package mysql

import (
	"errors"
	"gorm.io/gorm"
	"log"
)

// Association 关联模型结构体
type Association struct {
	Query string
	Args  interface{}
}

type BaseMapper[T any] struct {
	Associations []Association // 关联
}

// Insert 新增
func (m *BaseMapper[T]) Insert(entity *T) error {
	log.Printf("insert %+v\n", entity)
	return db.Create(entity).Error
}

// Delete 删除
func (m *BaseMapper[T]) Delete(entity T) error {
	log.Printf("delete %+v\n", entity)
	return db.Delete(&entity).Error
}

// Update 更新
func (m *BaseMapper[T]) Update(entity *T, omits ...interface{}) error {
	log.Printf("update %+v\n", &entity)
	if len(omits) > 0 {
		other := omits[1:]
		return db.Select(omits[0], other...).Updates(entity).Error
	}
	return db.Save(entity).Error
}

// Detail 详情
func (m *BaseMapper[T]) Detail(entity T) (res T, err error) {
	log.Printf("detail %+v\n", entity)
	err = db.First(&entity, entity).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return res, nil
	}
	return res, err
}

// List 列表
func (m *BaseMapper[T]) List(entity *T) (res []T, err error) {
	if entity == nil {
		err = db.Order("created_at desc").Find(&res).Error
	} else {
		err = db.Where(entity).Order("created_at desc").Find(&res).Error
	}

	if err != nil {
		return nil, err
	}
	return res, nil
}

// ListWithPage 列表带分页
func (m *BaseMapper[T]) ListWithPage(entity *T, page, pageSize int) (res []T, err error) {

	var tx *gorm.DB

	if m.Associations != nil && len(m.Associations) > 0 {
		for _, v := range m.Associations {
			if tx != nil {
				tx = tx.Preload(v.Query, v.Args)
			} else {
				tx = db.Preload(v.Query, v.Args)
			}

		}
	}

	if tx == nil {
		tx = db
	}

	if entity == nil {
		err = tx.Order("created_at desc").Offset((page - 1) * pageSize).Limit(pageSize).Find(&res).Error
	} else {
		err = tx.Where(entity).Order("created_at desc").Offset((page - 1) * pageSize).Limit(pageSize).Find(&res).Error
	}

	if err != nil {
		return nil, err
	}
	return res, nil
}

// First 单条记录
func (m *BaseMapper[T]) First(entity T) (res T, err error) {
	log.Printf("first %+v\n", entity)
	err = db.First(&res, entity).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return res, nil
	}
	return res, err
}