如何减少golang的完美时间？

Question

I'm making a cron job for the booking charge automatic. The admin set the automatic charge after 2 hour of booking completion then I Get all the booking completed before 2 hours from the current time and charge them automatic. But the problem arise in the end of the day is that current_date= 10/10/2018 current_time= 1:00AM and automatic_charge_hours= 2 (hours) means it will get all the bookings which are completed 2 hours before the current_time and current_date. In 24hour format it will get all the bookings of the 23 hours(11:00PM of date 09/10/2018) of the previous date . But in my condition it will turn it into zero below is my condition:-

package main

import (
  "fmt"
  "time"
  "strings"
)

func main() {
timeZone, _ := time.LoadLocation("America/New_York")
currDate := time.Now().In(timeZone).Format("2006-01-02 00:00:00 -0000")
onlyDate := strings.Split(currDate, " ")
hours, _ := 1, 0
if hours-int(2) < 0 {
    hours = 0
} else {
    hours = hours - int(2)
}
fmt.Println(hours, onlyDate[0])
}

playground link https://play.golang.org/p/w7LIoTp9xN0

How will I change it. Any suggestions please.

Answer 1

if hours-int(2) < 0 {
    hours = 0
} else {
    hours = hours - int(2)
}

Explicitly sets hours to zero when hours are negative.

If you change hours = 0 to hours = 24 + (hours-int(2)) it returns 23.

See https://play.golang.org/p/FyXIn5gjIXk

Anyhow, Instead of manipulating hours by hand, you should use time functions.

Update: Use time functions:

package main

import (
    "fmt"
    "time"
)

func main() {
    t, err := time.Parse("01.02.2006 03:04:00", "10.10.2018 01:00:00")
    if err != nil {
        panic(err)
    }
    then := t.Add(time.Duration( -2 ) * time.Hour)
    fmt.Printf("%v
", then)
}

https://play.golang.org/p/0r6q7Vvai2h