package main

import (
	"fmt"
	"sync"
	"time"

	"github.com/vbauerster/mpb"
	"github.com/vbauerster/mpb/decor"
)

func main() {
	var wg sync.WaitGroup
	p := mpb.New(mpb.WithWaitGroup(&wg))

	wantPanic := "Upps!!!"
	numBars := 3
	wg.Add(numBars)

	for i := 0; i < numBars; i++ {
		name := fmt.Sprintf("b#%02d:", i)
		bar := p.AddBar(100, mpb.BarID(i), mpb.PrependDecorators(
			func(s *decor.Statistics, _ chan<- int, _ <-chan int) string {
				// s.Current == 42 may never happen, if sleep btw increments is
				// too short, thus using s.Current >= 42
				if s.ID == 1 && s.Current >= 42 {
					panic(wantPanic)
				}
				return name
			},
		))

		go func() {
			defer wg.Done()
			for i := 0; i < 100; i++ {
				time.Sleep(50 * time.Millisecond)
				bar.Increment()
			}
		}()
	}

	p.Wait()
}