package main

import (
	"database/sql/driver"
	"encoding/json"
	"fmt"
	_ "github.com/go-sql-driver/mysql"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/schema"
	"strings"
	"time"
)

type Student struct {
	Id       int
	Name     string
	Age      int
	Sex      string
	CreateAt time.Time
}

// TableName 指定表名
func (Student) TableName() string {
	return "student"
}

// LocalTime 別名
type LocalTime time.Time

func (t LocalTime) MarshalJSON() ([]byte, error) {
	tTime := time.Time(t)
	return []byte(fmt.Sprintf("\"%v\"", tTime.Format("2006-01-02 15:04:05"))), nil
}

func (t LocalTime) Value() (driver.Value, error) {
	// LocalTime 轉(zhuǎn)換成 time.Time 類型
	tTime := time.Time(t)
	return tTime.Format("2006-01-02 15:04:05"), nil
}

func (t *LocalTime) UnmarshalJSON(data []byte) error {
	if string(data) == "null" {
		return nil
	}
	var err error
	//前端接收的時間字符串
	str := string(data)
	//去除接收的str收尾多余的"
	timeStr := strings.Trim(str, "\"")
	t1, err := time.Parse("2006-01-02 15:04:05", timeStr)
	*t = LocalTime(t1)
	return err
}

type StudentLocal struct {
	Id       int
	Name     string
	Age      int
	Sex      string
	CreateAt LocalTime
}

// TableName 指定表名
func (StudentLocal) TableName() string {
	return "student"
}

var db *gorm.DB
var err error

func init() {
	//dsn格式 user:pass@tcp(ip:port)/dbname?charset=utf8mb4&parseTime=True&loc=Local
	dsn := "user:pass@tcp(127.0.0.1:3306)/test?charset=utf8mb4&parseTime=True&loc=Local"
	db, err = gorm.Open(mysql.Open(dsn), &gorm.Config{
		NamingStrategy: schema.NamingStrategy{
			TablePrefix:   "",   // 表前綴
			SingularTable: true, // 禁用表名復(fù)數(shù)
		}})
	if err != nil {
		panic(err)
	}
}

func main() {
	var student Student
	db.First(&student) // 取第一條到student
	js, _ := json.Marshal(student)
	fmt.Println(string(js))
	// {"Id":1,"Name":"張三","Age":20,"Sex":"男","CreateAt":"2022-12-06T17:49:06+08:00"}

	var studentLocal StudentLocal
	db.First(&studentLocal) // 取第一條到student

	js, _ = json.Marshal(studentLocal)
	fmt.Println(string(js))
	// {"Id":1,"Name":"張三","Age":20,"Sex":"男","CreateAt":"2022-12-06 17:49:06"}

	b, _ := studentLocal.CreateAt.MarshalJSON()
	fmt.Println(string(b))
	// "2022-12-06 17:49:06"

	value, _ := studentLocal.CreateAt.Value()
	fmt.Println(value)
	// 2022-12-06 17:49:06
}