import { CanActivate, ExecutionContext, Injectable, UnauthorizedException } from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { Observable } from 'rxjs';
import { GuardMetadata } from '../enums';
import { MicroServiceSub } from '../enums';
import { MicroServiceGuardService } from './services';
import { AppLogger } from '../../logger';

@Injectable()
export class MicroServiceGuard implements CanActivate {

  private readonly TAG: string = `${this.constructor.name}`;

  constructor(private readonly reflector: Reflector, private readonly microServiceGuardService: MicroServiceGuardService) {
    AppLogger.log('Init', this.TAG);
  }

  canActivate(
    context: ExecutionContext,
  ): boolean | Promise<boolean> | Observable<boolean> {
    const request: any = context.switchToHttp().getRequest();
    if (request && request.headers && request.headers.authorization) {
      const jwt: string = request.headers.authorization;
      const microServiceAllowed: MicroServiceSub = this.reflector.get(GuardMetadata.MICRO_SERVICE, context.getHandler());
      const microServiceSub: string = this.microServiceGuardService.getMicroServiceSub(microServiceAllowed);
      return this.validateRequest(jwt, microServiceSub);
    }
    throw new UnauthorizedException();
  }

  async validateRequest(token: string, microServiceAllowed: string): Promise<boolean> {
    try {
      const isValid: boolean = await this.microServiceGuardService.verify(token, microServiceAllowed);
      if (!isValid) {
        throw new UnauthorizedException();
      }
      return isValid;
    } catch (e) {
      throw new UnauthorizedException();
    }
  }

}