using Microsoft.Extensions.Options;
using System.Collections.Concurrent;
using YD_TrainingCompetition_Api.Models;
using YD_TrainingCompetition_Api.Options;

namespace YD_TrainingCompetition_Api.Services;

public sealed class HikvisionAlarmStore : IHikvisionAlarmStore
{
    private readonly ConcurrentQueue<AlarmRecord> _alarms = new();
    private readonly ConcurrentDictionary<string, HikvisionCameraStatus> _cameraStatuses = new(StringComparer.OrdinalIgnoreCase);
    private readonly HikvisionOptions _options;
    private readonly ILogger<HikvisionAlarmStore> _logger;
    private int _alarmCount;

    public HikvisionAlarmStore(IOptions<HikvisionOptions> options, ILogger<HikvisionAlarmStore> logger)
    {
        _options = options.Value;
        _logger = logger;
    }

    public void Add(AlarmRecord record)
    {
        _alarms.Enqueue(record);

        var newCount = Interlocked.Increment(ref _alarmCount);

        // 超出上限则移除最旧的记录
        while (newCount > _options.MaxAlarmRecords)
        {
            if (_alarms.TryDequeue(out _))
            {
                Interlocked.Decrement(ref _alarmCount);
                newCount--;
            }
        }

        _logger.LogInformation("Alarm stored: DeviceId={DeviceId}, Id={Id}, QueueSize={Size}",
            record.DeviceId, record.Id, newCount);
    }

    public IReadOnlyCollection<AlarmRecord> GetAll()
    {
        return _alarms.Reverse().ToArray();
    }

    public IReadOnlyCollection<AlarmRecord> GetByDeviceId(string deviceId)
    {
        return _alarms
            .Where(x => string.Equals(x.DeviceId, deviceId, StringComparison.OrdinalIgnoreCase))
            .Reverse()
            .ToArray();
    }

    public AlarmRecord? GetLatest()
    {
        return _alarms.LastOrDefault();
    }

    public AlarmRecord? GetLatestByDevice(string deviceId)
    {
        return _alarms
            .LastOrDefault(x => string.Equals(x.DeviceId, deviceId, StringComparison.OrdinalIgnoreCase));
    }

    public void UpdateCameraStatus(HikvisionCameraStatus status)
    {
        status.LastSeen = DateTimeOffset.UtcNow;
        _cameraStatuses[status.DeviceId] = status;
    }

    public IReadOnlyCollection<HikvisionCameraStatus> GetAllCameraStatuses()
    {
        return _cameraStatuses.Values
            .OrderBy(x => x.DeviceId, StringComparer.OrdinalIgnoreCase)
            .ToArray();
    }

    public HikvisionCameraStatus? GetCameraStatus(string deviceId)
    {
        return _cameraStatuses.TryGetValue(deviceId, out var status) ? status : null;
    }

    public void ClearAlarms()
    {
        while (_alarms.TryDequeue(out _))
        {
            Interlocked.Decrement(ref _alarmCount);
        }
        _logger.LogInformation("All alarms cleared");
    }
}