import type { WorkflowPublicationStatus, WorkflowListPublicationStatus } from '@n8n/api-types';
import {
	WorkflowPublicationOutboxRepository,
	type WorkflowPublicationTriggerStatus,
	WorkflowPublicationTriggerStatusRepository,
} from '@n8n/db';
import { Service } from '@n8n/di';

@Service()
export class WorkflowPublicationStatusService {
	constructor(
		private readonly outboxRepository: WorkflowPublicationOutboxRepository,
		private readonly triggerStatusRepository: WorkflowPublicationTriggerStatusRepository,
	) {}

	/**
	 * Get the publication status of a workflow.
	 *
	 * The status is derived from the in-flight publication (if any) and the current
	 * trigger statuses. The outbox is consulted only to detect an in-flight
	 * publication; settled state comes entirely from the trigger statuses.
	 *
	 * NOTE: we only update the trigger statuses when a publication is completed,
	 * so if there is a publication in progress, the trigger statuses may not reflect the latest state.
	 */
	async getStatus(workflowId: string): Promise<WorkflowPublicationStatus> {
		const [inFlightPublication, currentTriggerStatuses] = await Promise.all([
			this.outboxRepository.findInFlightByWorkflowId(workflowId),
			this.triggerStatusRepository.findByWorkflowId(workflowId),
		]);

		const triggers = currentTriggerStatuses.map((r) => ({
			nodeId: r.nodeId,
			status: r.status,
			errorMessage: r.errorMessage,
		}));

		const isPublishing = inFlightPublication !== null;
		const pendingVersionId = inFlightPublication?.publishedVersionId ?? null;

		// The settled rows ARE the running triggers; if none are activated, nothing is live.
		const activatedRow = currentTriggerStatuses.find((r) => r.status === 'activated');
		const liveVersionId = activatedRow?.versionId ?? null;

		const status = this.deriveStatus(isPublishing, currentTriggerStatuses);
		return { status, liveVersionId, pendingVersionId, triggers };
	}

	/**
	 * Batch-derive the terminal publication status for many workflows, for the list view.
	 *
	 * Unlike getStatus, this does NOT consult the outbox: the list surfaces only settled
	 * states (published/partial/failed) and deliberately never shows in_progress. Workflows
	 * with no trigger rows are omitted (the card falls back to its legacy indicator).
	 */
	async getListStatusesByWorkflowIds(
		workflowIds: string[],
	): Promise<Map<string, WorkflowListPublicationStatus>> {
		const counts = await this.triggerStatusRepository.getStatusCountsByWorkflowIds(workflowIds);

		const statuses = new Map<string, WorkflowListPublicationStatus>();
		// getStatusCountsByWorkflowIds only returns workflows with ≥1 settled row, so total is always ≥1.
		for (const [workflowId, { total, failed }] of counts) {
			statuses.set(workflowId, this.deriveSettledStatus(total, failed));
		}
		return statuses;
	}

	private deriveStatus(
		isPublishing: boolean,
		currentTriggerStatuses: WorkflowPublicationTriggerStatus[],
	): WorkflowPublicationStatus['status'] {
		if (isPublishing) return 'in_progress';
		if (currentTriggerStatuses.length === 0) return 'not_published';
		const failed = currentTriggerStatuses.filter((r) => r.status === 'failed').length;
		return this.deriveSettledStatus(currentTriggerStatuses.length, failed);
	}

	/**
	 * The one settled-state ladder, shared by the detail and list derivations so
	 * the two endpoints can never disagree about the same trigger rows.
	 */
	private deriveSettledStatus(total: number, failed: number): WorkflowListPublicationStatus {
		if (failed === 0) return 'published';
		return failed < total ? 'partial' : 'failed';
	}
}