package com.ruoyi.system.service.impl;

import java.time.Duration;
import java.time.Instant;
import java.util.LinkedHashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
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.ChannelIdentity;
import com.ruoyi.device.model.DetectedChannel;
import com.ruoyi.device.model.DetectedDeviceMetadata;
import com.ruoyi.device.model.DeviceWorkStatus;
import com.ruoyi.device.model.RealtimeSnapshot;
import com.ruoyi.device.registry.DeviceAdapterRegistry;
import com.ruoyi.system.domain.vo.AdapterDiscoveryResult;
import org.springframework.stereotype.Service;

/** 将适配器观测写入 Redis 候选存储，不创建正式 MySQL 设备或通道。 */
@Service
public class DeviceDiscoveryPersistenceService
{
    private static final Duration MINIMUM_CANDIDATE_LIFETIME = Duration.ofSeconds(30);
    private final DeviceDiscoveryCandidateStore candidateStore;

    public DeviceDiscoveryPersistenceService(DeviceDiscoveryCandidateStore candidateStore)
    {
        this.candidateStore = candidateStore;
    }

    /** 执行设备发现和可用通道查询，并将本轮观测写入 Redis 候选。 */
    public AdapterDiscoveryResult discover(DeviceAdapterRegistry registry, DiscoverySource source)
    {
        DiscoveryObservation observation = registry.execute(source.adapterCode(), runtime -> {
            List<DetectedChannel> channels = runtime.discoverChannels();
            Set<ChannelIdentity> available = channels.stream()
                    .filter(DetectedChannel::available)
                    .map(DetectedChannel::identity)
                    .collect(java.util.stream.Collectors.toCollection(LinkedHashSet::new));
            Map<ChannelIdentity, RealtimeSnapshot> snapshots = available.isEmpty()
                    ? Map.of() : runtime.inquire(available);
            return new DiscoveryObservation(channels, snapshots);
        });
        Instant observedAt = Instant.now();
        return persist(source, observation.channels(), observation.snapshots(), observedAt);
    }

    /** upsert 本轮发现和实时状态；未返回设备由 expiresAt 控制淘汰。 */
    private AdapterDiscoveryResult persist(DiscoverySource source, List<DetectedChannel> detected,
            Map<ChannelIdentity, RealtimeSnapshot> snapshots, Instant observedAt)
    {
        Map<CabinetKey, List<DetectedChannel>> grouped = detected.stream().collect(
                java.util.stream.Collectors.groupingBy(
                        item -> new CabinetKey(item.identity().devtype(), item.identity().devid()),
                        LinkedHashMap::new, java.util.stream.Collectors.toList()));
        Duration lifetime = Duration.ofMillis(Math.max(MINIMUM_CANDIDATE_LIFETIME.toMillis(),
                (long) source.pollIntervalMs() * 3));
        List<CabinetCandidate> candidates = grouped.entrySet().stream()
                .map(entry -> toCandidate(source, entry.getKey(), entry.getValue(), snapshots,
                        observedAt, observedAt.plus(lifetime)))
                .toList();
        candidateStore.recordCabinets(candidates);
        return new AdapterDiscoveryResult(grouped.size(), detected.size(), observedAt);
    }

    private CabinetCandidate toCandidate(DiscoverySource source, CabinetKey key, List<DetectedChannel> channels,
            Map<ChannelIdentity, RealtimeSnapshot> snapshots, Instant observedAt, Instant expiresAt)
    {
        DetectedDeviceMetadata metadata = channels.get(0).deviceMetadata();
        String name = metadata.name() == null
                ? source.adapterName() + " " + key.devtype() + "-" + key.devid()
                : metadata.name();
        String ip = channels.stream().map(DetectedChannel::serverIp)
                .filter(value -> value != null && !value.isBlank()).findFirst().orElse(null);
        List<ChannelCandidate> channelCandidates = channels.stream().map(item -> {
            RealtimeSnapshot snapshot = snapshots.get(item.identity());
            DeviceWorkStatus status = snapshot == null || snapshot.workStatus() == null
                    ? DeviceWorkStatus.UNKNOWN : snapshot.workStatus();
            return new ChannelCandidate(item.identity(), item.available(), status, observedAt);
        }).toList();
        return new CabinetCandidate(source.adapterCode(), source.adapterId(),
                source.adapterCode() + "-" + key.devtype() + "-" + key.devid(),
                key.devtype(), key.devid(), ip, metadata.macAddress(), name,
                metadata.manufacturer(), metadata.model(), channelCandidates, observedAt, expiresAt);
    }

    /** 发现来源只携带候选标识和过期计算所需配置，不复用数据库实体。 */
    public record DiscoverySource(String adapterCode, Long adapterId, String adapterName, int pollIntervalMs) { }

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

    private record CabinetKey(int devtype, int devid) { }
}