using System.Collections.Concurrent;
using AVSCartonShipmentVerifier.DTOs;

namespace AVSCartonShipmentVerifier.Services;

public sealed class InMemoryScanHistoryStore : IScanHistoryStore
{
    private const int MaxItems = 5;
    private readonly ConcurrentQueue<ScannedRecordDto> _records = new();
    private readonly Lock _syncLock = new();

    public Task AddAsync(ScannedRecordDto record, CancellationToken cancellationToken = default)
    {
        lock (_syncLock)
        {
            _records.Enqueue(record);
            while (_records.Count > MaxItems)
            {
                _records.TryDequeue(out _);
            }
        }

        return Task.CompletedTask;
    }

    public Task<IReadOnlyCollection<ScannedRecordDto>> GetLastFiveAsync(CancellationToken cancellationToken = default)
    {
        lock (_syncLock)
        {
            return Task.FromResult<IReadOnlyCollection<ScannedRecordDto>>(_records.Reverse().ToArray());
        }
    }
}