package com.zksy.api.service;

import com.zksy.api.domain.AlarmData;
import com.zksy.api.mapper.AlarmDataMapper;
import com.zksy.api.mapper.AlarmLogMapper;
import com.zksy.api.enums.AlarmLogOperTypeEnum;
import com.zksy.api.support.AlarmLifecycleSupport;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.support.TransactionTemplate;

import java.time.LocalDateTime;
import java.util.List;
import java.util.Objects;

/**
 * 采集告警及离线告警的统一入库规则；告警处理状态与设备实时报警状态互相独立。
 */
@Slf4j
@Service
public class CollectionAlarmWriter {
    private final AlarmDataMapper mapper;
    private final AlarmLogMapper logMapper;
    private final TransactionTemplate transaction;

    public CollectionAlarmWriter(AlarmDataMapper mapper, AlarmLogMapper logMapper, PlatformTransactionManager transactionManager) {
        this.mapper = mapper;
        this.logMapper = logMapper;
        transaction = new TransactionTemplate(transactionManager);
        transaction.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRES_NEW);
        transaction.setIsolationLevel(TransactionDefinition.ISOLATION_READ_COMMITTED);
        transaction.setTimeout(10);
    }

    /**
     * 已有未处理告警时，同级跳过，等级升降则更新原记录及对应采集值。
     *
     * @return true表示新增，false表示复用原记录（更新或跳过）；真实入库失败抛出异常。
     */
    public boolean saveOrUpdateUnhandled(AlarmData alarm) {
        if (alarm == null) throw new IllegalArgumentException("告警不能为空");
        validateKey(alarm.getDeviceCode(), alarm.getWarningCode());
        String warningName = firstNonBlank(mapper.selectWarningName(alarm.getWarningCode()),
                alarm.getWarningCode(), "监测报警");
        alarm.setAlarmContent(AlarmLifecycleSupport.alarmContent(warningName,
                alarm.getActualValue(), alarm.getMinValue(), alarm.getMaxValue(),
                mapper.selectWarningUnit(alarm.getWarningCode())));

        if (alarm.getCreateTime() == null) alarm.setCreateTime(LocalDateTime.now());
        if (alarm.getAlarmStatus() == null) alarm.setAlarmStatus(0);

        return Boolean.TRUE.equals(transaction.execute(status -> {
            lockKey(alarm.getDeviceCode(), alarm.getWarningCode());
            AlarmData existing = mapper.selectUnhandledAlarmForUpdate(alarm.getDeviceCode(), alarm.getWarningCode());
            if (existing != null) {
                // 缺失等级的报文不能清除已有有效等级；真实采集端提供1-4级。
                if (alarm.getAlarmLevel() != null && !Objects.equals(existing.getAlarmLevel(), alarm.getAlarmLevel())) {
                    if (mapper.updateUnhandledAlarmLevel(existing.getId(), alarm) != 1) {
                        throw new IllegalStateException("未处理告警等级更新未成功");
                    }
                    log.info("更新未处理告警等级: deviceCode={}, warningCode={}, alarmId={}, level={}->{}",
                            alarm.getDeviceCode(), alarm.getWarningCode(), existing.getId(), existing.getAlarmLevel(), alarm.getAlarmLevel());
                } else {
                    log.debug("跳过同级未处理告警: deviceCode={}, warningCode={}, existingAlarmId={}",
                            alarm.getDeviceCode(), alarm.getWarningCode(), existing.getId());
                }
                return false;
            }
            // 新记录由程序赋号；复用/恢复已有记录不会生成或修改号码，不信任请求带入的号码。
            if (!Integer.valueOf(1).equals(mapper.lockAlarmNumberGeneration())) {
                throw new IllegalStateException("未取得报警单号生成事务锁");
            }
            alarm.setAlarmNo(AlarmLifecycleSupport.nextAlarmNo(mapper::existsAlarmNo));
            if (mapper.insert(alarm) != 1) throw new IllegalStateException("告警入库未成功");
            writeLifecycleLog(alarm.getId(), AlarmLogOperTypeEnum.CREATED, alarm.getAlarmContent(), "监测系统", alarm.getCreateTime(), 0L);
            return true;
        }));
    }

    private String firstNonBlank(String... values) {
        for (String value : values) {
            if (value != null && !value.trim().isEmpty()) return value.trim();
        }
        return "监测报警";
    }

    /**
     * 有效恢复数据才调用；0行表示无待处理告警，重复正常上报不会改写历史处理信息。
     */
    public int markRecovered(String deviceCode, String warningCode) {
        validateKey(deviceCode, warningCode);
        return transaction.execute(status -> {
            lockKey(deviceCode, warningCode);
            List<String> alarmIds = mapper.selectRecoverableAlarmIdsForUpdate(deviceCode, warningCode);
            for (String alarmId : alarmIds) {
                long beforeLogId = logMapper.latestLogId(alarmId);
                if (mapper.markAlarmRecovered(alarmId) != 1) throw new IllegalStateException("告警恢复更新未成功");
                writeLifecycleLog(alarmId, AlarmLogOperTypeEnum.HANDLED,
                        "监测恢复，报警自动解除", "系统自动", LocalDateTime.now(), beforeLogId);
            }
            int count = alarmIds.size();
            if (count > 0) {
                log.info("正常采集数据自动处理告警: deviceCode={}, warningCode={}, count={}", deviceCode, warningCode, count);
            }
            return count;
        });
    }

    private void writeLifecycleLog(String alarmId, AlarmLogOperTypeEnum type, String description,
                                   String actor, LocalDateTime time, long afterLogId) {
        if (alarmId == null || alarmId.trim().isEmpty()) throw new IllegalStateException("报警日志缺少报警ID");
        int count = logMapper.insertLifecycleIfAbsent(alarmId, type.getCode(), description, actor, time, afterLogId);
        if (count != 1 && !(count == 0 && logMapper.existsLifecycle(alarmId, type.getCode(), afterLogId))) {
            throw new IllegalStateException("报警日志写入失败");
        }
    }

    private void lockKey(String deviceCode, String warningCode) {
        if (!Integer.valueOf(1).equals(mapper.lockAlarmKey(deviceCode, warningCode))) {
            throw new IllegalStateException("未取得告警入库事务锁");
        }
    }

    private void validateKey(String deviceCode, String warningCode) {
        if (deviceCode == null || deviceCode.trim().isEmpty() || warningCode == null || warningCode.trim().isEmpty()) {
            throw new IllegalArgumentException("告警必须包含device_code和warning_code");
        }
    }
}