package service

import (
	"encoding/json"
	"errors"
	"fmt"
	"strconv"

	"git.huangwc.com/pig/pig-farm-controller/internal/app/dto"
	"git.huangwc.com/pig/pig-farm-controller/internal/domain/device"
	"git.huangwc.com/pig/pig-farm-controller/internal/infra/models"
	"git.huangwc.com/pig/pig-farm-controller/internal/infra/repository"
)

// ErrDeviceInUse 表示设备正在被任务使用，无法删除
var ErrDeviceInUse = errors.New("设备正在被一个或多个任务使用，无法删除")

// DeviceService 定义了应用层的设备服务接口，用于协调设备相关的业务逻辑。
type DeviceService interface {
	CreateDevice(req *dto.CreateDeviceRequest) (*dto.DeviceResponse, error)
	GetDevice(id string) (*dto.DeviceResponse, error)
	ListDevices() ([]*dto.DeviceResponse, error)
	UpdateDevice(id string, req *dto.UpdateDeviceRequest) (*dto.DeviceResponse, error)
	DeleteDevice(id string) error
	ManualControl(id string, req *dto.ManualControlDeviceRequest) error

	CreateAreaController(req *dto.CreateAreaControllerRequest) (*dto.AreaControllerResponse, error)
	GetAreaController(id string) (*dto.AreaControllerResponse, error)
	ListAreaControllers() ([]*dto.AreaControllerResponse, error)
	UpdateAreaController(id string, req *dto.UpdateAreaControllerRequest) (*dto.AreaControllerResponse, error)
	DeleteAreaController(id string) error

	CreateDeviceTemplate(req *dto.CreateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error)
	GetDeviceTemplate(id string) (*dto.DeviceTemplateResponse, error)
	ListDeviceTemplates() ([]*dto.DeviceTemplateResponse, error)
	UpdateDeviceTemplate(id string, req *dto.UpdateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error)
	DeleteDeviceTemplate(id string) error
}

// deviceService 是 DeviceService 接口的具体实现。
type deviceService struct {
	deviceRepo         repository.DeviceRepository
	areaControllerRepo repository.AreaControllerRepository
	deviceTemplateRepo repository.DeviceTemplateRepository
	deviceDomainSvc    device.Service // 依赖领域服务
}

// NewDeviceService 创建一个新的 DeviceService 实例。
func NewDeviceService(
	deviceRepo repository.DeviceRepository,
	areaControllerRepo repository.AreaControllerRepository,
	deviceTemplateRepo repository.DeviceTemplateRepository,
	deviceDomainSvc device.Service,
) DeviceService {
	return &deviceService{
		deviceRepo:         deviceRepo,
		areaControllerRepo: areaControllerRepo,
		deviceTemplateRepo: deviceTemplateRepo,
		deviceDomainSvc:    deviceDomainSvc,
	}
}

// --- Devices ---

func (s *deviceService) CreateDevice(req *dto.CreateDeviceRequest) (*dto.DeviceResponse, error) {
	propertiesJSON, err := json.Marshal(req.Properties)
	if err != nil {
		return nil, err // Consider wrapping this error for better context
	}

	device := &models.Device{
		Name:             req.Name,
		DeviceTemplateID: req.DeviceTemplateID,
		AreaControllerID: req.AreaControllerID,
		Location:         req.Location,
		Properties:       propertiesJSON,
	}

	if err := device.SelfCheck(); err != nil {
		return nil, err
	}

	if err := s.deviceRepo.Create(device); err != nil {
		return nil, err
	}

	createdDevice, err := s.deviceRepo.FindByID(device.ID)
	if err != nil {
		return nil, err
	}

	return dto.NewDeviceResponse(createdDevice)
}

func (s *deviceService) GetDevice(id string) (*dto.DeviceResponse, error) {
	device, err := s.deviceRepo.FindByIDString(id)
	if err != nil {
		return nil, err
	}
	return dto.NewDeviceResponse(device)
}

func (s *deviceService) ListDevices() ([]*dto.DeviceResponse, error) {
	devices, err := s.deviceRepo.ListAll()
	if err != nil {
		return nil, err
	}
	return dto.NewListDeviceResponse(devices)
}

func (s *deviceService) UpdateDevice(id string, req *dto.UpdateDeviceRequest) (*dto.DeviceResponse, error) {
	existingDevice, err := s.deviceRepo.FindByIDString(id)
	if err != nil {
		return nil, err
	}

	propertiesJSON, err := json.Marshal(req.Properties)
	if err != nil {
		return nil, err
	}

	existingDevice.Name = req.Name
	existingDevice.DeviceTemplateID = req.DeviceTemplateID
	existingDevice.AreaControllerID = req.AreaControllerID
	existingDevice.Location = req.Location
	existingDevice.Properties = propertiesJSON

	if err := existingDevice.SelfCheck(); err != nil {
		return nil, err
	}

	if err := s.deviceRepo.Update(existingDevice); err != nil {
		return nil, err
	}

	updatedDevice, err := s.deviceRepo.FindByID(existingDevice.ID)
	if err != nil {
		return nil, err
	}

	return dto.NewDeviceResponse(updatedDevice)
}

func (s *deviceService) DeleteDevice(id string) error {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return err
	}
	deviceID := uint(idUint)

	// 检查设备是否存在
	_, err = s.deviceRepo.FindByID(deviceID)
	if err != nil {
		return err // 如果未找到，会返回 gorm.ErrRecordNotFound
	}

	// 在删除前检查设备是否被任务使用
	inUse, err := s.deviceRepo.IsDeviceInUse(deviceID)
	if err != nil {
		// 如果检查过程中发生数据库错误，则返回错误
		return fmt.Errorf("检查设备使用情况失败: %w", err)
	}
	if inUse {
		// 如果设备正在被使用，则返回特定的业务错误
		return ErrDeviceInUse
	}

	// 只有在未被使用时，才执行删除操作
	return s.deviceRepo.Delete(deviceID)
}

func (s *deviceService) ManualControl(id string, req *dto.ManualControlDeviceRequest) error {
	dev, err := s.deviceRepo.FindByIDString(id)
	if err != nil {
		return err
	}

	if req.Action == nil {
		return s.deviceDomainSvc.Collect(dev.AreaControllerID, []*models.Device{dev})
	} else {
		action := device.DeviceActionStart
		switch *req.Action {
		case "off":
			action = device.DeviceActionStop
		case "on":
			action = device.DeviceActionStart
		default:
			return errors.New("invalid action")
		}
		return s.deviceDomainSvc.Switch(dev, action)
	}
}

// --- Area Controllers ---

func (s *deviceService) CreateAreaController(req *dto.CreateAreaControllerRequest) (*dto.AreaControllerResponse, error) {
	propertiesJSON, err := json.Marshal(req.Properties)
	if err != nil {
		return nil, err
	}

	ac := &models.AreaController{
		Name:       req.Name,
		NetworkID:  req.NetworkID,
		Location:   req.Location,
		Properties: propertiesJSON,
	}

	if err := ac.SelfCheck(); err != nil {
		return nil, err
	}

	if err := s.areaControllerRepo.Create(ac); err != nil {
		return nil, err
	}

	return dto.NewAreaControllerResponse(ac)
}

func (s *deviceService) GetAreaController(id string) (*dto.AreaControllerResponse, error) {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return nil, err
	}
	ac, err := s.areaControllerRepo.FindByID(uint(idUint))
	if err != nil {
		return nil, err
	}
	return dto.NewAreaControllerResponse(ac)
}

func (s *deviceService) ListAreaControllers() ([]*dto.AreaControllerResponse, error) {
	acs, err := s.areaControllerRepo.ListAll()
	if err != nil {
		return nil, err
	}
	return dto.NewListAreaControllerResponse(acs)
}

func (s *deviceService) UpdateAreaController(id string, req *dto.UpdateAreaControllerRequest) (*dto.AreaControllerResponse, error) {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return nil, err
	}

	existingAC, err := s.areaControllerRepo.FindByID(uint(idUint))
	if err != nil {
		return nil, err
	}

	propertiesJSON, err := json.Marshal(req.Properties)
	if err != nil {
		return nil, err
	}

	existingAC.Name = req.Name
	existingAC.NetworkID = req.NetworkID
	existingAC.Location = req.Location
	existingAC.Properties = propertiesJSON

	if err := existingAC.SelfCheck(); err != nil {
		return nil, err
	}

	if err := s.areaControllerRepo.Update(existingAC); err != nil {
		return nil, err
	}

	return dto.NewAreaControllerResponse(existingAC)
}

func (s *deviceService) DeleteAreaController(id string) error {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return err
	}

	_, err = s.areaControllerRepo.FindByID(uint(idUint))
	if err != nil {
		return err
	}

	return s.areaControllerRepo.Delete(uint(idUint))
}

// --- Device Templates ---

func (s *deviceService) CreateDeviceTemplate(req *dto.CreateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error) {
	commandsJSON, err := json.Marshal(req.Commands)
	if err != nil {
		return nil, err
	}

	valuesJSON, err := json.Marshal(req.Values)
	if err != nil {
		return nil, err
	}

	deviceTemplate := &models.DeviceTemplate{
		Name:         req.Name,
		Manufacturer: req.Manufacturer,
		Description:  req.Description,
		Category:     req.Category,
		Commands:     commandsJSON,
		Values:       valuesJSON,
	}

	if err := deviceTemplate.SelfCheck(); err != nil {
		return nil, err
	}

	if err := s.deviceTemplateRepo.Create(deviceTemplate); err != nil {
		return nil, err
	}

	return dto.NewDeviceTemplateResponse(deviceTemplate)
}

func (s *deviceService) GetDeviceTemplate(id string) (*dto.DeviceTemplateResponse, error) {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return nil, err
	}
	deviceTemplate, err := s.deviceTemplateRepo.FindByID(uint(idUint))
	if err != nil {
		return nil, err
	}
	return dto.NewDeviceTemplateResponse(deviceTemplate)
}

func (s *deviceService) ListDeviceTemplates() ([]*dto.DeviceTemplateResponse, error) {
	deviceTemplates, err := s.deviceTemplateRepo.ListAll()
	if err != nil {
		return nil, err
	}
	return dto.NewListDeviceTemplateResponse(deviceTemplates)
}

func (s *deviceService) UpdateDeviceTemplate(id string, req *dto.UpdateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error) {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return nil, err
	}

	existingDeviceTemplate, err := s.deviceTemplateRepo.FindByID(uint(idUint))
	if err != nil {
		return nil, err
	}

	commandsJSON, err := json.Marshal(req.Commands)
	if err != nil {
		return nil, err
	}

	valuesJSON, err := json.Marshal(req.Values)
	if err != nil {
		return nil, err
	}

	existingDeviceTemplate.Name = req.Name
	existingDeviceTemplate.Manufacturer = req.Manufacturer
	existingDeviceTemplate.Description = req.Description
	existingDeviceTemplate.Category = req.Category
	existingDeviceTemplate.Commands = commandsJSON
	existingDeviceTemplate.Values = valuesJSON

	if err := existingDeviceTemplate.SelfCheck(); err != nil {
		return nil, err
	}

	if err := s.deviceTemplateRepo.Update(existingDeviceTemplate); err != nil {
		return nil, err
	}

	return dto.NewDeviceTemplateResponse(existingDeviceTemplate)
}

func (s *deviceService) DeleteDeviceTemplate(id string) error {
	idUint, err := strconv.ParseUint(id, 10, 64)
	if err != nil {
		return err
	}

	_, err = s.deviceTemplateRepo.FindByID(uint(idUint))
	if err != nil {
		return err
	}

	return s.deviceTemplateRepo.Delete(uint(idUint))
}