using MediatR;
using Microsoft.Extensions.Logging;
using CellularManagement.Domain.Common;
using CellularManagement.Domain.Entities.Device;
using CellularManagement.Domain.Repositories;
using CellularManagement.Domain.Repositories.Device;
using CellularManagement.Domain.Repositories.Base;
using CellularManagement.Domain.Services;
using X1.DynamicClientCore.Features;
using X1.DynamicClientCore.Models;
using X1.DynamicClientCore.Interfaces;

namespace CellularManagement.Application.Features.Devices.Commands.CreateDevice;

/// <summary>
/// 创建设备命令处理器
/// </summary>
public class CreateDeviceCommandHandler : IRequestHandler<CreateDeviceCommand, OperationResult<CreateDeviceResponse>>
{
    private readonly ICellularDeviceRepository _deviceRepository;
    private readonly ILogger<CreateDeviceCommandHandler> _logger;
    private readonly IUnitOfWork _unitOfWork;
    private readonly ICurrentUserService _currentUserService;
    private readonly IBaseInstrumentClient _instrumentClient;
    private readonly IServiceEndpointManager _endpointManager;

    /// <summary>
    /// 初始化命令处理器
    /// </summary>
    public CreateDeviceCommandHandler(
        ICellularDeviceRepository deviceRepository,
        ILogger<CreateDeviceCommandHandler> logger,
        IUnitOfWork unitOfWork,
        ICurrentUserService currentUserService,
        IBaseInstrumentClient instrumentClient,
        IServiceEndpointManager endpointManager)
    {
        _deviceRepository = deviceRepository;
        _logger = logger;
        _unitOfWork = unitOfWork;
        _currentUserService = currentUserService;
        _instrumentClient = instrumentClient;
        _endpointManager = endpointManager;
    }

    /// <summary>
    /// 处理创建设备命令
    /// </summary>
    public async Task<OperationResult<CreateDeviceResponse>> Handle(CreateDeviceCommand request, CancellationToken cancellationToken)
    {
        // 验证请求参数
        var validationResult = ValidateRequest(request);
        if (!validationResult.IsSuccess)
        {
            return OperationResult<CreateDeviceResponse>.CreateFailure(validationResult.ErrorMessages);
        }

        _logger.LogInformation("开始创建设备，设备名称: {DeviceName}, IP地址: {IpAddress}", 
            request.DeviceName, request.IpAddress);

        // 验证用户认证
        var currentUserId = ValidateUserAuthentication();
        if (!currentUserId.IsSuccess)
        {
            return OperationResult<CreateDeviceResponse>.CreateFailure(currentUserId.ErrorMessages);
        }

        // 创建服务端点
        var serviceEndpoint = CreateServiceEndpoint(request);

        // 获取设备序列号
        var serialNumberResult = await GetDeviceSerialNumberAsync(request, serviceEndpoint, cancellationToken);
        if (!serialNumberResult.IsSuccess)
        {
            return OperationResult<CreateDeviceResponse>.CreateFailure(serialNumberResult.ErrorMessages);
        }

        var serialNumber = serialNumberResult.Data;

        // 验证序列号
        if (string.IsNullOrWhiteSpace(serialNumber))
        {
            _logger.LogError("获取到的序列号为空");
            return OperationResult<CreateDeviceResponse>.CreateFailure("无法获取设备序列号");
        }

        // 检查序列号是否已存在
        if (await _deviceRepository.SerialNumberExistsAsync(serialNumber, cancellationToken))
        {
            _logger.LogWarning("设备序列号已存在: {SerialNumber}", serialNumber);
            return OperationResult<CreateDeviceResponse>.CreateFailure($"设备序列号 {serialNumber} 已存在");
        }

        // 生成设备编号
        var deviceCode = await GenerateDeviceCodeAsync(serialNumber, cancellationToken);

        // 验证设备编号
        if (string.IsNullOrWhiteSpace(deviceCode))
        {
            _logger.LogError("生成的设备编号为空");
            return OperationResult<CreateDeviceResponse>.CreateFailure("生成设备编号失败");
        }

        // 创建设备并保存
        var deviceResult = await CreateAndSaveDeviceAsync(request, serialNumber, deviceCode, currentUserId.Data, cancellationToken);
        if (!deviceResult.IsSuccess)
        {
            return OperationResult<CreateDeviceResponse>.CreateFailure(deviceResult.ErrorMessages);
        }

        var device = deviceResult.Data;

        // 设备保存成功后，修改端点名称并重新添加
        serviceEndpoint.Name = deviceCode;
        _endpointManager.AddOrUpdateEndpoint(serviceEndpoint);
        _logger.LogDebug("设备保存成功后，已添加服务端点: {EndpointName}", deviceCode);

        // 构建响应
        var response = new CreateDeviceResponse
        {
            DeviceId = device.Id,
            DeviceName = device.Name,
            SerialNumber = device.SerialNumber,
            DeviceCode = device.DeviceCode,
            Description = device.Description,
            AgentPort = device.AgentPort,
            IsEnabled = device.IsEnabled,
            IsRunning = device.IsRunning,
            CreatedAt = device.CreatedAt
        };

        _logger.LogInformation("设备创建成功，设备ID: {DeviceId}, 设备名称: {DeviceName}, 序列号: {SerialNumber}", 
            device.Id, device.Name, device.SerialNumber);
        
        return OperationResult<CreateDeviceResponse>.CreateSuccess(response);
    }

    /// <summary>
    /// 验证请求参数
    /// </summary>
    private OperationResult<bool> ValidateRequest(CreateDeviceCommand request)
    {
        if (request == null)
        {
            _logger.LogError("请求参数为空");
            return OperationResult<bool>.CreateFailure("请求参数不能为空");
        }

        if (string.IsNullOrWhiteSpace(request.DeviceName))
        {
            _logger.LogError("设备名称为空");
            return OperationResult<bool>.CreateFailure("设备名称不能为空");
        }

        if (string.IsNullOrWhiteSpace(request.IpAddress))
        {
            _logger.LogError("IP地址为空");
            return OperationResult<bool>.CreateFailure("IP地址不能为空");
        }

        if (request.AgentPort <= 0 || request.AgentPort > 65535)
        {
            _logger.LogError("Agent端口无效: {AgentPort}", request.AgentPort);
            return OperationResult<bool>.CreateFailure("Agent端口必须在1-65535之间");
        }

        return OperationResult<bool>.CreateSuccess(true);
    }

    /// <summary>
    /// 验证用户认证
    /// </summary>
    private OperationResult<string> ValidateUserAuthentication()
    {
        var currentUserId = _currentUserService.GetCurrentUserId();
        if (string.IsNullOrEmpty(currentUserId))
        {
            _logger.LogError("无法获取当前用户ID，用户可能未认证");
            return OperationResult<string>.CreateFailure("用户未认证，无法创建设备");
        }
        return OperationResult<string>.CreateSuccess(currentUserId);
    }

    /// <summary>
    /// 获取设备序列号
    /// </summary>
    private async Task<OperationResult<string>> GetDeviceSerialNumberAsync(CreateDeviceCommand request, ServiceEndpoint serviceEndpoint, CancellationToken cancellationToken)
    {
        
        try
        {
            // 添加服务端点到管理器
            _endpointManager.AddOrUpdateEndpoint(serviceEndpoint);
            _logger.LogDebug("已添加服务端点: {EndpointName}", serviceEndpoint.Name);

            // 获取设备序列号
            var serialNumber = await _instrumentClient.GetDeviceSerialNumberAsync(serviceEndpoint.Name, null, cancellationToken);
            
            if (string.IsNullOrEmpty(serialNumber))
            {
                _logger.LogWarning("无法通过IP地址获取设备序列号，IP地址: {IpAddress}", request.IpAddress);
                // 获取序列号失败时清理服务端点
                _endpointManager.RemoveEndpoint(serviceEndpoint.Name);
                _logger.LogDebug("已清理服务端点: {EndpointName}", serviceEndpoint.Name);
                return OperationResult<string>.CreateFailure($"无法通过IP地址 {request.IpAddress} 获取设备序列号，请检查设备连接状态");
            }

            _logger.LogInformation("成功获取设备序列号: {SerialNumber}, IP地址: {IpAddress}", serialNumber, request.IpAddress);
            
            // 获取序列号成功后，移除临时服务端点
            _endpointManager.RemoveEndpoint(serviceEndpoint.Name);
            _logger.LogDebug("已移除临时服务端点: {EndpointName}", serviceEndpoint.Name);
            
            return OperationResult<string>.CreateSuccess(serialNumber);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "获取设备序列号时发生异常，IP地址: {IpAddress}", request.IpAddress);
            // 发生异常时清理服务端点
            _endpointManager.RemoveEndpoint(serviceEndpoint.Name);
            _logger.LogDebug("已清理服务端点: {EndpointName}", serviceEndpoint.Name);
            return OperationResult<string>.CreateFailure($"获取设备序列号时发生错误: {ex.Message}");
        }
    }

    /// <summary>
    /// 生成设备编号
    /// </summary>
    private async Task<string> GenerateDeviceCodeAsync(string serialNumber, CancellationToken cancellationToken)
    {
        // 获取当前设备总数
        var deviceCount = await _deviceRepository.GetDeviceCountAsync(cancellationToken);
        var nextNumber = deviceCount + 1;
        
        // 计算需要的位数，确保至少3位数
        var digitCount = CalculateRequiredDigits(nextNumber);
        
        // 格式化序号，动态补0，确保从000开始
        var formattedNumber = nextNumber.ToString($"D{digitCount}");
        
        // 生成设备编号格式：DEV-000-SN, DEV-001-SN, DEV-002-SN 等
        var deviceCode = $"DEV-{formattedNumber}-{serialNumber}";
        
        _logger.LogDebug("生成设备编号: {DeviceCode}, 设备总数: {DeviceCount}, 位数: {DigitCount}", deviceCode, deviceCount, digitCount);
        
        return deviceCode;
    }

    /// <summary>
    /// 计算需要的位数
    /// </summary>
    private int CalculateRequiredDigits(int number)
    {
        if (number <= 0) return 3; // 从000开始，至少3位数
        
        // 计算位数：确保至少3位数，从000开始
        // 1-999用3位，1000-9999用4位，10000-99999用5位，以此类推
        var calculatedDigits = (int)Math.Floor(Math.Log10(number)) + 1;
        return Math.Max(calculatedDigits, 3); // 确保至少3位数
    }

    /// <summary>
    /// 创建服务端点配置
    /// </summary>
    private ServiceEndpoint CreateServiceEndpoint(CreateDeviceCommand request)
    {
        return new ServiceEndpoint
        {
            Name = $"DEV-{Guid.NewGuid():N}",
            Ip = request.IpAddress,
            Port = request.AgentPort,
            Protocol = "http",
            BasePath= "/api/v1",
            Timeout = 10,
            Enabled = true
        };
    }

    /// <summary>
    /// 创建设备并保存到数据库
    /// </summary>
    private async Task<OperationResult<CellularDevice>> CreateAndSaveDeviceAsync(
        CreateDeviceCommand request, 
        string serialNumber, 
        string deviceCode,
        string currentUserId, 
        CancellationToken cancellationToken)
    {
        try
        {
            // 创建设备实体
            var device = CellularDevice.Create(
                name: request.DeviceName,
                serialNumber: serialNumber,
                deviceCode: deviceCode,
                description: request.Description,
                agentPort: request.AgentPort,
                ipAddress: request.IpAddress,
                createdBy: currentUserId,
                isEnabled: request.IsEnabled,
                isRunning: request.IsRunning);

            // 保存设备
            await _deviceRepository.AddDeviceAsync(device, cancellationToken);

            // 保存更改到数据库
            await _unitOfWork.SaveChangesAsync(cancellationToken);

            return OperationResult<CellularDevice>.CreateSuccess(device);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "创建设备实体时发生错误，设备名称: {DeviceName}", request.DeviceName);
            return OperationResult<CellularDevice>.CreateFailure($"创建设备时发生错误: {ex.Message}");
        }
    }
}