using FrameworkDAL.DTO.EIPConversation;
using GB5Shared.DTO.Framework.Login;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace FrameworkBLL.EIPConversation.EIPHandlers.ChannelHandler
{
    public class SlackChannelHandler : IEIPChannelHandler
    {
        // Interface property
        public string ChannelName => "SLACK";

        private readonly ILogger<SlackChannelHandler> _logger;
        private readonly IConfiguration _configuration;
        private readonly HttpClient _httpClient;

        public SlackChannelHandler(
            ILogger<SlackChannelHandler> logger,
            IConfiguration configuration,
            HttpClient httpClient)
        {
            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
            _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
            _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
        }

        // Single CanHandle implementation
        public bool CanHandle(string channel) =>
            string.Equals(channel, ChannelName, StringComparison.OrdinalIgnoreCase);

        public async Task<EIPChannelResponseDTO> SendAsync(
            EIPResponseContext context,
            LoginDTO loginDTO,
            CancellationToken cancellationToken)
        {
            if (context == null)
                throw new ArgumentNullException(nameof(context));

            if (loginDTO == null)
                throw new ArgumentNullException(nameof(loginDTO));

            var webhookUrl = _configuration["Slack:WebhookUrl"];
            var defaultChannel = _configuration["Slack:DefaultChannel"];
            var defaultUserName = _configuration["Slack:DefaultUserName"];
            var defaultIcon = _configuration["Slack:DefaultIconEmoji"];

            if (string.IsNullOrWhiteSpace(webhookUrl))
                throw new InvalidOperationException("Slack WebhookUrl not configured.");

            var stopwatch = System.Diagnostics.Stopwatch.StartNew();

            try
            {
                cancellationToken.ThrowIfCancellationRequested();

                _logger.LogInformation(
                    "SLACK SEND START | Tenant={Tenant} | Channel={Channel}",
                    context.TenantId,
                    defaultChannel);

                // Build Slack Block Kit message
                var payload = new
                {
                    channel = defaultChannel,
                    username = defaultUserName,
                    icon_emoji = defaultIcon,
                    blocks = new object[]
                    {
                        new
                        {
                            type = "section",
                            text = new
                            {
                                type = "mrkdwn",
                                text = context.Message
                            }
                        }
                    }
                };

                var json = JsonSerializer.Serialize(payload);
                var content = new StringContent(json, Encoding.UTF8, "application/json");

                var response = await _httpClient.PostAsync(
                    webhookUrl,
                    content,
                    cancellationToken);

                stopwatch.Stop();

                var responseContent = await response.Content.ReadAsStringAsync(cancellationToken);

                if (!response.IsSuccessStatusCode)
                {
                    _logger.LogError(
                        "SLACK SEND FAILED | Tenant={Tenant} | StatusCode={StatusCode} | Response={Response}",
                        context.TenantId,
                        response.StatusCode,
                        responseContent);

                    return new EIPChannelResponseDTO
                    {
                        IsSent = false,
                        Status = "FAILED",
                        ErrorMessage = responseContent
                    };
                }

                _logger.LogInformation(
                    "SLACK SEND SUCCESS | Tenant={Tenant} | DurationMs={Duration}",
                    context.TenantId,
                    stopwatch.ElapsedMilliseconds);

                return new EIPChannelResponseDTO
                {
                    IsSent = true,
                    ExternalMessageId = Guid.NewGuid().ToString(),
                    Status = "SENT"
                };
            }
            catch (OperationCanceledException)
            {
                _logger.LogWarning(
                    "SLACK SEND CANCELLED | Tenant={Tenant}",
                    context?.TenantId);

                throw;
            }
            catch (Exception ex)
            {
                stopwatch.Stop();

                _logger.LogError(ex,
                    "SLACK SEND ERROR | Tenant={Tenant} | DurationMs={Duration}",
                    context?.TenantId,
                    stopwatch.ElapsedMilliseconds);

                return new EIPChannelResponseDTO
                {
                    IsSent = false,
                    Status = "FAILED",
                    ErrorMessage = ex.Message
                };
            }
        }
    }
}