package com.ruoyi.energymeter.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.ruoyi.energymeter.constant.EnergyMeterConstants;
import com.ruoyi.energymeter.mapper.EnergyMeterDeviceMapper;
import com.ruoyi.energymeter.mapper.EnergyMeterMeasurementMapper;
import com.ruoyi.energymeter.pojo.EnergyMeterDevice;
import com.ruoyi.energymeter.pojo.EnergyMeterMeasurement;
import com.ruoyi.energymeter.service.EnergyMeterDemoService;
import com.ruoyi.energymeter.util.EnergyMeterSupport;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.List;

/**
 * 演示数据实现：气表按天生成模拟表码与用量。
 *
 * <p>模拟值是“设备ID + 日期”的确定性函数，重复生成同一天结果一致，便于核对。</p>
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class EnergyMeterDemoServiceImpl implements EnergyMeterDemoService {

    private final EnergyMeterDeviceMapper deviceMapper;
    private final EnergyMeterMeasurementMapper measurementMapper;

    @Override
    @Transactional(rollbackFor = Exception.class)
    public int generateGasDemo(LocalDate date) {
        if (date == null) {
            return 0;
        }
        LambdaQueryWrapper<EnergyMeterDevice> wrapper = new LambdaQueryWrapper<>();
        wrapper.eq(EnergyMeterDevice::getMeterType, EnergyMeterConstants.TYPE_GAS)
                .eq(EnergyMeterDevice::getSimulated, 1)
                .eq(EnergyMeterDevice::getEnabled, 1);
        List<EnergyMeterDevice> devices = deviceMapper.selectList(wrapper);
        if (devices.isEmpty()) {
            return 0;
        }

        int generated = 0;
        LocalDateTime measureTime = date.atStartOfDay();
        for (EnergyMeterDevice device : devices) {
            if (hasUsage(device.getId(), measureTime)) {
                // 数据已存在时只刷新采集时间，保证“最近采集/在线”反映最近一次自动生成
                deviceMapper.markCollectSuccess(device.getId(), EnergyMeterSupport.now());
                continue;
            }
            BigDecimal usage = simulatedUsage(device.getId(), date);
            BigDecimal previous = previousReading(device, measureTime);
            BigDecimal reading = previous.add(usage);

            EnergyMeterMeasurement usagePoint = new EnergyMeterMeasurement();
            usagePoint.setTenantId(device.getTenantId());
            usagePoint.setMeterId(device.getId());
            usagePoint.setMetricCode(EnergyMeterConstants.METRIC_GAS_USAGE);
            usagePoint.setGranularity(EnergyMeterConstants.GRANULARITY_DAY);
            usagePoint.setMeasureTime(measureTime);
            usagePoint.setMetricValue(usage);
            usagePoint.setUnit(EnergyMeterConstants.UNIT_GAS);
            usagePoint.setSourceApi(EnergyMeterConstants.SOURCE_MANUAL);
            usagePoint.setSourceRecordTime(measureTime);
            usagePoint.setCollectedAt(EnergyMeterSupport.now());
            usagePoint.setRemark("模拟数据：每日用量");

            EnergyMeterMeasurement readingPoint = new EnergyMeterMeasurement();
            readingPoint.setTenantId(device.getTenantId());
            readingPoint.setMeterId(device.getId());
            readingPoint.setMetricCode(EnergyMeterConstants.METRIC_GAS_READING);
            readingPoint.setGranularity(EnergyMeterConstants.GRANULARITY_POINT);
            readingPoint.setMeasureTime(measureTime);
            readingPoint.setMetricValue(reading);
            readingPoint.setUnit(EnergyMeterConstants.UNIT_GAS);
            readingPoint.setSourceApi(EnergyMeterConstants.SOURCE_MANUAL);
            readingPoint.setSourceRecordTime(measureTime);
            readingPoint.setCollectedAt(EnergyMeterSupport.now());
            readingPoint.setRemark("模拟数据：每日表码");

            measurementMapper.upsertBatch(List.of(usagePoint, readingPoint));

            // 采集时间按实际执行时间记录，而不是数据所属日期的 00:00
            deviceMapper.markCollectSuccess(device.getId(), EnergyMeterSupport.now());
            generated++;
        }
        log.info("气表演示数据生成完成 date={} 设备数={}", date, generated);
        return generated;
    }

    private boolean hasUsage(Long meterId, LocalDateTime measureTime) {
        LambdaQueryWrapper<EnergyMeterMeasurement> wrapper = new LambdaQueryWrapper<>();
        wrapper.eq(EnergyMeterMeasurement::getMeterId, meterId)
                .eq(EnergyMeterMeasurement::getMetricCode, EnergyMeterConstants.METRIC_GAS_USAGE)
                .eq(EnergyMeterMeasurement::getMeasureTime, measureTime);
        return measurementMapper.selectCount(wrapper) > 0;
    }

    /**
     * 上一期表码：取该日期之前的最近一条示值，没有就用设备起始表码。
     */
    private BigDecimal previousReading(EnergyMeterDevice device, LocalDateTime measureTime) {
        EnergyMeterMeasurement previous = measurementMapper.selectPreviousPoint(device.getId(),
                EnergyMeterConstants.METRIC_GAS_READING, measureTime);
        if (previous != null && previous.getMetricValue() != null) {
            return previous.getMetricValue();
        }
        return device.getInitialReading() == null ? BigDecimal.ZERO : device.getInitialReading();
    }

    /**
     * 确定性模拟用量：按食品厂蒸煮/灭菌的实际用气量估算。
     *
     * <p>估算口径：蒸煮锅按 4~6 m³/h、每天 6~8 小时，单台约 25~35 m³/天；
     * 灭菌锅、小煮锅约 14~20 m³/天。基础值按设备区分，再叠加季节波动与噪点。</p>
     */
    private BigDecimal simulatedUsage(Long meterId, LocalDate date) {
        long seed = meterId * 131L + date.toEpochDay();
        double base = 14 + (meterId % 5) * 5;
        double season = base * 0.1 * Math.sin(2 * Math.PI * date.getDayOfYear() / 365);
        double noise = ((seed * 37 % 200) / 200.0 - 0.5) * 3;
        double usage = Math.max(2, base + season + noise);
        return BigDecimal.valueOf(usage).setScale(2, RoundingMode.HALF_UP);
    }
}