package service

import (
	"dianshang/internal/model"
	"dianshang/internal/repository"
	"dianshang/pkg/utils"
	"errors"
)

// PlatformService 平台服务
type PlatformService struct {
	platformRepo *repository.PlatformRepository
	productRepo  *repository.ProductRepository
}

// NewPlatformService 创建平台服务
func NewPlatformService(platformRepo *repository.PlatformRepository, productRepo *repository.ProductRepository) *PlatformService {
	return &PlatformService{
		platformRepo: platformRepo,
		productRepo:  productRepo,
	}
}

// GetPlatformList 获取平台列表
func (s *PlatformService) GetPlatformList(page, pageSize int, status *int, name string) ([]model.Platform, *utils.Pagination, error) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 || pageSize > 100 {
		pageSize = 10
	}

	// 如果不需要分页，获取所有平台
	if page == 0 && pageSize == 0 {
		platforms, err := s.platformRepo.GetAll()
		return platforms, nil, err
	}

	offset := (page - 1) * pageSize
	
	// TODO: 实现带筛选的分页查询
	// 暂时先返回所有平台
	platforms, err := s.platformRepo.GetAll()
	if err != nil {
		return nil, nil, err
	}

	// 简单筛选
	var filteredPlatforms []model.Platform
	for _, p := range platforms {
		if status != nil && p.Status != *status {
			continue
		}
		if name != "" && p.Name != name && p.Code != name {
			continue
		}
		filteredPlatforms = append(filteredPlatforms, p)
	}

	total := len(filteredPlatforms)
	
	// 分页
	start := offset
	end := offset + pageSize
	if start > total {
		start = total
	}
	if end > total {
		end = total
	}
	
	result := filteredPlatforms[start:end]
	
	pagination := utils.NewPagination(page, pageSize)
	pagination.Total = int64(total)
	
	return result, pagination, nil
}

// GetPlatformByID 根据ID获取平台
func (s *PlatformService) GetPlatformByID(id uint) (*model.Platform, error) {
	return s.platformRepo.GetByID(id)
}

// GetPlatformByCode 根据代码获取平台
func (s *PlatformService) GetPlatformByCode(code string) (*model.Platform, error) {
	return s.platformRepo.GetByCode(code)
}

// CreatePlatform 创建平台
func (s *PlatformService) CreatePlatform(platform *model.Platform) error {
	// 检查平台代码是否已存在
	existing, _ := s.platformRepo.GetByCode(platform.Code)
	if existing != nil {
		return errors.New("平台代码已存在")
	}

	return s.platformRepo.Create(platform)
}

// UpdatePlatform 更新平台
func (s *PlatformService) UpdatePlatform(id uint, updates map[string]interface{}) error {
	// 检查平台是否存在
	_, err := s.platformRepo.GetByID(id)
	if err != nil {
		return errors.New("平台不存在")
	}

	// 如果更新代码，检查是否与其他平台冲突
	if code, ok := updates["code"].(string); ok {
		existing, _ := s.platformRepo.GetByCode(code)
		if existing != nil && existing.ID != id {
			return errors.New("平台代码已被其他平台使用")
		}
	}

	return s.platformRepo.Update(id, updates)
}

// DeletePlatform 删除平台
func (s *PlatformService) DeletePlatform(id uint) error {
	// 检查平台是否存在
	_, err := s.platformRepo.GetByID(id)
	if err != nil {
		return errors.New("平台不存在")
	}

	// TODO: 检查是否有分类关联到该平台
	// 可以选择级联删除或禁止删除

	return s.platformRepo.Delete(id)
}

// GetAllActivePlatforms 获取所有启用的平台
func (s *PlatformService) GetAllActivePlatforms() ([]model.Platform, error) {
	platforms, err := s.platformRepo.GetAll()
	if err != nil {
		return nil, err
	}

	// 过滤启用的平台
	var activePlatforms []model.Platform
	for _, p := range platforms {
		if p.Status == 1 {
			activePlatforms = append(activePlatforms, p)
		}
	}

	return activePlatforms, nil
}