package offsitekeys

import (
	"context"
	"fmt"
	"strings"
	"testing"
	"time"

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

// R-895 slice 2: the hub's own listing, compared day to day. Fixtures are `ls -l` outputs in the provider's shape
// (slice 1's parser) on a real store; the clock is the wall clock because the window ledger stamps rows with SQLite's
// datetime('now').

const snapDir = "/home/felhom-repo/snapshots"

func snapID(n int) string { return fmt.Sprintf("%08x%056x", 0xa1b2c300+n, n+1) }

// lsOut renders `ls -l` lines for ids uploaded at the given times (year-less form, as the provider prints recent files).
func lsOut(files map[string]time.Time) string {
	var b strings.Builder
	b.WriteString("total 8\n")
	for id, at := range files {
		fmt.Fprintf(&b, "-rw------- 1 u1-sub4 u1-sub4 324 %s %s\n", at.UTC().Format("Jan _2 15:04"), id)
	}
	return b.String()
}

type evt struct{ typ, sev, msg string }

// watchFixture: a provisioned customer whose box key is registered AND confirmed (the pinned tier), events captured.
func watchFixture(t *testing.T) (*Service, *fakeFS, *[]evt) {
	t.Helper()
	s, fs, _ := svcFixture(t)
	var events []evt
	s.Emit = func(_, typ, sev, msg, _, _ string) { events = append(events, evt{typ, sev, msg}) }
	pub, fp := newKey(t)
	if _, err := s.RegisterKey(context.Background(), "c1", pub); err != nil {
		t.Fatal(err)
	}
	if _, err := s.ConfirmKey(context.Background(), "c1", fp); err != nil {
		t.Fatal(err)
	}
	events = nil
	return s, fs, &events
}

func ofType(events []evt, typ string) []evt {
	var out []evt
	for _, e := range events {
		if e.typ == typ {
			out = append(out, e)
		}
	}
	return out
}

func reportRun(t *testing.T, st *store.Store, at time.Time) {
	t.Helper()
	if err := st.SaveReport("c1", []byte(`{"controller_version":"0.330.0","offsite":{"enabled":true,"last_run":"`+at.UTC().Format(time.RFC3339)+`"}}`)); err != nil {
		t.Fatal(err)
	}
}

// THE CONSEQUENCE, through the production entry point (the 07:10 AuditAll): day 1 is the baseline (no alarm), day 2
// shows three snapshots gone with no clean-up window → ONE offsite_snapshots_vanished (error), and the same listing on
// day 3 does not repeat it. RED-PROOF (REPORT, 2026-10-17 night): with the `len(gone) > explains` verdict replaced by
// `false`, this fails with `vanished events = 0, want 1`.
func TestSnapshotWatch_VanishedOutsideAWindowAlarmsOnce(t *testing.T) {
	s, fs, events := watchFixture(t)
	now := time.Now().UTC()
	files := map[string]time.Time{}
	for i := 0; i < 10; i++ {
		files[snapID(i)] = now.Add(-time.Duration(48+i) * time.Hour).Truncate(time.Minute)
	}
	fs.files[snapDir] = lsOut(files)
	s.AuditAll(context.Background(), nil)
	if n := len(ofType(*events, EventSnapshotsVanished)) + len(ofType(*events, EventSnapshotsUnexplained)); n != 0 {
		t.Fatalf("the first listing is a baseline: %d snapshot event(s), want 0 (%+v)", n, *events)
	}
	if _, ok := s.Store.GetOffsiteSnapshotListing("c1"); !ok {
		t.Fatal("the first listing was not stored as the baseline")
	}

	for i := 0; i < 3; i++ {
		delete(files, snapID(i))
	}
	fs.files[snapDir] = lsOut(files)
	s.AuditAll(context.Background(), nil)
	v := ofType(*events, EventSnapshotsVanished)
	if len(v) != 1 {
		t.Fatalf("vanished events = %d, want 1 (events: %+v)", len(v), *events)
	}
	if v[0].sev != "error" || !strings.Contains(v[0].msg, "3 snapshot file(s) gone") || !strings.Contains(v[0].msg, shortID(snapID(0))) {
		t.Fatalf("event = %+v — want severity error naming 3 files and the first id", v[0])
	}

	s.AuditAll(context.Background(), nil)
	if n := len(ofType(*events, EventSnapshotsVanished)); n != 1 {
		t.Fatalf("the same listing again raised the alarm again: %d events, want still 1", n)
	}
}

// A clean-up window the hub opened explains up to what it removed; more than that still alarms.
func TestSnapshotWatch_WindowExplainsUpToItsCredit(t *testing.T) {
	for _, tc := range []struct {
		name      string
		gone      int
		wantAlarm bool
	}{{"within the window's removal", 4, false}, {"beyond it", 7, true}} {
		t.Run(tc.name, func(t *testing.T) {
			s, _, events := watchFixture(t)
			now := time.Now().UTC()
			all := map[string]time.Time{}
			for i := 0; i < 20; i++ {
				all[snapID(i)] = now.Add(-time.Duration(48+i) * time.Hour).Truncate(time.Minute)
			}
			if err := s.Store.SetOffsiteSnapshotListing("c1", store.OffsiteSnapshotListing{ListedAt: now.Add(-24 * time.Hour), Entries: all}); err != nil {
				t.Fatal(err)
			}
			// The window: 20 → 15, so it explains 5 removals (min of its cap 10 and its reported drop).
			id, err := s.Store.OpenOffsiteWindowRow("c1", now.Add(windowLength), 20, MaxRemove(20))
			if err != nil {
				t.Fatal(err)
			}
			if _, err := s.Store.CloseOffsiteWindowRow(id, 15, "pruned", "box"); err != nil {
				t.Fatal(err)
			}
			cur := map[string]time.Time{}
			for k, v := range all {
				cur[k] = v
			}
			for i := 0; i < tc.gone; i++ {
				delete(cur, snapID(i))
			}
			v, _ := s.CheckSnapshotListing("c1", SnapshotListing{Files: len(cur), Entries: cur}, time.Now().UTC().Add(time.Second))
			got := len(ofType(*events, EventSnapshotsVanished)) == 1
			if got != tc.wantAlarm || (v > 0) != tc.wantAlarm {
				t.Fatalf("%d gone with a window crediting 5: alarm=%v (vanished=%d), want %v", tc.gone, got, v, tc.wantAlarm)
			}
		})
	}
}

// A new file uploaded inside a run the box reported is explained; one uploaded at a time no run explains warns — and a
// file younger than an hour is neither judged nor stored (tomorrow judges it with its run's report in hand).
func TestSnapshotWatch_AppearedOutsideEveryRunWarns(t *testing.T) {
	s, _, events := watchFixture(t)
	now := time.Now().UTC()
	old := map[string]time.Time{snapID(0): now.Add(-72 * time.Hour).Truncate(time.Minute)}
	if err := s.Store.SetOffsiteSnapshotListing("c1", store.OffsiteSnapshotListing{ListedAt: now.Add(-24 * time.Hour), Entries: old}); err != nil {
		t.Fatal(err)
	}
	run := now.Add(-8 * time.Hour).Truncate(time.Second)
	reportRun(t, s.Store, run)

	inRun := snapID(1) // uploaded 20 minutes before the run ended
	fake := snapID(2)  // uploaded 4 hours AFTER the run ended — no run explains it
	young := snapID(3) // 10 minutes old at listing time
	cur := map[string]time.Time{
		snapID(0): old[snapID(0)],
		inRun:     run.Add(-20 * time.Minute).Truncate(time.Minute),
		fake:      run.Add(4 * time.Hour).Truncate(time.Minute),
		young:     now.Add(-10 * time.Minute).Truncate(time.Minute),
	}
	_, u := s.CheckSnapshotListing("c1", SnapshotListing{Files: len(cur), Entries: cur}, now)
	w := ofType(*events, EventSnapshotsUnexplained)
	if u != 1 || len(w) != 1 {
		t.Fatalf("unexplained=%d events=%d, want exactly the one fake (events %+v)", u, len(w), *events)
	}
	if w[0].sev != "warning" || !strings.Contains(w[0].msg, shortID(fake)) || strings.Contains(w[0].msg, shortID(inRun)) {
		t.Fatalf("event = %+v — want a warning naming %s and not %s", w[0], shortID(fake), shortID(inRun))
	}
	base, _ := s.Store.GetOffsiteSnapshotListing("c1")
	if _, ok := base.Entries[young]; ok {
		t.Fatal("a 10-minute-old file was stored in the baseline — it must be judged tomorrow, not silently accepted")
	}
	if _, ok := base.Entries[fake]; !ok {
		t.Fatal("the judged file is not in the new baseline — tomorrow would warn again")
	}
}

// The repository moved aside → the baseline is dropped, so the new, empty repository is a baseline and not "every
// snapshot vanished".
func TestSnapshotWatch_MoveAsideResetsTheBaseline(t *testing.T) {
	s, fs, events := watchFixture(t)
	now := time.Now().UTC()
	if err := s.Store.SetOffsiteSnapshotListing("c1", store.OffsiteSnapshotListing{ListedAt: now.Add(-24 * time.Hour),
		Entries: map[string]time.Time{snapID(0): now.Add(-72 * time.Hour)}}); err != nil {
		t.Fatal(err)
	}
	fs.dirs["/home/felhom-repo"] = true
	if _, err := s.MoveAside(context.Background(), "c1"); err != nil {
		t.Fatal(err)
	}
	if _, ok := s.Store.GetOffsiteSnapshotListing("c1"); ok {
		t.Fatal("the baseline survived a move-aside")
	}
	s.CheckSnapshotListing("c1", SnapshotListing{}, now)
	if n := len(ofType(*events, EventSnapshotsVanished)); n != 0 {
		t.Fatalf("an empty new repository after a move-aside raised %d vanished event(s)", n)
	}
}

// Without a confirmed append-only key the box may prune by itself: vanishing is not judged.
func TestSnapshotWatch_UnpinnedTierDoesNotJudgeVanishing(t *testing.T) {
	s, _, _ := svcFixture(t)
	var events []evt
	s.Emit = func(_, typ, sev, msg, _, _ string) { events = append(events, evt{typ, sev, msg}) }
	now := time.Now().UTC()
	if err := s.Store.SetOffsiteSnapshotListing("c1", store.OffsiteSnapshotListing{ListedAt: now.Add(-24 * time.Hour),
		Entries: map[string]time.Time{snapID(0): now.Add(-72 * time.Hour), snapID(1): now.Add(-73 * time.Hour)}}); err != nil {
		t.Fatal(err)
	}
	s.CheckSnapshotListing("c1", SnapshotListing{Entries: map[string]time.Time{snapID(1): now.Add(-73 * time.Hour)}}, now)
	if n := len(ofType(events, EventSnapshotsVanished)); n != 0 {
		t.Fatalf("unpinned tier: %d vanished event(s), want 0", n)
	}
}

// Both events are operator-only (a missing customerMessages entry is NOT a block — the v0.78.0 defect).
func TestSnapshotWatch_EventsAreOperatorOnly(t *testing.T) {
	for _, et := range []string{EventSnapshotsVanished, EventSnapshotsUnexplained} {
		if !notify.IsOperatorOnly(et) {
			t.Errorf("%s is not in notify.operatorOnlyEvents — it would reach a household as raw English", et)
		}
	}
}

func TestExplainedByRun_Bounds(t *testing.T) {
	r := time.Date(2026, 10, 17, 3, 0, 0, 0, time.UTC)
	for _, tc := range []struct {
		at   time.Time
		want bool
	}{
		{r, true},
		{r.Add(snapTimeSlack), true},
		{r.Add(snapTimeSlack + time.Minute), false},
		{r.Add(-snapRunSpan - snapTimeSlack), true},
		{r.Add(-snapRunSpan - snapTimeSlack - time.Minute), false},
		{time.Time{}, false},
	} {
		if got := explainedByRun(tc.at, []time.Time{r}); got != tc.want {
			t.Errorf("upload %v vs run %v: explained=%v, want %v", tc.at, r, got, tc.want)
		}
	}
}