import { Service } from '@n8n/di';
import { DataSource, IsNull, Repository } from '@n8n/typeorm';

import { InstanceAiCheckpoint } from '../entities/instance-ai-checkpoint.entity';

@Service()
export class InstanceAiCheckpointRepository extends Repository<InstanceAiCheckpoint> {
	constructor(dataSource: DataSource) {
		super(InstanceAiCheckpoint, dataSource.manager);
	}

	/**
	 * Live (non-expired) checkpoints for a thread, newest first. Used to
	 * surface in-flight messages from suspended runs whose `messageList`
	 * hasn't been committed back to `instance_ai_messages` yet — the SDK
	 * only saves the turn delta to memory at the end of a successful loop,
	 * so messages from a turn that suspended at HITL live only in the
	 * checkpoint blob until the run resumes and completes.
	 */
	async findActiveByThreadId(threadId: string): Promise<InstanceAiCheckpoint[]> {
		return await this.find({
			where: { threadId, expiredAt: IsNull() },
			order: { createdAt: 'DESC' },
		});
	}
}