using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Amazon.CloudWatch;
using System.Collections.Concurrent;
using TradeIdeasCommon.Models;
using Newtonsoft.Json;
namespace TradeIdeasCommon.Services.Metrics
{
    public sealed class AwsMetricsService
    {
        private readonly ILogger<AwsMetricsService> _logger;
        private readonly IAmazonCloudWatch _cloudWatch;
        private bool _running = false;
        private readonly BlockingCollection<AwsPutMetricsRequest> _bcqPutMetricDataRequests;

        public AwsMetricsService(ILogger<AwsMetricsService> logger, IAmazonCloudWatch cloudWatch)
        {
            _logger = logger;
            _cloudWatch = cloudWatch;
            _bcqPutMetricDataRequests =  new BlockingCollection<AwsPutMetricsRequest>(new ConcurrentQueue<AwsPutMetricsRequest>());

            //Start the Monitor Worker for AWS Cloud Watch Metrics
            _running = true;
            Task.Run(async () => await PutMetricsWorker());
        }
        public async Task<ServiceResult> PutMetrics(AwsPutMetricsRequest putMetricsRequest)
        {
            //This is a fire and forget method with no blocking
            //The item is enqueued and processed by a worker thread. 

            foreach( var item in putMetricsRequest.PutMetricDataRequest.MetricData)
            {
                if (item.TimestampUtc == DateTime.MinValue)
                    item.TimestampUtc = DateTime.UtcNow;
            }

            var result = new ServiceResult();

            result.Status = _bcqPutMetricDataRequests.TryAdd(putMetricsRequest) ? ServiceResultStatuses.Success : ServiceResultStatuses.ServerError;

            await Task.CompletedTask;

            return result;
        }
        private async Task PutMetricsWorker()
        {

            try
            {
                while (_running)
                {
                    try
                    {
                        if (_bcqPutMetricDataRequests.TryTake(out AwsPutMetricsRequest putMetricsRequest, 1000))
                        {
                            _logger.LogInformation("Logging Metrics...");

                            var response = await _cloudWatch.PutMetricDataAsync(putMetricsRequest.PutMetricDataRequest);

                            if ( response.HttpStatusCode != System.Net.HttpStatusCode.OK)
                                _logger.LogWarning($"{putMetricsRequest.RequestId} failed with code:{response.HttpStatusCode} for request:{JsonConvert.SerializeObject(putMetricsRequest)}");
                        }
                    }
                    catch (Exception ex)
                    {
                        _logger.LogError(ex, ex.Message);
                    }

                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, ex.Message);
            }

        }

    }
}