using System;
using CacheManager.Core;
using Kreta.BusinessLogic.Interfaces;
using Kreta.Core;
using Kreta.Framework.Caching;

namespace Kreta.BusinessLogic.Caching
{
    public class FileServiceCache : GenericCache<string>
    {
        private static readonly string PublicTokenCache = $"{Constants.Cache.CacheKeyPrefix}{nameof(PublicTokenCache)}";

        private static readonly string PrivateTokenCache = $"{Constants.Cache.CacheKeyPrefix}{nameof(PrivateTokenCache)}";

        public FileServiceCache(Framework.Caching.CacheManager cacheManager) : base(cacheManager, nameof(FileServiceCache)) { }

        public string GetPublicToken(ITokenServiceHelper tokenServiceHelper, bool forceUpdate = false)
            => !forceUpdate
                ? Get(PublicTokenCache) ?? SetPublicTokenFromService(tokenServiceHelper)
                : SetPublicTokenFromService(tokenServiceHelper);

        public string GetPrivateToken(ITokenServiceHelper tokenServiceHelper, bool forceUpdate = false)
            => !forceUpdate
                ? Get(PrivateTokenCache) ?? SetPrivateTokenFromService(tokenServiceHelper)
                : SetPrivateTokenFromService(tokenServiceHelper);

        private string SetPrivateTokenFromService(ITokenServiceHelper tokenServiceHelper)
        {
            var (token, expiresIn) = tokenServiceHelper.GetPrivateTokenWithExpiresIn();

            AddTokentToCache(PrivateTokenCache, token, expiresIn);

            return token;
        }

        private string SetPublicTokenFromService(ITokenServiceHelper tokenServiceHelper)
        {
            var (token, expiresIn) = tokenServiceHelper.GetPublicTokenWithExpiresIn();

            AddTokentToCache(PublicTokenCache, token, expiresIn);

            return token;
        }

        private void AddTokentToCache(string key, string token, int expiresIn)
        {
            AddOrUpdate(key, token, oldValue => token);
            Expire(key, ExpirationMode.Absolute, GetExpirationTime(expiresIn));
        }

        private TimeSpan GetExpirationTime(int expiresIn)
        {
            var timeout = new TimeSpan(0, 0, expiresIn);
            var offsetTime = new TimeSpan(0, 1, 0);

            if (timeout > offsetTime)
            {
                timeout -= offsetTime;
            }

            return timeout;
        }
    }
}