using FinlyticAssets.Util;
using FinlyticCore.Models;

namespace FinlyticAssets.Services;

/// <summary>
/// A hosted service responsible for managing the lifecycle of the MQTT client connection
/// when the application starts up and shuts down.
/// </summary>
public class MqttConnectionService : IHostedService
{
    private readonly AssetsMqttClient _mqttClient;
    private readonly IConfiguration _configuration;

    /// <summary>
    /// Initializes a new instance of the <see cref="MqttConnectionService"/> class.
    /// </summary>
    /// <param name="mqttClient">The MQTT client wrapper instance.</param>
    /// <param name="configuration">The application configuration provider.</param>
    public MqttConnectionService(AssetsMqttClient mqttClient, IConfiguration configuration)
    {
        _mqttClient = mqttClient;
        _configuration = configuration;
    }

    /// <summary>
    /// Starts the MQTT client connection using settings resolved from configuration.
    /// </summary>
    /// <param name="cancellationToken">A token to monitor for cancellation requests.</param>
    /// <returns>A task representing the asynchronous start operation.</returns>
    public async Task StartAsync(CancellationToken cancellationToken)
    {
        var config = new MqttConfiguration()
        {
            Host = _configuration["MQTT__Host"]!,
            Port = Convert.ToInt32(_configuration["MQTT__Port"]!),
            ClientId = $"{_configuration["MQTT__ClientId"]!}_{Guid.NewGuid()}"
        };

        await _mqttClient.ConnectAsync(config);
    }

    /// <summary>
    /// Stops and disconnects the MQTT client connection.
    /// </summary>
    /// <param name="cancellationToken">A token to monitor for cancellation requests.</param>
    /// <returns>A task representing the asynchronous stop operation.</returns>
    public async Task StopAsync(CancellationToken cancellationToken)
    {
        await _mqttClient.DisconnectAsync();
    }
}