package nomad

import (
	"testing"
	"time"

	"github.com/hashicorp/nomad/nomad/mock"
	"github.com/hashicorp/nomad/nomad/structs"
)

var (
	defaultSched = []string{
		structs.JobTypeService,
		structs.JobTypeBatch,
	}
)

func testBroker(t *testing.T, timeout time.Duration) *EvalBroker {
	if timeout == 0 {
		timeout = 5 * time.Second
	}
	b, err := NewEvalBroker(timeout)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	return b
}

func TestEvalBroker_Enqueue_Dequeue_Nack_Ack(t *testing.T) {
	b := testBroker(t, 0)

	// Enqueue, but broker is disabled!
	eval := mock.Eval()
	err := b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Verify nothing was done
	stats := b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}

	if b.Enabled() {
		t.Fatalf("should not be enabled")
	}

	// Enable the broker, and enqueue
	b.SetEnabled(true)
	err = b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Double enqueue is a no-op
	err = b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	if !b.Enabled() {
		t.Fatalf("should be enabled")
	}

	// Verify enqueue is done
	stats = b.Stats()
	if stats.TotalReady != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Ready != 1 {
		t.Fatalf("bad: %#v", stats)
	}

	// Dequeue should work
	out, token, err := b.Dequeue(defaultSched, time.Second)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != eval {
		t.Fatalf("bad : %#v", out)
	}

	tokenOut, ok := b.Outstanding(out.ID)
	if !ok {
		t.Fatalf("should be outstanding")
	}
	if tokenOut != token {
		t.Fatalf("Bad: %#v %#v", token, tokenOut)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Ready != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Unacked != 1 {
		t.Fatalf("bad: %#v", stats)
	}

	// Nack with wrong token should fail
	err = b.Nack(eval.ID, "foobarbaz")
	if err == nil {
		t.Fatalf("should fail to nack")
	}

	// Nack back into the queue
	err = b.Nack(eval.ID, token)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	if _, ok := b.Outstanding(out.ID); ok {
		t.Fatalf("should not be outstanding")
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Ready != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Unacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}

	// Dequeue should work again
	out2, token2, err := b.Dequeue(defaultSched, time.Second)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out2 != eval {
		t.Fatalf("bad : %#v", out2)
	}
	if token2 == token {
		t.Fatalf("should get a new token")
	}

	tokenOut2, ok := b.Outstanding(out.ID)
	if !ok {
		t.Fatalf("should be outstanding")
	}
	if tokenOut2 != token2 {
		t.Fatalf("Bad: %#v %#v", token2, tokenOut2)
	}

	// Ack with wrong token
	err = b.Ack(eval.ID, "zip")
	if err == nil {
		t.Fatalf("should fail to ack")
	}

	// Ack finally
	err = b.Ack(eval.ID, token2)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	if _, ok := b.Outstanding(out.ID); ok {
		t.Fatalf("should not be outstanding")
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Ready != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.ByScheduler[eval.Type].Unacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
}

func TestEvalBroker_Serialize_DuplicateJobID(t *testing.T) {
	b := testBroker(t, 0)
	b.SetEnabled(true)

	eval := mock.Eval()
	err := b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	eval2 := mock.Eval()
	eval2.JobID = eval.JobID
	eval2.CreateIndex = eval.CreateIndex + 1
	err = b.Enqueue(eval2)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	eval3 := mock.Eval()
	eval3.JobID = eval.JobID
	eval3.CreateIndex = eval.CreateIndex + 2
	err = b.Enqueue(eval3)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	stats := b.Stats()
	if stats.TotalReady != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 2 {
		t.Fatalf("bad: %#v", stats)
	}

	// Dequeue should work
	out, token, err := b.Dequeue(defaultSched, time.Second)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != eval {
		t.Fatalf("bad : %#v", out)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 2 {
		t.Fatalf("bad: %#v", stats)
	}

	// Ack out
	err = b.Ack(eval.ID, token)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 1 {
		t.Fatalf("bad: %#v", stats)
	}

	// Dequeue should work
	out, token, err = b.Dequeue(defaultSched, time.Second)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != eval2 {
		t.Fatalf("bad : %#v", out)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 1 {
		t.Fatalf("bad: %#v", stats)
	}

	// Ack out
	err = b.Ack(eval2.ID, token)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 0 {
		t.Fatalf("bad: %#v", stats)
	}

	// Dequeue should work
	out, token, err = b.Dequeue(defaultSched, time.Second)
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != eval3 {
		t.Fatalf("bad : %#v", out)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 1 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 0 {
		t.Fatalf("bad: %#v", stats)
	}

	// Ack out
	err = b.Ack(eval3.ID, token)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Check the stats
	stats = b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalBlocked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
}

func TestEvalBroker_Enqueue_Disable(t *testing.T) {
	b := testBroker(t, 0)

	// Enqueue
	eval := mock.Eval()
	b.SetEnabled(true)
	err := b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Flush via SetEnabled
	b.SetEnabled(false)

	// Check the stats
	stats := b.Stats()
	if stats.TotalReady != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if stats.TotalUnacked != 0 {
		t.Fatalf("bad: %#v", stats)
	}
	if _, ok := stats.ByScheduler[eval.Type]; ok {
		t.Fatalf("bad: %#v", stats)
	}
}

func TestEvalBroker_Dequeue_Timeout(t *testing.T) {
	b := testBroker(t, 0)
	b.SetEnabled(true)

	start := time.Now()
	out, _, err := b.Dequeue(defaultSched, 5*time.Millisecond)
	end := time.Now()

	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != nil {
		t.Fatalf("unexpected: %#v", out)
	}

	if diff := end.Sub(start); diff < 5*time.Millisecond {
		t.Fatalf("bad: %#v", diff)
	}
}

// Ensure higher priority dequeued first
func TestEvalBroker_Dequeue_Priority(t *testing.T) {
	b := testBroker(t, 0)
	b.SetEnabled(true)

	eval1 := mock.Eval()
	eval1.Priority = 10
	b.Enqueue(eval1)

	eval2 := mock.Eval()
	eval2.Priority = 30
	b.Enqueue(eval2)

	eval3 := mock.Eval()
	eval3.Priority = 20
	b.Enqueue(eval3)

	out1, _, _ := b.Dequeue(defaultSched, time.Second)
	if out1 != eval2 {
		t.Fatalf("bad: %#v", out1)
	}

	out2, _, _ := b.Dequeue(defaultSched, time.Second)
	if out2 != eval3 {
		t.Fatalf("bad: %#v", out2)
	}

	out3, _, _ := b.Dequeue(defaultSched, time.Second)
	if out3 != eval1 {
		t.Fatalf("bad: %#v", out3)
	}
}

// Ensure FIFO at fixed priority
func TestEvalBroker_Dequeue_FIFO(t *testing.T) {
	b := testBroker(t, 0)
	b.SetEnabled(true)
	NUM := 100

	for i := 0; i < NUM; i++ {
		eval1 := mock.Eval()
		eval1.CreateIndex = uint64(i)
		eval1.ModifyIndex = uint64(i)
		b.Enqueue(eval1)
	}

	for i := 0; i < NUM; i++ {
		out1, _, _ := b.Dequeue(defaultSched, time.Second)
		if out1.CreateIndex != uint64(i) {
			t.Fatalf("bad: %d %#v", i, out1)
		}
	}
}

// Ensure fairness between schedulers
func TestEvalBroker_Dequeue_Fairness(t *testing.T) {
	b := testBroker(t, 0)
	b.SetEnabled(true)
	NUM := 100

	for i := 0; i < NUM; i++ {
		eval1 := mock.Eval()
		if i < (NUM / 2) {
			eval1.Type = structs.JobTypeService
		} else {
			eval1.Type = structs.JobTypeBatch
		}
		b.Enqueue(eval1)
	}

	counter := 0
	for i := 0; i < NUM; i++ {
		out1, _, _ := b.Dequeue(defaultSched, time.Second)

		switch out1.Type {
		case structs.JobTypeService:
			if counter < 0 {
				counter = 0
			}
			counter += 1
		case structs.JobTypeBatch:
			if counter > 0 {
				counter = 0
			}
			counter -= 1
		}

		// This will fail randomly at times. It is very hard to
		// test deterministically that its acting randomly.
		if counter >= 25 || counter <= -25 {
			t.Fatalf("unlikely sequence: %d", counter)
		}
	}
}

// Ensure we get unblocked
func TestEvalBroker_Dequeue_Blocked(t *testing.T) {
	b := testBroker(t, 0)
	b.SetEnabled(true)

	// Start with a blocked dequeue
	outCh := make(chan *structs.Evaluation, 1)
	go func() {
		start := time.Now()
		out, _, err := b.Dequeue(defaultSched, time.Second)
		end := time.Now()
		outCh <- out
		if err != nil {
			t.Fatalf("err: %v", err)
		}
		if d := end.Sub(start); d < 5*time.Millisecond {
			t.Fatalf("bad: %v", d)
		}
	}()

	// Wait for a bit
	time.Sleep(5 * time.Millisecond)

	// Enqueue
	eval := mock.Eval()
	err := b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Ensure dequeue
	select {
	case out := <-outCh:
		if out != eval {
			t.Fatalf("bad: %v", out)
		}
	case <-time.After(time.Second):
		t.Fatalf("timeout")
	}
}

// Ensure we nack in a timely manner
func TestEvalBroker_Nack_Timeout(t *testing.T) {
	b := testBroker(t, 5*time.Millisecond)
	b.SetEnabled(true)

	// Enqueue
	eval := mock.Eval()
	err := b.Enqueue(eval)
	if err != nil {
		t.Fatalf("err: %v", err)
	}

	// Dequeue
	out, _, err := b.Dequeue(defaultSched, time.Second)
	start := time.Now()
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != eval {
		t.Fatalf("bad: %v", out)
	}

	// Dequeue, should block on Nack timer
	out, _, err = b.Dequeue(defaultSched, time.Second)
	end := time.Now()
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	if out != eval {
		t.Fatalf("bad: %v", out)
	}

	// Check the nack timer
	if diff := end.Sub(start); diff < 5*time.Millisecond {
		t.Fatalf("bad: %#v", diff)
	}
}