using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Wabbajack.Common;
using Wabbajack.Server.DataLayer;

namespace Wabbajack.Server.Services
{
    public class MetricsKeyCache : IStartable
    {
        private ILogger<MetricsKeyCache> _logger;
        private SqlService _sql;
        private HashSet<string> _knownKeys = new();
        private AsyncLock _lock = new();

        public MetricsKeyCache(ILogger<MetricsKeyCache> logger, SqlService sql)
        {
            _logger = logger;
            _sql = sql;
        }

        public async Task<bool> IsValidKey(string key)
        {
            using (var _ = await _lock.WaitAsync())
            {
                if (_knownKeys.Contains(key)) return true;
            }

            if (await _sql.ValidMetricsKey(key))
            {
                using var _ = await _lock.WaitAsync();
                _knownKeys.Add(key);
                return true;
            }

            return false;
        }

        public async Task AddKey(string key)
        {
            using (var _ = await _lock.WaitAsync())
            {
                if (_knownKeys.Contains(key)) return;
                _knownKeys.Add(key);
            }

            await _sql.AddMetricsKey(key);
        }

        public void Start()
        {
            _knownKeys = (_sql.AllKeys().Result).ToHashSet();
        }

        public async Task<long> KeyCount()
        {
            using var _ = await _lock.WaitAsync();
            return _knownKeys.Count;
        }
    }
}