export function broadcastCommentDeleted(
  commentId: string,
  dumpId: string,
): void {
  for (const client of clients) {
    send(client.socket, { type: "comment_deleted", commentId, dumpId });
  }
}

export function broadcastCommentUpdated(comment: Comment): void {
  for (const client of clients) {
    send(client.socket, { type: "comment_updated", comment });
  }
}

export function handleClientPong(client: WsClient): void {
  client.pongReceived = true;
}

// Keepalive: ping all clients every 30s, disconnect non-responsive ones
const PING_INTERVAL = 30_000;

setInterval(() => {
  for (const client of clients) {
    if (client.socket.readyState !== WebSocket.OPEN) {
      clients.delete(client);
      continue;
    }
    // Disconnect if no pong since last ping (pongReceived starts undefined, skip first cycle)
    if (client.pongReceived === false) {
      client.socket.close(1001, "Ping timeout");
      clients.delete(client);
      continue;
    }
    client.pongReceived = false;
    send(client.socket, { type: "ping" });
  }
}, PING_INTERVAL);