using Confluent.Kafka;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using JiShe.CollectBus.Kafka.Attributes;
using Volo.Abp.DependencyInjection;
using JiShe.CollectBus.Kafka.AdminClient;
using static Confluent.Kafka.ConfigPropertyNames;

namespace JiShe.CollectBus.Kafka.Consumer
{
    public abstract class ConsumerService<TKey, TValue> : IConsumerService<TKey, TValue>, IDisposable, ISingletonDependency
    {
        private readonly ILogger<ConsumerService<TKey, TValue>> _logger;
        private CancellationTokenSource _cancellationTokenSource;

        protected ConsumerService(IConfiguration configuration, ILogger<ConsumerService<TKey, TValue>> logger)
        {
            _logger = logger;
            GetInstance(configuration);
        }


        public IConsumer<TKey, TValue> Instance { get; set; } = default;

        public IConsumer<TKey, TValue> GetInstance(IConfiguration configuration)
        {
            var enableAuthorization = bool.Parse(configuration["Kafka:EnableAuthorization"]);
            var consumerConfig = new ConsumerConfig
            {
                BootstrapServers = configuration["Kafka:BootstrapServers"],
                AutoOffsetReset = AutoOffsetReset.Earliest
            };

            if (enableAuthorization)
            {
                consumerConfig.SecurityProtocol = SecurityProtocol.SaslPlaintext;
                consumerConfig.SaslMechanism = SaslMechanism.Plain;
                consumerConfig.SaslUsername = configuration["Kafka:SaslUserName"];
                consumerConfig.SaslPassword = configuration["Kafka:SaslPassword"];
            }
            Instance = new ConsumerBuilder<TKey, TValue>(consumerConfig).Build();
            return Instance;
        }

        public async Task SubscribeAsync(string topic, Func<TKey, TValue, Task> messageHandler)
        {
            _cancellationTokenSource = new CancellationTokenSource();
            Instance.Subscribe(topic);

            try
            {
                while (!_cancellationTokenSource.Token.IsCancellationRequested)
                {
                    var result = Instance.Consume(_cancellationTokenSource.Token);
                    if (result != null)
                    {
                        await messageHandler(result.Message.Key, result.Message.Value);
                    }
                }
            }
            catch (OperationCanceledException)
            {
                Instance.Close();
            }
        }

        public void Unsubscribe()
        {
            _cancellationTokenSource?.Cancel();
            Instance?.Unsubscribe();
        }

        public void Dispose()
        {
            Unsubscribe();
            Instance?.Dispose();
            _cancellationTokenSource?.Dispose();
        }
    }
}