package backup

import (
	"os"
	"path/filepath"
	"testing"
	"time"

	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
)

// R-894: the on-disk newest success per tier survives a restart (a new state from the same file).
func TestBackupSuccessState_SurvivesRestart(t *testing.T) {
	path := filepath.Join(t.TempDir(), "backup-success-state.json")
	s := NewBackupSuccessState(path)
	at := time.Date(2026, 10, 1, 20, 15, 0, 0, time.UTC)
	if err := s.RecordBackupSuccess("felhom-pbs", hub.Backup{VMID: 9201, Success: true, StartedAt: at.Format(time.RFC3339)}); err != nil {
		t.Fatal(err)
	}
	got, ok := NewBackupSuccessState(path).LastKnownSuccess("felhom-pbs", 9201)
	if !ok || !got.Equal(at) {
		t.Fatalf("after a restart the saved copy must read back; got %v ok=%v", got, ok)
	}
	if _, ok := NewBackupSuccessState(path).LastKnownSuccess("local", 9201); ok {
		t.Fatal("another tier must not borrow this tier's copy")
	}
}

// Only a NEWER success replaces the saved one; failures and unparseable times are ignored.
func TestBackupSuccessState_KeepsNewestSuccessOnly(t *testing.T) {
	path := filepath.Join(t.TempDir(), "s.json")
	s := NewBackupSuccessState(path)
	newer := time.Date(2026, 10, 5, 0, 0, 0, 0, time.UTC)
	older := newer.Add(-48 * time.Hour)
	for _, b := range []hub.Backup{
		{VMID: 1, Success: true, StartedAt: newer.Format(time.RFC3339)},
		{VMID: 1, Success: true, StartedAt: older.Format(time.RFC3339)},                 // older: ignored
		{VMID: 1, Success: false, StartedAt: newer.Add(time.Hour).Format(time.RFC3339)}, // failure: ignored
		{VMID: 1, Success: true, StartedAt: "not-a-time"},                               // unparseable: ignored
	} {
		if err := s.RecordBackupSuccess("t", b); err != nil {
			t.Fatal(err)
		}
	}
	if got, _ := NewBackupSuccessState(path).LastKnownSuccess("t", 1); !got.Equal(newer) {
		t.Fatalf("want the newest success %v, got %v", newer, got)
	}
}

// A corrupt file degrades to "nothing known" (the pre-R-894 DUE answer), never a crash.
func TestBackupSuccessState_CorruptFileIsEmpty(t *testing.T) {
	path := filepath.Join(t.TempDir(), "s.json")
	if err := os.WriteFile(path, []byte("{not json"), 0o600); err != nil {
		t.Fatal(err)
	}
	if _, ok := NewBackupSuccessState(path).LastKnownSuccess("t", 1); ok {
		t.Fatal("a corrupt file must read as nothing known")
	}
}