package service

import (
	"context"
	"encoding/json"

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

// DeviceTemplateService 定义了应用层的设备模板服务接口。
type DeviceTemplateService interface {
	CreateDeviceTemplate(ctx context.Context, req *dto.CreateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error)
	GetDeviceTemplate(ctx context.Context, id uint32) (*dto.DeviceTemplateResponse, error)
	ListDeviceTemplates(ctx context.Context) ([]*dto.DeviceTemplateResponse, error)
	UpdateDeviceTemplate(ctx context.Context, id uint32, req *dto.UpdateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error)
	DeleteDeviceTemplate(ctx context.Context, id uint32) error
}

// deviceTemplateService 是 DeviceTemplateService 接口的具体实现。
type deviceTemplateService struct {
	ctx                context.Context
	deviceTemplateRepo repository.DeviceTemplateRepository
}

// NewDeviceTemplateService 创建一个新的 DeviceTemplateService 实例。
func NewDeviceTemplateService(
	ctx context.Context,
	deviceTemplateRepo repository.DeviceTemplateRepository,
) DeviceTemplateService {
	return &deviceTemplateService{
		ctx:                ctx,
		deviceTemplateRepo: deviceTemplateRepo,
	}
}

func (s *deviceTemplateService) CreateDeviceTemplate(ctx context.Context, req *dto.CreateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error) {
	serviceCtx := logs.AddFuncName(ctx, s.ctx, "CreateDeviceTemplate")
	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(serviceCtx, deviceTemplate); err != nil {
		return nil, err
	}

	return dto.NewDeviceTemplateResponse(deviceTemplate)
}

func (s *deviceTemplateService) GetDeviceTemplate(ctx context.Context, id uint32) (*dto.DeviceTemplateResponse, error) {
	serviceCtx := logs.AddFuncName(ctx, s.ctx, "GetDeviceTemplate")
	deviceTemplate, err := s.deviceTemplateRepo.FindByID(serviceCtx, id)
	if err != nil {
		return nil, err
	}
	return dto.NewDeviceTemplateResponse(deviceTemplate)
}

func (s *deviceTemplateService) ListDeviceTemplates(ctx context.Context) ([]*dto.DeviceTemplateResponse, error) {
	serviceCtx := logs.AddFuncName(ctx, s.ctx, "ListDeviceTemplates")
	deviceTemplates, err := s.deviceTemplateRepo.ListAll(serviceCtx)
	if err != nil {
		return nil, err
	}
	return dto.NewListDeviceTemplateResponse(deviceTemplates)
}

func (s *deviceTemplateService) UpdateDeviceTemplate(ctx context.Context, id uint32, req *dto.UpdateDeviceTemplateRequest) (*dto.DeviceTemplateResponse, error) {
	serviceCtx := logs.AddFuncName(ctx, s.ctx, "UpdateDeviceTemplate")
	existingDeviceTemplate, err := s.deviceTemplateRepo.FindByID(serviceCtx, id)
	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(serviceCtx, existingDeviceTemplate); err != nil {
		return nil, err
	}

	return dto.NewDeviceTemplateResponse(existingDeviceTemplate)
}

func (s *deviceTemplateService) DeleteDeviceTemplate(ctx context.Context, id uint32) error {
	serviceCtx := logs.AddFuncName(ctx, s.ctx, "DeleteDeviceTemplate")

	// 1. 检查是否存在
	_, err := s.deviceTemplateRepo.FindByID(serviceCtx, id)
	if err != nil {
		return err
	}

	// 2. 检查是否被使用（业务逻辑）
	inUse, err := s.deviceTemplateRepo.IsInUse(serviceCtx, id)
	if err != nil {
		return err
	}
	if inUse {
		return ErrDeviceTemplateInUse // 返回业务错误
	}

	// 3. 执行删除
	return s.deviceTemplateRepo.Delete(serviceCtx, id)
}