ai/models/ListView.go

package models

import (
	"encoding/json"
	"log"
	"main/configs"
)

type ListView struct {
	Code     int64         `json:"code"`
	Page     int64         `json:"page"`
	PageSize int64         `json:"page_size"`
	Total    int64         `json:"total"`
	Next     bool          `json:"next"`
	List     []interface{} `json:"list"`
}

// 輸出JSON給瀏覽器
func (listview *ListView) ToJSON() []byte {

	// 即使list爲空，也要返回空的JSON數組
	if listview.List == nil {
		listview.List = make([]interface{}, 0)
	}

	// 輸出格式化的JSON
	b, err := json.MarshalIndent(listview, "", "  ")
	if err != nil {
		log.Println(err)
		return nil
	}
	return b
}

// 查詢數據(分頁, 每頁數量, 排序, 條件, 關聯, 獲取總數)
func (listview *ListView) Read(name string, page int64, page_size int64) error {

	// 獲取數據庫連接
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return err
	}

	// 獲取總數
	var total int64
	err = db.QueryRow("SELECT COUNT(*) FROM " + name).Scan(&total)
	if err != nil {
		log.Println(err)
		return err
	}

	// 獲取數據
	rows, err := db.Query("SELECT * FROM "+name+" LIMIT ?, ?", (page-1)*page_size, page_size)
	if err != nil {
		log.Println(err)
		return err
	}
	defer rows.Close()

	// 將數據轉換成對象
	switch name {
	case "images":
		for rows.Next() {
			var image Image
			err = rows.Scan(&image.ID, &image.Name, &image.CreatedAt, &image.UpdatedAt)
			if err != nil {
				log.Println(err)
				return err
			}
			listview.List = append(listview.List, image)
		}
	case "models":
		for rows.Next() {
			var model Model
			err = rows.Scan(&model.ID, &model.Name, &model.CreatedAt, &model.UpdatedAt)
			if err != nil {
				log.Println(err)
				return err
			}
			listview.List = append(listview.List, model)
		}
	default:
		for rows.Next() {
			var object Object
			err = rows.Scan(&object.ID, &object.Name, &object.CreatedAt, &object.UpdatedAt)
			if err != nil {
				log.Println(err)
				return err
			}
			listview.List = append(listview.List, object)
		}
	}

	// 設置返回值
	listview.Code = 0
	listview.Page = page
	listview.PageSize = page_size
	listview.Total = total
	listview.Next = total > page*page_size

	return nil
}

type Object struct {
	ID        int64  `json:"id"`
	Name      string `json:"name"`
	CreatedAt string `json:"created_at"`
	UpdatedAt string `json:"updated_at"`
	tablename string
}

type Image struct {
	Object
}

type Model struct {
	Object
	Type string `json:"type"`
}

type Tag struct {
	Object
}

type User struct {
	Object
}

type Task struct {
	Object
}

type ObjectInterface interface {
	Create() error
	Delete() error
	Update() error
	Get() error
	GetAll() ([]Object, error)
	GetPage(page int64, page_size int64) (ListView, error)
	ToJSON() []byte
}

// 按照名稱返回響應的對象類型
func GetObject(name string, id int64) ObjectInterface {
	switch name {
	case "images":
		return &Image{
			Object{tablename: name, ID: id},
		}
	default:
		return &Object{tablename: name, ID: id}
	}
}

// 創建對象
func (d *Object) Create() error {
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return err
	}
	stmt, err := db.Prepare("INSERT INTO " + d.tablename + "(name, created_at, updated_at) values(?, ?, ?)")
	if err != nil {
		log.Println(err)
		return err
	}
	defer stmt.Close()
	result, err := stmt.Exec(d.Name, d.CreatedAt, d.UpdatedAt)
	if err != nil {
		log.Println(err)
		return err
	}
	id, err := result.LastInsertId()
	if err != nil {
		return err
	}
	d.ID = id
	return nil
}

// 刪除對象
func (d *Object) Delete() error {
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return err
	}
	stmt, err := db.Prepare("DELETE FROM " + d.tablename + " WHERE id = ?")
	if err != nil {
		log.Println(err)
		return err
	}
	defer stmt.Close()
	_, err = stmt.Exec(d.ID)
	if err != nil {
		log.Println(err)
		return err
	}
	return nil
}

// 更新對象
func (d *Object) Update() error {
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return err
	}
	stmt, err := db.Prepare("UPDATE " + d.tablename + " SET name = ?, updated_at = ? WHERE id = ?")
	if err != nil {
		log.Println(err)
		return err
	}
	defer stmt.Close()
	_, err = stmt.Exec(d.Name, d.UpdatedAt, d.ID)
	if err != nil {
		log.Println(err)
		return err
	}
	return nil
}

// 獲取對象
func (d *Object) Get() error {
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return err
	}
	stmt, err := db.Prepare("SELECT * FROM " + d.tablename + " WHERE id = ?")
	if err != nil {
		log.Println(err)
		return err
	}
	defer stmt.Close()
	row := stmt.QueryRow(d.ID)
	err = row.Scan(&d.ID, &d.Name, &d.CreatedAt, &d.UpdatedAt)
	if err != nil {
		log.Println(err)
		return err
	}
	return nil
}

// 獲取所有對象
func (d *Object) GetAll() ([]Object, error) {
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return nil, err
	}
	stmt, err := db.Prepare("SELECT * FROM " + d.tablename)
	if err != nil {
		log.Println(err)
		return nil, err
	}
	defer stmt.Close()
	rows, err := stmt.Query()
	if err != nil {
		log.Println(err)
		return nil, err
	}
	defer rows.Close()
	var list []Object
	for rows.Next() {
		var item Object
		err = rows.Scan(&item.ID, &item.Name, &item.CreatedAt, &item.UpdatedAt)
		if err != nil {
			log.Println(err)
			return nil, err
		}
		list = append(list, item)
	}
	return list, nil
}

// 獲取分頁對象
func (d *Object) GetPage(page int64, page_size int64) (ListView, error) {
	db, err := configs.GetDB()
	if err != nil {
		log.Println(err)
		return ListView{}, err
	}
	stmt, err := db.Prepare("SELECT * FROM " + d.tablename + " LIMIT ?, ?")
	if err != nil {
		log.Println(err)
		return ListView{}, err
	}
	defer stmt.Close()
	rows, err := stmt.Query((page-1)*page_size, page_size)
	if err != nil {
		log.Println(err)
		return ListView{}, err
	}
	defer rows.Close()
	var list []interface{}
	for rows.Next() {
		var item Object
		err = rows.Scan(&item.ID, &item.Name, &item.CreatedAt, &item.UpdatedAt)
		if err != nil {
			log.Println(err)
			return ListView{}, err
		}
		list = append(list, item)
	}
	var listview ListView
	listview.Code = 0
	listview.Page = page
	listview.PageSize = page_size
	listview.List = list
	return listview, nil
}

// 轉換為格式化的JSON
func (d *Object) ToJSON() []byte {
	b, err := json.MarshalIndent(d, "", "  ")
	if err != nil {
		log.Println(err)
		return nil
	}
	return b
}