package storage

import (
	"time"

	"goalfymax-admin/internal/models"
	"gorm.io/gorm"
)

type InviteCodeStorage interface {
	Create(inviteCode *models.InviteCode) error
	GetByID(id uint) (*models.InviteCode, error)
	GetByCode(code string) (*models.InviteCode, error)
	List(req *models.InviteCodeListRequest) ([]models.InviteCode, int64, error)
	Update(inviteCode *models.InviteCode) error
	Delete(id uint) error
	GetStatistics() (*models.InviteCodeStatistics, error)
	IsExpired(inviteCode *models.InviteCode) bool
}

type inviteCodeStorage struct {
	db *gorm.DB
}

func NewInviteCodeStorage() InviteCodeStorage {
	return &inviteCodeStorage{db: DB}
}

func (s *inviteCodeStorage) Create(inviteCode *models.InviteCode) error {
	// 若目标库缺少 is_used 列，则在插入时省略该列，避免 Unknown column 错误
	if columnExistsIsUsed(s.db) {
		return s.db.Create(inviteCode).Error
	}
	return s.db.Omit("is_used").Create(inviteCode).Error
}

func (s *inviteCodeStorage) GetByID(id uint) (*models.InviteCode, error) {
	var inviteCode models.InviteCode
	err := s.db.Where("deleted_at IS NULL").First(&inviteCode, id).Error
	if err != nil {
		return nil, err
	}
	return &inviteCode, nil
}

func (s *inviteCodeStorage) GetByCode(code string) (*models.InviteCode, error) {
	var inviteCode models.InviteCode
	err := s.db.Where("code = ? AND deleted_at IS NULL", code).First(&inviteCode).Error
	if err != nil {
		return nil, err
	}
	return &inviteCode, nil
}

// IsExpired 检查邀请码是否过期
func (s *inviteCodeStorage) IsExpired(inviteCode *models.InviteCode) bool {
	if inviteCode.ExpiresAt == nil {
		return false // 没有设置过期时间，永不过期
	}
	return time.Now().After(*inviteCode.ExpiresAt)
}

func (s *inviteCodeStorage) List(req *models.InviteCodeListRequest) ([]models.InviteCode, int64, error) {
	var inviteCodes []models.InviteCode
	var total int64

	query := s.db.Model(&models.InviteCode{}).Where("deleted_at IS NULL")

	// 筛选条件
	if req.Code != "" {
		query = query.Where("code LIKE ?", "%"+req.Code+"%")
	}
	// 仅当存在 is_used 列时才应用过滤
	if req.IsUsed != nil {
		if columnExistsIsUsed(s.db) {
			query = query.Where("is_used = ?", *req.IsUsed)
		}
	}
	if req.StartTime != "" {
		query = query.Where("created_at >= ?", req.StartTime)
	}
	if req.EndTime != "" {
		query = query.Where("created_at <= ?", req.EndTime)
	}

	// 获取总数
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	// 分页查询
	offset := (req.Page - 1) * req.Size
	err := query.Order("created_at DESC").Offset(offset).Limit(req.Size).Find(&inviteCodes).Error
	if err != nil {
		return nil, 0, err
	}

	return inviteCodes, total, nil
}

func (s *inviteCodeStorage) Update(inviteCode *models.InviteCode) error {
	return s.db.Save(inviteCode).Error
}

func (s *inviteCodeStorage) Delete(id uint) error {
	return s.db.Delete(&models.InviteCode{}, id).Error
}

func (s *inviteCodeStorage) GetStatistics() (*models.InviteCodeStatistics, error) {
	var stats models.InviteCodeStatistics

	// 总数
	var total int64
	if err := s.db.Model(&models.InviteCode{}).Where("deleted_at IS NULL").Count(&total).Error; err != nil {
		return nil, err
	}
	stats.Total = int(total)

	// is_used 列可能不存在，存在时统计已使用/未使用
	if columnExistsIsUsed(s.db) {
		var used int64
		if err := s.db.Model(&models.InviteCode{}).Where("deleted_at IS NULL AND is_used = ?", true).Count(&used).Error; err != nil {
			return nil, err
		}
		stats.Used = int(used)

		var unused int64
		if err := s.db.Model(&models.InviteCode{}).Where("deleted_at IS NULL AND is_used = ?", false).Count(&unused).Error; err != nil {
			return nil, err
		}
		stats.Unused = int(unused)
	} else {
		// 列不存在时，给出合理默认值
		stats.Used = 0
		stats.Unused = int(total)
	}

	// 今日新增
	today := time.Now().Format("2006-01-02")
	var todayCreated int64
	if err := s.db.Model(&models.InviteCode{}).Where("deleted_at IS NULL AND DATE(created_at) = ?", today).Count(&todayCreated).Error; err != nil {
		return nil, err
	}
	stats.TodayCreated = int(todayCreated)

	return &stats, nil
}

// columnExistsIsUsed 检查当前数据库中 admin_invite_codes 表是否存在 is_used 列
func columnExistsIsUsed(db *gorm.DB) bool {
	var count int64
	// 使用当前连接的数据库名
	db.Raw("SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ? AND COLUMN_NAME = 'is_used'", "admin_invite_codes").Scan(&count)
	return count > 0
}