package host

import (
	"testing"

	"github.com/carlosframework/platform/internal/hostclaim"
)

// M9: an admitted wake attempt keeps its writer only across adjacent forward
// steps it has checked. Its checkpoint advances on each one; a skipped step
// or a step back from the checkpoint refuses and leaves it unchanged.
func TestPlan9Fix1WakeAttemptAdvancesOneCheckedStepAtATime(t *testing.T) {
	probing := plan9D1Session(hostclaim.PhaseLandingProbing, 11)
	probed := plan9D1Session(hostclaim.PhaseLandingProbed, 11)
	committed := plan9D1Session(hostclaim.PhaseLandingCommitted, 11)

	skip := &claimWakeAttempt{observed: probing}
	if skip.advance(committed, hostclaim.SessionContinues) {
		t.Fatal("probing advanced straight to committed")
	}
	if got, _ := skip.snapshot(); got.Claim.Op.Phase != hostclaim.PhaseLandingProbing {
		t.Fatalf("a refused step moved the checkpoint to %q", got.Claim.Op.Phase)
	}

	a := &claimWakeAttempt{observed: probing}
	if !a.advance(probed, hostclaim.SessionContinues) || !a.advance(committed, hostclaim.SessionContinues) {
		t.Fatal("checked adjacent steps ended the session")
	}
	if a.advance(probed, hostclaim.SessionContinues) || a.advance(probing, hostclaim.SessionContinues) {
		t.Fatal("a step back from the checkpoint kept the session")
	}
	if !a.advance(committed, hostclaim.SessionContinues) {
		t.Fatal("the checkpoint's own phase ended the session")
	}
	if a.advance(plan9D1Session(hostclaim.PhaseLandingCommitted, 12), hostclaim.SessionContinues) {
		t.Fatal("a new session kept the checkpoint")
	}
}