package pubsub

import (
	"sync"
	"testing"
	"time"
)

func TestDupePublisher(t *testing.T) {
	pt := NewProgressTracker()

	if _, err := pt.Publish(); err != nil {
		t.Fatalf("First publisher should not give error, err:%v", err)
	}

	if _, err := pt.Publish(); err == nil {
		t.Fatal("Dupe publisher should give error but got nil")
	} else {
		t.Logf("Got err: %v", err)
	}
}

func TestSubSub(t *testing.T) {
	pt := NewProgressTracker()
	c1 := pt.Subscribe()
	select {
	case <-c1:
	default:
	}
	if c1 == nil {
		t.Fatal("Subscriber should not get a nil channel")
	}
	c2 := pt.Subscribe()
	if c2 == nil {
		t.Fatal("Subscriber should not get a nil channel")
	}
}

func TestPubSub(t *testing.T) {
	pt := NewProgressTracker()
	pc, err := pt.Publish()
	if err != nil {
		t.Fatalf("Unexpected err: %v", err)
	}
	if pc == nil {
		t.Fatal("Should not get nil channel")
	}
	sc := pt.Subscribe()
	if sc == nil {
		t.Fatal("Should not get nil channel")
	}
	wg := sync.WaitGroup{}
	wg.Add(1)
	c := 0
	testc := make(chan int)
	go func() {
		for range sc {
			if c == 0 {
				close(testc)
			}
			c++
		}
		wg.Done()
	}()
	for i := 0; i < 10; i++ {
		pc <- "blah"
		time.Sleep(166 * time.Millisecond)
		if i == 5 {
			<-testc
		}
	}
	close(pc)
	wg.Wait()
	if c == 0 {
		t.Fatal("There should be atleast one update")
	}
	t.Logf("c is :%d", c)
	sc2 := pt.Subscribe()
	if sc2 != nil {
		t.Fatal("Subscriber after publisher done should return nil")
	}
}