package com.yunhai.flowcenter.engine;

import com.yunhai.flowcenter.entity.FlwDef;
import com.yunhai.flowcenter.entity.FlwInstance;
import com.yunhai.flowcenter.enums.FlwEnums;
import com.yunhai.flowcenter.repository.FlwDefRepository;
import com.yunhai.flowcenter.repository.FlwInstanceRepository;
import com.yunhai.flowcenter.repository.FlwTaskRepository;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

/**
 * 节点放行推进（AFTER_COMMIT 监听器经代理调用本 bean，REQUIRES_NEW 生效——
 * 事务已提交后的同步监听阶段没有活动事务，@Modifying 批量语句必须有新事务承载）：
 * 该节点待办清零且办件在途才推进；并发冲突由 flw_instance.version 乐观锁暴露，监听器层负责重试。
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class FlowAdvanceService {

    private final FlwInstanceRepository instanceRepository;
    private final FlwDefRepository defRepository;
    private final FlwTaskRepository taskRepository;
    private final FlowEngine flowEngine;

    /** @return 是否实际推进了 */
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public boolean tryAdvance(Long instanceId, String nodeId) {
        FlwInstance instance = instanceRepository.findById(instanceId).orElse(null);
        if (instance == null
                || instance.getStatus() != FlwEnums.InstanceStatus.APPROVING.getCode()) {
            return false;
        }
        // 已推进过的节点不再放行（currentNodes 由引擎在放行时移除，乐观锁保证互斥）
        String current = instance.getCurrentNodes();
        boolean active = current != null && java.util.Arrays.stream(current.split(","))
                .anyMatch(nodeId::equals);
        if (!active) {
            return false;
        }
        long pending = taskRepository.findByInstanceIdAndStatus(instanceId,
                FlwEnums.TaskStatus.PENDING.getCode()).stream()
                .filter(t -> nodeId.equals(t.getNodeId()))
                .count();
        if (pending > 0) {
            return false;
        }
        FlwDef def = defRepository.findById(instance.getDefId()).orElse(null);
        if (def == null) {
            log.error("[flow-center] 办件定义缺失，推进中止：instance={} defId={}",
                    instanceId, instance.getDefId());
            return false;
        }
        flowEngine.continueAdvance(instance, def, nodeId);
        instanceRepository.save(instance);
        return true;
    }
}