import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { IS_PUBLIC_KEY } from '../decorators/public.decorator';
import { AuthTokenService } from '../auth-token.service';

@Injectable()
export class JwtAuthGuard implements CanActivate {
  constructor(
    private readonly reflector: Reflector,
    private readonly authToken: AuthTokenService,
  ) {}

  canActivate(context: ExecutionContext) {
    const isPublic = this.reflector.getAllAndOverride<boolean>(IS_PUBLIC_KEY, [
      context.getHandler(),
      context.getClass(),
    ]);

    if (isPublic) {
      return true;
    }

    const request = context.switchToHttp().getRequest();
    const token = this.extractBearerToken(request.headers?.authorization);

    if (!token) {
      throw new UnauthorizedException('Token de autenticação não informado');
    }

    request.user = this.authToken.verifyToken(token);

    return true;
  }

  private extractBearerToken(authorization?: string) {
    const [type, token] = String(authorization || '').split(' ');

    if (type?.toLowerCase() !== 'bearer' || !token) {
      return null;
    }

    return token;
  }
}