using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Kreta.Framework.Caching;

namespace Kreta.Framework.Localization
{
    /// <summary>
    /// Kivételek nyelvesítésére szolgáló <see cref="ILocalizer"/> megvalósítás.
    /// </summary>
    internal class ExceptionLocalizer : ILocalizer
    {
        private static object SyncObject = new object();
        // <<Monostate>>
        private static readonly Dictionary<Type, FriendlyNameAttribute> friendlyNameAttributeCache = new Dictionary<Type, FriendlyNameAttribute>();

        string ILocalizer.Localize(object value, CultureInfo cultureInfo)
        {
            return Localize((Exception)value, cultureInfo);
        }

        public virtual string Localize(Exception exception, CultureInfo cultureInfo)
        {
            FriendlyNameAttribute attribute;
            lock (SyncObject)
            {
                var exceptionType = exception.GetType();
                if (!friendlyNameAttributeCache.TryGetValue(exceptionType, out attribute))
                {
                    attribute = (FriendlyNameAttribute)exceptionType.GetCustomAttributes(typeof(FriendlyNameAttribute), true).FirstOrDefault(); //inherited but allowed only one
                    friendlyNameAttributeCache[exceptionType] = attribute;
                }
            }

            if (attribute != null)
            {
                if (attribute.StringResourceId == -1)
                {
                    return string.Empty;
                }

                return SDAServer.Instance.CacheManager.AquireCache<StringResourcesCache>().Get(attribute.StringResourceId, cultureInfo.LCID, attribute.DisplayText);
            }
            return exception.Message;
        }
    }
}