using Azure.Core.Serialization;
using Microsoft.Azure.Cosmos;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using System;
using System.Collections.Concurrent;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.IO;
using System.Threading.Tasks;
namespace TEAMModelOS.SDK.DI
{
    public class AzureCosmosFactory
    {
        private readonly IServiceProvider _services;
        private readonly IOptionsMonitor<AzureCosmosFactoryOptions> _optionsMonitor;
        private readonly ILogger _logger;
        //private Option _option;
        private ConcurrentDictionary<string, CosmosClient> CosmosClients { get; } = new ConcurrentDictionary<string, CosmosClient>();

        //   private CosmosDatabase database { get; set; }

        public AzureCosmosFactory(IServiceProvider services, IOptionsMonitor<AzureCosmosFactoryOptions> optionsMonitor, ILogger<AzureCosmosFactory> logger)
        {
            if (services == null) throw new ArgumentNullException(nameof(services));
            if (optionsMonitor == null) throw new ArgumentNullException(nameof(optionsMonitor));

            _services = services;
            _optionsMonitor = optionsMonitor;
            _logger = logger;
        }

        /// <summary>
        /// 取得CosmosClient，支持安全執行緒
        /// </summary>
        /// <param name="name"></param>
        /// <param name="region">可以使用Regions.{區域}設置，指定此屬性後，SDK會首選該區域來執行操作。此外，SDK會自動選擇後備的地理複製區域以實現高可用性。如果未指定此屬性，則SDK會將寫區域用作所有操作的首選區域</param>
        /// <returns></returns>
        public CosmosClient GetCosmosClient(string? region = null, string name = "Default")
        {
            try
            {
                //CosmosClientOptions 的 SerializerOptions = new CosmosSerializationOptions() { PropertyNamingPolicy = CosmosPropertyNamingPolicy.CamelCase } 
                //需等待官方修正

                JsonSerializerOptions jsonSerializerOptions = new JsonSerializerOptions()
                {
                  //  DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
                };
                var cm = CosmosClients.GetOrAdd(name, x => new CosmosClient(_optionsMonitor.Get(name).CosmosConnectionString, new CosmosClientOptions()
                {
                    Serializer= new CosmosSystemTextJsonSerializer(jsonSerializerOptions),
                    ApplicationRegion = region
                }));
                return cm;
            }
            catch (Exception e)
            {
                _logger?.LogWarning(e, e.Message);
                throw;
            }
        }
    }
    /// <summary>
    /// Uses <see cref="Azure.Core.Serialization.JsonObjectSerializer"/> which leverages System.Text.Json providing a simple API to interact with on the Azure SDKs.
    /// </summary>
    // <SystemTextJsonSerializer>
    public class CosmosSystemTextJsonSerializer : CosmosSerializer
    {
        private readonly JsonSerializerOptions _serializerOptions;

        public CosmosSystemTextJsonSerializer(JsonSerializerOptions jsonSerializerOptions)
        {
            this._serializerOptions = jsonSerializerOptions;
        }

        public override T FromStream<T>(Stream stream)
        {
            using (stream)
            {
                if (typeof(Stream).IsAssignableFrom(typeof(T)))
                {
                    return (T)(object)stream;
                }
                return JsonSerializer.Deserialize<T>(stream, _serializerOptions);
            }
        }

        public   override Stream ToStream<T>(T input)
        {
            var outputStream = new MemoryStream();
             JsonSerializer.Serialize<T>(outputStream, input, _serializerOptions);

            // A BREAKPOINT HERE AND A LOOK INSIDE 'outputStream' shows that ALL the fields have been serialized EXCEPT 'Id' or 'id.
            outputStream.Position = 0;
            return outputStream;
        }
    }
    // </SystemTextJsonSerializer>
}