package com.ruoyi.device.simulator;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.CollectorHistoryAppend;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.CollectorHistoryBatch;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.CollectorMeasurementRecord;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.BtsHistoryRecord;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.BtsHistoryBatch;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.RecentRequest;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.SimulatorState;
import com.ruoyi.device.simulator.BtsSimulatorStateStore.BtsPlaybackState;

/** 测试和独立协议合同使用的内存状态存储。 */
public final class InMemoryBtsSimulatorStateStore implements BtsSimulatorStateStore
{
    private SimulatorState state;
    private List<RecentRequest> recentRequests = List.of();
    private final Map<String, ArrayList<CollectorMeasurementRecord>> collectorHistory = new LinkedHashMap<>();
    private final Map<String, ArrayList<BtsHistoryRecord>> btsHistory = new LinkedHashMap<>();
    private final Map<String, BtsPlaybackState> btsPlayback = new LinkedHashMap<>();

    public InMemoryBtsSimulatorStateStore() { }

    public InMemoryBtsSimulatorStateStore(SimulatorState state)
    {
        this.state = state;
    }

    @Override
    public synchronized SimulatorState loadOrInitialize(SimulatorState defaultState)
    {
        if (state == null) state = defaultState;
        return state;
    }

    @Override
    public synchronized void save(SimulatorState state)
    {
        this.state = state;
    }

    @Override
    public synchronized void save(SimulatorState state, List<CollectorHistoryAppend> historyAppends)
    {
        for (CollectorHistoryAppend append : historyAppends)
        {
            ArrayList<CollectorMeasurementRecord> history = collectorHistory.computeIfAbsent(
                    append.collectorCode(), key -> new ArrayList<>());
            history.addAll(append.records());
            int overflow = history.size() - (int) MAX_HISTORY_RECORDS;
            if (overflow > 0) history.subList(0, overflow).clear();
        }
        this.state = state;
    }

    @Override
    public synchronized CollectorHistoryBatch loadCollectorHistoryPage(String collectorCode, long offset,
            int limit, boolean reverse)
    {
        if (offset < 0) throw new IllegalArgumentException("offset must not be negative");
        if (limit < 1 || limit > MAX_HISTORY_BATCH_SIZE)
            throw new IllegalArgumentException("limit must be between 1 and " + MAX_HISTORY_BATCH_SIZE);
        List<CollectorMeasurementRecord> history = collectorHistory.getOrDefault(collectorCode,
                new ArrayList<>());
        long total = history.size();
        int from = (int) Math.min(offset, total);
        int count = Math.min(limit, history.size() - from);
        List<CollectorMeasurementRecord> records = new ArrayList<>(count);
        if (reverse)
        {
            for (int index = history.size() - 1 - from; index >= history.size() - from - count; index--)
                records.add(history.get(index));
        }
        else
        {
            records.addAll(history.subList(from, from + count));
        }
        long nextOffset = from + records.size();
        return new CollectorHistoryBatch(offset, nextOffset, nextOffset < total, total, records);
    }

    @Override
    public synchronized void saveAndDeleteCollectorHistory(SimulatorState state, String collectorCode)
    {
        collectorHistory.remove(collectorCode);
        this.state = state;
    }

    @Override
    public synchronized BtsHistoryBatch loadBtsHistoryPage(String historyKey, long offset, int limit)
    {
        List<BtsHistoryRecord> history = btsHistory.getOrDefault(historyKey, new ArrayList<>());
        int from = (int) Math.min(offset, history.size());
        int count = Math.min(limit, history.size() - from);
        List<BtsHistoryRecord> records = new ArrayList<>(history.subList(from, from + count));
        long next = from + records.size();
        return new BtsHistoryBatch(offset, next, next < history.size(), history.size(), records);
    }

    @Override
    public synchronized void appendBtsHistory(String historyKey, BtsHistoryRecord record)
    {
        ArrayList<BtsHistoryRecord> history = btsHistory.computeIfAbsent(historyKey, key -> new ArrayList<>());
        history.add(record);
        if (history.size() > MAX_HISTORY_RECORDS) history.remove(0);
    }

    @Override
    public synchronized BtsPlaybackState loadBtsPlaybackState(String historyKey)
    {
        return btsPlayback.get(historyKey);
    }

    @Override
    public synchronized void saveBtsPlaybackState(String historyKey, BtsPlaybackState playback)
    {
        btsPlayback.put(historyKey, playback);
    }

    @Override
    public synchronized void deleteBtsPlaybackState(String historyKey)
    {
        btsPlayback.remove(historyKey);
    }

    @Override
    public synchronized void deleteBtsHistory(String historyKey)
    {
        btsHistory.remove(historyKey);
    }

    @Override
    public synchronized void saveBtsPlaybackAndAppendHistory(String historyKey, BtsPlaybackState playback,
            List<BtsHistoryRecord> records)
    {
        ArrayList<BtsHistoryRecord> history = btsHistory.computeIfAbsent(historyKey, key -> new ArrayList<>());
        history.addAll(records);
        int overflow = history.size() - (int) MAX_HISTORY_RECORDS;
        if (overflow > 0) history.subList(0, overflow).clear();
        btsPlayback.put(historyKey, playback);
    }

    @Override
    public synchronized List<RecentRequest> loadRecentRequests()
    {
        return recentRequests;
    }

    @Override
    public synchronized void saveRecentRequests(List<RecentRequest> requests)
    {
        recentRequests = List.copyOf(requests);
    }

    @Override
    public synchronized void reset(SimulatorState defaultState)
    {
        state = defaultState;
        recentRequests = List.of();
        collectorHistory.clear();
        btsHistory.clear();
        btsPlayback.clear();
    }
}