import { EventsHandler, IEventHandler } from '@nestjs/cqrs';
import {
  SprintClosedEvent,
  SprintCreatedEvent,
  SprintDeletedEvent,
  SprintStartedEvent,
  SprintStatus,
  SprintUpdatedEvent,
} from '@task-stream/api/tracker/domain';
import { UpsertMaterializedIssueRepository } from '../ports/upsert-materialized-issue.repository';
import { UpsertMaterializedSprintRepository } from '../ports/upsert-materialized-sprint.repository';
import { ReadModelNotifier, versionOf } from './read-model-notifier';

type SprintEvent =
  | SprintCreatedEvent
  | SprintUpdatedEvent
  | SprintStartedEvent
  | SprintClosedEvent
  | SprintDeletedEvent;

/** The sprints view (`sprints_view`), one document per sprint. */
@EventsHandler(
  SprintCreatedEvent,
  SprintUpdatedEvent,
  SprintStartedEvent,
  SprintClosedEvent,
  SprintDeletedEvent,
)
export class SprintEventHandler implements IEventHandler<SprintEvent> {
  constructor(
    private readonly sprints: UpsertMaterializedSprintRepository,
    private readonly issues: UpsertMaterializedIssueRepository,
    private readonly notifier: ReadModelNotifier,
  ) {}

  async handle(event: SprintEvent) {
    const version = versionOf(event);
    const id = event.aggregateId;
    if (event instanceof SprintCreatedEvent) {
      await this.sprints.upsert({ ...event.sprint, version });
    } else if (event instanceof SprintUpdatedEvent) {
      await this.sprints.upsert({ id, ...event.changes, version });
      // Tickets show its name.
      if (event.changes.name)
        await this.issues.renameSprint(id, event.changes.name);
    } else if (event instanceof SprintStartedEvent) {
      await this.sprints.upsert({
        id,
        status: SprintStatus.ACTIVE,
        startedAt: event.occurredAt,
        version,
      });
    } else if (event instanceof SprintClosedEvent) {
      await this.sprints.upsert({
        id,
        status: SprintStatus.CLOSED,
        closedAt: event.occurredAt,
        version,
      });
    } else {
      await this.sprints.remove(id);
    }
    await this.notifier.sprint(id, event);
  }
}