package services

import (
	"errors"

	"git.beifan.cn/trace-system/backend-go/database"
	"git.beifan.cn/trace-system/backend-go/models"
)

// CompaniesService 企业管理服务
type CompaniesService struct{}

// FindAll 获取所有企业列表
func (s *CompaniesService) FindAll(page int, limit int, search string) ([]models.Company, int, int, error) {
	var companies []models.Company
	var total int64

	offset := (page - 1) * limit
	db := database.DB

	// 搜索条件
	if search != "" {
		db = db.Where("company_name LIKE ?", "%"+search+"%")
	}

	// 获取总数
	db.Count(&total)

	// 分页查询
	result := db.Order("created_at DESC").Offset(offset).Limit(limit).Find(&companies)
	if result.Error != nil {
		return nil, 0, 0, errors.New("查询企业列表失败")
	}

	totalPages := (int(total) + limit - 1) / limit

	return companies, int(total), totalPages, nil
}

// Create 创建企业
func (s *CompaniesService) Create(companyName string) (*models.Company, error) {
	// 检查企业是否已存在
	var existingCompany models.Company
	result := database.DB.Where("company_name = ?", companyName).First(&existingCompany)
	if result.Error == nil {
		return nil, errors.New("企业名称已存在")
	}

	company := models.Company{
		CompanyName: companyName,
		IsActive:    true,
	}

	result = database.DB.Create(&company)
	if result.Error != nil {
		return nil, errors.New("创建企业失败")
	}

	return &company, nil
}

// Update 更新企业信息
func (s *CompaniesService) Update(companyName string, newCompanyName string, isActive bool) (*models.Company, error) {
	var company models.Company
	result := database.DB.Where("company_name = ?", companyName).First(&company)
	if result.Error != nil {
		return nil, errors.New("企业不存在")
	}

	// 如果企业名称已变更，检查新名称是否已存在
	if newCompanyName != companyName {
		var existingCompany models.Company
		checkResult := database.DB.Where("company_name = ?", newCompanyName).First(&existingCompany)
		if checkResult.Error == nil {
			return nil, errors.New("企业名称已存在")
		}

		company.CompanyName = newCompanyName
	}

	company.IsActive = isActive

	result = database.DB.Save(&company)
	if result.Error != nil {
		return nil, errors.New("更新企业信息失败")
	}

	return &company, nil
}

// Delete 删除企业
func (s *CompaniesService) Delete(companyName string) error {
	var company models.Company
	result := database.DB.Where("company_name = ?", companyName).First(&company)
	if result.Error != nil {
		return errors.New("企业不存在")
	}

	// 检查企业是否有关联的序列号
	var serialCount int64
	database.DB.Model(&models.Serial{}).Where("company_name = ?", companyName).Count(&serialCount)
	if serialCount > 0 {
		return errors.New("企业下还有序列号，无法删除")
	}

	result = database.DB.Delete(&company)
	if result.Error != nil {
		return errors.New("删除企业失败")
	}

	return nil
}

// GetStatsOverview 获取企业统计概览
func (s *CompaniesService) GetStatsOverview() (*models.CompanyStatsOverviewDTO, error) {
	stats := &models.CompanyStatsOverviewDTO{}

	if err := database.DB.Model(&models.Company{}).Count(&stats.TotalCompanies).Error; err != nil {
		return nil, errors.New("统计企业总数失败")
	}

	if err := database.DB.Model(&models.Company{}).Where("is_active = ?", true).Count(&stats.ActiveCompanies).Error; err != nil {
		return nil, errors.New("统计启用企业数量失败")
	}

	stats.InactiveCompanies = stats.TotalCompanies - stats.ActiveCompanies

	if err := database.DB.Model(&models.Serial{}).Count(&stats.TotalSerials).Error; err != nil {
		return nil, errors.New("统计企业赋码总数失败")
	}

	if err := database.DB.Model(&models.Serial{}).Where("is_active = ?", true).Count(&stats.ActiveSerials).Error; err != nil {
		return nil, errors.New("统计有效企业赋码数量失败")
	}

	stats.RevokedSerials = stats.TotalSerials - stats.ActiveSerials

	if err := database.DB.Model(&models.EmployeeSerial{}).Count(&stats.TotalEmployeeSerials).Error; err != nil {
		return nil, errors.New("统计员工赋码总数失败")
	}

	if err := database.DB.Model(&models.EmployeeSerial{}).Where("is_active = ?", true).Count(&stats.ActiveEmployeeSerials).Error; err != nil {
		return nil, errors.New("统计有效员工赋码数量失败")
	}

	stats.RevokedEmployeeSerials = stats.TotalEmployeeSerials - stats.ActiveEmployeeSerials

	return stats, nil
}