package quiesce

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

// R-518 (cheap half) — a tier whose storage the agent reports ABSENT is not attempted, and no app is
// stopped for it. BIGNIGHT: the apps stayed stopped through a felhom-pbs tier whose storage did not
// exist, then that tier failed.

type skipRecorder struct {
	mu      sync.Mutex
	skipped []string
}

func (r *skipRecorder) BackupFailed(string, string, string) {}
func (r *skipRecorder) BackupRecovered(string, string)      {}
func (r *skipRecorder) BackupTierSkipped(tier, _ string) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.skipped = append(r.skipped, tier)
}

// RED-PROOF (run 2026-09-15, recorded in REPORT.md): with skipAbsentTiers returning its input
// unchanged, the manual run started [local felhom-pbs] and this failed at "absent tier was attempted".
func TestManualRun_AbsentTierSkipped(t *testing.T) {
	be := newTierBackend()
	be.tiers = []BackupTier{{Target: "local", Primary: true}, {Target: "felhom-pbs", StorageAbsent: true}}
	be.phases["local"] = []string{phaseDone}
	st := &fakeStacks{running: []string{"immich"}}
	l := newTierLoop(t, be, st, nil)
	rec := &skipRecorder{}
	l.SetTierNotifier(rec)

	if err := l.quiesceAndPollTiers(context.Background(), l.allTiersForManualRun(context.Background())); err != nil {
		t.Fatalf("manual cycle: %v", err)
	}
	if got := be.startedTargets(); len(got) != 1 || got[0] != "local" {
		t.Fatalf("absent tier was attempted: started=%v", got)
	}
	if stops, starts := len(st.stoppedNames()), len(st.startedNames()); stops != 1 || starts != 1 {
		t.Fatalf("want one stop/start for the local tier, got %d/%d", stops, starts)
	}
	// A second resolution in the same absence does not notify again.
	_ = l.allTiersForManualRun(context.Background())
	if len(rec.skipped) != 1 || rec.skipped[0] != "felhom-pbs" {
		t.Fatalf("want exactly one skip notice for felhom-pbs, got %v", rec.skipped)
	}
}

// Only the absent tier is due → no quiesce at all.
func TestScheduled_OnlyAbsentTierDue_NoQuiesce(t *testing.T) {
	be := newTierBackend()
	be.tiers = []BackupTier{{Target: "local", Primary: true}, {Target: "felhom-pbs", StorageAbsent: true}}
	be.dueSet["felhom-pbs"] = true
	st := &fakeStacks{running: []string{"immich"}}
	l := newTierLoop(t, be, st, nil)
	l.now = func() time.Time { return time.Date(2026, 9, 15, 1, 0, 0, 0, time.UTC) }
	_ = l.runOnce(context.Background())
	if stops := len(st.stoppedNames()); stops != 0 {
		t.Fatalf("an app was stopped for a tier whose storage does not exist (stops=%d)", stops)
	}
	if got := be.startedTargets(); len(got) != 0 {
		t.Fatalf("absent tier started: %v", got)
	}
}

// Unknown/legacy storage (StorageAbsent=false) is never skipped — fail toward backing up.
func TestManualRun_UnknownStorageNotSkipped(t *testing.T) {
	be := newTierBackend()
	be.tiers = []BackupTier{{Target: "local", Primary: true}, {Target: "felhom-pbs"}}
	be.phases["local"] = []string{phaseDone}
	be.phases["felhom-pbs"] = []string{phaseDone}
	l := newTierLoop(t, be, &fakeStacks{running: []string{"immich"}}, nil)
	if got := l.allTiersForManualRun(context.Background()); len(got) != 2 {
		t.Fatalf("a tier without an absent verdict was dropped: %v", got)
	}
}