using System;
using System.Threading;
using System.Threading.Tasks;
using FrameworkDAL.DTO.EIPConversation;
using GB5Shared.DTO.Framework.Login;
using Microsoft.Extensions.Logging;

namespace FrameworkBLL.EIPConversation.EIPHandlers.ChannelHandler
{
    // ============================================================
    // AppChatChannelHandler — IEIPChannelHandler for the AppChat
    // (in-app SignalR) channel.
    //
    // The hub (EIPChatHub) handles actual SignalR delivery directly
    // after receiving EIPExecutionResultDTO from the BLL, so this
    // handler exists only to satisfy the response engine's channel
    // lookup for EIPChannelType.AppChat ("APPCHAT"). It is a
    // deliberate no-op: it logs the outbound message and returns
    // success so the pipeline completes cleanly.
    //
    // Auto-registered by assembly scan — no manual DI entry needed.
    // ============================================================
    public class AppChatChannelHandler : IEIPChannelHandler
    {
        public string ChannelName => "APPCHAT";

        private readonly ILogger<AppChatChannelHandler> _logger;

        public AppChatChannelHandler(ILogger<AppChatChannelHandler> logger)
            => _logger = logger ?? throw new ArgumentNullException(nameof(logger));

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

        public Task<EIPChannelResponseDTO> SendAsync(
            EIPResponseContext context,
            LoginDTO loginDTO,
            CancellationToken cancellationToken)
        {
            cancellationToken.ThrowIfCancellationRequested();

            _logger.LogInformation(
                "AppChatChannelHandler: delivery logged | Recipient={Recipient} | Tenant={Tenant} | Step={Step} | Completed={IsCompleted}",
                context.Recipient,
                context.TenantId,
                context.CurrentStepCode,
                context.IsCompleted);

            return Task.FromResult(new EIPChannelResponseDTO
            {
                IsSent            = true,
                ExternalMessageId = Guid.NewGuid().ToString(),
                Status            = "APPCHAT_DELIVERED_VIA_HUB"
            });
        }
    }
}