Let the garden keep what she was given, not only what she sought

Two halves of the same idea, both read out of work Petal already
records.

Planting: an accepted collocation is a learnable chunk, so it becomes a
phrase card. The scheduler didn't need to know — a three-word chunk
climbs the ladder exactly like a looked-up word. What needed care was
deciding what *isn't* a chunk (single words are word choice; a
six-word-plus "collocation" is a rewritten sentence, and sentences make
miserable flashcards), and that the example must be the *corrected*
sentence — the stored draft still holds the phrasing she just left
behind. Re-accepting the same chunk leaves the existing card alone
rather than resetting a schedule it has been climbing. The whole thing
is best-effort: accepting an edit must never fail because a flashcard
couldn't be made.

The growth journal: kept this month beside kept the month before, the
phrasing that stuck, the patterns that faded. The queries were the easy
part; the honesty is the feature. "Stuck" needs the phrase in a *second*
document, because one document is just the edit where she left it.
"Faded" says nothing at all unless she has been writing lately —
otherwise a month away from Petal comes back to her as progress, which
is the one way this could lie. And a suggestion had to start recording
when she *decided* it, not when the model proposed it, so 0012 adds
resolved_at and backfills the old rows to their created_at.

It lives as a second tab in the garden, and it feeds the kitten: after
an accept she now sometimes hears something true of her alone, once per
line, half the time, never waited for.

Claude-Session: https://claude.ai/code/session_016y6gyuHkQXPiEuW8RGQyua

internal/suggestions/growth.go

@@ -0,0 +1,230 @@
+package suggestions
+
+import (
+	"net/http"
+
+	"gitea.parodia.dev/drwily/petal/internal/auth"
+	"gitea.parodia.dev/drwily/petal/internal/httputil"
+	"gitea.parodia.dev/drwily/petal/internal/vocab"
+)
+
+// The growth journal.
+//
+// The suggestions table already records everything this needs — it is purely a
+// read-side view, with no new capture and no model call. Two framing rules
+// decide what may appear here, and they are enforced in the SQL rather than left
+// to the copy:
+//
+//  1. It reports growth, never an error tally. Nothing counts what she got
+//     wrong this month; the signals are things that *stopped* happening and
+//     phrasing that *stuck*.
+//  2. It only ever compares the writer to her own past self. There is no
+//     target, no average, no other user anywhere in these queries.
+//
+// A quiet month is quiet: every signal below is omitted rather than softened
+// when the data isn't there, because an invented milestone is worse than none.
+
+// Journal is one writer's growth over the recent windows.
+type Journal struct {
+	// Kept / KeptBefore are edits she took on board in the last 30 days and in
+	// the 30 before that — her own past self, the only comparison offered.
+	Kept       int `json:"kept"`
+	KeptBefore int `json:"kept_before"`
+	// Stuck: phrasing she was given that now turns up across her own writing.
+	Stuck []Chunk `json:"stuck"`
+	// Faded: things she used to need fixing and hasn't, recently.
+	Faded []Fade `json:"faded"`
+}
+
+// Chunk is a phrase that has stuck: it appears in Docs of her documents now.
+type Chunk struct {
+	Phrase string `json:"phrase"`
+	Docs   int    `json:"docs"`
+}
+
+// Fade is a pattern that has stopped appearing. Times is how often it came up
+// during the earlier window — context for "and not since", never a scoreboard.
+type Fade struct {
+	Pattern string `json:"pattern"`
+	Times   int    `json:"times"`
+}
+
+// Journal windows, in days. `recent` is the month being reported on; `history`
+// reaches back far enough that a pattern's absence means something (one quiet
+// fortnight doesn't).
+const (
+	recentDays  = 30
+	historyDays = 120
+	maxSignals  = 3 // per list: a journal is a couple of warm lines, not a report
+)
+
+// growth serves GET /api/suggestions/growth.
+func (h *Handler) growth(w http.ResponseWriter, r *http.Request) {
+	userID := auth.UserID(r.Context())
+	j := Journal{Stuck: []Chunk{}, Faded: []Fade{}}
+
+	err := h.DB.QueryRow(
+		`SELECT
+		   sum(CASE WHEN s.resolved_at >= datetime('now', '-30 days') THEN 1 ELSE 0 END),
+		   sum(CASE WHEN s.resolved_at <  datetime('now', '-30 days')
+		             AND s.resolved_at >= datetime('now', '-60 days') THEN 1 ELSE 0 END)
+		   FROM suggestions s JOIN documents d ON d.id = s.doc_id
+		  WHERE d.user_id = ? AND s.status = 'accepted' AND s.resolved_at IS NOT NULL`,
+		userID,
+	).Scan(&nullInt{&j.Kept}, &nullInt{&j.KeptBefore})
+	if err != nil {
+		httputil.ServerError(w, err)
+		return
+	}
+
+	stuck, err := h.stuck(userID)
+	if err != nil {
+		httputil.ServerError(w, err)
+		return
+	}
+	j.Stuck = stuck
+
+	faded, err := h.faded(userID)
+	if err != nil {
+		httputil.ServerError(w, err)
+		return
+	}
+	j.Faded = faded
+
+	httputil.WriteJSON(w, http.StatusOK, j)
+}
+
+// stuck finds accepted phrasing that now appears in more than one of her own
+// documents. One document is just the edit itself, still sitting where it was
+// applied; a second is her reaching for the phrase on her own, which is the
+// whole claim the line makes.
+func (h *Handler) stuck(userID string) ([]Chunk, error) {
+	rows, err := h.DB.Query(
+		`SELECT DISTINCT s.replacement
+		   FROM suggestions s JOIN documents d ON d.id = s.doc_id
+		  WHERE d.user_id = ? AND s.status = 'accepted'
+		    AND s.resolved_at >= datetime('now', '-120 days')
+		    AND trim(s.replacement) != ''
+		  ORDER BY s.resolved_at DESC
+		  LIMIT 40`,
+		userID,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	// vocab.PhraseKey is the same definition of "a learnable chunk" the garden
+	// plants, so the journal and the garden can never disagree about what counts.
+	var phrases []string
+	for rows.Next() {
+		var replacement string
+		if err := rows.Scan(&replacement); err != nil {
+			return nil, err
+		}
+		if key := vocab.PhraseKey(replacement); key != "" {
+			phrases = append(phrases, key)
+		}
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	out := []Chunk{}
+	for _, p := range phrases {
+		var docs int
+		if err := h.DB.QueryRow(
+			`SELECT count(*) FROM documents WHERE user_id = ? AND instr(lower(content_text), ?) > 0`,
+			userID, p,
+		).Scan(&docs); err != nil {
+			return nil, err
+		}
+		if docs >= 2 {
+			out = append(out, Chunk{Phrase: p, Docs: docs})
+		}
+	}
+	sortDesc(out, func(c Chunk) int { return c.Docs })
+	return trim(out, maxSignals), nil
+}
+
+// faded finds patterns she used to be corrected on during the earlier part of
+// the history window and hasn't been since.
+//
+// The guard that makes this honest: it says nothing at all unless she has
+// actually been writing lately. Without it, a month away from Petal would be
+// reported back to her as progress, which is the one way this feature could lie.
+func (h *Handler) faded(userID string) ([]Fade, error) {
+	var wroteRecently int
+	if err := h.DB.QueryRow(
+		`SELECT count(*) FROM suggestions s JOIN documents d ON d.id = s.doc_id
+		  WHERE d.user_id = ? AND s.resolved_at >= datetime('now', '-30 days')`,
+		userID,
+	).Scan(&wroteRecently); err != nil {
+		return nil, err
+	}
+	if wroteRecently == 0 {
+		return []Fade{}, nil
+	}
+
+	rows, err := h.DB.Query(
+		`SELECT lower(trim(s.original)) AS pattern, count(*) AS times
+		   FROM suggestions s JOIN documents d ON d.id = s.doc_id
+		  WHERE d.user_id = ? AND s.status = 'accepted'
+		    AND s.resolved_at <  datetime('now', '-30 days')
+		    AND s.resolved_at >= datetime('now', '-120 days')
+		    AND trim(s.original) != ''
+		    AND pattern NOT IN (
+		          SELECT lower(trim(s2.original))
+		            FROM suggestions s2 JOIN documents d2 ON d2.id = s2.doc_id
+		           WHERE d2.user_id = ? AND s2.status = 'accepted'
+		             AND s2.resolved_at >= datetime('now', '-30 days'))
+		  GROUP BY pattern
+		 HAVING times >= 2
+		  ORDER BY times DESC
+		  LIMIT 3`,
+		userID, userID,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	out := []Fade{}
+	for rows.Next() {
+		var f Fade
+		if err := rows.Scan(&f.Pattern, &f.Times); err != nil {
+			return nil, err
+		}
+		out = append(out, f)
+	}
+	return out, rows.Err()
+}
+
+// nullInt scans a possibly-NULL aggregate into an int (SUM over no rows is
+// NULL, which is a zero here, not an error).
+type nullInt struct{ dst *int }
+
+func (n *nullInt) Scan(v any) error {
+	switch t := v.(type) {
+	case int64:
+		*n.dst = int(t)
+	case nil:
+		*n.dst = 0
+	}
+	return nil
+}
+
+func sortDesc[T any](s []T, key func(T) int) {
+	for i := 1; i < len(s); i++ {
+		for j := i; j > 0 && key(s[j]) > key(s[j-1]); j-- {
+			s[j], s[j-1] = s[j-1], s[j]
+		}
+	}
+}
+
+func trim[T any](s []T, n int) []T {
+	if len(s) > n {
+		return s[:n]
+	}
+	return s
+}

internal/suggestions/growth_test.go

@@ -0,0 +1,156 @@
+package suggestions
+
+import (
+	"encoding/json"
+	"net/http"
+	"strconv"
+	"testing"
+
+	"gitea.parodia.dev/drwily/petal/internal/db"
+)
+
+// resolved seeds one already-settled suggestion, dated `daysAgo` at the moment
+// she decided it (the journal reads decisions, not proposals).
+func resolved(t *testing.T, h *Handler, docID, status, original, replacement string, daysAgo int) {
+	t.Helper()
+	_, err := h.DB.Exec(
+		`INSERT INTO suggestions (doc_id, from_pos, to_pos, original, replacement, explanation, type, status, created_at, resolved_at)
+		 VALUES (?, 0, 0, ?, ?, '', 'collocation', ?, datetime('now', ?), datetime('now', ?))`,
+		docID, original, replacement, status,
+		"-"+strconv.Itoa(daysAgo)+" days", "-"+strconv.Itoa(daysAgo)+" days",
+	)
+	if err != nil {
+		t.Fatalf("seed resolved suggestion: %v", err)
+	}
+}
+
+func seedDoc(t *testing.T, h *Handler, userID, text string) string {
+	t.Helper()
+	var id string
+	if err := h.DB.QueryRow(
+		`INSERT INTO documents (user_id, content_text) VALUES (?, ?) RETURNING id`, userID, text,
+	).Scan(&id); err != nil {
+		t.Fatalf("seed doc: %v", err)
+	}
+	return id
+}
+
+func readJournal(t *testing.T, srv http.Handler) Journal {
+	t.Helper()
+	rec := do(t, srv, http.MethodGet, "/suggestions/growth", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("growth: got %d, want 200 (body %s)", rec.Code, rec.Body.String())
+	}
+	var j Journal
+	if err := json.Unmarshal(rec.Body.Bytes(), &j); err != nil {
+		t.Fatalf("decode journal: %v", err)
+	}
+	return j
+}
+
+// TestJournalIsEmptyForANewWriter: nothing to report reports nothing. Empty
+// lists, not nulls, so the frontend never has to guess.
+func TestJournalIsEmptyForANewWriter(t *testing.T) {
+	srv, _, _ := newTestServer(t, &stubClient{})
+	j := readJournal(t, srv)
+	if j.Kept != 0 || j.KeptBefore != 0 || len(j.Stuck) != 0 || len(j.Faded) != 0 {
+		t.Fatalf("new writer got a journal: %+v", j)
+	}
+}
+
+// TestKeptComparesHerToHerOwnPastSelf.
+func TestKeptCountsTwoWindows(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	for i := 0; i < 3; i++ {
+		resolved(t, h, docID, "accepted", "do a decision", "make a decision", 5)
+	}
+	resolved(t, h, docID, "accepted", "big rain", "heavy rain", 40)
+	resolved(t, h, docID, "rejected", "no thanks", "no, thank you", 5) // decisions kept only
+	resolved(t, h, docID, "accepted", "long ago", "long since", 200)   // outside both windows
+
+	j := readJournal(t, srv)
+	if j.Kept != 3 {
+		t.Errorf("Kept = %d, want 3", j.Kept)
+	}
+	if j.KeptBefore != 1 {
+		t.Errorf("KeptBefore = %d, want 1", j.KeptBefore)
+	}
+}
+
+// TestStuckNeedsASecondDocument: a phrase sitting in the one document it was
+// applied to has not stuck — it's just the edit, where she left it. A second
+// document is her reaching for it herself, which is the claim the line makes.
+func TestStuckNeedsASecondDocument(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	if _, err := h.DB.Exec(`UPDATE documents SET content_text = ? WHERE id = ?`,
+		"I had to make a decision.", docID); err != nil {
+		t.Fatalf("set content: %v", err)
+	}
+	resolved(t, h, docID, "accepted", "do a decision", "make a decision", 10)
+	resolved(t, h, docID, "accepted", "do a photo", "take a photo", 10)
+
+	if j := readJournal(t, srv); len(j.Stuck) != 0 {
+		t.Fatalf("one document counted as sticking: %+v", j.Stuck)
+	}
+
+	// She uses it again, elsewhere, on her own.
+	seedDoc(t, h, db.LocalUserID, "Later I had to Make A Decision about the flat.")
+	j := readJournal(t, srv)
+	if len(j.Stuck) != 1 {
+		t.Fatalf("Stuck = %+v, want just the phrase she reused", j.Stuck)
+	}
+	if j.Stuck[0].Phrase != "make a decision" || j.Stuck[0].Docs != 2 {
+		t.Errorf("Stuck[0] = %+v, want {make a decision 2} (case-insensitive)", j.Stuck[0])
+	}
+}
+
+// TestFadedNeedsRecentWriting is the guard that keeps this feature honest: a
+// month away from Petal must never be reported back as progress.
+func TestFadedNeedsRecentWriting(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	resolved(t, h, docID, "accepted", "在 the morning", "in the morning", 60)
+	resolved(t, h, docID, "accepted", "在 the morning", "in the morning", 55)
+
+	if j := readJournal(t, srv); len(j.Faded) != 0 {
+		t.Fatalf("silence reported as growth: %+v", j.Faded)
+	}
+
+	// She has been writing again this month — now the absence means something.
+	resolved(t, h, docID, "accepted", "big rain", "heavy rain", 3)
+	j := readJournal(t, srv)
+	if len(j.Faded) != 1 || j.Faded[0].Pattern != "在 the morning" || j.Faded[0].Times != 2 {
+		t.Fatalf("Faded = %+v, want the pattern she stopped needing (twice, back then)", j.Faded)
+	}
+}
+
+// TestFadedExcludesWhatStillHappens: a pattern corrected again this month has
+// not faded, however often it came up before.
+func TestFadedExcludesWhatStillHappens(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	resolved(t, h, docID, "accepted", "在 the morning", "in the morning", 60)
+	resolved(t, h, docID, "accepted", "在 the morning", "in the morning", 55)
+	resolved(t, h, docID, "accepted", "在 the morning", "in the morning", 2)
+
+	if j := readJournal(t, srv); len(j.Faded) != 0 {
+		t.Fatalf("Faded = %+v, want empty — it still happens", j.Faded)
+	}
+}
+
+// TestJournalIsPerWriter: another account's learning is never anyone else's
+// journal, and the only comparison Petal draws is with her own past self.
+func TestJournalIsPerWriter(t *testing.T) {
+	srv, _, h := newTestServer(t, &stubClient{})
+	if _, err := h.DB.Exec(`INSERT INTO users (id, email) VALUES ('bob', 'bob@example.com')`); err != nil {
+		t.Fatalf("seed user: %v", err)
+	}
+	bobDoc := seedDoc(t, h, "bob", "Bob had to make a decision.")
+	seedDoc(t, h, "bob", "Bob will make a decision again.")
+	resolved(t, h, bobDoc, "accepted", "do a decision", "make a decision", 5)
+	resolved(t, h, bobDoc, "accepted", "big rain", "heavy rain", 60)
+	resolved(t, h, bobDoc, "accepted", "big rain", "heavy rain", 55)
+
+	j := readJournal(t, srv)
+	if j.Kept != 0 || j.KeptBefore != 0 || len(j.Stuck) != 0 || len(j.Faded) != 0 {
+		t.Fatalf("bob's learning leaked into the local user's journal: %+v", j)
+	}
+}

internal/suggestions/handlers.go

@@ -11,6 +11,7 @@ import (
 	"encoding/json"
 	"errors"
 	"io"
+	"log"
 	"net/http"
 	"strings"
 
@@ -20,6 +21,7 @@ import (
 	"gitea.parodia.dev/drwily/petal/internal/db"
 	"gitea.parodia.dev/drwily/petal/internal/httputil"
 	"gitea.parodia.dev/drwily/petal/internal/llm"
+	"gitea.parodia.dev/drwily/petal/internal/vocab"
 )
 
 // Handler holds the dependencies for the checkpoint + suggestion routes. The
@@ -60,6 +62,10 @@ func (h *Handler) RegisterDocRoutes(r chi.Router) {
 // actions.
 func (h *Handler) Routes() chi.Router {
 	r := chi.NewRouter()
+	// The growth journal reads the same table these actions write, so it lives
+	// here rather than growing its own mount. A literal segment, so it can never
+	// be shadowed by an id.
+	r.Get("/growth", h.growth)
 	r.Post("/{id}/accept", h.accept)
 	r.Post("/{id}/dismiss", h.dismiss)
 	r.Post("/{id}/chat", h.chat)
@@ -577,7 +583,7 @@ func (h *Handler) dismiss(w http.ResponseWriter, r *http.Request) {
 // no rows and surfaces as a 404.
 func (h *Handler) setStatus(w http.ResponseWriter, r *http.Request, status string) {
 	res, err := h.DB.Exec(
-		`UPDATE suggestions SET status = ?
+		`UPDATE suggestions SET status = ?, resolved_at = datetime('now')
 		  WHERE id = ? AND status = ?
 		    AND doc_id IN (SELECT id FROM documents WHERE user_id = ?)`,
 		status, chi.URLParam(r, "id"), db.SuggestionStatusPending,
@@ -591,9 +597,72 @@ func (h *Handler) setStatus(w http.ResponseWriter, r *http.Request, status strin
 		httputil.ErrorJSON(w, http.StatusNotFound, "pending suggestion not found")
 		return
 	}
+	if status == db.SuggestionStatusAccepted {
+		h.plant(chi.URLParam(r, "id"), auth.UserID(r.Context()))
+	}
 	w.WriteHeader(http.StatusNoContent)
 }
 
+// plant grows an accepted collocation into a vocabulary-garden phrase card. It
+// runs after the status write and swallows its own errors: accepting an edit is
+// the thing the writer asked for, and it must not fail — or even feel slower —
+// because a flashcard couldn't be made.
+//
+// Only collocations are planted. The other families correct *this* sentence
+// ("their" → "there", a comma, a clearer clause); a collocation is the one that
+// hands over a reusable chunk, which is the only thing worth reviewing in a week.
+func (h *Handler) plant(id, userID string) {
+	var s db.Suggestion
+	var contentText string
+	err := h.DB.QueryRow(
+		`SELECT s.type, s.original, s.replacement, s.explanation, s.doc_id, d.content_text
+		   FROM suggestions s JOIN documents d ON d.id = s.doc_id
+		  WHERE s.id = ? AND d.user_id = ?`,
+		id, userID,
+	).Scan(&s.Type, &s.Original, &s.Replacement, &s.Explanation, &s.DocID, &contentText)
+	if err != nil {
+		if !errors.Is(err, sql.ErrNoRows) {
+			log.Printf("suggestions: could not read %s for planting: %v", id, err)
+		}
+		return
+	}
+	if s.Type != db.SuggestionTypeCollocation || strings.TrimSpace(s.Replacement) == "" {
+		return
+	}
+	// The stored text is still the pre-accept draft — the client applies the
+	// replacement in the editor. Correct the sentence here so the flashcard
+	// quizzes the phrasing she is keeping, not the one she just left behind.
+	docID := s.DocID
+	if _, err := vocab.Plant(h.DB, userID, vocab.Phrase{
+		Text:    s.Replacement,
+		Meaning: s.Explanation,
+		Example: correctedSentence(contentText, s.Original, s.Replacement),
+		DocID:   &docID,
+	}); err != nil {
+		log.Printf("suggestions: could not plant %s: %v", id, err)
+	}
+}
+
+// correctedSentence returns the sentence of contentText containing original,
+// with original swapped for replacement. Returns "" when the original isn't
+// found (the draft moved on) — a card with no example still reviews, just
+// without the cloze, so there's nothing to fall back to and nothing to guess.
+func correctedSentence(contentText, original, replacement string) string {
+	idx := strings.Index(contentText, original)
+	if original == "" || idx < 0 {
+		return ""
+	}
+	start := strings.LastIndexAny(contentText[:idx], ".!?\n")
+	end := strings.IndexAny(contentText[idx+len(original):], ".!?\n")
+	if end < 0 {
+		end = len(contentText)
+	} else {
+		end += idx + len(original) + 1 // keep the terminator
+	}
+	sentence := strings.TrimSpace(contentText[start+1 : end])
+	return strings.Replace(sentence, original, replacement, 1)
+}
+
 // locate finds the plaintext offsets of original within contentText. Returns
 // (-1, -1) when not found; the frontend anchors by string regardless, so a miss
 // here is non-fatal.

internal/suggestions/plant_test.go

@@ -0,0 +1,186 @@
+package suggestions
+
+import (
+	"net/http"
+	"testing"
+
+	"gitea.parodia.dev/drwily/petal/internal/db"
+)
+
+// seedSuggestion writes one pending suggestion against the seeded doc, after
+// replacing the doc's text so the sentence around `original` is under the test's
+// control.
+func seedSuggestion(t *testing.T, h *Handler, docID, text, sType, original, replacement, explanation string) string {
+	t.Helper()
+	if _, err := h.DB.Exec(`UPDATE documents SET content_text = ? WHERE id = ?`, text, docID); err != nil {
+		t.Fatalf("set content: %v", err)
+	}
+	var id string
+	err := h.DB.QueryRow(
+		`INSERT INTO suggestions (doc_id, from_pos, to_pos, original, replacement, explanation, type, status)
+		 VALUES (?, 0, 0, ?, ?, ?, ?, 'pending') RETURNING id`,
+		docID, original, replacement, explanation, sType,
+	).Scan(&id)
+	if err != nil {
+		t.Fatalf("seed suggestion: %v", err)
+	}
+	return id
+}
+
+type card struct {
+	word, definition, example string
+	interval                  int
+}
+
+func gardenCards(t *testing.T, h *Handler) []card {
+	t.Helper()
+	rows, err := h.DB.Query(
+		`SELECT word, definition, example, interval_days FROM vocab_words WHERE user_id = ? ORDER BY word`,
+		db.LocalUserID,
+	)
+	if err != nil {
+		t.Fatalf("read garden: %v", err)
+	}
+	defer rows.Close()
+	var out []card
+	for rows.Next() {
+		var c card
+		if err := rows.Scan(&c.word, &c.definition, &c.example, &c.interval); err != nil {
+			t.Fatalf("scan: %v", err)
+		}
+		out = append(out, c)
+	}
+	return out
+}
+
+// TestAcceptedCollocationIsPlanted walks the whole hand-over: a collocation the
+// writer accepts becomes a phrase card whose example is the *corrected*
+// sentence, so the flashcard quizzes the phrasing she kept.
+func TestAcceptedCollocationIsPlanted(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	id := seedSuggestion(t, h, docID,
+		"Yesterday was hard. I had to do a decision about the job. Then I slept.",
+		db.SuggestionTypeCollocation, "do a decision", "make a decision",
+		"English pairs “make” with “decision”.")
+
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept: got %d, want 204", rec.Code)
+	}
+
+	cards := gardenCards(t, h)
+	if len(cards) != 1 {
+		t.Fatalf("garden has %d cards, want 1: %+v", len(cards), cards)
+	}
+	got := cards[0]
+	if got.word != "make a decision" {
+		t.Errorf("word = %q, want %q", got.word, "make a decision")
+	}
+	if got.example != "I had to make a decision about the job." {
+		t.Errorf("example = %q — want the corrected sentence, bounded to its own sentence", got.example)
+	}
+	if got.definition != "English pairs “make” with “decision”." {
+		t.Errorf("definition = %q, want the explanation", got.definition)
+	}
+	if got.interval != 1 {
+		t.Errorf("interval_days = %d, want 1 (due tomorrow, like a fresh capture)", got.interval)
+	}
+}
+
+// TestOnlyCollocationsArePlanted: the other families correct this sentence and
+// hand over nothing reusable. A dismissed collocation is not a lesson either.
+func TestOnlyCollocationsArePlanted(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+
+	grammar := seedSuggestion(t, h, docID, "I has two apples.",
+		db.SuggestionTypeGrammar, "I has", "I have", "Subject–verb agreement.")
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+grammar+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept grammar: got %d", rec.Code)
+	}
+
+	dismissed := seedSuggestion(t, h, docID, "We must take a photo of it.",
+		db.SuggestionTypeCollocation, "do a photo", "take a photo", "Photos are taken.")
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+dismissed+"/dismiss", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("dismiss: got %d", rec.Code)
+	}
+
+	if cards := gardenCards(t, h); len(cards) != 0 {
+		t.Fatalf("garden grew %d card(s) from a grammar fix and a dismissal: %+v", len(cards), cards)
+	}
+}
+
+// TestPlantingIsIdempotentAndNeverResets: accepting the same chunk again is
+// evidence it's still being learned — the worst possible response is to wipe the
+// card's first context and the schedule it has been climbing.
+func TestPlantingIsIdempotentAndNeverResets(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	first := seedSuggestion(t, h, docID, "I had to do a decision.",
+		db.SuggestionTypeCollocation, "do a decision", "make a decision", "First explanation.")
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+first+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept: got %d", rec.Code)
+	}
+	// The card climbs a little.
+	if _, err := h.DB.Exec(
+		`UPDATE vocab_words SET reps = 3, interval_days = 7 WHERE user_id = ? AND word = 'make a decision'`,
+		db.LocalUserID,
+	); err != nil {
+		t.Fatalf("advance card: %v", err)
+	}
+
+	second := seedSuggestion(t, h, docID, "Later I must do a decision again.",
+		db.SuggestionTypeCollocation, "do a decision", "make a decision", "Second explanation.")
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+second+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept again: got %d", rec.Code)
+	}
+
+	cards := gardenCards(t, h)
+	if len(cards) != 1 {
+		t.Fatalf("garden has %d cards, want 1 (one chunk, one card)", len(cards))
+	}
+	if cards[0].definition != "First explanation." {
+		t.Errorf("definition = %q — the existing card should win", cards[0].definition)
+	}
+	if cards[0].example != "I had to make a decision." {
+		t.Errorf("example = %q — the first context should survive", cards[0].example)
+	}
+	if cards[0].interval != 7 {
+		t.Errorf("interval_days = %d, want 7 — progress must not be reset", cards[0].interval)
+	}
+}
+
+// TestSentenceRewriteIsNotAPhraseCard: a "collocation" long enough to be a
+// rewritten sentence makes a miserable flashcard, so it is dropped rather than
+// planted — and the accept still succeeds.
+func TestSentenceRewriteIsNotAPhraseCard(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	long := "I would like to take this opportunity to thank you for everything"
+	id := seedSuggestion(t, h, docID, "I want thank you for everything.",
+		db.SuggestionTypeCollocation, "I want thank you for everything", long, "More natural.")
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept: got %d, want 204 — a skipped card must never fail the accept", rec.Code)
+	}
+	if cards := gardenCards(t, h); len(cards) != 0 {
+		t.Fatalf("planted a sentence as a phrase card: %+v", cards)
+	}
+}
+
+func TestCorrectedSentence(t *testing.T) {
+	const text = "One thing. I had to do a decision fast! Another thing."
+	cases := []struct {
+		name, original, replacement, want string
+	}{
+		{"bounded to its sentence", "do a decision", "make a decision", "I had to make a decision fast!"},
+		{"original no longer present", "do a choice", "make a choice", ""},
+		{"empty original", "", "make a decision", ""},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := correctedSentence(text, tc.original, tc.replacement); got != tc.want {
+				t.Errorf("correctedSentence = %q, want %q", got, tc.want)
+			}
+		})
+	}
+	// A document with no terminator at all is one sentence, and still works.
+	if got := correctedSentence("i had to do a decision", "do a decision", "make a decision"); got != "i had to make a decision" {
+		t.Errorf("unterminated doc: got %q", got)
+	}
+}