using System;
using System.Threading;
using System.Threading.Tasks;
using BlueWest.Cryptography;
using BlueWest.Data.Application;
using Microsoft.Extensions.Hosting;
using Redis.OM;
using Redis.OM.Searching;

namespace BlueWest.WebApi.Session
{
    /// <summary>
    /// Session Provider Context
    /// </summary>
    public sealed class SessionDataService : IHostedService, ISessionCache
    {
        private readonly RedisConnectionProvider _provider;
        private RedisCollection<SessionToken> _sessionTokens;
        /// <summary>
        /// Index Creation Device
        /// </summary>
        /// <param name="provider">Redis connection</param>
        public SessionDataService(
            RedisConnectionProvider provider)
        {
            _provider = provider;
            _sessionTokens = (RedisCollection<SessionToken>)provider.RedisCollection<SessionToken>();
        }

        /// <summary>
        /// Empty constructor
        /// </summary>
        public SessionDataService() { }

        /// <summary>
        /// Get a session token by the respective Id.
        /// </summary>
        /// <param name="tokenId"></param>
        /// <returns></returns>
        public async Task<SessionToken> GetSessionTokenByIdAsync(string tokenId)
        {
            return  await _sessionTokens.Where(x => x.Id == tokenId)
                .FirstOrDefaultAsync();
        }

        /// <summary>
        /// Create a new session token
        /// </summary>
        /// <param name="token"></param>
        public async Task AddSessionToken(SessionToken token)
        {
            await _sessionTokens.InsertAsync(token);
        }

        /// <inheritdoc />
        public async Task SaveAsync()
        {
           await _sessionTokens.SaveAsync();
        }

        /// <summary>
        /// Save session data 
        /// </summary>
        public void Save()
        {
            _sessionTokens.Save();
        }


        /// <summary>
        /// Gets a Bearer By Access Token Id
        /// </summary>
        /// <param name="sessionTokenId"></param>
        public async Task<string> GetBearerByAccessTokenId(string sessionTokenId)
        {
            var accessToken = await _sessionTokens.Where(t => t.Id == sessionTokenId)
                .FirstOrDefaultAsync();
            
            if (accessToken == null) return string.Empty;
            
            if (accessToken.IsValid)
            {
                var createdDate = DateTime.UnixEpoch.AddMilliseconds(accessToken.CreatedDate);
                if (createdDate.AddMilliseconds(accessToken.ValidFor) < DateTime.Now)
                {
                    accessToken.IsValid = false;
                }
            }
                
            await _sessionTokens.SaveAsync();

            return accessToken.IsValid ?  accessToken.AccessToken : string.Empty;
        }

        /// <inheritdoc />
        public async Task StartAsync(CancellationToken cancellationToken)
        {
            await _provider.Connection.CreateIndexAsync(typeof(SessionToken));        
        }

        /// <inheritdoc />
        public Task StopAsync(CancellationToken cancellationToken)
        {
            return Task.CompletedTask;        
        }
    }
}