import type { UseCase, UseCaseOutputPort } from '@core/shared/application';
import { Result } from '@core/shared/application/Result';
import type { ApplicationErrorCode } from '@core/shared/errors/ApplicationErrorCode';
import type { IDriverRepository } from '../../domain/repositories/IDriverRepository';

/**
 * Input type for retrieving total number of drivers.
 */
export type GetTotalDriversInput = {};

/**
 * Domain result model for the total number of drivers.
 */
export type GetTotalDriversResult = {
  totalDrivers: number;
};

export type GetTotalDriversErrorCode = 'REPOSITORY_ERROR';

export class GetTotalDriversUseCase implements UseCase<GetTotalDriversInput, void, GetTotalDriversErrorCode> {
  constructor(
    private readonly driverRepository: IDriverRepository,
    private readonly output: UseCaseOutputPort<GetTotalDriversResult>,
  ) {}

  async execute(
    _input: GetTotalDriversInput,
  ): Promise<Result<void, ApplicationErrorCode<GetTotalDriversErrorCode, { message: string }>>> {
    void _input;
    try {
      const drivers = await this.driverRepository.findAll();
      const result: GetTotalDriversResult = { totalDrivers: drivers.length };

      this.output.present(result);

      return Result.ok(void 0);
    } catch (error) {
      const message = (error as Error | undefined)?.message ?? 'Failed to compute total drivers';

      return Result.err({
        code: 'REPOSITORY_ERROR',
        details: { message },
      });
    }
  }
}