package release

import (
	"context"
	"crypto/ed25519"
	"errors"
	"os"
	"slices"
	"strings"
	"testing"
	"time"
)

// ctx is the package's test context; the older tests in this file shadow it
// with their own local one, harmlessly.
var ctx = context.Background()

func TestTrashAppRoundTrip(t *testing.T) {
	ctx := context.Background()
	s := NewDirStore(t.TempDir())
	now := time.Date(2026, 8, 4, 16, 0, 0, 0, time.UTC)

	// The key path is a wire contract: later tasks (route hiding, the purge
	// pass) string-match "deleted.json" independently of this package.
	if got, want := AppTombstoneKey("bab", "derp"), "apps/bab/derp/deleted.json"; got != want {
		t.Fatalf("AppTombstoneKey(bab, derp) = %q, want %q", got, want)
	}

	// Absent: (nil, nil), not an error.
	if tomb, err := ReadAppTombstone(ctx, s, "bab", "derp"); err != nil || tomb != nil {
		t.Fatalf("absent marker: got %v, %v; want nil, nil", tomb, err)
	}
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", now); err != nil {
		t.Fatalf("TrashApp: %v", err)
	}
	tomb, err := ReadAppTombstone(ctx, s, "bab", "derp")
	if err != nil || tomb == nil {
		t.Fatalf("ReadAppTombstone: got %v, %v", tomb, err)
	}
	if tomb.Account != "bab" || tomb.App != "derp" || tomb.Actor != "paul@keymail.dev" || !tomb.DeletedAt.Equal(now) {
		t.Fatalf("tombstone fields: %+v", tomb)
	}
	// Idempotent: trashing a trashed app is nil and does NOT move the clock.
	if err := TrashApp(ctx, s, "bab", "derp", "eve@keymail.dev", now.Add(time.Hour)); err != nil {
		t.Fatalf("second TrashApp: %v", err)
	}
	tomb2, _ := ReadAppTombstone(ctx, s, "bab", "derp")
	if !tomb2.DeletedAt.Equal(now) || tomb2.Actor != "paul@keymail.dev" {
		t.Fatalf("second trash rewrote the marker: %+v", tomb2)
	}
	// Restore deletes the marker; restoring an untrashed app is fine.
	if err := RestoreApp(ctx, s, "bab", "derp"); err != nil {
		t.Fatalf("RestoreApp: %v", err)
	}
	if tomb, _ := ReadAppTombstone(ctx, s, "bab", "derp"); tomb != nil {
		t.Fatalf("marker survived restore: %+v", tomb)
	}
	if err := RestoreApp(ctx, s, "bab", "derp"); err != nil {
		t.Fatalf("restore of untrashed app: %v", err)
	}
}

// TestReadAppTombstoneParsesWireShape pins the JSON tags against the spec's
// exact example body — a struct-tag typo would still fail the negative
// tests above (any parse error refuses), so only a positive round-trip on
// literal bytes catches it.
func TestReadAppTombstoneParsesWireShape(t *testing.T) {
	ctx := context.Background()
	s := NewDirStore(t.TempDir())
	body := []byte(`{"schema":1,"account":"bab","app":"derp","deleted_at":"2026-08-04T16:00:00Z","actor":"paul@keymail.dev"}`)
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "derp"), body, ""); err != nil {
		t.Fatal(err)
	}
	tomb, err := ReadAppTombstone(ctx, s, "bab", "derp")
	if err != nil || tomb == nil {
		t.Fatalf("ReadAppTombstone: got %v, %v", tomb, err)
	}
	want := time.Date(2026, 8, 4, 16, 0, 0, 0, time.UTC)
	if tomb.Account != "bab" || tomb.App != "derp" || tomb.Actor != "paul@keymail.dev" || !tomb.DeletedAt.Equal(want) {
		t.Fatalf("tombstone fields: %+v", tomb)
	}
	// The schema is part of the shape, not decoration: the refusal below
	// only means anything if the happy path really carries a 1.
	if tomb.Schema != 1 {
		t.Fatalf("schema = %d, want 1", tomb.Schema)
	}
}

// A marker written by a future box, in a shape this one has never seen, is
// refused — and refusal is the safe direction: the app keeps serving and
// keeps its bytes until this box is upgraded. Believing an unknown schema
// would hide or destroy on terms nobody here can read.
func TestReadAppTombstoneRefusesUnknownSchema(t *testing.T) {
	ctx := context.Background()
	s := NewDirStore(t.TempDir())
	body := []byte(`{"schema":2,"account":"bab","app":"derp","deleted_at":"2026-08-04T16:00:00Z","actor":"paul@keymail.dev"}`)
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "derp"), body, ""); err != nil {
		t.Fatal(err)
	}
	tomb, err := ReadAppTombstone(ctx, s, "bab", "derp")
	if err == nil {
		t.Fatalf("schema 2 marker was believed: %+v", tomb)
	}
	if !strings.Contains(err.Error(), "schema 2") {
		t.Errorf("error %q does not name the schema it refused", err)
	}
	// And the refusal must reach the destructive path as a refusal, not as
	// "no marker" — PurgeApp errors rather than deciding there is nothing
	// to purge.
	if err := PurgeApp(ctx, s, nil, "bab", "derp", time.Now()); err == nil || errors.Is(err, ErrNotTrashed) {
		t.Errorf("PurgeApp on an unreadable-schema marker: %v, want a refusal", err)
	}
	// A schema-0 body (the field missing entirely) is refused for the same
	// reason: a marker that does not say what it is, is not a marker.
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "noschema"),
		[]byte(`{"account":"bab","app":"noschema","deleted_at":"2026-08-04T16:00:00Z"}`), ""); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadAppTombstone(ctx, s, "bab", "noschema"); err == nil {
		t.Fatal("schema-less marker was not refused")
	}
}

func TestReadAppTombstoneRefusesDisagreement(t *testing.T) {
	ctx := context.Background()
	s := NewDirStore(t.TempDir())
	// A marker whose body claims a different app than its path is a lie
	// about identity: error, never acted on.
	body := []byte(`{"schema":1,"account":"bab","app":"OTHER","deleted_at":"2026-08-04T16:00:00Z","actor":"x@y.z"}`)
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "derp"), body, ""); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadAppTombstone(ctx, s, "bab", "derp"); err == nil {
		t.Fatal("path/body disagreement was not refused")
	}
	// Malformed JSON: error too.
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "junk"), []byte("{"), ""); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadAppTombstone(ctx, s, "bab", "junk"); err == nil {
		t.Fatal("malformed marker was not refused")
	}
	// Zero deleted_at: refused — the cooloff clock would never expire and
	// the marker would be acted on with no timestamp to reason from.
	body = []byte(`{"schema":1,"account":"bab","app":"noat","actor":"x@y.z"}`)
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "noat"), body, ""); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadAppTombstone(ctx, s, "bab", "noat"); err == nil {
		t.Fatal("marker with zero deleted_at was not refused")
	}
}

// recordingStore is a Store that remembers the ORDER of Delete calls. The
// purge's marker-last discipline is not observable from final state (in the
// happy path everything is gone either way) — only from the sequence.
type recordingStore struct {
	Store
	deletes *[]string
}

func (r recordingStore) Delete(ctx context.Context, key string) error {
	*r.deletes = append(*r.deletes, key)
	return r.Store.Delete(ctx, key)
}

// seedApp lays down a plausible app: two channel pointers, a manifest, an
// artifact. The purge has to take all of them.
func seedApp(t *testing.T, s Store, acct, app string) []string {
	t.Helper()
	keys := []string{
		"apps/" + acct + "/" + app + "/channels/stable.json",
		"apps/" + acct + "/" + app + "/channels/canary/x.json",
		"apps/" + acct + "/" + app + "/releases/1.0.0/manifest.json",
		"apps/" + acct + "/" + app + "/releases/1.0.0/app.tar.gz",
	}
	for _, k := range keys {
		if _, err := s.Put(context.Background(), k, []byte("{}"), ""); err != nil {
			t.Fatal(err)
		}
	}
	return keys
}

func listUnder(t *testing.T, s Store, prefix string) []string {
	t.Helper()
	keys, err := s.List(context.Background(), prefix)
	if err != nil {
		t.Fatal(err)
	}
	slices.Sort(keys)
	return keys
}

// Contract 1: purge without a marker is destruction without an instruction.
func TestPurgeAppRefusesWhenNotTrashed(t *testing.T) {
	s := NewDirStore(t.TempDir())
	_, pub := testKeys(t)
	keys := seedApp(t, s, "bab", "derp")
	err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now())
	if !errors.Is(err, ErrNotTrashed) {
		t.Fatalf("PurgeApp on a live app = %v, want ErrNotTrashed", err)
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) != len(keys) {
		t.Fatalf("a refused purge destroyed objects: %v", got)
	}
	// A marker that exists but cannot be believed is not an instruction
	// either: ReadAppTombstone's error propagates and nothing is destroyed.
	if _, err := s.Put(ctx, AppTombstoneKey("bab", "derp"), []byte("{"), ""); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err == nil {
		t.Fatal("purge acted on an unparseable marker")
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) != len(keys)+1 {
		t.Fatalf("a refused purge destroyed objects: %v", got)
	}
}

// Contract 2: no public key means the production flag cannot be verified,
// which means the app cannot be PROVEN non-production. Refuse.
func TestPurgeAppRefusesWithoutAPublicKey(t *testing.T) {
	s := NewDirStore(t.TempDir())
	keys := seedApp(t, s, "bab", "derp")
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	for _, pub := range []ed25519.PublicKey{nil, {}, make([]byte, 8)} {
		if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err == nil {
			t.Fatalf("purge with a %d-byte key was allowed", len(pub))
		}
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) != len(keys)+1 {
		t.Fatalf("a refused purge destroyed objects: %v", got)
	}
}

// Contract 3: production ON refuses; an UNREADABLE flag refuses (unreadable
// is not off); ABSENT is fine, because most apps never had a flag at all.
func TestPurgeAppRefusesProductionAndUnreadableFlags(t *testing.T) {
	priv, pub := testKeys(t)

	// ON.
	s := NewDirStore(t.TempDir())
	seedApp(t, s, "bab", "derp")
	if err := SetProduction(ctx, s, priv, "bab", "derp", true, "paul@keymail.dev"); err != nil {
		t.Fatal(err)
	}
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err == nil {
		t.Fatal("purge destroyed a production-flagged app")
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) == 0 {
		t.Fatal("a refused purge destroyed objects")
	}

	// UNREADABLE: the object is there but does not verify.
	s = NewDirStore(t.TempDir())
	seedApp(t, s, "bab", "derp")
	if _, err := s.Put(ctx, ProductionKey("bab", "derp"), []byte(`{"payload":"zz","sig":"zz"}`), ""); err != nil {
		t.Fatal(err)
	}
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err == nil {
		t.Fatal("purge treated an unreadable production flag as off")
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) == 0 {
		t.Fatal("a refused purge destroyed objects")
	}

	// OFF, explicitly: purges.
	s = NewDirStore(t.TempDir())
	seedApp(t, s, "bab", "derp")
	if err := SetProduction(ctx, s, priv, "bab", "derp", false, "paul@keymail.dev"); err != nil {
		t.Fatal(err)
	}
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err != nil {
		t.Fatalf("purge of an explicitly non-production app: %v", err)
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) != 0 {
		t.Fatalf("purge left objects behind: %v", got)
	}
}

// Contract 4: everything under the prefix goes, and the MARKER GOES LAST, so
// a purge that dies half-way leaves a trashed app with fewer objects rather
// than a live app with holes.
func TestPurgeAppDestroysEverythingMarkerLast(t *testing.T) {
	base := NewDirStore(t.TempDir())
	var deletes []string
	s := recordingStore{Store: base, deletes: &deletes}
	_, pub := testKeys(t)
	seedApp(t, s, "bab", "derp")
	// A neighbouring app in the same account must be untouched: the prefix
	// ends in "/" precisely so "derp" never reaches "derpy".
	seedApp(t, s, "bab", "derpy")
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err != nil {
		t.Fatalf("PurgeApp: %v", err)
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) != 0 {
		t.Fatalf("purge left objects behind: %v", got)
	}
	if got := listUnder(t, s, "apps/bab/derpy/"); len(got) != 4 {
		t.Fatalf("purge reached the neighbouring app: %v", got)
	}
	marker := AppTombstoneKey("bab", "derp")
	if len(deletes) == 0 || deletes[len(deletes)-1] != marker {
		t.Fatalf("delete order %v — the marker must go LAST", deletes)
	}
	if slices.Index(deletes, marker) != len(deletes)-1 {
		t.Fatalf("marker deleted more than once / early: %v", deletes)
	}
}

// Contract 4b (discussion #219, item 2): the app's open ledgers go too. They
// live under ledgers/<acct>/<app>/, outside the app's own prefix, and a purge
// that left them handed them to the next app of the same name. Swept before
// the marker, and a neighbouring app's ledgers stay.
func TestPurgeAppSweepsTheAppsLedgers(t *testing.T) {
	base := NewDirStore(t.TempDir())
	var deletes []string
	s := recordingStore{Store: base, deletes: &deletes}
	_, pub := testKeys(t)
	seedApp(t, s, "bab", "derp")
	for _, key := range []string{
		"ledgers/bab/derp/ledgers.json",
		"ledgers/bab/derp/carbon/HEAD.json",
		"ledgers/bab/derp/carbon/entries/20261003T000000Z-0123456789ab.json",
		"ledgers/bab/derp/carbon/blobs/" + strings.Repeat("a", 64),
		"ledgers/bab/derpy/ledgers.json",
	} {
		if _, err := s.Put(ctx, key, []byte(`{}`), ""); err != nil {
			t.Fatal(err)
		}
	}
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err != nil {
		t.Fatalf("PurgeApp: %v", err)
	}
	if got := listUnder(t, s, LedgerAppPrefix("bab", "derp")); len(got) != 0 {
		t.Fatalf("purge left the app's ledgers behind: %v", got)
	}
	if got := listUnder(t, s, LedgerAppPrefix("bab", "derpy")); len(got) != 1 {
		t.Fatalf("purge reached the neighbouring app's ledgers: %v", got)
	}
	if marker := AppTombstoneKey("bab", "derp"); deletes[len(deletes)-1] != marker {
		t.Fatalf("delete order %v — the marker must go LAST", deletes)
	}
}

// Contract 5: idempotent. A half-purged app converges on a second pass, and
// an already-purged one reports ErrNotTrashed — which the caller reads as
// "done", not as a failure.
func TestPurgeAppIsIdempotent(t *testing.T) {
	s := NewDirStore(t.TempDir())
	_, pub := testKeys(t)
	seedApp(t, s, "bab", "derp")
	if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now()); err != nil {
		t.Fatal(err)
	}
	// Half-purged: some objects already gone, marker still standing.
	if err := s.Delete(ctx, "apps/bab/derp/channels/stable.json"); err != nil {
		t.Fatal(err)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err != nil {
		t.Fatalf("purge of a half-purged app: %v", err)
	}
	if got := listUnder(t, s, "apps/bab/derp/"); len(got) != 0 {
		t.Fatalf("purge left objects behind: %v", got)
	}
	if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); !errors.Is(err, ErrNotTrashed) {
		t.Fatalf("second purge = %v, want ErrNotTrashed", err)
	}
}

// storeJSON writes apps/<acct>/<app>/store.json, overwriting whatever is
// there — the purge guard's input, hand-rolled here because release cannot
// import objstore (objstore imports release). The bytes ARE the contract.
func storeJSON(t *testing.T, s Store, acct, app, body string) {
	t.Helper()
	key := "apps/" + acct + "/" + app + "/store.json"
	_, etag, err := s.Get(ctx, key)
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		t.Fatal(err)
	}
	if _, err := s.Put(ctx, key, []byte(body), etag); err != nil {
		t.Fatal(err)
	}
}

// Contract 6: a store with backend estate refuses the purge. Auto-purge runs
// on boxes; boxes hold no backend authority, so a swept store.json is a paid
// bucket nothing remembers. BOTH witnesses count: `provisioned` (the finished
// store) and `grant` (a grant that may have crashed after creating the bucket
// and the IAM user but before recording them). A declared-only record has no
// estate behind it and is swept like any other object.
func TestPurgeAppRefusesProvisionedOrGrantedStore(t *testing.T) {
	_, pub := testKeys(t)

	for _, tc := range []struct {
		name string
		body string
	}{
		{"provisioned", `{"schema":1,"app":"derp","declared":{"env_prefix":"CARLOS_STORE"},"provisioned":{"bucket":"carlos-store-tito-bab-derp","key_id":"AKIA"}}`},
		// A grant block with NO provisioned block: the earliest bucket-visible
		// witness that backend estate may already exist.
		{"grant-only", `{"schema":1,"app":"derp","declared":{"env_prefix":"CARLOS_STORE"},"grant":{"backend":"aws","by":"paul@keymail.dev"}}`},
		// Unreadable is not "no store" — same direction as the production flag.
		{"unparseable", `{"schema":1,`},
	} {
		t.Run(tc.name, func(t *testing.T) {
			s := NewDirStore(t.TempDir())
			keys := seedApp(t, s, "bab", "derp")
			storeJSON(t, s, "bab", "derp", tc.body)
			if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now().Add(-31*24*time.Hour)); err != nil {
				t.Fatal(err)
			}
			err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now())
			if !errors.Is(err, ErrStoreProvisioned) {
				t.Fatalf("PurgeApp = %v, want ErrStoreProvisioned", err)
			}
			// The refusal names the app: one line in the auto-purge log has to
			// be enough to know which store needs tearing down.
			if !strings.Contains(err.Error(), "bab/derp") {
				t.Errorf("refusal %q does not name the app", err)
			}
			if got := listUnder(t, s, "apps/bab/derp/"); len(got) != len(keys)+2 {
				t.Fatalf("a refused purge destroyed objects: %v", got)
			}
		})
	}

	// Declared-only: no backend estate exists, so the purge proceeds and
	// sweeps store.json along with everything else.
	t.Run("declared-only", func(t *testing.T) {
		s := NewDirStore(t.TempDir())
		seedApp(t, s, "bab", "derp")
		storeJSON(t, s, "bab", "derp", `{"schema":1,"app":"derp","declared":{"env_prefix":"CARLOS_STORE"}}`)
		if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now().Add(-31*24*time.Hour)); err != nil {
			t.Fatal(err)
		}
		if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err != nil {
			t.Fatalf("PurgeApp of a declared-only store: %v", err)
		}
		if got := listUnder(t, s, "apps/bab/derp/"); len(got) != 0 {
			t.Fatalf("purge left objects behind: %v", got)
		}
	})

	// An explicitly null block is absent, not present: a record that has been
	// torn down keeps its keys with null values and must not wedge the purge.
	t.Run("null-blocks", func(t *testing.T) {
		s := NewDirStore(t.TempDir())
		seedApp(t, s, "bab", "derp")
		storeJSON(t, s, "bab", "derp", `{"schema":1,"app":"derp","grant":null,"provisioned":null}`)
		if err := TrashApp(ctx, s, "bab", "derp", "paul@keymail.dev", time.Now().Add(-31*24*time.Hour)); err != nil {
			t.Fatal(err)
		}
		if err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now()); err != nil {
			t.Fatalf("PurgeApp of a torn-down store: %v", err)
		}
	})
}

// erroringGetStore fails Get for one key with something that is NOT
// os.ErrNotExist — the transport-level "I cannot tell you whether this app
// has a store" the guard must refuse on.
type erroringGetStore struct {
	Store
	failKey string
}

func (e erroringGetStore) Get(ctx context.Context, key string) ([]byte, string, error) {
	if key == e.failKey {
		return nil, "", errors.New("injected: get failed")
	}
	return e.Store.Get(ctx, key)
}

// Contract 6b: a store record the box cannot READ refuses too. "I could not
// ask" is not "there is no store".
func TestPurgeAppRefusesUnreadableStoreRecord(t *testing.T) {
	_, pub := testKeys(t)
	base := NewDirStore(t.TempDir())
	s := erroringGetStore{Store: base, failKey: "apps/bab/derp/store.json"}
	keys := seedApp(t, base, "bab", "derp")
	if err := TrashApp(ctx, base, "bab", "derp", "paul@keymail.dev", time.Now().Add(-31*24*time.Hour)); err != nil {
		t.Fatal(err)
	}
	err := PurgeApp(ctx, s, pub, "bab", "derp", time.Now())
	if err == nil {
		t.Fatal("purge acted on an unreadable store record")
	}
	if got := listUnder(t, base, "apps/bab/derp/"); len(got) != len(keys)+1 {
		t.Fatalf("a refused purge destroyed objects: %v", got)
	}
}