import { CanActivate, ExecutionContext, Injectable } from '@nestjs/common';
import { PermissionGuardService } from './services';
import { Reflector } from '@nestjs/core';
import { PermissionModeConditional } from './interfaces';
import { AuthorizationGuardProvider } from './providers';

@Injectable()
export class AuthorizationGuard implements CanActivate {
  public static MODE_METADATA_KEY: string = 'modes';
  public static RESOURCE_METADATA_KEY: string = 'resource';

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

  constructor(private readonly permissionGuardService: PermissionGuardService,
              private readonly reflector: Reflector,
              private readonly authorizationGuardProvider: AuthorizationGuardProvider) {
  }

  public async canActivate(context: ExecutionContext): Promise<boolean> {
    const modes: Array<PermissionModeConditional<any>> =
      this.reflector.get<Array<PermissionModeConditional<any>>>(AuthorizationGuard.MODE_METADATA_KEY, context.getHandler());
    const headers = context.getArgByIndex(0).headers;
    const request = context.switchToHttp().getRequest();
    return await this.authorizationGuardProvider.canActivate(request, headers, modes, request.resourceName, request.resourceId);
  }
}