import { Request, Response, NextFunction } from 'express';
import jwt from 'jsonwebtoken';

const AUTH_HOST          = process.env.AUTH_HOST          ?? 'https://account.rokojori.com';
const AUTH_INTERNAL_HOST = process.env.AUTH_INTERNAL_HOST ?? AUTH_HOST;
const JWT_SECRET         = process.env.JWT_SECRET         ?? '';
const COOKIE_DOMAIN      = process.env.COOKIE_DOMAIN      ?? '.rokojori.com';

export interface JwtUser {
  userId:   string;
  email:    string;
  roles:    string[];
  products: string[];
  settings: Record<string, unknown>;
}

declare global {
  namespace Express {
    interface Request {
      user?: JwtUser;
    }
  }
}

function extractToken( req: Request ): string | undefined {
  const cookie = req.cookies?.accessToken as string | undefined;
  if ( cookie ) return cookie;
  const header = req.headers.authorization;
  if ( header?.startsWith( 'Bearer ' ) ) return header.slice( 7 );
  return undefined;
}

function isApiRequest( req: Request ): boolean {
  return req.path.startsWith( '/api/' );
}

function cookieOpts( maxAge: number ) {
  return {
    domain:   COOKIE_DOMAIN,
    httpOnly: true,
    secure:   process.env.NODE_ENV === 'production',
    sameSite: 'lax' as const,
    path:     '/',
    maxAge
  };
}

interface RefreshResult {
  accessToken:  string;
  refreshToken: string;
}

async function tryRefresh( refreshToken: string ): Promise<RefreshResult | null> {
  const url = `${AUTH_INTERNAL_HOST}/api/auth/refresh`;
  console.log( '[auth] tryRefresh →', url );
  try {
    const r = await fetch( url, {
      method:  'POST',
      headers: { 'Content-Type': 'application/json' },
      body:    JSON.stringify( { refreshToken } )
    } );
    console.log( '[auth] tryRefresh status:', r.status );
    if ( !r.ok ) {
      const body = await r.text();
      console.log( '[auth] tryRefresh error body:', body );
      return null;
    }
    const data = await r.json() as Partial<RefreshResult>;
    if ( !data.accessToken || !data.refreshToken ) {
      console.log( '[auth] tryRefresh missing tokens in response:', Object.keys( data ) );
      return null;
    }
    console.log( '[auth] tryRefresh succeeded' );
    return { accessToken: data.accessToken, refreshToken: data.refreshToken };
  } catch ( err ) {
    console.log( '[auth] tryRefresh fetch error:', err );
    return null;
  }
}

export function jwtMiddleware( req: Request, res: Response, next: NextFunction ): void {
  const token = extractToken( req );

  if ( !token ) { next(); return; }

  try {
    req.user = jwt.verify( token, JWT_SECRET ) as JwtUser;
    next();
  } catch ( err: unknown ) {
    if ( !( err instanceof jwt.TokenExpiredError ) ) { next(); return; }

    if ( !isApiRequest( req ) ) {
      const redirect = encodeURIComponent( req.protocol + '://' + req.get( 'host' ) + req.originalUrl );
      res.redirect( `${AUTH_HOST}/api/auth/refresh-session?redirect=${redirect}` );
      return;
    }

    // API request with expired token — try transparent refresh via refreshToken cookie
    console.log( '[auth] expired token on API route:', req.path );
    const refreshToken = req.cookies?.refreshToken as string | undefined;
    if ( !refreshToken ) {
      console.log( '[auth] no refreshToken cookie — cannot refresh' );
      next(); return;
    }

    tryRefresh( refreshToken ).then( result => {
      if ( !result ) {
        console.log( '[auth] refresh failed, returning 401 for:', req.path );
        next(); return;
      }
      res.cookie( 'accessToken',  result.accessToken,  cookieOpts( 60 * 60 * 1000 ) );
      res.cookie( 'refreshToken', result.refreshToken, cookieOpts( 30 * 24 * 60 * 60 * 1000 ) );
      try {
        req.user = jwt.verify( result.accessToken, JWT_SECRET ) as JwtUser;
      } catch { /* fall through — requireAuth will return 401 */ }
      next();
    } ).catch( () => next() );
  }
}

export function requireAuth( req: Request, res: Response, next: NextFunction ): void {
  if ( !req.user ) {
    res.status( 401 ).json( { error: 'Not authenticated' } );
    return;
  }
  next();
}