package link

import (
	"errors"
	"testing"
	"time"

	"github.com/nats-io/nats.go"
)

// An ask a machine holds but does not start gets no heartbeat, and the bus hands it to another machine after the ack
// wait, so two machines run one check (issue 1649).

type fakeHeld struct{ msgs []*nats.Msg }

func (f *fakeHeld) NextMsg(time.Duration) (*nats.Msg, error) {
	if len(f.msgs) == 0 {
		return nil, nats.ErrTimeout
	}
	m := f.msgs[0]
	f.msgs = f.msgs[1:]
	return m, nil
}

type brokenHeld struct{}

func (brokenHeld) NextMsg(time.Duration) (*nats.Msg, error) { return nil, errors.New("closed") }

func TestEveryMessageAPullHoldsIsHandedBackBeforeABuildStarts(t *testing.T) {
	a := &fakeHeld{msgs: []*nats.Msg{{Subject: "a1"}, {Subject: "a2"}}}
	b := &fakeHeld{msgs: []*nats.Msg{{Subject: "b1"}}}
	var back []string
	n := handBackHeld([]heldSource{a, brokenHeld{}, b}, func(m *nats.Msg) { back = append(back, m.Subject) })
	if n != 3 || len(back) != 3 || back[0] != "a1" || back[2] != "b1" {
		t.Fatalf("handed back %d %v; want a1 a2 b1", n, back)
	}
	if n := handBackHeld([]heldSource{a, b}, func(*nats.Msg) { t.Fatal("handed back what was not held") }); n != 0 {
		t.Fatalf("a second pass handed back %d", n)
	}
}

func TestAnAskAnotherBuilderIsRunningIsADuplicateAndYoursIsNot(t *testing.T) {
	r := aPullCheck("build-1", 423, "head-4771ee53aa", "trunk-0123456789", false)
	run := CheckRunning{Head: r.Ref, Trunk: "trunk-0123456789", Builder: "shanks", Build: "build-1", Started: time.Now()}
	for name, c := range map[string]struct {
		running CheckRunning
		found   bool
		me      string
		dup     bool
	}{
		"another builder runs this very ask": {run, true, "ace", true},
		"this builder runs it itself":        {run, true, "shanks", false},
		"nobody runs it":                     {CheckRunning{}, false, "ace", false},
		"another ask of the same head":       {CheckRunning{Head: r.Ref, Trunk: "trunk-0123456789", Builder: "shanks", Build: "build-0"}, true, "ace", false},
		"the same ask at another head":       {CheckRunning{Head: "head-other-0000", Trunk: "trunk-0123456789", Builder: "shanks", Build: "build-1"}, true, "ace", false},
	} {
		if got := duplicateOf(c.running, c.found, r, c.me) != ""; got != c.dup {
			t.Errorf("%s: duplicate = %v; want %v", name, got, c.dup)
		}
	}
}