package backoff

import (
	"errors"
	"math/rand"
	"testing"
	"time"
)

func TestMaxTriesHappy(t *testing.T) {
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	max := 17 + r.Intn(13)
	bo := WithMaxRetries(&ZeroBackOff{}, uint64(max))

	// Load up the tries count, but reset should clear the record
	for ix := 0; ix < max/2; ix++ {
		bo.NextBackOff()
	}
	bo.Reset()

	// Now fill the tries count all the way up
	for ix := 0; ix < max; ix++ {
		d := bo.NextBackOff()
		if d == Stop {
			t.Errorf("returned Stop on try %d", ix)
		}
	}

	// We have now called the BackOff max number of times, we expect
	// the next result to be Stop, even if we try it multiple times
	for ix := 0; ix < 7; ix++ {
		d := bo.NextBackOff()
		if d != Stop {
			t.Error("invalid next back off")
		}
	}

	// Reset makes it all work again
	bo.Reset()
	d := bo.NextBackOff()
	if d == Stop {
		t.Error("returned Stop after reset")
	}
}

// https://github.com/cenkalti/backoff/issues/80
func TestMaxTriesZero(t *testing.T) {
	var called int

	b := WithMaxRetries(&ZeroBackOff{}, 0)

	err := Retry(func() error {
		called++
		return errors.New("err")
	}, b)

	if err == nil {
		t.Errorf("error expected, nil found")
	}
	if called != 1 {
		t.Errorf("operation is called %d times", called)
	}
}