CellularManagement/src/CellularManagement.Application/Features/Devices/Queries/GetDeviceById/GetDeviceByIdQueryHandler.cs

using CellularManagement.Domain.Common;
using CellularManagement.Domain.Entities.Device;
using CellularManagement.Domain.Repositories;
using CellularManagement.Domain.Repositories.Device;
using MediatR;
using Microsoft.Extensions.Logging;

namespace CellularManagement.Application.Features.Devices.Queries.GetDeviceById;

/// <summary>
/// 根据ID获取设备查询处理器
/// </summary>
public class GetDeviceByIdQueryHandler : IRequestHandler<GetDeviceByIdQuery, OperationResult<GetDeviceByIdResponse>>
{
    private readonly ICellularDeviceRepository _deviceRepository;
    private readonly ILogger<GetDeviceByIdQueryHandler> _logger;

    /// <summary>
    /// 初始化查询处理器
    /// </summary>
    public GetDeviceByIdQueryHandler(
        ICellularDeviceRepository deviceRepository,
        ILogger<GetDeviceByIdQueryHandler> logger)
    {
        _deviceRepository = deviceRepository;
        _logger = logger;
    }

    /// <summary>
    /// 处理查询请求
    /// </summary>
    public async Task<OperationResult<GetDeviceByIdResponse>> Handle(GetDeviceByIdQuery request, CancellationToken cancellationToken)
    {
        try
        {
            _logger.LogInformation("开始查询设备，设备ID: {DeviceId}", request.DeviceId);

            var device = await _deviceRepository.GetDeviceByIdAsync(request.DeviceId, cancellationToken);
            
            if (device == null)
            {
                _logger.LogWarning("未找到设备，设备ID: {DeviceId}", request.DeviceId);
                return OperationResult<GetDeviceByIdResponse>.CreateFailure($"未找到ID为 {request.DeviceId} 的设备");
            }

            var response = new GetDeviceByIdResponse
            {
                DeviceId = device.Id,
                DeviceName = device.Name,
                SerialNumber = device.SerialNumber,
                DeviceType = device.DeviceType?.Name ?? "未知",
                Status = device.Status?.Name ?? "未知",
                ProtocolVersion = device.ProtocolVersion?.Version ?? "未知",
                FirmwareVersion = device.FirmwareVersion,
                CreatedAt = device.CreatedAt
            };

            _logger.LogInformation("成功查询到设备，设备ID: {DeviceId}", request.DeviceId);
            return OperationResult<GetDeviceByIdResponse>.CreateSuccess(response);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "查询设备时发生错误，设备ID: {DeviceId}", request.DeviceId);
            return OperationResult<GetDeviceByIdResponse>.CreateFailure($"查询设备时发生错误: {ex.Message}");
        }
    }
}