package plan

import (
	"backend/internal/dto"
	"backend/internal/model"
	"backend/utils"
	"errors"

	"gorm.io/gorm"
)

// PlanService 定价计划业务逻辑层 // Logan.Li
type PlanService struct {
	db *gorm.DB
}

// NewPlanService 创建 service 实例 // Logan.Li
func NewPlanService(db *gorm.DB) *PlanService {
	return &PlanService{db: db}
}

// List 分页查询定价计划 // Logan.Li
func (s *PlanService) List(page, pageSize int, productID uint) ([]dto.PlanResponse, int64, error) {
	var plans []model.Plan
	var total int64

	query := s.db.Model(&model.Plan{}).Preload("Product")
	if productID > 0 {
		query = query.Where("product_id = ?", productID)
	}

	query.Count(&total)
	if err := query.Order("sort_order ASC, created_at DESC").
		Offset((page - 1) * pageSize).Limit(pageSize).
		Find(&plans).Error; err != nil {
		return nil, 0, err
	}

	results := make([]dto.PlanResponse, 0, len(plans))
	for _, p := range plans {
		results = append(results, toPlanResponse(p))
	}
	return results, total, nil
}

// GetByProduct 查询某产品的上架计划（公开接口） // Logan.Li
func (s *PlanService) GetByProduct(productID uint) ([]dto.PlanResponse, error) {
	var plans []model.Plan
	if err := s.db.Where("product_id = ? AND status = ?", productID, 1).
		Order("sort_order ASC").Find(&plans).Error; err != nil {
		return nil, errors.New("获取定价计划失败")
	}
	results := make([]dto.PlanResponse, 0, len(plans))
	for _, p := range plans {
		results = append(results, toPlanResponse(p))
	}
	return results, nil
}

// Create 创建定价计划 // Logan.Li
func (s *PlanService) Create(req dto.PlanCreate) (*dto.PlanResponse, error) {
	var product model.Product
	if err := s.db.First(&product, req.ProductID).Error; err != nil {
		return nil, errors.New("产品不存在")
	}

	status := 1
	if req.Status != nil {
		status = *req.Status
	}
	currency := req.Currency
	if currency == "" {
		currency = "USD"
	}

	plan := model.Plan{
		ProductID:  req.ProductID,
		Name:       req.Name,
		PlanType:   req.PlanType,
		Price:      req.Price,
		Currency:   currency,
		Duration:   req.Duration,
		MaxDevices: req.MaxDevices,
		Features:   utils.FormatFeatures(req.Features),
		SortOrder:  req.SortOrder,
		Status:     status,
	}
	if err := s.db.Create(&plan).Error; err != nil {
		return nil, errors.New("创建定价计划失败")
	}
	resp := toPlanResponse(plan)
	return &resp, nil
}

// Update 更新定价计划 // Logan.Li
func (s *PlanService) Update(id uint, req dto.PlanUpdate) (*dto.PlanResponse, error) {
	var plan model.Plan
	if err := s.db.First(&plan, id).Error; err != nil {
		return nil, errors.New("定价计划不存在")
	}

	updates := map[string]interface{}{}
	if req.Name != "" {
		updates["name"] = req.Name
	}
	if req.Price != nil {
		updates["price"] = *req.Price
	}
	if req.Currency != "" {
		updates["currency"] = req.Currency
	}
	if req.Duration != nil {
		updates["duration"] = *req.Duration
	}
	if req.MaxDevices != nil {
		updates["max_devices"] = *req.MaxDevices
	}
	if req.Features != nil {
		updates["features"] = utils.FormatFeatures(req.Features)
	}
	if req.SortOrder != nil {
		updates["sort_order"] = *req.SortOrder
	}
	if req.Status != nil {
		updates["status"] = *req.Status
	}

	if err := s.db.Model(&plan).Updates(updates).Error; err != nil {
		return nil, errors.New("更新定价计划失败")
	}
	s.db.First(&plan, id)
	resp := toPlanResponse(plan)
	return &resp, nil
}

// Delete 删除定价计划 // Logan.Li
func (s *PlanService) Delete(id uint) error {
	return s.db.Delete(&model.Plan{}, id).Error
}

// ToggleStatus 切换上下架状态 // Logan.Li
func (s *PlanService) ToggleStatus(id uint, status int) error {
	return s.db.Model(&model.Plan{}).Where("id = ?", id).Update("status", status).Error
}

// toPlanResponse 模型转响应 DTO // Logan.Li
func toPlanResponse(p model.Plan) dto.PlanResponse {
	return dto.PlanResponse{
		ID:         p.ID,
		ProductID:  p.ProductID,
		Name:       p.Name,
		PlanType:   p.PlanType,
		Price:      p.Price,
		Currency:   p.Currency,
		Duration:   p.Duration,
		MaxDevices: p.MaxDevices,
		Features:   utils.ParseFeatures(p.Features),
		SortOrder:  p.SortOrder,
		Status:     p.Status,
	}
}