import { createHmac } from "node:crypto";
import { AccessToken, RoomServiceClient, TrackSource } from "livekit-server-sdk";
import type { MeetingRole } from "./token";

function requiredEnv(name: "LIVEKIT_URL" | "LIVEKIT_API_KEY" | "LIVEKIT_API_SECRET"): string {
  const value = process.env[name];
  if (!value) throw new Error(`${name} is not set`);
  return value;
}

export function getLiveKitClientUrl(): string {
  return requiredEnv("LIVEKIT_URL").replace(/^http:/, "ws:").replace(/^https:/, "wss:").replace(/\/$/, "");
}

function getLiveKitApiUrl(): string {
  return requiredEnv("LIVEKIT_URL").replace(/^ws:/, "http:").replace(/^wss:/, "https:").replace(/\/$/, "");
}

/** Stable opaque room name; the public event slug is never sent to LiveKit logs. */
export function getLiveKitRoomName(eventSlug: string): string {
  const secret = requiredEnv("LIVEKIT_API_SECRET");
  return `anouma-${createHmac("sha256", secret).update(eventSlug).digest("hex").slice(0, 32)}`;
}

export async function createLiveKitToken(args: {
  eventSlug: string;
  participantId: string;
  name: string;
  role: MeetingRole;
  clientId?: string;
}): Promise<string> {
  const room = getLiveKitRoomName(args.eventSlug);
  const token = new AccessToken(requiredEnv("LIVEKIT_API_KEY"), requiredEnv("LIVEKIT_API_SECRET"), {
    identity: args.participantId,
    name: args.name,
    ttl: "2h",
    metadata: JSON.stringify({ role: args.role, clientId: args.clientId }),
  });
  token.addGrant({
    roomJoin: true,
    room,
    canPublish: true,
    canSubscribe: true,
    canPublishData: true,
    canPublishSources: args.role === "host"
      ? [TrackSource.CAMERA, TrackSource.MICROPHONE, TrackSource.SCREEN_SHARE, TrackSource.SCREEN_SHARE_AUDIO]
      : [TrackSource.CAMERA, TrackSource.MICROPHONE],
  });
  return token.toJwt();
}

export function getLiveKitRoomService(): RoomServiceClient {
  return new RoomServiceClient(getLiveKitApiUrl(), requiredEnv("LIVEKIT_API_KEY"), requiredEnv("LIVEKIT_API_SECRET"));
}