using Confluent.Kafka;
using Microsoft.Extensions.Configuration;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using static Confluent.Kafka.ConfigPropertyNames;

namespace DG.Kafka
{
    internal class KafkaProducer : IKafkaProducer
    {
        private static List<Consumer> _consumers { get; set; } = new List<Consumer>();
        private Dictionary<string, IProducer<Null, string>> _producers;
        public KafkaProducer()
        {
            _consumers = KafkaClient.Default.ConfigurationManager.GetSection("Consumers").Get<List<Consumer>>();
            _producers = new Dictionary<string, IProducer<Null, string>>();
            foreach (var consumer in _consumers)
            {
                var config = new ProducerConfig
                {
                    BootstrapServers = consumer.Host,
                };
                var topic = consumer.Topic;
                Action<DeliveryReport<Null, string>> handler = r =>
                    Console.WriteLine(!r.Error.IsError
                        ? $"Delivered message to {r.TopicPartitionOffset}"
                        : $"Delivery Error: {r.Error.Reason}");
                _producers.Add(consumer.Topic, new ProducerBuilder<Null, string>(config).Build());
            }
        }

        public async Task ProduceAsync<TMessage>(string? topic, TMessage message)
        {
            var producer = _producers.First().Value;
            if (!string.IsNullOrEmpty(topic))
            {
                producer = _producers.GetValueOrDefault(topic);
            }
            await producer.ProduceAsync(topic, new Message<Null, string> { Value = JsonSerializer.Serialize(message) });
            producer.Flush();
        }
    }
}