import jwt from 'jsonwebtoken';

export interface JitsiUser {
  id: string;
  name: string;
  email?: string;
  avatar?: string;
  role: 'INSTRUCTOR' | 'CLIENT' | 'SUPER_ADMIN';
}

export interface JitsiRoomOptions {
  tenantSlug: string;
  classSessionId: string;
  timestamp?: number;
}

export interface JitsiTokenOptions {
  roomName: string;
  tenantSlug: string;
  user: JitsiUser;
  expiresInSeconds?: number;
}

const JITSI_DOMAIN = process.env.JITSI_DOMAIN || 'jitsi.my127001.ca';
const JITSI_APP_ID = process.env.JITSI_APP_ID || 'fitness-app';
const JITSI_PUBLIC_URL = process.env.JITSI_PUBLIC_URL || `https://${JITSI_DOMAIN}`;

/**
 * 1. Generates deterministic, tenant-isolated Jitsi room name:
 * Format: ${tenantSlug}_${classSessionId}_${timestamp}
 */
export function generateJitsiRoomName(
  tenantSlug: string,
  classSessionId: string,
  timestamp: number = Date.now()
): string {
  const cleanSlug = tenantSlug.toLowerCase().replace(/[^a-z0-9_-]/g, '-');
  const cleanSessionId = classSessionId.replace(/[^a-z0-9_-]/g, '-');
  return `${cleanSlug}_${cleanSessionId}_${timestamp}`;
}

/**
 * 2. Generates a signed Jitsi JWT token for host (INSTRUCTOR) or participant (CLIENT)
 */
export function generateJitsiToken({
  roomName,
  tenantSlug,
  user,
  expiresInSeconds = 7200, // 2 hours
}: JitsiTokenOptions): string {
  const secret = process.env.JITSI_APP_SECRET;
  if (!secret) {
    throw new Error('JITSI_APP_SECRET is required to sign classroom access tokens');
  }

  const isHost = user.role === 'INSTRUCTOR' || user.role === 'SUPER_ADMIN';
  const nowInSeconds = Math.floor(Date.now() / 1000);

  const payload = {
    aud: 'jitsi',
    iss: JITSI_APP_ID,
    sub: JITSI_DOMAIN,
    room: roomName,
    iat: nowInSeconds,
    nbf: nowInSeconds - 5,
    exp: nowInSeconds + expiresInSeconds,
    context: {
      user: {
        id: user.id,
        name: user.name,
        email: user.email || `${user.id}@${tenantSlug}.local`,
        avatar: user.avatar,
        moderator: isHost,
      },
      features: {
        recording: isHost,
        livestreaming: isHost,
        screenSharing: true,
        lobby: isHost,
      },
      tenant: tenantSlug,
    },
  };

  return jwt.sign(payload, secret, {
    algorithm: 'HS256',
    header: {
      typ: 'JWT',
      alg: 'HS256',
    },
  });
}

/**
 * 3. Constructs the meeting room URL with unbranded options
 */
export function generateJitsiMeetingUrl(roomName: string, token?: string): string {
  const base = `${JITSI_PUBLIC_URL}/${encodeURIComponent(roomName)}`;
  if (!token) return base;
  return `${base}?jwt=${encodeURIComponent(token)}`;
}

/**
 * Pre-set feature flags and config overrides for unbranded classrooms
 */
export const DEFAULT_JITSI_CONFIG_OVERRIDES = {
  disableThirdPartyRequests: true,
  defaultLanguage: 'en',
  hideLobbyButton: false,
  toolbarButtons: [
    'microphone',
    'camera',
    'desktop',
    'chat',
    'raisehand',
    'tileview',
    'hangup',
  ],
  disableDeepLinking: true,
  prejoinPageEnabled: false,
  startWithAudioMuted: false,
  startWithVideoMuted: false,
  enableWelcomePage: false,
  enableClosePage: false,
  disableInviteFunctions: true,
};

export const DEFAULT_JITSI_INTERFACE_OVERRIDES = {
  SHOW_JITSI_WATERMARK: false,
  SHOW_WATERMARK_FOR_GUESTS: false,
  SHOW_BRAND_WATERMARK: false,
  DEFAULT_BACKGROUND: '#121212',
  SHOW_PROMOTIONAL_CLOSE_PAGE: false,
  MOBILE_APP_PROMO: false,
  HIDE_DEEP_LINKING_LOGO: true,
  TOOLBAR_ALWAYS_VISIBLE: false,
};

export { JITSI_DOMAIN, JITSI_PUBLIC_URL, JITSI_APP_ID };