using System;
using System.Collections.Generic;
using System.Net;
using System.Text;
using System.Threading;
using System.Web.Script.Serialization;

namespace TellmePdmsPluging.Network
{
    internal class BatchTaskResultCallbackService
    {
        private readonly string _serverAddress;
        private readonly string _token;
        private readonly string _softwareId;
        private readonly JavaScriptSerializer _serializer = new JavaScriptSerializer();
        private readonly int[] _retryDelaysMs = new[] { 1000, 3000, 5000 };

        public BatchTaskResultCallbackService(string serverAddress, string token, string softwareId)
        {
            _serverAddress = NormalizeServerAddress(serverAddress);
            _token = token ?? string.Empty;
            _softwareId = string.IsNullOrEmpty(softwareId) ? "pdms" : softwareId;
        }

        public void NotifyTaskResultAsync(string executionId, bool success, string errorMessage, object result)
        {
            if (string.IsNullOrEmpty(executionId))
            {
                return;
            }

            if (string.IsNullOrEmpty(_serverAddress) || string.IsNullOrEmpty(_token))
            {
                return;
            }

            ThreadPool.QueueUserWorkItem(_ =>
            {
                TryPostWithRetries(executionId, success, errorMessage, result);
            });
        }

        private void TryPostWithRetries(string executionId, bool success, string errorMessage, object result)
        {
            string callbackUrl = _serverAddress + "/api/v1/plugin-callbacks/task-result";

            var payload = new Dictionary<string, object>
            {
                { "execution_id", executionId },
                { "software_id", _softwareId },
                { "status", success ? "success" : "failed" },
                { "error_message", success ? null : GetFailedErrorMessage(errorMessage) },
                { "result", success ? (result ?? new Dictionary<string, object>()) : new Dictionary<string, object>() },
                { "finished_at", DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ") },
                { "token", _token }
            };

            string json = _serializer.Serialize(payload);

            for (int attempt = 0; attempt < _retryDelaysMs.Length + 1; attempt++)
            {
                if (PostJson(callbackUrl, json))
                {
                    return;
                }

                if (attempt < _retryDelaysMs.Length)
                {
                    Thread.Sleep(_retryDelaysMs[attempt]);
                }
            }
        }

        private static bool PostJson(string url, string json)
        {
            try
            {
                var request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = "POST";
                request.ContentType = "application/json";
                request.Timeout = 15000;

                byte[] data = Encoding.UTF8.GetBytes(json);
                request.ContentLength = data.Length;

                using (var stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }

                using (var response = (HttpWebResponse)request.GetResponse())
                {
                    int statusCode = (int)response.StatusCode;
                    return statusCode >= 200 && statusCode < 300;
                }
            }
            catch
            {
                return false;
            }
        }

        private static string NormalizeServerAddress(string serverAddress)
        {
            if (string.IsNullOrEmpty(serverAddress))
            {
                return null;
            }

            string value = serverAddress.Trim();
            while (value.EndsWith("/", StringComparison.Ordinal))
            {
                value = value.Substring(0, value.Length - 1);
            }

            return value;
        }

        private static string GetFailedErrorMessage(string errorMessage)
        {
            return string.IsNullOrEmpty(errorMessage) ? "UNKNOWN_ERROR" : errorMessage;
        }
    }
}