import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { JwtService } from '@nestjs/jwt';
import { Request } from 'express';

@Injectable()
export class AuthGuard implements CanActivate {
  constructor(
    private jwtService: JwtService,
    private configService: ConfigService,
  ) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const request = context.switchToHttp().getRequest();
    const jwtToken = this.extractTokenFromCookie(request);
    const csrfToken = this.extractTokenFromHeader(request);

    if (!jwtToken || !csrfToken) {
      throw new UnauthorizedException();
    }

    try {
      const payload = await this.jwtService.verifyAsync(jwtToken, {
        secret: this.configService.get<string>('JWT_SECRET'),
      });

      if (payload.csrf !== csrfToken) {
        throw new UnauthorizedException('Invalid CSRF token');
      }

      request['user'] = payload;
    } catch {
      throw new UnauthorizedException();
    }
    return true;
  }

  private extractTokenFromHeader(request: any): string | undefined {
    const token = request.headers['x-csrf-token'];
    return token;
  }

  private extractTokenFromCookie(request: Request): string | undefined {
    return request.cookies?.access_token;
  }
}