using Microsoft.ApplicationInsights.DataContracts;
using System.Text;
using System.Text.Json;

namespace Core.Telemetry
{
	public record SeqConfiguration(string IngestionEndpoint, string ApiKey, string Environment);


	public class SeqHttpClient
	{
		HttpClient _httpClient;

		public SeqHttpClient(SeqConfiguration seqConfiguration)
		{
			_httpClient = new HttpClient()
			{
				BaseAddress = new Uri("http://localhost:5341"),
				Timeout = TimeSpan.FromSeconds(30)
			};

			_httpClient.DefaultRequestHeaders.Accept.Clear();
			_httpClient.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
			if (seqConfiguration.ApiKey != null)
				_httpClient.DefaultRequestHeaders.Add("X-Seq-ApiKey", seqConfiguration.ApiKey);
		}

		public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage httpRequestMessage, CancellationToken cancellationToken)
		{
			return await _httpClient.SendAsync(httpRequestMessage, cancellationToken);
		}
	}


	public class SeqLogger
	{
		private readonly SeqHttpClient _httpClient;
		private readonly string _environmentName;
		private readonly string _machineName;
		private readonly SeqConfiguration _configuration;

		public SeqLogger(SeqHttpClient httpClient, string environmentName, SeqConfiguration configuration)
		{
			_httpClient = httpClient;
			_environmentName = configuration.Environment;
			_machineName = Environment.MachineName;
		}

		public async Task LogTraceTelemetryAsync(TraceTelemetry trace, CancellationToken cancellationToken = default)
		{
			var seqEvent = new Dictionary<string, object>
		{
			{ "@t", trace.Timestamp.UtcDateTime.ToString("o") },
			{ "@mt", trace.Message },
			{ "@l", MapSeverityToLevel(trace.SeverityLevel) },
			{ "Environment", _environmentName },
			{ "MachineName", _machineName }
		};

			foreach (var prop in trace.Properties)
			{
				seqEvent.Add(prop.Key, prop.Value);
			}

			await SendToSeqAsync(seqEvent, cancellationToken);
		}

		public async Task LogEventTelemetryAsync(EventTelemetry evt, CancellationToken cancellationToken = default)
		{
			var seqEvent = new Dictionary<string, object>
		{
			{ "@t", evt.Timestamp.UtcDateTime.ToString("o") },
			{ "@mt", evt.Name },
			{ "@l", "Information" },
			{ "Environment", _environmentName },
			{ "MachineName", _machineName }
		};

			foreach (var prop in evt.Properties)
			{
				seqEvent.Add(prop.Key, prop.Value);
			}

			foreach (var metric in evt.Metrics)
			{
				seqEvent.Add($"metric_{metric.Key}", metric.Value);
			}

			await SendToSeqAsync(seqEvent, cancellationToken);
		}

		public async Task LogExceptionTelemetryAsync(ExceptionTelemetry ex, CancellationToken cancellationToken = default)
		{
			var seqEvent = new Dictionary<string, object>
		{
			{ "@t", ex.Timestamp.UtcDateTime.ToString("o") },
			{ "@mt", ex.Exception.Message },
			{ "@l", "Error" },
			{ "Environment", _environmentName },
			{ "MachineName", _machineName },
			{ "ExceptionType", ex.Exception.GetType().Name },
			{ "StackTrace", ex.Exception.StackTrace }
		};

			foreach (var prop in ex.Properties)
			{
				seqEvent.Add(prop.Key, prop.Value);
			}

			await SendToSeqAsync(seqEvent, cancellationToken);
		}

		public async Task LogDependencyTelemetryAsync(DependencyTelemetry dep, CancellationToken cancellationToken = default)
		{
			var seqEvent = new Dictionary<string, object>
		{
			{ "@t", dep.Timestamp.UtcDateTime.ToString("o") },
			{ "@mt", $"Dependency: {dep.Name}" },
			{ "@l", dep.Success??true ? "Information" : "Error" },
			{ "Environment", _environmentName },
			{ "MachineName", _machineName },
			{ "DependencyType", dep.Type },
			{ "Target", dep.Target },
			{ "Duration", dep.Duration.TotalMilliseconds }
		};

			foreach (var prop in dep.Properties)
			{
				seqEvent.Add(prop.Key, prop.Value);
			}

			await SendToSeqAsync(seqEvent, cancellationToken);
		}

		public async Task LogRequestTelemetryAsync(RequestTelemetry req, CancellationToken cancellationToken = default)
		{
			var seqEvent = new Dictionary<string, object>
		{
			{ "@t", req.Timestamp.UtcDateTime.ToString("o") },
			{ "@mt", $"Request: {req.Name}" },
			{ "@l", req.Success??true ? "Information" : "Error" },
			{ "Environment", _environmentName },
			{ "MachineName", _machineName },
			{ "Url", req.Url },
			{ "ResponseCode", req.ResponseCode },
			{ "Duration", req.Duration.TotalMilliseconds }
		};

			foreach (var prop in req.Properties)
			{
				seqEvent.Add(prop.Key, prop.Value);
			}

			await SendToSeqAsync(seqEvent, cancellationToken);
		}

		private async Task SendToSeqAsync(Dictionary<string, object> seqEvent, CancellationToken cancellationToken)
		{
			var content = new StringContent(
				Newtonsoft.Json.JsonConvert.SerializeObject(seqEvent),
				Encoding.UTF8,
				"application/vnd.serilog.clef");

			var requestMessage = new HttpRequestMessage(HttpMethod.Post, "/ingest/clef")
			{
				Content = content
			};

			await _httpClient.SendAsync(requestMessage, cancellationToken);
		}

		private string MapSeverityToLevel(SeverityLevel? severity)
		{
			return severity switch
			{
				SeverityLevel.Verbose => "Verbose",
				SeverityLevel.Information => "Information",
				SeverityLevel.Warning => "Warning",
				SeverityLevel.Error => "Error",
				SeverityLevel.Critical => "Fatal",
				_ => "Information"
			};
		}
	}
}