package com.yunhai.flowcenter.notify;

import com.yunhai.flowcenter.engine.FlowEvent;
import com.yunhai.flowcenter.entity.FlwInstance;
import com.yunhai.flowcenter.entity.FlwTask;
import com.yunhai.flowcenter.repository.FlwInstanceRepository;
import com.yunhai.flowcenter.repository.FlwTaskRepository;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.transaction.event.TransactionPhase;
import org.springframework.transaction.event.TransactionalEventListener;

import java.util.Collections;

/**
 * 站内信/待办角标通知（概览 §七 契约，回调通知"业务系统"、本类通知"人"，两通道互不替代）：
 * - 任务到达：msgType=2、bizType=flow.task、msgNo=task:{taskId}、jumpPath=/task/{taskId}、todo +1
 * - 任务被办理：todo -1（办理人）
 * - 完成/拒绝/撤回：msgType=1、bizType=flow.result、content 必填（结果+意见）、msgNo 带 version
 *   （重提重启多轮终态互不幂等吞掉）
 * - 催办：bizType=flow.urge、msgNo=urge:{taskId}:{第N次}
 * 全部在 AFTER_COMMIT 监听器里发送，失败不阻断（UserMsgClient 内部容错）。
 */
@Slf4j
@Component
@RequiredArgsConstructor
public class UserMsgNotifier {

    private final UserMsgClient userMsgClient;
    private final FlwTaskRepository taskRepository;
    private final FlwInstanceRepository instanceRepository;

    @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT, fallbackExecution = true)
    public void onFlowEvent(FlowEvent event) {
        switch (event.getType()) {
            case TASK_CREATED:
                notifyTaskCreated(event);
                break;
            case TASK_HANDLED:
                notifyTaskHandled(event);
                break;
            case RETURNED:
                notifyReturned(event);
                break;
            case TRANSFERRED:
                notifyTaskCreated(event);
                break;
            case COMPLETED:
            case REJECTED:
            case WITHDRAWN:
                notifyResult(event);
                break;
            case URGE:
                notifyUrge(event);
                break;
            default:
                break;
        }
    }

    private void notifyTaskCreated(FlowEvent event) {
        FlwTask task = taskRepository.findById(event.getTaskId()).orElse(null);
        FlwInstance instance = instanceOf(event.getInstanceId());
        if (task == null || instance == null) {
            return;
        }
        String title = "您有新的待办：" + safe(instance.getBizTitle());
        String content = "「" + safe(instance.getBizTitle()) + "」等待您审批"
                + (task.getNodeName() == null ? "" : "（" + task.getNodeName() + "）");
        userMsgClient.sendUserMsg(instance.getSchId().intValue(),
                Collections.singletonList(task.getAssigneeId()), 2,
                "flow.task", String.valueOf(instance.getId()), title, content,
                "/task/" + task.getId(), "task:" + task.getId(), 30);
        userMsgClient.todoInc(instance.getSchId().intValue(),
                Collections.singletonList(task.getAssigneeId()), 1);
    }

    private void notifyTaskHandled(FlowEvent event) {
        FlwTask task = taskRepository.findById(event.getTaskId()).orElse(null);
        FlwInstance instance = instanceOf(event.getInstanceId());
        if (task == null || instance == null) {
            return;
        }
        userMsgClient.todoInc(instance.getSchId().intValue(),
                Collections.singletonList(task.getAssigneeId()), -1);
    }

    /**
     * 退回：通知被退回节点的全部新待办人（RETURNED 事件 data.targetNodeIds 由服务层带上——
     * 退回重建任务在事件发布前已提交，这里按节点查待办即可）；todo 角标由 notifyTaskCreated
     * 通用链路在引擎重建任务时已发过，这里只补一条带退回意见的消息。
     */
    private void notifyReturned(FlowEvent event) {
        FlwInstance instance = instanceOf(event.getInstanceId());
        if (instance == null || event.getData() == null) {
            return;
        }
        Object fromNode = event.getData().get("fromNodeName");
        Object opinion = event.getData().get("opinion");
        StringBuilder content = new StringBuilder("「").append(safe(instance.getBizTitle())).append("」")
                .append("被退回（").append(fromNode == null ? "" : fromNode).append("）");
        if (opinion != null && !String.valueOf(opinion).isEmpty()) {
            content.append("，意见：").append(opinion);
        }
        java.util.List<Integer> targets = event.getData().get("targetUserIds") == null
                ? Collections.emptyList()
                : (java.util.List<Integer>) event.getData().get("targetUserIds");
        if (targets.isEmpty()) {
            return;
        }
        userMsgClient.sendUserMsg(instance.getSchId().intValue(), targets, 1,
                "flow.returned", String.valueOf(instance.getId()),
                "办件被退回：" + safe(instance.getBizTitle()), content.toString(),
                "/instance/" + instance.getId(),
                "returned:" + instance.getId() + ":" + instance.getVersion(), 30);
    }

    private void notifyResult(FlowEvent event) {
        FlwInstance instance = instanceOf(event.getInstanceId());
        if (instance == null) {
            return;
        }
        Object result = event.getData() == null ? null : event.getData().get("result");
        String outcome;
        String bizTitle = safe(instance.getBizTitle());
        switch (event.getType()) {
            case COMPLETED:
                outcome = "已通过审批";
                break;
            case REJECTED:
                outcome = "审批被拒绝";
                break;
            default:
                outcome = "已撤回";
                break;
        }
        StringBuilder content = new StringBuilder("您提交的「" + bizTitle + "」" + outcome);
        if (result != null) {
            content.append("（结果：").append(result).append("）");
        }
        Object opinion = event.getData() == null ? null : event.getData().get("opinion");
        if (opinion != null && !String.valueOf(opinion).isEmpty()) {
            content.append("，意见：").append(opinion);
        }
        userMsgClient.sendUserMsg(instance.getSchId().intValue(),
                Collections.singletonList(instance.getSubmitterId()), 1,
                "flow.result", String.valueOf(instance.getId()),
                "办件状态更新：" + bizTitle, content.toString(),
                "/instance/" + instance.getId(),
                "result:" + instance.getId() + ":" + instance.getVersion(), 30);
    }

    private void notifyUrge(FlowEvent event) {
        FlwTask task = taskRepository.findById(event.getTaskId()).orElse(null);
        FlwInstance instance = instanceOf(event.getInstanceId());
        if (task == null || instance == null) {
            return;
        }
        int count = task.getUrgeCount() == null ? 1 : task.getUrgeCount();
        String content = "「" + safe(instance.getBizTitle()) + "」任务（"
                + (task.getNodeName() == null ? task.getNodeId() : task.getNodeName())
                + "）被催办（第 " + count + " 次），请尽快办理";
        userMsgClient.sendUserMsg(instance.getSchId().intValue(),
                Collections.singletonList(task.getAssigneeId()), 1,
                "flow.urge", String.valueOf(instance.getId()),
                "催办提醒：" + safe(instance.getBizTitle()), content,
                "/task/" + task.getId(), "urge:" + task.getId() + ":" + count, 7);
    }

    private FlwInstance instanceOf(Long instanceId) {
        return instanceId == null ? null : instanceRepository.findById(instanceId).orElse(null);
    }

    private static String safe(String s) {
        return s == null ? "" : s;
    }
}