package com.ruoyi.system.service.impl;

import java.io.IOException;
import java.time.Instant;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import jakarta.annotation.PreDestroy;
import org.springframework.stereotype.Service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
import com.ruoyi.device.bts.BtsDevelopmentSimulator;
import com.ruoyi.device.bts.BtsDevelopmentSimulator.CollectorSnapshot;
import com.ruoyi.device.discovery.DeviceDiscoveryCandidateStore;
import com.ruoyi.device.discovery.DeviceDiscoveryCandidateStore.CabinetCandidate;
import com.ruoyi.device.discovery.DeviceDiscoveryCandidateStore.ChannelCandidate;
import com.ruoyi.device.model.Measurement;
import com.ruoyi.system.domain.TTest;
import com.ruoyi.system.domain.TTestBattery;
import com.ruoyi.system.service.ITestLiveService;
import com.ruoyi.system.service.ITestLiveService.TestPlanRow;
import com.ruoyi.system.service.ITestLiveService.TestPlanSnapshot;
import com.ruoyi.system.service.ITTestService;
import com.ruoyi.system.mapper.TTestMapper;

/** 将设备最新快照转换为测试视角，并托管 SSE 连接生命周期。 */
@Service
public class TTestLiveServiceImpl implements ITestLiveService
{
    private final ITTestService tests;
    private final DeviceDiscoveryCandidateStore candidates;
    private final BtsDevelopmentSimulator simulator;
    private final TTestMapper mapper;
    private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(2);

    @Autowired
    public TTestLiveServiceImpl(ITTestService tests, DeviceDiscoveryCandidateStore candidates,
            BtsDevelopmentSimulator simulator, TTestMapper mapper)
    { this.tests = tests; this.candidates = candidates; this.simulator = simulator; this.mapper = mapper; }

    public TTestLiveServiceImpl(ITTestService tests, DeviceDiscoveryCandidateStore candidates,
            BtsDevelopmentSimulator simulator)
    { this(tests, candidates, simulator, null); }

    @Override public LiveState current(Long testId)
    {
        TTest test = tests.selectTestById(testId);
        List<CabinetCandidate> cabinets = candidates.snapshot(Instant.now()).cabinets();
        List<LiveSource> sources = new ArrayList<>();
        boolean receiving = "RECEIVING".equals(test.getReceptionStatus());
        for (TTestBattery battery : test.getBatteries() == null ? List.<TTestBattery>of() : test.getBatteries())
        {
            if (battery.getBinding() != null)
                sources.add(snapshotFor(cabinetSource(battery, cabinets), receiving));
            if (battery.getCollectorId() != null)
                sources.add(snapshotFor(collectorSource(battery), receiving));
        }
        List<Map<String, Object>> exceptions = new ArrayList<>();
        if (receiving)
            exceptions.addAll(sources.stream().filter(source -> !"COLLECTOR".equals(source.sourceType())
                    && "OFFLINE".equals(source.deviceStatus()))
                    .map(source -> Map.<String, Object>of("sourceType", source.sourceType(), "sourceId", source.sourceId(),
                            "batteryNo", source.batteryNo(), "status", source.deviceStatus(), "message", "数据来源当前不可观测"))
                    .toList());
        // 完成或暂停后只保留历史异常事实，实时控制台不再展示开放预警。
        if (receiving && mapper != null) {
            mapper.selectWarningExceptions(testId, "OPEN").forEach(item -> exceptions.add(Map.of(
                    "exceptionId", item.getExceptionId(), "sourceType", item.getSourceType(),
                    "metricCode", item.getMetricCode(), "value", item.getAbnormalValue(), "unit", item.getUnit(),
                    "status", item.getExceptionStatus(), "message", "测试预警异常")));
        }
        String testStatus = test.getTestStatus();
        TestPlanSnapshot testPlan = detectorTestPlan(test);
        return new LiveState(testId, testStatus, test.getReceptionStatus(), Instant.now(), sources, exceptions, testPlan);
    }

    private TestPlanSnapshot detectorTestPlan(TTest test)
    {
        if (test.getBatteries() == null) return null;
        for (TTestBattery battery : test.getBatteries())
        {
            if (battery.getBinding() == null || battery.getBinding().getDevid() == null
                    || battery.getBinding().getChlid() == null) continue;
            try
            {
                var source = "NOT_STARTED".equals(test.getReceptionStatus())
                        ? simulator.btsTest(battery.getBinding().getDevid(), battery.getBinding().getChlid(), 1)
                        : simulator.btsTest(battery.getBinding().getDevid(), battery.getBinding().getChlid());
                List<TestPlanRow> rows = source.rows().stream()
                        .map(row -> new TestPlanRow(row.rowType(), row.stepNo(), row.cyclePosition(), row.stepName(), row.durationSeconds(),
                                row.voltageV(), row.executionStatus(), row.cycleCount(), row.recordCount()))
                        .toList();
                return new TestPlanSnapshot(source.currentCycleNo(), source.currentStepNo(),
                        source.plannedCycleCount(), rows);
            }
            catch (IllegalArgumentException ignored) { /* 登记设备尚未被开发模拟器提供时保持无方案事实。 */ }
        }
        return null;
    }

    private LiveSource snapshotFor(LiveSource fresh, boolean receiving)
    {
        // 暂停或停止只停止数据请求；设备状态仍以本次查询的最新事实为准，采集快照不继续展示。
        if (!receiving)
            return withoutSnapshot(fresh);
        return fresh;
    }

    private LiveSource withoutSnapshot(LiveSource source)
    {
        return new LiveSource(source.sourceType(), source.sourceId(), source.batteryNo(), source.deviceStatus(), Map.of());
    }

    @Override public SseEmitter stream(Long testId)
    {
        SseEmitter emitter = createEmitter();
        try { sendAll(emitter, testId); }
        catch (IOException exception)
        {
            // 客户端刷新或离开页面会断开连接，不能再交给全局异常处理器写 SSE JSON。
            emitter.complete();
            return emitter;
        }
        catch (RuntimeException exception) { emitter.completeWithError(exception); return emitter; }
        ScheduledFuture<?> future = scheduler.scheduleAtFixedRate(() -> {
            try { sendAll(emitter, testId); }
            catch (IOException exception)
            {
                // 写出失败表示 SSE 客户端已断开，静默结束连接。
                emitter.complete();
            }
            catch (RuntimeException exception) { emitter.completeWithError(exception); }
        }, 3, 3, TimeUnit.SECONDS);
        emitter.onCompletion(() -> future.cancel(false));
        emitter.onTimeout(() -> future.cancel(false));
        emitter.onError(error -> future.cancel(false));
        return emitter;
    }

    /** 创建实时流发射器，供断连生命周期测试替换。 */
    protected SseEmitter createEmitter()
    {
        return new SseEmitter(0L);
    }

    private void sendAll(SseEmitter emitter, Long testId) throws IOException
    {
        LiveState state = current(testId);
        emitter.send(SseEmitter.event().name("snapshot").data(state));
        emitter.send(SseEmitter.event().name("device-status").data(state.sources()));
        emitter.send(SseEmitter.event().name("reception-status").data(Map.of("testId", testId, "receptionStatus", state.receptionStatus())));
        emitter.send(SseEmitter.event().name("test-status").data(Map.of("testId", testId, "testStatus", state.testStatus())));
        emitter.send(SseEmitter.event().name("exception").data(state.exceptions()));
        emitter.send(SseEmitter.event().name("heartbeat").data(Map.of("at", state.updatedAt())));
    }

    private LiveSource cabinetSource(TTestBattery battery, List<CabinetCandidate> cabinets)
    {
        var binding = battery.getBinding();
        for (CabinetCandidate cabinet : cabinets) for (ChannelCandidate channel : cabinet.channels())
            if (Objects.equals(channel.identity().devtype(), binding.getDevtype())
                    && Objects.equals(channel.identity().devid(), binding.getDevid())
                    && Objects.equals(channel.identity().subdevid(), binding.getSubdevid())
                    && Objects.equals(channel.identity().chlid(), binding.getChlid()))
                return new LiveSource("CABINET_CHANNEL", binding.getChannelId(), battery.getBatteryNo(),
                        channel.online() ? "ONLINE" : "OFFLINE",
                        channel.online() ? snapshot(channel) : Map.of());
        return new LiveSource("CABINET_CHANNEL", binding.getChannelId(), battery.getBatteryNo(), "OFFLINE", Map.of());
    }

    private Map<String, Object> snapshot(ChannelCandidate channel)
    {
        Map<String, Object> value = new LinkedHashMap<>();
        if (channel.latestSnapshot() == null) return value;
        value.put("source", "检测柜");
        value.put("observedAt", channel.latestSnapshot().receivedAt());
        // BTS 核心采样字段是快照的一等事实，不能只依赖动态 measurements 展示。
        value.put("currentA", channel.latestSnapshot().currentA());
        value.put("voltageV", channel.latestSnapshot().voltageV());
        value.put("capacityAh", channel.latestSnapshot().capacityAh());
        value.put("energyWh", channel.latestSnapshot().energyWh());
        // 实时方案需要设备当前循环和实际工步；这些字段只用于快照展示，不形成历史采集事实。
        value.put("cycleNo", channel.latestSnapshot().cycleNo());
        value.put("stepNo", channel.latestSnapshot().stepNo());
        value.put("stepType", channel.latestSnapshot().stepType());
        value.put("totalTimeSeconds", channel.latestSnapshot().totalTimeSeconds());
        value.put("measurements", channel.latestSnapshot().measurements().entrySet().stream().map(entry -> {
            Measurement measurement = entry.getValue();
            return Map.of("metricCode", entry.getKey(), "value", measurement.value(), "unit", measurement.unit());
        }).toList());
        List<String> units = new ArrayList<>();
        if (channel.latestSnapshot().currentA() != null) units.add("A");
        if (channel.latestSnapshot().voltageV() != null) units.add("V");
        if (channel.latestSnapshot().capacityAh() != null) units.add("Ah");
        if (channel.latestSnapshot().energyWh() != null) units.add("Wh");
        units.addAll(channel.latestSnapshot().measurements().values().stream().map(Measurement::unit).toList());
        value.put("units", units.stream().filter(item -> item != null && !item.isBlank()).distinct().toList());
        return value;
    }

    private LiveSource collectorSource(TTestBattery battery)
    {
        for (CollectorSnapshot collector : simulator.snapshot().collectors()) if (collector.collectorId() == battery.getCollectorId())
        {
            Map<String, Object> value = new LinkedHashMap<>();
            value.put("source", "采集器"); value.put("sampleIntervalMs", collector.sampleIntervalMs());
            value.put("measurements", collector.latestMeasurements());
            value.put("units", collector.latestMeasurements().stream().map(item -> item.unit()).distinct().toList());
            collector.latestMeasurements().stream().map(item -> item.serverReceivedAt()).max(Instant::compareTo)
                    .ifPresent(observedAt -> value.put("observedAt", observedAt));
            return new LiveSource("COLLECTOR", (long) collector.collectorId(), battery.getBatteryNo(),
                    collector.online() ? "ONLINE" : "OFFLINE", collector.online() ? value : Map.of());
        }
        return new LiveSource("COLLECTOR", battery.getCollectorId(), battery.getBatteryNo(), "OFFLINE", Map.of());
    }

    @PreDestroy void shutdown() { scheduler.shutdownNow(); }
}