import jwt from 'jsonwebtoken';
import crypto from 'crypto';

export function parseExpiryToSeconds(expiry: string): number {
  const match = expiry.match(/^(\d+)([smhd])$/);
  if (!match) return 15 * 60;
  const [, num, unit] = match;
  const n = parseInt(num, 10);
  switch (unit) {
    case 's': return n;
    case 'm': return n * 60;
    case 'h': return n * 3600;
    case 'd': return n * 86400;
    default: return 15 * 60;
  }
}

function requireSecret(name: string): string {
  const value = process.env[name];
  if (!value) {
    throw new Error(
      `FATAL: JWT secrets not configured — missing ${name}.\n` +
      'Set JWT_ACCESS_SECRET, JWT_REFRESH_SECRET, JWT_SUPERADMIN_SECRET in environment variables.'
    );
  }
  return value;
}

const ACCESS_TOKEN_SECRET = requireSecret('JWT_ACCESS_SECRET');
const REFRESH_TOKEN_SECRET = requireSecret('JWT_REFRESH_SECRET');
const SUPERADMIN_TOKEN_SECRET = requireSecret('JWT_SUPERADMIN_SECRET');
const BOT_TOKEN_SECRET = process.env.JWT_BOT_SECRET || ACCESS_TOKEN_SECRET;

const ACCESS_TOKEN_EXPIRY = process.env.JWT_ACCESS_EXPIRES || '14d';
const REFRESH_TOKEN_EXPIRY_REMEMBER = process.env.JWT_REFRESH_EXPIRES_REMEMBER || '90d';
const REFRESH_TOKEN_EXPIRY_SESSION = process.env.JWT_REFRESH_EXPIRES_SESSION || '30d';
const SUPERADMIN_TOKEN_EXPIRY = process.env.JWT_SUPERADMIN_EXPIRES || '1h';
const BOT_TOKEN_EXPIRY = process.env.JWT_BOT_EXPIRES || '10m';

export interface TokenPayload {
  userId: number;
  organizationId: number;
  appRole: string;
  role?: string; // legacy fallback for old tokens
}

export interface BotServiceTokenPayload {
  botId: number;
  organizationId: number;
  type: 'bot_service';
}

export interface SuperAdminTokenPayload {
  superAdminId: number;
  email: string;
  isSuperAdmin: true;
}

export interface TokenPair {
  accessToken: string;
  refreshToken: string;
  expiresIn: number;
  familyId?: string;
}

export function generateTokens(payload: TokenPayload, remember: boolean = false, familyId?: string): TokenPair {
  // Ensure we don't include legacy role in new tokens
  const { role, ...cleanPayload } = payload as any;
  const accessToken = jwt.sign(cleanPayload, ACCESS_TOKEN_SECRET, {
    expiresIn: ACCESS_TOKEN_EXPIRY as jwt.SignOptions['expiresIn'],
    issuer: 'workflow-system',
    audience: 'workflow-users'
  });

  const refreshToken = jwt.sign(cleanPayload, REFRESH_TOKEN_SECRET, {
    expiresIn: (remember ? REFRESH_TOKEN_EXPIRY_REMEMBER : REFRESH_TOKEN_EXPIRY_SESSION) as jwt.SignOptions['expiresIn'],
    issuer: 'workflow-system',
    audience: 'workflow-users'
  });

  return {
    accessToken,
    refreshToken,
    expiresIn: parseExpiryToSeconds(ACCESS_TOKEN_EXPIRY),
    familyId
  };
}

export function verifyAccessToken(token: string): TokenPayload {
  const decoded = jwt.verify(token, ACCESS_TOKEN_SECRET, {
    algorithms: ['HS256'],
    issuer: 'workflow-system',
    audience: 'workflow-users',
  }) as TokenPayload;
  // Fallback for old tokens that used 'role' instead of 'appRole'
  if (!decoded.appRole && decoded.role) {
    decoded.appRole = decoded.role;
  }
  return decoded;
}

export function verifyRefreshToken(token: string): TokenPayload {
  const decoded = jwt.verify(token, REFRESH_TOKEN_SECRET, {
    algorithms: ['HS256'],
    issuer: 'workflow-system',
    audience: 'workflow-users',
  }) as TokenPayload;
  // Fallback for old tokens that used 'role' instead of 'appRole'
  if (!decoded.appRole && decoded.role) {
    decoded.appRole = decoded.role;
  }
  return decoded;
}

export function generateVerificationToken(): string {
  return crypto.randomBytes(32).toString('hex');
}

export function generateResetToken(): string {
  return crypto.randomBytes(32).toString('hex');
}

export function generateBotServiceToken(botId: number, organizationId: number): string {
  const payload: BotServiceTokenPayload = {
    botId,
    organizationId,
    type: 'bot_service'
  };

  return jwt.sign(payload, BOT_TOKEN_SECRET, {
    expiresIn: BOT_TOKEN_EXPIRY as jwt.SignOptions['expiresIn'],
    issuer: 'workflow-system',
    audience: 'workflow-bots'
  });
}

export function verifyBotServiceToken(token: string): BotServiceTokenPayload {
  const payload = jwt.verify(token, BOT_TOKEN_SECRET, {
    issuer: 'workflow-system',
    audience: 'workflow-bots'
  }) as BotServiceTokenPayload;

  if (payload.type !== 'bot_service') {
    throw new Error('Invalid token type');
  }

  return payload;
}

export function generateSuperAdminToken(payload: SuperAdminTokenPayload): string {
  return jwt.sign(payload, SUPERADMIN_TOKEN_SECRET, {
    expiresIn: SUPERADMIN_TOKEN_EXPIRY as jwt.SignOptions['expiresIn'],
    issuer: 'workflow-system',
    audience: 'workflow-superadmin'
  });
}

export function verifySuperAdminToken(token: string): SuperAdminTokenPayload {
  const payload = jwt.verify(token, SUPERADMIN_TOKEN_SECRET, {
    issuer: 'workflow-system',
    audience: 'workflow-superadmin'
  }) as SuperAdminTokenPayload;

  if (!payload.isSuperAdmin) {
    throw new Error('Invalid super admin token');
  }

  return payload;
}