using System;
using WingServerCommon.Log;
using WingServerCommon.Interfaces.OpLog;
namespace WingServerCommon.Interfaces.Cache
{
    public class CacheMaintenance
    {
        private static CacheMaintenance _instance;
        private readonly Dictionary<Type, ICacheManager> _instances;

        public static CacheMaintenance Instance
        {
            get { return _instance ?? (_instance = new CacheMaintenance()); }
        }

        private CacheMaintenance()
        {
            _instances = new Dictionary<Type, ICacheManager>();
            Register(typeof(IDeviceInfosManager), new DeviceInfosManager());
            Register(typeof(IOrganizationsManager), new OrganizationsManager());
            Register(typeof(IDiagnosisModulesManager), new DiagnosisModulesManager());
            Register(typeof(IReportPostersManager), new ReportPostersManager());
            Register(typeof(IDistributedServerInfosManager), new DistributedServerInfosManager());
            Register(typeof(ITokensManager), new TokensManager());
            Register(typeof(IIPManager), new IPManager());
            Register(typeof(IConsultationRecordManager), new ConsultationRecordManager());
            Register(typeof(ICourseInfosManager), new CourseInfosManager());
            Register(typeof(IUserInfoManager), new UserInfoManager());
            Register(typeof(IGradingProtectionConfigManager), new GradingProtectionConfigManager());
            Register(typeof(IControllingParametersManager), new ControllingParametersManager());
            DatabaseCollection.CollectionDocumentChanged += OnCollectionDocumentChanged;
        }

        private void OnCollectionDocumentChanged(Object sender, CollectionDocumentChangedArgs args)
        {
            var typeName = $"I{args.CollectionName}Manager";
            //var type = Type.GetType(typeName);
            var type = _instances.FirstOrDefault(i => i.Key.Name == typeName).Key;
            if (type == null)
            {
                // Logger.WriteLineWarn($"CacheMaintenance manager never existed, typeName:{typeName}");
                return;
            }
            ICacheManager manager;
            if (_instances.TryGetValue(type, out manager))
            {
                manager.RemoveMany(args);
            }
        }

        /// <summary>
        /// Register a cache manager to cache maintenance
        /// </summary>
        /// <param name="type"></param>
        /// <param name="manager"></param>
        private void Register(Type type, ICacheManager manager)
        {
            if (_instances.ContainsKey(typeof(Type)))
            {
                Logger.WriteLineWarn("Register duplicate type");
            }
            else
            {
                _instances.Add(type, manager);
            }
        }

        public T Get<T>()
        {
            ICacheManager manager;
            if (_instances.TryGetValue(typeof(T), out manager))
            {
                return (T)manager;
            }
            throw new Exception("Invalid type");
        }
    }
}