package com.ruoyi.system.service.impl;

import java.time.Duration;
import java.time.Instant;
import java.time.ZoneId;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.stereotype.Service;
import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONObject;
import com.ruoyi.common.exception.ServiceException;
import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.device.api.DeviceAdapterException;
import com.ruoyi.device.model.AdapterCapabilities;
import com.ruoyi.device.model.ChannelIdentity;
import com.ruoyi.device.model.DetectedChannel;
import com.ruoyi.device.model.RealtimeSnapshot;
import com.ruoyi.device.registry.AdapterInstanceConfig;
import com.ruoyi.device.registry.AdapterRegistryException;
import com.ruoyi.device.registry.DeviceAdapterRegistry;
import com.ruoyi.system.domain.TDetectionChannel;
import com.ruoyi.system.domain.TDeviceAdapter;
import com.ruoyi.system.domain.vo.AdapterDiscoveryResult;
import com.ruoyi.system.mapper.TDeviceAdapterMapper;
import com.ruoyi.system.service.DeviceAdapterErrorCodes;
import com.ruoyi.system.service.IDeviceAdapterService;

@Service
public class DeviceAdapterServiceImpl implements IDeviceAdapterService
{
    private static final String ENABLED = "0";
    private static final String DISABLED = "1";
    private static final String READ_ONLY_CAPABILITIES =
            "{\"discovery\":true,\"realtimeObservation\":true,\"historyDownload\":true,\"control\":false}";

    private final TDeviceAdapterMapper mapper;
    private final DeviceAdapterRegistry registry;
    private final DeviceDiscoveryPersistenceService persistence;

    public DeviceAdapterServiceImpl(TDeviceAdapterMapper mapper, DeviceAdapterRegistry registry,
            DeviceDiscoveryPersistenceService persistence)
    {
        this.mapper = mapper;
        this.registry = registry;
        this.persistence = persistence;
    }

    /** 按管理端筛选条件查询适配器及其运行状态。 */
    @Override
    public List<TDeviceAdapter> selectList(TDeviceAdapter query) { return mapper.selectDeviceAdapterList(query); }

    /** 查询适配器详情；实例不存在时抛出稳定业务错误。 */
    @Override
    public TDeviceAdapter selectById(Long adapterId)
    {
        TDeviceAdapter adapter = mapper.selectDeviceAdapterById(adapterId);
        if (adapter == null) throw error("设备适配器实例不存在", DeviceAdapterErrorCodes.NOT_FOUND);
        return adapter;
    }

    /** 幂等注册应用托管的只读适配器；不预写检测柜或通道事实。 */
    @Override
    public TDeviceAdapter ensureManagedAdapter(TDeviceAdapter adapter)
    {
        normalizeAndValidate(adapter);
        AdapterCapabilities capabilities = parseCapabilities(adapter.getCapabilities());
        if (capabilities.control())
            throw error("当前里程碑只允许只读设备适配器", DeviceAdapterErrorCodes.INVALID_CONFIG);
        adapter.setStatus(ENABLED);
        adapter.setConnectionStatus("DISCONNECTED");
        adapter.setDelFlag("0");
        mapper.upsertManagedDeviceAdapter(adapter);
        TDeviceAdapter registered = mapper.selectDeviceAdapterByCode(adapter.getAdapterCode());
        if (registered == null) throw error("托管设备适配器注册失败", DeviceAdapterErrorCodes.NOT_FOUND);
        return registered;
    }

    /** 新增默认禁用的只读适配器配置。 */
    @Override
    public int insert(TDeviceAdapter adapter)
    {
        normalizeAndValidate(adapter);
        if (mapper.selectDeviceAdapterByCode(adapter.getAdapterCode()) != null)
            throw error("适配器编码已存在", DeviceAdapterErrorCodes.DUPLICATE_CODE);
        adapter.setCapabilities(READ_ONLY_CAPABILITIES);
        adapter.setStatus(DISABLED);
        adapter.setConnectionStatus("DISCONNECTED");
        adapter.setDelFlag("0");
        try { return mapper.insertDeviceAdapter(adapter); }
        catch (DuplicateKeyException exception) { throw error("适配器编码已存在", DeviceAdapterErrorCodes.DUPLICATE_CODE); }
    }

    /** 更新配置；已启用实例会同步运行时注册表。 */
    @Override
    public int update(TDeviceAdapter adapter)
    {
        TDeviceAdapter current = selectById(adapter.getAdapterId());
        normalizeAndValidate(adapter);
        adapter.setAdapterCode(current.getAdapterCode());
        adapter.setCapabilities(current.getCapabilities());
        int rows = mapper.updateDeviceAdapter(adapter);
        if (ENABLED.equals(current.getStatus()))
        {
            adapter.setStatus(ENABLED);
            registry.synchronize(toRuntimeConfig(adapter));
        }
        return rows;
    }

    /** 启停适配器并同步其运行时实例。 */
    @Override
    public int changeStatus(Long adapterId, boolean enabled, String updateBy)
    {
        TDeviceAdapter adapter = selectById(adapterId);
        String status = enabled ? ENABLED : DISABLED;
        if (status.equals(adapter.getStatus())) return 1;
        int rows = mapper.updateDeviceAdapterStatus(adapterId, status, updateBy);
        adapter.setStatus(status);
        registry.synchronize(toRuntimeConfig(adapter));
        return rows;
    }

    /** 执行一次发现和实时观测，并事务性写入通道事实。 */
    @Override
    public AdapterDiscoveryResult discover(Long adapterId)
    {
        TDeviceAdapter adapter = selectById(adapterId);
        if (!ENABLED.equals(adapter.getStatus()))
            throw error("设备适配器实例未启用", DeviceAdapterErrorCodes.DISABLED);
        try
        {
            registry.synchronize(toRuntimeConfig(adapter));
            DiscoveryObservation observation = registry.execute(adapter.getAdapterCode(), runtime -> {
                List<DetectedChannel> channels = runtime.discoverChannels();
                Set<ChannelIdentity> available = channels.stream()
                        .filter(DetectedChannel::available)
                        .map(DetectedChannel::identity)
                        .collect(Collectors.toCollection(LinkedHashSet::new));
                return new DiscoveryObservation(channels, available.isEmpty() ? Map.of() : runtime.inquire(available));
            });
            Instant observedAt = Instant.now();
            AdapterDiscoveryResult result = persistence.persist(adapter, observation.channels(),
                    observation.snapshots(), observedAt);
            mapper.updateDiscoverySuccess(adapterId, observedAt);
            return result;
        }
        catch (DeviceAdapterException exception)
        {
            return failDiscovery(adapterId, exception.failureCode(), exception);
        }
        catch (AdapterRegistryException exception)
        {
            return failDiscovery(adapterId, "ADAPTER_FAILURE", exception);
        }
    }

    /** 查询指定适配器已发现且未删除的通道。 */
    @Override
    public List<TDetectionChannel> selectChannels(Long adapterId)
    {
        selectById(adapterId);
        return mapper.selectDetectionChannelsByAdapterId(adapterId);
    }

    /** 启动时恢复所有已启用适配器的运行时注册。 */
    @Override
    public void synchronizeEnabledAdapters()
    {
        mapper.selectEnabledDeviceAdapters().forEach(adapter -> registry.synchronize(toRuntimeConfig(adapter)));
    }

    /** 轮询达到周期的已启用适配器，并持久化失败状态后继续调度。 */
    @Override
    public void pollDueAdapters()
    {
        Instant now = Instant.now();
        for (TDeviceAdapter adapter : mapper.selectEnabledDeviceAdapters())
        {
            Instant lastAttempt = adapter.getLastAttemptAtUtc();
            if (lastAttempt != null && Duration.between(lastAttempt, now).toMillis() < adapter.getPollIntervalMs()) continue;
            try { discover(adapter.getAdapterId()); }
            catch (ServiceException ignored) { /* 失败状态已持久化，下一轮按周期重试。 */ }
        }
    }

    private AdapterDiscoveryResult failDiscovery(Long adapterId, String errorCode, RuntimeException exception)
    {
        mapper.updateDiscoveryFailure(adapterId, errorCode, exception.getMessage());
        throw error("设备发现失败：" + exception.getMessage(), DeviceAdapterErrorCodes.DISCOVERY_FAILED);
    }

    private void normalizeAndValidate(TDeviceAdapter adapter)
    {
        adapter.setAdapterCode(StringUtils.trim(adapter.getAdapterCode()));
        adapter.setAdapterName(StringUtils.trim(adapter.getAdapterName()));
        adapter.setAdapterType(StringUtils.trim(adapter.getAdapterType()).toUpperCase(Locale.ROOT));
        adapter.setHost(StringUtils.trim(adapter.getHost()));
        adapter.setTimezoneId(StringUtils.trim(adapter.getTimezoneId()));
        adapter.setRemark(StringUtils.trim(adapter.getRemark()));
        if (!"BTS".equals(adapter.getAdapterType()))
            throw error("不支持的适配器类型", DeviceAdapterErrorCodes.UNSUPPORTED_TYPE);
        if (!Boolean.TRUE.equals(adapter.getReadOnly()))
            throw error("当前里程碑只允许只读设备适配器", DeviceAdapterErrorCodes.INVALID_CONFIG);
        try
        {
            if (adapter.getPort() == null || adapter.getPort() < 1 || adapter.getPort() > 65535
                    || adapter.getPollIntervalMs() == null || adapter.getPollIntervalMs() < 1000
                    || StringUtils.isBlank(adapter.getAdapterCode()) || StringUtils.isBlank(adapter.getAdapterName())
                    || StringUtils.isBlank(adapter.getHost())) throw new IllegalArgumentException();
            ZoneId.of(adapter.getTimezoneId());
        }
        catch (RuntimeException exception)
        {
            throw error("设备适配器配置不正确", DeviceAdapterErrorCodes.INVALID_CONFIG);
        }
    }

    private AdapterInstanceConfig toRuntimeConfig(TDeviceAdapter adapter)
    {
        return new AdapterInstanceConfig(adapter.getAdapterCode(), adapter.getAdapterType(), adapter.getHost(),
                adapter.getPort(), adapter.getPollIntervalMs(), adapter.getTimezoneId(),
                ENABLED.equals(adapter.getStatus()), parseCapabilities(adapter.getCapabilities()));
    }

    private AdapterCapabilities parseCapabilities(String capabilities)
    {
        JSONObject value = JSON.parseObject(capabilities);
        if (value == null) throw error("设备适配器能力配置不正确", DeviceAdapterErrorCodes.INVALID_CONFIG);
        return new AdapterCapabilities(value.getBooleanValue("discovery"),
                value.getBooleanValue("realtimeObservation"), value.getBooleanValue("historyDownload"),
                value.getBooleanValue("control"));
    }

    private ServiceException error(String message, int code) { return new ServiceException(message, code); }

    private record DiscoveryObservation(List<DetectedChannel> channels,
            Map<ChannelIdentity, RealtimeSnapshot> snapshots)
    {
    }
}