import { FastifyInstance } from 'fastify';
import fp from 'fastify-plugin';
import { UnauthorizedError, ForbiddenError } from '../utils/errors.js';
import { config } from '../utils/config.js';
import type { JwtPayload } from '../types/auth.js';

// Extend @fastify/jwt's type system for admin JWT
declare module '@fastify/jwt' {
  interface FastifyJWT {
    payload: JwtPayload;
  }
}

async function adminAuthMiddleware(app: FastifyInstance): Promise<void> {
  app.addHook('onRequest', async (request) => {
    if (!request.url.startsWith('/v1/admin')) {
      return;
    }

    // Skip public admin endpoints
    const publicPaths = ['/v1/admin/auth', '/v1/admin/auth/login'];
    if (publicPaths.some((p) => request.url === p)) {
      return;
    }

    const authHeader = request.headers.authorization;
    if (!authHeader?.startsWith('Bearer ')) {
      throw new UnauthorizedError('Missing admin token');
    }

    const token = authHeader.slice(7);

    // Try JWT verification first (new way)
    try {
      const decoded = app.jwt.verify<JwtPayload>(token);
      if (decoded.authType === 'admin') {
        // Successfully verified admin JWT - request.jwtVerify() will attach the decoded payload
        return;
      }
    } catch {
      // JWT verification failed, try fallback (backward compatibility)
    }

    // Fallback: ADMIN_TOKEN (legacy way)
    if (token === config.ADMIN_TOKEN) {
      // Manually attach a fake decoded payload for legacy token
      request.jwtVerify = async () => ({
        userId: 'legacy-admin',
        authType: 'admin',
        role: 'super_admin',
      });
      return;
    }

    throw new ForbiddenError('Invalid admin token');
  });
}

export default fp(adminAuthMiddleware);