more cart

pkg/cart/recovery/logging_notifier.go

@@ -0,0 +1,59 @@
+package recovery
+
+import (
+	"context"
+	"log"
+
+	"git.k6n.net/mats/go-cart-actor/pkg/cart"
+)
+
+// LoggingNotifier is the v0 default: it writes one INFO line per candidate
+// and returns nil. It deliberately does NOT pretend to send anything.
+//
+// Future implementations (MailerSend, FCM, APNs) implement the same Notifier
+// interface; the scanner doesn't change. LoggingNotifier also serves as the
+// "dry-run" mode in production by leaving the seam unconfigured.
+type LoggingNotifier struct{}
+
+// NewLoggingNotifier returns a Notifier that logs every candidate. The struct
+// is empty today; the constructor is kept for parity with future notifiers
+// that need credentials / config.
+func NewLoggingNotifier() *LoggingNotifier { return &LoggingNotifier{} }
+
+// NotifyAbandoned logs the cart id, contact present, and a tiny summary.
+// Push tokens are summarized by platform only — never log the raw token, so
+// a misconfigured log aggregator can't leak device handles.
+func (LoggingNotifier) NotifyAbandoned(_ context.Context, c RecoveryCandidate) error {
+	hasEmail := c.Email != ""
+	hasPush := len(c.PushTokens) > 0
+	channel := "none"
+	switch {
+	case hasEmail && hasPush:
+		channel = "email+push"
+	case hasEmail:
+		channel = "email"
+	case hasPush:
+		channel = "push"
+	}
+	log.Printf(
+		"recovery [dry-run]: cart=%d user=%q channel=%s items=%d total=%d currency=%s email=%q pushPlatforms=%v lastChangeUnix=%d",
+		c.CartID,
+		c.UserID,
+		channel,
+		c.ItemCount,
+		c.TotalIncVat,
+		c.Currency,
+		c.Email,
+		platformsOf(c.PushTokens),
+		c.LastChangeUnix,
+	)
+	return nil
+}
+
+func platformsOf(tokens []cart.PushToken) []string {
+	out := make([]string, 0, len(tokens))
+	for _, t := range tokens {
+		out = append(out, t.Platform)
+	}
+	return out
+}

pkg/cart/recovery/logging_notifier_test.go

@@ -0,0 +1,94 @@
+package recovery
+
+import (
+	"bytes"
+	"context"
+	"log"
+	"strings"
+	"testing"
+
+	"git.k6n.net/mats/go-cart-actor/pkg/cart"
+)
+
+// captureLog writes log output to an in-memory buffer for inspection.
+func captureLog(t *testing.T) *bytes.Buffer {
+	t.Helper()
+	buf := &bytes.Buffer{}
+	orig := log.Writer()
+	flags := log.Flags()
+	prefix := log.Prefix()
+	log.SetOutput(buf)
+	log.SetFlags(0)
+	log.SetPrefix("")
+	t.Cleanup(func() {
+		log.SetOutput(orig)
+		log.SetFlags(flags)
+		log.SetPrefix(prefix)
+	})
+	return buf
+}
+
+func TestLoggingNotifier_LogsPlatformsNotTokens(t *testing.T) {
+	buf := captureLog(t)
+	n := LoggingNotifier{}
+	err := n.NotifyAbandoned(context.Background(), RecoveryCandidate{
+		CartID:     1,
+		Email:      "doc@example.com",
+		PushTokens: []cart.PushToken{{Platform: "fcm", Token: "SECRET-TOKEN-MUST-NOT-LEAK"}, {Platform: "apns", Token: "ALSO-SECRET-2"}},
+	})
+	if err != nil {
+		t.Fatalf("NotifyAbandoned: %v", err)
+	}
+	out := buf.String()
+	if !strings.Contains(out, "doc@example.com") {
+		t.Errorf("expected email in log: %s", out)
+	}
+	if !strings.Contains(out, "[fcm apns]") {
+		t.Errorf("expected bracketed platform list in log: %s", out)
+	}
+	for _, leak := range []string{"SECRET-TOKEN-MUST-NOT-LEAK", "ALSO-SECRET-2"} {
+		if strings.Contains(out, leak) {
+			t.Errorf("token leaked into log: %s line=%s", leak, out)
+		}
+	}
+}
+
+func TestLoggingNotifier_ClassifiesChannel(t *testing.T) {
+	buf := captureLog(t)
+	n := LoggingNotifier{}
+	cases := []struct {
+		name    string
+		cand    RecoveryCandidate
+		wantSub string
+	}{
+		{
+			name: "email+push",
+			cand: RecoveryCandidate{Email: "a@b.c", PushTokens: []cart.PushToken{{Platform: "fcm"}}},
+			wantSub: "channel=email+push",
+		},
+		{
+			name:    "email only",
+			cand:    RecoveryCandidate{Email: "a@b.c"},
+			wantSub: "channel=email",
+		},
+		{
+			name:    "push only",
+			cand:    RecoveryCandidate{PushTokens: []cart.PushToken{{Platform: "fcm"}}},
+			wantSub: "channel=push",
+		},
+		{
+			name:    "no contact",
+			cand:    RecoveryCandidate{},
+			wantSub: "channel=none",
+		},
+	}
+	for _, tc := range cases {
+		buf.Reset()
+		if err := n.NotifyAbandoned(context.Background(), tc.cand); err != nil {
+			t.Fatalf("%s: %v", tc.name, err)
+		}
+		if !strings.Contains(buf.String(), tc.wantSub) {
+			t.Errorf("%s: log missing %q; got: %s", tc.name, tc.wantSub, buf.String())
+		}
+	}
+}

pkg/cart/recovery/recovery.go

@@ -0,0 +1,49 @@
+// Package recovery is the v0 abandoned-cart-recovery seam.
+//
+// The contract is intentionally narrow: a Scanner finds candidates whose last
+// mutation is within an "abandoned" window and that have BOTH an attachable
+// contact (email and/or push tokens) and items in the cart, then hands them
+// to a Notifier. The Notifier decides what to do — for now a logging shim.
+//
+// The seam intentionally avoids:
+//
+//   - Email/push-token delivery (lives in the notifier impl).
+//   - Idempotency tracking ("did we already notify?"). v0: scanner windows
+//     are sized so a cart falls in once per detection threshold. Real
+//     idempotency is the next pass — see suggest_followups / plan-commerce-
+//     maturity C3.
+//   - Cross-pod coordination. Each cart pod owns its own shard of event logs
+//     (replicated read cache, no leader), so per-pod scanning is correct.
+//     A future AMQP fan-out of `cart.recovery.candidate` would let a single
+//     dedicated notifier consume instead — out of scope here.
+package recovery
+
+import (
+	"context"
+
+	"git.k6n.net/mats/go-cart-actor/pkg/cart"
+)
+
+// RecoveryCandidate is the projectable "we'd remind this shopper" shape.
+// Fields surface just enough for a future email template / push payload; the
+// underlying grain carries everything else.
+type RecoveryCandidate struct {
+	CartID      cart.CartId
+	UserID      string // empty if the cart hasn't been linked to a profile
+	Email       string
+	PushTokens  []cart.PushToken
+	ItemCount   int
+	TotalIncVat int64 // minor units (money.Cents == int64)
+	Currency    string
+	// LastChange is best-effort: the scanner reads the event-log file's
+	// modification time. A pending notifier shouldn't use it as the canonical
+	// "when was this cart touched?" wall clock — see cart.LastChange.
+	LastChangeUnix int64
+}
+
+// Notifier is the seam a real email/push implementation plugs into. The
+// LoggingNotifier is the v0 default. The cart service ships the seam even
+// before a real send exists so call-sites and tracking can be wired once.
+type Notifier interface {
+	NotifyAbandoned(ctx context.Context, c RecoveryCandidate) error
+}

pkg/cart/recovery/recovery_test.go

@@ -0,0 +1,257 @@
+package recovery
+
+import (
+	"context"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"testing"
+	"time"
+
+	"git.k6n.net/mats/go-cart-actor/pkg/actor"
+	"git.k6n.net/mats/go-cart-actor/pkg/cart"
+	messages "git.k6n.net/mats/go-cart-actor/proto/cart"
+	"google.golang.org/protobuf/proto"
+)
+
+// writeFixtureLog writes a synthetic `<id>.events.log` to dir with the given
+// mutations, then pins the file's mtime AFTER Close so the canonical
+// DiskStorage.SaveLoop flush can't overwrite it on test machines that run
+// the inner save() during teardown.
+func writeFixtureLog(t *testing.T, dir string, id uint64, mtime time.Time, muts []proto.Message) {
+	t.Helper()
+	path := filepath.Join(dir, strconv.FormatUint(id, 10)+".events.log")
+
+	reg := cart.NewCartMultationRegistry(cart.NewCartMutationContext(nil))
+	storage := actor.NewDiskStorage[cart.CartGrain](dir, reg)
+	if err := storage.AppendMutations(id, muts...); err != nil {
+		t.Fatalf("AppendMutations for fixture %d: %v", id, err)
+	}
+	// DiskStorage.Close runs save() which opens+appends the file; that
+	// updates mtime. Pin AFTER Close so the test mtime wins.
+	storage.Close()
+	if err := os.Chtimes(path, mtime, mtime); err != nil {
+		t.Fatalf("Chtimes %s: %v", path, err)
+	}
+}
+
+// silenceLogs redirects the standard logger while the scanner runs so test
+// output stays readable.
+func silenceLogs(t *testing.T) {
+	t.Helper()
+	orig := log.Writer()
+	prevFlags := log.Flags()
+	log.SetOutput(devNull{})
+	log.SetFlags(0)
+	t.Cleanup(func() {
+		log.SetOutput(orig)
+		log.SetFlags(prevFlags)
+	})
+}
+
+type devNull struct{}
+
+func (devNull) Write(p []byte) (int, error) { return len(p), nil }
+
+func TestScanner_FindsCandidateInWindow(t *testing.T) {
+	silenceLogs(t)
+	dir := t.TempDir()
+	now := time.Date(2026, 7, 1, 12, 0, 0, 0, time.UTC)
+
+	reg := cart.NewCartMultationRegistry(cart.NewCartMutationContext(nil))
+	storage := actor.NewDiskStorage[cart.CartGrain](dir, reg)
+
+	// Cart that became eligible exactly in the middle of the window:
+	// delay 1h, window 1h → eligible mtime ∈ [now-2h, now-1h].
+	mtime := now.Add(-90 * time.Minute)
+	writeFixtureLog(t, dir, 42, mtime, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 1, Price: 1000, Sku: "A"},
+		&messages.SetRecoveryContact{Email: "abandoned@example.com"},
+	})
+	defer storage.Close()
+
+	scanner := NewScanner(dir, storage)
+	got, err := scanner.Scan(context.Background(), time.Hour, time.Hour, now)
+	if err != nil {
+		t.Fatalf("Scan: %v", err)
+	}
+	if len(got) != 1 {
+		t.Fatalf("candidates = %d, want 1; full result=%+v", len(got), got)
+	}
+	c := got[0]
+	if c.CartID != cart.CartId(42) {
+		t.Errorf("CartID = %d, want 42", c.CartID)
+	}
+	if c.Email != "abandoned@example.com" {
+		t.Errorf("Email = %q, want abandoned@example.com", c.Email)
+	}
+	if c.ItemCount != 1 {
+		t.Errorf("ItemCount = %d, want 1", c.ItemCount)
+	}
+	if c.TotalIncVat != 1000 {
+		t.Errorf("TotalIncVat = %d, want 1000 (AddItem price 1000)", c.TotalIncVat)
+	}
+}
+
+func TestScanner_SkipsCartsOutsideWindow(t *testing.T) {
+	silenceLogs(t)
+	dir := t.TempDir()
+	now := time.Date(2026, 7, 1, 12, 0, 0, 0, time.UTC)
+
+	reg := cart.NewCartMultationRegistry(cart.NewCartMutationContext(nil))
+	storage := actor.NewDiskStorage[cart.CartGrain](dir, reg)
+
+	// Too fresh (mtime = now-30m, inside the 1h "still active" cutoff).
+	fresh := now.Add(-30 * time.Minute)
+	writeFixtureLog(t, dir, 7, fresh, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 1, Price: 1000},
+		&messages.SetRecoveryContact{Email: "fresh@example.com"},
+	})
+	// Too old (mtime = now-25h, past the 2h window upper bound).
+	old := now.Add(-25 * time.Hour)
+	writeFixtureLog(t, dir, 8, old, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 1, Price: 1000},
+		&messages.SetRecoveryContact{Email: "old@example.com"},
+	})
+	// Inside window with NO contact (eligibility gate).
+	mid := now.Add(-90 * time.Minute)
+	writeFixtureLog(t, dir, 9, mid, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 1, Price: 1000},
+		// no SetRecoveryContact
+	})
+	defer storage.Close()
+
+	scanner := NewScanner(dir, storage)
+	got, err := scanner.Scan(context.Background(), time.Hour, time.Hour, now)
+	if err != nil {
+		t.Fatalf("Scan: %v", err)
+	}
+	if len(got) != 0 {
+		t.Fatalf("candidates = %d, want 0 (all filtered out); result=%+v", len(got), got)
+	}
+}
+
+func TestScanner_FindsPushOnlyCandidate(t *testing.T) {
+	silenceLogs(t)
+	dir := t.TempDir()
+	now := time.Date(2026, 7, 1, 12, 0, 0, 0, time.UTC)
+
+	reg := cart.NewCartMultationRegistry(cart.NewCartMutationContext(nil))
+	storage := actor.NewDiskStorage[cart.CartGrain](dir, reg)
+
+	mtime := now.Add(-75 * time.Minute)
+	writeFixtureLog(t, dir, 11, mtime, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 1, Price: 1000},
+		&messages.SetRecoveryContact{
+			PushTokens: []*messages.PushToken{
+				{Platform: "fcm", Token: "tok-1"},
+				{Platform: "apns", Token: "tok-2"},
+			},
+		},
+	})
+	defer storage.Close()
+
+	scanner := NewScanner(dir, storage)
+	got, err := scanner.Scan(context.Background(), time.Hour, time.Hour, now)
+	if err != nil {
+		t.Fatalf("Scan: %v", err)
+	}
+	if len(got) != 1 {
+		t.Fatalf("candidates = %d, want 1", len(got))
+	}
+	if got[0].Email != "" {
+		t.Errorf("Email = %q, want empty (push-only)", got[0].Email)
+	}
+	if len(got[0].PushTokens) != 2 {
+		t.Fatalf("PushTokens = %d, want 2", len(got[0].PushTokens))
+	}
+}
+
+func TestScanner_IgnoresWishlistCarts(t *testing.T) {
+	silenceLogs(t)
+	dir := t.TempDir()
+	now := time.Date(2026, 7, 1, 12, 0, 0, 0, time.UTC)
+
+	reg := cart.NewCartMultationRegistry(cart.NewCartMutationContext(nil))
+	storage := actor.NewDiskStorage[cart.CartGrain](dir, reg)
+
+	mtime := now.Add(-90 * time.Minute)
+	writeFixtureLog(t, dir, 13, mtime, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 1, Price: 1000},
+		&messages.SetRecoveryContact{Email: "wishlist@example.com"},
+		&messages.SetCartType{Type: messages.CartType_WISHLIST},
+	})
+	defer storage.Close()
+
+	scanner := NewScanner(dir, storage)
+	got, err := scanner.Scan(context.Background(), time.Hour, time.Hour, now)
+	if err != nil {
+		t.Fatalf("Scan: %v", err)
+	}
+	if len(got) != 0 {
+		t.Fatalf("wishlist candidate leaked: got %+v", got)
+	}
+}
+
+// TestScanner_TotalPostReplay verifies the bug fix: replay does not run the
+// post-mutation processor, so the scanner MUST call UpdateTotals to surface
+// an accurate TotalIncVat.
+func TestScanner_TotalPostReplay(t *testing.T) {
+	silenceLogs(t)
+	dir := t.TempDir()
+	now := time.Date(2026, 7, 1, 12, 0, 0, 0, time.UTC)
+
+	reg := cart.NewCartMultationRegistry(cart.NewCartMutationContext(nil))
+	storage := actor.NewDiskStorage[cart.CartGrain](dir, reg)
+
+	mtime := now.Add(-75 * time.Minute)
+	writeFixtureLog(t, dir, 21, mtime, []proto.Message{
+		&messages.AddItem{ItemId: 1, Quantity: 2, Price: 500, Sku: "A"},
+		&messages.AddItem{ItemId: 2, Quantity: 1, Price: 1500, Sku: "B"},
+		&messages.SetRecoveryContact{Email: "totals@example.com"},
+	})
+	defer storage.Close()
+
+	scanner := NewScanner(dir, storage)
+	got, err := scanner.Scan(context.Background(), time.Hour, time.Hour, now)
+	if err != nil {
+		t.Fatalf("Scan: %v", err)
+	}
+	if len(got) != 1 {
+		t.Fatalf("candidates = %d, want 1", len(got))
+	}
+	// 2*500 + 1*1500 = 2500 inc-vat
+	if got[0].TotalIncVat != 2500 {
+		t.Errorf("TotalIncVat = %d, want 2500 (1000+1500 across two lines)", got[0].TotalIncVat)
+	}
+	if got[0].ItemCount != 2 {
+		t.Errorf("ItemCount = %d, want 2", got[0].ItemCount)
+	}
+}
+
+// TestIsValidEmail sanity for the optional helper exported for notifiers.
+func TestIsValidEmail(t *testing.T) {
+	if !IsValidEmail("user@example.com") {
+		t.Errorf("user@example.com should be valid")
+	}
+	if IsValidEmail("not-an-email") {
+		t.Errorf("not-an-email should be invalid")
+	}
+}
+
+// TestFileIDFor verifies the helper that parses <id>.events.log filenames.
+func TestFileIDFor(t *testing.T) {
+	if id, ok := fileIDFor("12345.events.log"); !ok || id != 12345 {
+		t.Errorf("12345.events.log -> %d, %v; want 12345, true", id, ok)
+	}
+	if _, ok := fileIDFor("not-a-number.events.log"); ok {
+		t.Errorf("non-numeric should fail")
+	}
+	if _, ok := fileIDFor("0.events.log"); ok {
+		t.Errorf("id=0 should fail (no implicit zero-cart grain)")
+	}
+	if _, ok := fileIDFor("garbage.txt"); ok {
+		t.Errorf("non-event-log suffix should fail")
+	}
+}

pkg/cart/recovery/scanner.go

@@ -0,0 +1,187 @@
+package recovery
+
+import (
+	"context"
+	"fmt"
+	"net/mail"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.k6n.net/mats/go-cart-actor/pkg/actor"
+	"git.k6n.net/mats/go-cart-actor/pkg/cart"
+	cart_messages "git.k6n.net/mats/go-cart-actor/proto/cart"
+)
+
+// Scanner finds RecoveryCandidates by scanning the per-pod event-log directory.
+//
+// The model:
+//   - Each cart pod owns a shard of `<id>.events.log` files under `dir`.
+//   - File mtime approximates "last successful mutation" cheaply — replay only
+//     when something lands in the window.
+//   - For each candidate file, replay the grain (a few kb, ms-scale) and build
+//     a RecoveryCandidate iff it has items + a contact.
+//
+// Two important implementation details:
+//
+//  1. After LoadEvents we MUST call UpdateTotals(). Replaying event handlers
+//     runs the per-mutation registered handlers (SetUserId, SetRecoveryContact,
+//     AddItem, ...) but NOT the post-mutation processors — those run only on
+//     the live mutation path (see cmd/cart/main.go::RegisterProcessor for the
+//     "Totals and promotions" pipeline). Without this call, g.TotalPrice is
+//     nil and TotalIncVat in the candidate is always 0.
+//
+//  2. Read-vs-write races: DiskStorage may be in the middle of appending while
+//     Scan reads. The bufio scanner will fail JSON-unmarshal on a torn line and
+//     we silently continue — LogEvents treats that as "skip", here we do too.
+//     A persistent unreadable file is a separate problem runPurge handles.
+//
+// v0 deliberately does NOT track "already notified" within this scanner —
+// the window sizing plus caller conventions give roughly-once delivery.
+// Idempotency is the next pass.
+type Scanner struct {
+	dir     string
+	storage *actor.DiskStorage[cart.CartGrain]
+}
+
+// NewScanner returns a Scanner over dir (the same CART_DIR used by the cart
+// service). storage must share the same dir so LoadEvents reading paths
+// match the scanning paths.
+func NewScanner(dir string, storage *actor.DiskStorage[cart.CartGrain]) *Scanner {
+	return &Scanner{dir: dir, storage: storage}
+}
+
+// Scan returns candidates whose event-log mtime falls in
+// [now-delay-window, now-delay] AND whose grain has items AND (email OR
+// push tokens). The half-open window semantics match the caller's intent:
+//
+//	"carts whose mtime is in this slice of the recent past"
+//
+// — younger than now-delay (still active) and older than now-delay-window
+// (never recovery-eligible yet).
+//
+// Empty slice + nil error means "no candidates this pass"; an error means the
+// pass itself failed and the caller should log + retry.
+func (s *Scanner) Scan(ctx context.Context, delay, window time.Duration, now time.Time) ([]RecoveryCandidate, error) {
+	if s == nil || s.storage == nil || s.dir == "" {
+		return nil, fmt.Errorf("recovery: scanner not configured")
+	}
+	if delay <= 0 {
+		return nil, nil
+	}
+	if window <= 0 {
+		window = delay
+	}
+
+	lower := now.Add(-(delay + window))
+	upper := now.Add(-delay)
+	entries, err := os.ReadDir(s.dir)
+	if err != nil {
+		return nil, fmt.Errorf("recovery: read dir %s: %w", s.dir, err)
+	}
+
+	out := make([]RecoveryCandidate, 0)
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		name := e.Name()
+		if !strings.HasSuffix(name, ".events.log") {
+			continue
+		}
+		id, ok := fileIDFor(name)
+		if !ok {
+			continue
+		}
+		info, infoErr := e.Info()
+		if infoErr != nil {
+			continue
+		}
+		mtime := info.ModTime()
+		// Closed window:
+		//   mtime BEFORE lower  → never reached the abandonment threshold yet.
+		//   mtime AFTER upper   → still too fresh (caller is actively using it).
+		if mtime.Before(lower) || mtime.After(upper) {
+			continue
+		}
+
+		grain := cart.NewCartGrain(id, mtime)
+		if loadErr := s.storage.LoadEvents(ctx, id, grain); loadErr != nil {
+			// Skip unreadable grains — they're purged separately by runPurge.
+			continue
+		}
+		// Replay does NOT run the Totals-and-promotions processor (see the
+		// package doc); recompute TotalPrice from the item list so the
+		// candidate TotalIncVat matches what the live API would return.
+		grain.UpdateTotals()
+		if !eligible(grain) {
+			continue
+		}
+		out = append(out, buildCandidate(id, grain, mtime))
+	}
+	return out, nil
+}
+
+// eligible mirrors "would we ever want to send a reminder?" — items present
+// and a contact available. The grain's own UpdateTotals has already been
+// run by every mutation's processor, so TotalPrice is reliable here.
+//
+// Wishlists / offers are excluded — a wishlist cart isn't forgotten, and an
+// offer cart has its own delivery semantics.
+func eligible(g *cart.CartGrain) bool {
+	if g == nil || len(g.Items) == 0 {
+		return false
+	}
+	switch g.Type {
+	case cart_messages.CartType_WISHLIST, cart_messages.CartType_OFFER:
+		return false
+	}
+	hasContact := strings.TrimSpace(g.Email) != "" || len(g.PushTokens) > 0
+	return hasContact
+}
+
+// buildCandidate projects the replayed grain into a RecoveryCandidate. Email
+// validation is intentionally lenient — we hand the value to the notifier
+// and the notifier decides what to send; rejecting "looks-invalid" addresses
+// here would just hide useful debugging signal from the dry-run logs.
+func buildCandidate(id uint64, g *cart.CartGrain, mtime time.Time) RecoveryCandidate {
+	var total int64
+	if g.TotalPrice != nil {
+		// tax.Price.IncVat is int64-backed via money.Cents. Reading the field
+		// directly keeps the recovery layer decoupled from platform/money
+		// internals.
+		total = int64(g.TotalPrice.IncVat)
+	}
+	tokens := make([]cart.PushToken, len(g.PushTokens))
+	copy(tokens, g.PushTokens)
+	return RecoveryCandidate{
+		CartID:         cart.CartId(id),
+		UserID:         g.UserId,
+		Email:          g.Email,
+		PushTokens:     tokens,
+		ItemCount:      len(g.Items),
+		TotalIncVat:    total,
+		Currency:       g.Currency,
+		LastChangeUnix: mtime.Unix(),
+	}
+}
+
+// IsValidEmail is exported as a convenience the notifier may use to decide
+// whether to actually send (MailerSend will reject invalid); the scanner
+// itself is permissive.
+func IsValidEmail(s string) bool {
+	_, err := mail.ParseAddress(s)
+	return err == nil
+}
+
+// fileIDFor is a small helper that extracts the grain id from an .events.log
+// filename. Returns 0/false if the name doesn't match the expected shape.
+func fileIDFor(name string) (uint64, bool) {
+	base := strings.TrimSuffix(name, ".events.log")
+	id, err := strconv.ParseUint(base, 10, 64)
+	if err != nil || id == 0 {
+		return 0, false
+	}
+	return id, true
+}