package com.yunhai.flowcenter.service;

import com.yunhai.flowcenter.engine.FlowDefModel;
import com.yunhai.flowcenter.engine.FlowEngine;
import com.yunhai.flowcenter.engine.FlowEvent;
import com.yunhai.flowcenter.entity.FlwDef;
import com.yunhai.flowcenter.entity.FlwInstance;
import com.yunhai.flowcenter.enums.FlwEnums;
import com.yunhai.flowcenter.repository.FlwBranchRepository;
import com.yunhai.flowcenter.repository.FlwDefRepository;
import com.yunhai.flowcenter.repository.FlwInstanceRepository;
import com.yunhai.flowcenter.repository.FlwTaskRepository;
import com.yunhai.platform.apistd.BizException;
import com.yunhai.platform.utils.exception.ErrorCode;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.HashMap;
import java.util.Map;

/**
 * 办件生命周期：代发起（幂等 + R4 重启重提）、撤回。
 *
 * <p><b>R4 驳回/撤回后重提语义（开工说明 §7#1，详设定稿）</b>：biz uk 命中已终态办件
 * （30 已拒绝 / 40 已撤回）时复用同一办件行"重启推进"——不新建、不报错：定义刷新为当前
 * 已发布版本、提交快照全量覆盖、旧分支行清空、残留待办失效、status 回 10、提交时间刷新、
 * version 自增（镜像方按 instanceVersion 单调推进到 10）。任务历史保留（1/2/3 状态行不动），
 * 轨迹跨轮连续。status=10/20（在途/已完成）命中则纯幂等返回原办件（duplicated=true）。
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class FlowInstanceService {

    private final FlwInstanceRepository instanceRepository;
    private final FlwDefRepository defRepository;
    private final FlwTaskRepository taskRepository;
    private final FlwBranchRepository branchRepository;
    private final FlowEngine flowEngine;
    private final ApplicationEventPublisher eventPublisher;

    /** 代发起申请体（oapi apply 与未来原生发起共用字段） */
    @RequiredArgsConstructor
    public static class ApplyCommand {
        public final Long schId;
        public final FlwDef def;
        public final String bizType;
        public final String bizId;
        public final String bizTitle;
        public final String bizUrl;
        public final String bizSnapshot;
        public final Integer submitterId;
        public final String submitterName;
        public final String formDataJson;
    }

    /** 代发起结果：instanceId + duplicated（命中既有办件=true，含重启重提） */
    @Transactional
    public ApplyOutcome apply(ApplyCommand cmd) {
        FlwInstance existing = instanceRepository
                .findBySchIdAndBizTypeAndBizId(cmd.schId, cmd.bizType, cmd.bizId).orElse(null);
        if (existing != null) {
            int status = existing.getStatus();
            if (status == FlwEnums.InstanceStatus.APPROVING.getCode()
                    || status == FlwEnums.InstanceStatus.COMPLETED.getCode()) {
                return new ApplyOutcome(existing.getId(), true);
            }
            // 30/40：R4 重启推进（复用办件行，定义/快照/时间刷新，重新走 START）
            restart(existing, cmd);
            return new ApplyOutcome(existing.getId(), true);
        }
        FlwInstance instance = new FlwInstance();
        instance.setSchId(cmd.schId);
        instance.setDefId(cmd.def.getId());
        instance.setDefCode(cmd.def.getCode());
        instance.setDefVersion(cmd.def.getVersion());
        instance.setBizType(cmd.bizType);
        instance.setBizId(cmd.bizId);
        instance.setBizTitle(cmd.bizTitle);
        instance.setBizUrl(cmd.bizUrl);
        instance.setBizSnapshot(cmd.bizSnapshot);
        instance.setFormDataJson(cmd.formDataJson);
        instance.setSubmitterId(cmd.submitterId);
        instance.setSubmitterName(cmd.submitterName);
        instance.setStatus(FlwEnums.InstanceStatus.APPROVING.getCode());
        instance.setSubmitTime(LocalDateTime.now());
        instanceRepository.saveAndFlush(instance);
        appendTraceEvent(instance, FlwEnums.TaskStatus.NODE_SUBMIT, "发起申请",
                FlwEnums.TaskStatus.SUBMITTED, cmd.submitterId, cmd.submitterName);
        flowEngine.startAdvance(instance, cmd.def);
        publishSubmitted(instance);
        return new ApplyOutcome(instance.getId(), false);
    }

    private void restart(FlwInstance instance, ApplyCommand cmd) {
        log.info("[flow-center] R4 重启推进：instance={} 原 status={} biz={}/{}",
                instance.getId(), instance.getStatus(), cmd.bizType, cmd.bizId);
        instance.setDefId(cmd.def.getId());
        instance.setDefCode(cmd.def.getCode());
        instance.setDefVersion(cmd.def.getVersion());
        instance.setBizTitle(cmd.bizTitle);
        instance.setBizUrl(cmd.bizUrl);
        instance.setBizSnapshot(cmd.bizSnapshot);
        instance.setFormDataJson(cmd.formDataJson);
        instance.setSubmitterId(cmd.submitterId);
        instance.setSubmitterName(cmd.submitterName);
        instance.setStatus(FlwEnums.InstanceStatus.APPROVING.getCode());
        instance.setSubmitTime(LocalDateTime.now());
        instance.setFinishTime(null);
        instanceRepository.saveAndFlush(instance);
        taskRepository.invalidatePendingByInstance(instance.getId());
        branchRepository.deleteByInstance(instance.getId());
        appendTraceEvent(instance, FlwEnums.TaskStatus.NODE_RESUBMIT, "重新提交",
                FlwEnums.TaskStatus.SUBMITTED, cmd.submitterId, cmd.submitterName);
        flowEngine.startAdvance(instance, cmd.def);
        publishSubmitted(instance);
    }

    /**
     * 撤回（概览 §5.3）：仅当尚无任何任务被办理时允许；全部待办失效、分支失效、办件=40。
     */
    @Transactional
    public void withdraw(Long schId, Long instanceId) {
        FlwInstance instance = requireInstance(schId, instanceId);
        if (instance.getStatus() != FlwEnums.InstanceStatus.APPROVING.getCode()) {
            throw new BizException(ErrorCode.PARAM_ERROR, "仅审批中的办件可撤回");
        }
        if (!taskRepository.findByInstanceIdAndStatusIn(instanceId,
                FlwEnums.TaskStatus.handledCodes()).isEmpty()) {
            throw new BizException(ErrorCode.PARAM_ERROR, "已有任务被办理，不能撤回");
        }
        instance.setStatus(FlwEnums.InstanceStatus.WITHDRAWN.getCode());
        instance.setFinishTime(LocalDateTime.now());
        instanceRepository.saveAndFlush(instance);
        taskRepository.invalidatePendingByInstance(instanceId);
        branchRepository.invalidateRunningByInstance(instanceId);
        appendTraceEvent(instance, FlwEnums.TaskStatus.NODE_WITHDRAW, "撤回申请",
                FlwEnums.TaskStatus.WITHDRAWN, instance.getSubmitterId(), instance.getSubmitterName());
        Map<String, Object> data = new HashMap<>();
        data.put("result", "WITHDRAWN");
        eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.WITHDRAWN, instanceId, null, data));
    }

    /**
     * 轨迹留痕事件行（2026-09-18）：办件级动作（发起/重新提交、撤回）也落一条 flw_task 行，
     * 让流程轨迹的时间线里这些动作本身可见（原实现只把待办批量置失效，撤回在轨迹上是空白）。
     *
     * <p>行 status=6/7 且 node_id 用保留值（submit/resubmit/withdraw，定义模型里不存在）——
     * 不参与引擎任何判断：不进待办（非 0）、不进已办（handledCodes 不含 6/7）、不挡撤回守卫、
     * 不进超期扫描与分支失效范围、示意图着色与退回目标解析也天然跳过。
     */
    private void appendTraceEvent(FlwInstance instance, String nodeId, String nodeName,
                                  FlwEnums.TaskStatus status, Integer operatorId, String operatorName) {
        LocalDateTime now = LocalDateTime.now();
        com.yunhai.flowcenter.entity.FlwTask row = new com.yunhai.flowcenter.entity.FlwTask();
        row.setInstanceId(instance.getId());
        row.setSchId(instance.getSchId());
        row.setNodeId(nodeId);
        row.setNodeName(nodeName);
        // assignee_id 非空：发起/撤回的操作人恒为提交人；缺失（脏数据）时落 0，不产生僵尸待办
        row.setAssigneeId(operatorId == null ? 0 : operatorId);
        row.setAssigneeName(operatorName);
        row.setStatus(status.getCode());
        row.setArriveTime(now);
        row.setHandleTime(now);
        row.setUrgeCount(0);
        taskRepository.save(row);
    }

    public FlwInstance requireInstance(Long schId, Long instanceId) {
        FlwInstance instance = instanceRepository.findById(instanceId)
                .orElseThrow(() -> new BizException(ErrorCode.PARAM_ERROR, "办件不存在：" + instanceId));
        if (!instance.getSchId().equals(schId)) {
            throw new BizException(ErrorCode.FORBIDDEN, "办件不属于该学校");
        }
        return instance;
    }

    public FlwDef requireDef(Long defId) {
        return defRepository.findById(defId)
                .orElseThrow(() -> new BizException(ErrorCode.PARAM_ERROR, "流程定义不存在：" + defId));
    }

    /**
     * 催办（概览 §5.3）：提交人/管理员对办件的全部待办任务各催一次（URGE 事件 → UserMsg 通道，
     * msgNo=urge:{taskId}:{N} 幂等）；次数上限取定义 settings.urge.maxTimes（默认 3；
     * enabled=false → 0 = 不限次）。非提交人调用须是本校管理员（控制器已按 BoaUser 判定放行）。
     */
    @Transactional
    public void urgeInstance(Long schId, Long instanceId, Integer operatorId) {
        FlwInstance instance = requireInstance(schId, instanceId);
        FlowDefModel model = flowEngine.parseModel(requireDef(instance.getDefId()));
        int maxTimes = urgeMaxTimes(model);
        java.util.List<com.yunhai.flowcenter.entity.FlwTask> pendings =
                taskRepository.findByInstanceIdAndStatus(instanceId,
                        com.yunhai.flowcenter.enums.FlwEnums.TaskStatus.PENDING.getCode());
        if (pendings.isEmpty()) {
            throw new BizException(ErrorCode.PARAM_ERROR, "无待办任务可催办");
        }
        for (com.yunhai.flowcenter.entity.FlwTask task : pendings) {
            if (maxTimes > 0 && task.getUrgeCount() >= maxTimes) {
                continue;
            }
            task.setUrgeCount(task.getUrgeCount() + 1);
            taskRepository.save(task);
            Map<String, Object> data = new HashMap<>();
            data.put("taskId", task.getId());
            data.put("urgeCount", task.getUrgeCount());
            eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.URGE,
                    instanceId, task.getId(), data));
        }
    }

    private static int urgeMaxTimes(FlowDefModel model) {
        if (model == null || model.settings == null || model.settings.urge == null) {
            return 3;
        }
        FlowDefModel.Urge urge = model.settings.urge;
        if (Boolean.FALSE.equals(urge.enabled)) {
            return 0;
        }
        return urge.maxTimes == null || urge.maxTimes <= 0 ? 3 : urge.maxTimes;
    }

    private void publishSubmitted(FlwInstance instance) {
        FlowDefModel model = flowEngine.parseModel(requireDef(instance.getDefId()));
        Map<String, Object> data = new HashMap<>();
        data.put("nodeSummary", FlowEngine.nodeSummary(model));
        eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.SUBMITTED, instance.getId(), null, data));
    }

    /** 代发起结果值对象 */
    @SuppressWarnings("unused")
    public static class ApplyOutcome {
        private final Long instanceId;
        private final boolean duplicated;

        public ApplyOutcome(Long instanceId, boolean duplicated) {
            this.instanceId = instanceId;
            this.duplicated = duplicated;
        }

        public Long getInstanceId() {
            return instanceId;
        }

        public boolean isDuplicated() {
            return duplicated;
        }
    }
}