import {
  Injectable,
  CanActivate,
  ExecutionContext,
  Scope,
  Logger,
  UnauthorizedException,
} from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { Observable } from 'rxjs';
import { SessionService, UsersSession } from 'src/core/sessions';
import { UNPROTECTED_URL } from '../constants';
import { PrivilegeService } from './services/privilege.service';

@Injectable({ scope: Scope.REQUEST })
export class JWTGuard implements CanActivate {
  constructor(
    protected readonly session: SessionService,
    protected readonly reflector: Reflector,
    protected readonly privilege: PrivilegeService,
  ) {}

  protected isPublic = false;
  protected userSession: UsersSession;

  canActivate(
    context: ExecutionContext,
  ): boolean | Promise<boolean> | Observable<boolean> {
    /**
     * Check if access url is protected or not
     * By default `isUnprotected` equals `false`
     */
    const isUnprotected = this.reflector.getAllAndOverride<boolean>(
      UNPROTECTED_URL,
      [context.getHandler(), context.getClass()],
    );
    this.isPublic = isUnprotected;
    this.session.setPublic(isUnprotected);
    if (isUnprotected) return true;

    /**
     * Check if request give the token or not
     * If there is not token in request, the transaction is failed
     * and return 401 `Unauthorize`
     */
    const request = context.switchToHttp().getRequest();
    const authorization = request.headers['authorization'];
    if (!authorization)
      throw new UnauthorizedException({
        code: 10002,
        message: 'Access denied, please login first!',
        error: 'TOKEN_NOT_PROVIDE',
      });

    const [, token] = authorization.split(' ');

    /**
     * Verify if token is valid token from login
     * if the token is'nt valid token, the transaction is failed
     * and return 401
     */
    try {
      this.userSession = this.session.verifyToken(token);
      Logger.log(`Access from ${this.userSession.name}`, 'AuthGuard');
      return true;
    } catch (error) {
      throw new UnauthorizedException({
        code: 10001,
        message:
          'You cant access this endpoint, because authentication inst valid',
        error: 'INVALID_TOKEN',
      });
    }
  }
}