using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Serilog.Context;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace ZB.MOM.WW.CBDDC.Network;

/// <summary>
/// Hosted service that automatically starts and stops the CBDDC node.
/// </summary>
public class CBDDCNodeService : IHostedService
{
    private readonly ICBDDCNode _node;
    private readonly ILogger<CBDDCNodeService> _logger;

    /// <summary>
    /// Initializes a new instance of the <see cref="CBDDCNodeService"/> class.
    /// </summary>
    /// <param name="node">The CBDDC node to manage.</param>
    /// <param name="logger">The logger instance.</param>
    public CBDDCNodeService(ICBDDCNode node, ILogger<CBDDCNodeService> logger)
    {
        _node = node;
        _logger = logger;
    }

    /// <summary>
    /// Starts the managed CBDDC node.
    /// </summary>
    /// <param name="cancellationToken">A token used to cancel startup.</param>
    /// <returns>A task that represents the asynchronous start operation.</returns>
    public async Task StartAsync(CancellationToken cancellationToken)
    {
        using var serviceContext = LogContext.PushProperty("Service", nameof(CBDDCNodeService));
        using var operationContext = LogContext.PushProperty("OperationId", Guid.NewGuid().ToString("N"));
        using var actionContext = LogContext.PushProperty("Action", "Start");

        try
        {
            _logger.LogInformation("Starting CBDDC Node Service...");

            // Check for cancellation before starting
            cancellationToken.ThrowIfCancellationRequested();

            await _node.Start();
            _logger.LogInformation("CBDDC Node Service started successfully");
        }
        catch (OperationCanceledException)
        {
            _logger.LogWarning("CBDDC Node Service start was cancelled");
            throw;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to start CBDDC Node Service");
            throw;
        }
    }

    /// <summary>
    /// Stops the managed CBDDC node.
    /// </summary>
    /// <param name="cancellationToken">A token used to cancel shutdown.</param>
    /// <returns>A task that represents the asynchronous stop operation.</returns>
    public async Task StopAsync(CancellationToken cancellationToken)
    {
        using var serviceContext = LogContext.PushProperty("Service", nameof(CBDDCNodeService));
        using var operationContext = LogContext.PushProperty("OperationId", Guid.NewGuid().ToString("N"));
        using var actionContext = LogContext.PushProperty("Action", "Stop");

        try
        {
            _logger.LogInformation("Stopping CBDDC Node Service...");
            await _node.Stop();
            _logger.LogInformation("CBDDC Node Service stopped successfully");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error occurred while stopping CBDDC Node Service");
            // Don't rethrow during shutdown to avoid breaking the shutdown process
        }
    }
}