Feature 12: Regular dinners and onboarding (#94)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>

internal/dinners/dinners.go

@@ -0,0 +1,551 @@
+// Package dinners keeps the household's dinners: adding Regulars by name or
+// recipe link, listing Regulars and the Quest log, editing, archiving and
+// favoriting, and grounding each dinner in a recipe. Names are deduplicated with the harness's dinner-name rules,
+// so the Regulars the household types and the Side quests the AI suggests
+// are compared the same way.
+package dinners
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"log/slog"
+	"math"
+	"net/url"
+	"slices"
+	"strings"
+	"sync"
+	"unicode/utf8"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/harness"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/recipes"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+)
+
+// Dinner statuses (the dinners.status column).
+const (
+	StatusSuggested = "suggested"
+	StatusQuestLog  = "quest_log"
+	StatusTried     = "tried"
+	StatusRegular   = "regular"
+	StatusArchived  = "archived"
+)
+
+// Limits on what a member may enter.
+const (
+	MaxNameChars   = 120
+	MaxRecipeURL   = 2048
+	MaxMinutes     = 1440 // a day; a crock-pot dinner fits
+	photoListWidth = 400  // the stored photo size lists show
+)
+
+// Methods and Difficulties are the values the dinners table allows.
+var (
+	Methods      = []string{"stovetop", "oven", "crockpot", "grill", "other"}
+	Difficulties = []string{"easy", "medium", "hard"}
+)
+
+// listable are the statuses List answers for.
+var listable = []string{StatusRegular, StatusQuestLog}
+
+// ErrNotFound is returned for an unknown dinner id.
+var ErrNotFound = errors.New("dinner not found")
+
+// Dinner is a dinner as the API shows it. It has no recipe_url: a pasted
+// link may carry a personal token, so it stays in the database for
+// grounding and never leaves the server.
+type Dinner struct {
+	ID              string  `json:"id"`
+	Name            string  `json:"name"`
+	Status          string  `json:"status"`
+	Origin          string  `json:"origin"`
+	Method          *string `json:"method"`
+	MinutesTotal    *int64  `json:"minutes_total"`
+	Difficulty      *string `json:"difficulty"`
+	Cuisine         *string `json:"cuisine"`
+	IsFavorite      bool    `json:"is_favorite"`
+	RecipeID        *string `json:"recipe_id"`
+	PhotoURL        *string `json:"photo_url"`
+	GroundingStatus string  `json:"grounding_status"`
+	// GroundingError is why grounding failed, one of the Reason codes;
+	// null unless GroundingStatus is failed.
+	GroundingError *string `json:"grounding_error"`
+	UpdatedBy      *string `json:"updated_by"`
+	CreatedAt      string  `json:"created_at"`
+	UpdatedAt      string  `json:"updated_at"`
+}
+
+// NewRegular is a Regular to add: its Name, which the household always
+// gives, and optionally the RecipeURL to ground it in. The name is never
+// taken from the link: a pasted link may carry a personal token anywhere in
+// it, and the name is shown in every dinner response.
+type NewRegular struct {
+	Name      *string
+	RecipeURL *string
+}
+
+// Patch edits a dinner. Nil fields are left as they are.
+type Patch struct {
+	Name         *string
+	Method       *string
+	MinutesTotal *int
+	Difficulty   *string
+}
+
+// Problem is one invalid field, named by its JSON key.
+type Problem struct {
+	Field  string
+	Reason string
+}
+
+// ValidationError lists every invalid field of a request.
+type ValidationError struct {
+	Problems []Problem
+}
+
+func (e *ValidationError) Error() string {
+	parts := make([]string, len(e.Problems))
+	for i, p := range e.Problems {
+		parts[i] = p.Field + ": " + p.Reason
+	}
+	return "invalid dinner: " + strings.Join(parts, "; ")
+}
+
+func invalid(field, reason string) *ValidationError {
+	return &ValidationError{Problems: []Problem{{Field: field, Reason: reason}}}
+}
+
+// DuplicateError is returned when a new or renamed dinner repeats an
+// unarchived one: its name is harness.Similar, or it has the same recipe
+// link.
+type DuplicateError struct {
+	Existing Dinner
+}
+
+func (e *DuplicateError) Error() string {
+	return fmt.Sprintf("%q is already a dinner (%s)", e.Existing.Name, e.Existing.Status)
+}
+
+// Service reads and changes dinners.
+type Service struct {
+	st        *store.Store
+	grounder  *recipes.Grounder
+	logger    *slog.Logger
+	groundJob *jobs.Kind[GroundJob]
+
+	// groundingsMu guards groundings: the KindGroundDinner jobs running,
+	// by dinner id, so archiving or renaming a dinner can stop them.
+	groundingsMu sync.Mutex
+	groundings   map[string]map[*runningGrounding]struct{}
+}
+
+// NewService returns a service over st that grounds dinners with grounder
+// and registers the KindGroundDinner job on runner, which must not have
+// started yet.
+func NewService(st *store.Store, grounder *recipes.Grounder, runner *jobs.Runner, logger *slog.Logger) (*Service, error) {
+	switch {
+	case st == nil:
+		return nil, errors.New("dinners: nil store")
+	case grounder == nil:
+		return nil, errors.New("dinners: nil grounder")
+	case runner == nil:
+		return nil, errors.New("dinners: nil job runner")
+	case logger == nil:
+		return nil, errors.New("dinners: nil logger")
+	}
+	s := &Service{st: st, grounder: grounder, logger: logger, groundings: make(map[string]map[*runningGrounding]struct{})}
+	kind, err := jobs.Register(runner, KindGroundDinner, s.runGroundJob, Reasons...)
+	if err != nil {
+		return nil, err
+	}
+	s.groundJob = kind
+	return s, nil
+}
+
+// Created is a new Regular with the id of the job grounding it, which is
+// nil when the job could not be enqueued and the dinner's grounding is
+// failed instead.
+type Created struct {
+	Dinner
+	GroundingJobID *string `json:"grounding_job_id"`
+}
+
+// CreateRegular adds a Regular named r.Name, keeping r.RecipeURL for
+// grounding when given, with status and origin regular and grounding_status
+// pending, recording updatedBy, and enqueues the KindGroundDinner job that grounds it. It returns without
+// waiting for the job. A name repeating an unarchived dinner is a
+// *DuplicateError. When the job cannot be enqueued, the stored dinner is
+// returned with grounding_status failed (ReasonGroundingError) and no job
+// id, so the household can fix its recipe by hand.
+func (s *Service) CreateRegular(ctx context.Context, r NewRegular, updatedBy string) (Created, error) {
+	d, err := s.createRegular(ctx, r, updatedBy)
+	if err != nil {
+		return Created{}, err
+	}
+	jobID, err := s.enqueueGrounding(ctx, d.ID, d.GroundingRevision)
+	if err != nil {
+		return Created{}, err
+	}
+	if jobID == nil {
+		row, err := db.New(s.st.Reader).GetDinner(context.WithoutCancel(ctx), d.ID)
+		if err != nil {
+			return Created{}, fmt.Errorf("dinners: read %s: %w", d.ID, err)
+		}
+		return Created{Dinner: fromRow(row)}, nil
+	}
+	return Created{Dinner: fromRow(d), GroundingJobID: jobID}, nil
+}
+
+// enqueueGrounding enqueues the KindGroundDinner job for pending dinner id
+// at grounding_revision revision and returns its id. When the job cannot be
+// enqueued, the dinner's grounding is failed with ReasonGroundingError, so
+// it is not left pending with no job, and the id is nil.
+func (s *Service) enqueueGrounding(ctx context.Context, id string, revision int64) (*string, error) {
+	jobID, err := s.groundJob.Enqueue(ctx, GroundJob{DinnerID: id, Revision: revision})
+	if err == nil {
+		return &jobID, nil
+	}
+	// The error is a database error, never a dependency's text.
+	s.logger.ErrorContext(ctx, "dinner grounding not enqueued", "dinner_id", id, "error", err)
+	if _, err := db.New(s.st.Writer).FailPendingDinnerGrounding(context.WithoutCancel(ctx), db.FailPendingDinnerGroundingParams{
+		GroundingError:    sql.NullString{String: ReasonGroundingError, Valid: true},
+		UpdatedAt:         store.Now().String(),
+		ID:                id,
+		GroundingRevision: revision,
+	}); err != nil {
+		return nil, fmt.Errorf("dinners: record failed grounding of %s: %w", id, err)
+	}
+	return nil, nil
+}
+
+func (s *Service) createRegular(ctx context.Context, r NewRegular, updatedBy string) (db.Dinner, error) {
+	if updatedBy == "" {
+		return db.Dinner{}, errors.New("dinners: create: no member to record as updated_by")
+	}
+	if r.Name == nil {
+		return db.Dinner{}, invalid("name", "give the dinner's name, with or without a recipe_url")
+	}
+	name, err := checkName(*r.Name)
+	if err != nil {
+		return db.Dinner{}, err
+	}
+	var recipeURL sql.NullString
+	if r.RecipeURL != nil {
+		u, err := checkRecipeURL(*r.RecipeURL)
+		if err != nil {
+			return db.Dinner{}, err
+		}
+		recipeURL = sql.NullString{String: u.String(), Valid: true}
+	}
+
+	var row db.Dinner
+	err = s.st.WithTx(ctx, func(tx *sql.Tx) error {
+		q := db.New(tx)
+		if err := checkUnique(ctx, q, "", name, recipeURL); err != nil {
+			return err
+		}
+		now := store.Now().String()
+		var err error
+		row, err = q.CreateDinner(ctx, db.CreateDinnerParams{
+			ID:              store.NewID(),
+			Name:            name,
+			NormalizedName:  harness.Normalize(name),
+			Status:          StatusRegular,
+			Origin:          "regular",
+			RecipeUrl:       recipeURL,
+			GroundingStatus: "pending",
+			UpdatedBy:       sql.NullString{String: updatedBy, Valid: true},
+			CreatedAt:       now,
+			UpdatedAt:       now,
+		})
+		if err != nil {
+			return fmt.Errorf("dinners: create: %w", err)
+		}
+		return nil
+	})
+	if err != nil {
+		return db.Dinner{}, err
+	}
+	return row, nil
+}
+
+// List returns the dinners with status, which must be regular or
+// quest_log, ordered by normalized name.
+func (s *Service) List(ctx context.Context, status string) ([]Dinner, error) {
+	if !slices.Contains(listable, status) {
+		return nil, invalid("status", "must be one of "+strings.Join(listable, ", "))
+	}
+	rows, err := db.New(s.st.Reader).ListDinnersByStatus(ctx, status)
+	if err != nil {
+		return nil, fmt.Errorf("dinners: list %s: %w", status, err)
+	}
+	out := make([]Dinner, len(rows))
+	for i, row := range rows {
+		out[i] = fromRow(row)
+	}
+	return out, nil
+}
+
+// Update applies p to dinner id, recording updatedBy. An invalid patch is a
+// *ValidationError and a new name repeating another unarchived dinner a
+// *DuplicateError; either changes nothing. Renaming a dinner still pending
+// clears its recipe_url, raises its grounding_revision and enqueues a fresh
+// KindGroundDinner job that grounds the new name: a job queued or running
+// for the old name or link carries the old revision, so it can no longer
+// write the dinner, and one running is stopped.
+func (s *Service) Update(ctx context.Context, id string, p Patch, updatedBy string) (Dinner, error) {
+	if updatedBy == "" {
+		return Dinner{}, errors.New("dinners: update: no member to record as updated_by")
+	}
+	name, err := p.validate()
+	if err != nil {
+		return Dinner{}, err
+	}
+
+	var row db.Dinner
+	var regrounding bool
+	err = s.st.WithTx(ctx, func(tx *sql.Tx) error {
+		q := db.New(tx)
+		cur, err := q.GetDinner(ctx, id)
+		if errors.Is(err, sql.ErrNoRows) {
+			return ErrNotFound
+		}
+		if err != nil {
+			return fmt.Errorf("dinners: read %s: %w", id, err)
+		}
+		params := db.UpdateDinnerParams{
+			ID:                cur.ID,
+			Name:              cur.Name,
+			NormalizedName:    cur.NormalizedName,
+			Status:            cur.Status,
+			Origin:            cur.Origin,
+			Method:            cur.Method,
+			MinutesTotal:      cur.MinutesTotal,
+			Difficulty:        cur.Difficulty,
+			Cuisine:           cur.Cuisine,
+			RecipeID:          cur.RecipeID,
+			RecipeUrl:         cur.RecipeUrl,
+			PhotoID:           cur.PhotoID,
+			GroundingStatus:   cur.GroundingStatus,
+			GroundingRevision: cur.GroundingRevision,
+			UpdatedBy:         sql.NullString{String: updatedBy, Valid: true},
+			UpdatedAt:         store.Now().String(),
+		}
+		if p.Name != nil {
+			if err := checkUnique(ctx, q, cur.ID, name, sql.NullString{}); err != nil {
+				return err
+			}
+			params.Name = name
+			params.NormalizedName = harness.Normalize(name)
+			if cur.GroundingStatus == GroundingPending && params.NormalizedName != cur.NormalizedName {
+				// The link was the old dinner's recipe; the new name is
+				// grounded by name, and a link can be given by hand.
+				params.RecipeUrl = sql.NullString{}
+				params.GroundingRevision++
+			}
+		}
+		if p.Method != nil {
+			params.Method = sql.NullString{String: *p.Method, Valid: true}
+		}
+		if p.MinutesTotal != nil {
+			params.MinutesTotal = sql.NullInt64{Int64: int64(*p.MinutesTotal), Valid: true}
+		}
+		if p.Difficulty != nil {
+			params.Difficulty = sql.NullString{String: *p.Difficulty, Valid: true}
+		}
+		row, err = q.UpdateDinner(ctx, params)
+		if err != nil {
+			return fmt.Errorf("dinners: update %s: %w", id, err)
+		}
+		regrounding = row.GroundingRevision != cur.GroundingRevision
+		return nil
+	})
+	if err != nil {
+		return Dinner{}, err
+	}
+	if regrounding {
+		s.stopGroundings(row.ID, row.GroundingRevision)
+		jobID, err := s.enqueueGrounding(ctx, row.ID, row.GroundingRevision)
+		if err != nil {
+			return Dinner{}, err
+		}
+		if jobID == nil {
+			row, err = db.New(s.st.Reader).GetDinner(context.WithoutCancel(ctx), row.ID)
+			if err != nil {
+				return Dinner{}, fmt.Errorf("dinners: read %s: %w", id, err)
+			}
+		}
+	}
+	return fromRow(row), nil
+}
+
+// Archive sets dinner id's status to archived, recording updatedBy. The row
+// is kept, so its name still counts for Side quest dedupe. A
+// KindGroundDinner job running for it is stopped.
+func (s *Service) Archive(ctx context.Context, id, updatedBy string) (Dinner, error) {
+	if updatedBy == "" {
+		return Dinner{}, errors.New("dinners: archive: no member to record as updated_by")
+	}
+	row, err := db.New(s.st.Writer).ArchiveDinner(ctx, db.ArchiveDinnerParams{
+		ID:        id,
+		UpdatedBy: sql.NullString{String: updatedBy, Valid: true},
+		UpdatedAt: store.Now().String(),
+	})
+	if errors.Is(err, sql.ErrNoRows) {
+		return Dinner{}, ErrNotFound
+	}
+	if err != nil {
+		return Dinner{}, fmt.Errorf("dinners: archive %s: %w", id, err)
+	}
+	s.stopGroundings(row.ID, math.MaxInt64)
+	return fromRow(row), nil
+}
+
+// ToggleFavorite flips dinner id's is_favorite, recording updatedBy.
+func (s *Service) ToggleFavorite(ctx context.Context, id, updatedBy string) (Dinner, error) {
+	if updatedBy == "" {
+		return Dinner{}, errors.New("dinners: favorite: no member to record as updated_by")
+	}
+	row, err := db.New(s.st.Writer).ToggleDinnerFavorite(ctx, db.ToggleDinnerFavoriteParams{
+		ID:        id,
+		UpdatedBy: sql.NullString{String: updatedBy, Valid: true},
+		UpdatedAt: store.Now().String(),
+	})
+	if errors.Is(err, sql.ErrNoRows) {
+		return Dinner{}, ErrNotFound
+	}
+	if err != nil {
+		return Dinner{}, fmt.Errorf("dinners: favorite %s: %w", id, err)
+	}
+	return fromRow(row), nil
+}
+
+// validate checks every field of p and returns its trimmed name.
+func (p Patch) validate() (string, error) {
+	var problems []Problem
+	var name string
+	if p.Name == nil && p.Method == nil && p.MinutesTotal == nil && p.Difficulty == nil {
+		return "", invalid("patch", "no fields to change")
+	}
+	if p.Name != nil {
+		n, err := checkName(*p.Name)
+		var verr *ValidationError
+		if errors.As(err, &verr) {
+			problems = append(problems, verr.Problems...)
+		}
+		name = n
+	}
+	if p.Method != nil && !slices.Contains(Methods, *p.Method) {
+		problems = append(problems, Problem{"method", "must be one of " + strings.Join(Methods, ", ")})
+	}
+	if p.MinutesTotal != nil && (*p.MinutesTotal < 1 || *p.MinutesTotal > MaxMinutes) {
+		problems = append(problems, Problem{"minutes_total", fmt.Sprintf("must be 1 to %d", MaxMinutes)})
+	}
+	if p.Difficulty != nil && !slices.Contains(Difficulties, *p.Difficulty) {
+		problems = append(problems, Problem{"difficulty", "must be one of " + strings.Join(Difficulties, ", ")})
+	}
+	if problems != nil {
+		return "", &ValidationError{Problems: problems}
+	}
+	return name, nil
+}
+
+// checkName returns raw trimmed, refusing a name that is empty, too long or
+// has no words left once normalized (so it could not be deduplicated).
+func checkName(raw string) (string, error) {
+	name := strings.TrimSpace(raw)
+	switch {
+	case name == "":
+		return "", invalid("name", "must not be empty")
+	case utf8.RuneCountInString(name) > MaxNameChars:
+		return "", invalid("name", fmt.Sprintf("must be at most %d characters", MaxNameChars))
+	case harness.Normalize(name) == "":
+		return "", invalid("name", "must name a dish, not only filler words")
+	}
+	return name, nil
+}
+
+// checkRecipeURL parses raw as an absolute https:// link to a recipe page,
+// the only kind recipe grounding fetches.
+func checkRecipeURL(raw string) (*url.URL, error) {
+	raw = strings.TrimSpace(raw)
+	if len(raw) > MaxRecipeURL {
+		return nil, invalid("recipe_url", fmt.Sprintf("must be at most %d bytes", MaxRecipeURL))
+	}
+	u, err := url.Parse(raw)
+	switch {
+	case err != nil:
+		return nil, invalid("recipe_url", "is not a URL")
+	case u.Scheme != "https" || u.Hostname() == "":
+		return nil, invalid("recipe_url", "must be an https:// link")
+	case u.User != nil:
+		return nil, invalid("recipe_url", "must not carry a user name or password")
+	}
+	return u, nil
+}
+
+// checkUnique returns a *DuplicateError when name is harness.Similar to an
+// unarchived dinner other than self, or recipeURL is one's recipe link: the
+// source_url of the recipe it is grounded in, else the recipe_url still
+// awaiting grounding.
+func checkUnique(ctx context.Context, q *db.Queries, self, name string, recipeURL sql.NullString) error {
+	rows, err := q.ListUnarchivedDinners(ctx)
+	if err != nil {
+		return fmt.Errorf("dinners: list for dedupe: %w", err)
+	}
+	for _, row := range rows {
+		if row.Dinner.ID == self {
+			continue
+		}
+		link := row.Dinner.RecipeUrl
+		if row.RecipeSourceUrl.Valid {
+			link = row.RecipeSourceUrl
+		}
+		if harness.Similar(name, row.Dinner.Name) || (recipeURL.Valid && link == recipeURL) {
+			return &DuplicateError{Existing: fromRow(row.Dinner)}
+		}
+	}
+	return nil
+}
+
+// PhotoURL is where the API serves a list-sized copy of photo id.
+func PhotoURL(id string) string {
+	return fmt.Sprintf("/media/photos/%s-%d.jpg", id, photoListWidth)
+}
+
+func fromRow(r db.Dinner) Dinner {
+	d := Dinner{
+		ID:              r.ID,
+		Name:            r.Name,
+		Status:          r.Status,
+		Origin:          r.Origin,
+		Method:          nullString(r.Method),
+		Difficulty:      nullString(r.Difficulty),
+		Cuisine:         nullString(r.Cuisine),
+		IsFavorite:      r.IsFavorite == 1,
+		RecipeID:        nullString(r.RecipeID),
+		GroundingStatus: r.GroundingStatus,
+		GroundingError:  nullString(r.GroundingError),
+		UpdatedBy:       nullString(r.UpdatedBy),
+		CreatedAt:       r.CreatedAt,
+		UpdatedAt:       r.UpdatedAt,
+	}
+	if r.MinutesTotal.Valid {
+		d.MinutesTotal = &r.MinutesTotal.Int64
+	}
+	if r.PhotoID.Valid {
+		u := PhotoURL(r.PhotoID.String)
+		d.PhotoURL = &u
+	}
+	return d
+}
+
+func nullString(s sql.NullString) *string {
+	if !s.Valid {
+		return nil
+	}
+	return &s.String
+}

internal/dinners/dinners_test.go

@@ -0,0 +1,74 @@
+package dinners_test
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+	"testing"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/dinners"
+)
+
+// TestCreateRegularNeverNamesFromLink: a Regular added with a recipe link
+// is named only by the household, so no part of the link — host, path,
+// query or fragment — is stored as its name or shown in a dinner or a
+// duplicate error, even a token of plain letters in the path.
+func TestCreateRegularNeverNamesFromLink(t *testing.T) {
+	t.Parallel()
+	e := newUnstartedEnv(t)
+	const link = "https://c.example/stew-key-abcdefghijklmno?sig=zyxwvut#frag"
+	leaks := []string{"c.example", "key", "abcdefghijklmno", "sig", "zyxwvut", "frag"}
+	check := func(what, text string) {
+		t.Helper()
+		lower := strings.ToLower(text)
+		for _, leak := range leaks {
+			if strings.Contains(lower, leak) {
+				t.Errorf("%s contains %q: %s", what, leak, text)
+			}
+		}
+	}
+
+	_, err := e.svc.CreateRegular(t.Context(), dinners.NewRegular{RecipeURL: ptr(link)}, member)
+	var verr *dinners.ValidationError
+	if !errors.As(err, &verr) {
+		t.Fatalf("link without a name: err = %v, want a *ValidationError", err)
+	}
+	check("validation error", verr.Error())
+
+	c, err := e.svc.CreateRegular(t.Context(), dinners.NewRegular{Name: ptr(" Sunday stew "), RecipeURL: ptr(link)}, member)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.Name != "Sunday stew" {
+		t.Errorf("name = %q, want the household's %q", c.Name, "Sunday stew")
+	}
+	created, err := json.Marshal(c)
+	if err != nil {
+		t.Fatal(err)
+	}
+	check("create response", string(created))
+	row := e.dinner(t, c.ID)
+	check("stored name", row.Name+" "+row.NormalizedName)
+	if row.RecipeUrl.String != link {
+		t.Errorf("stored recipe_url = %q, want %q kept for grounding", row.RecipeUrl.String, link)
+	}
+
+	list, err := e.svc.List(t.Context(), dinners.StatusRegular)
+	if err != nil {
+		t.Fatal(err)
+	}
+	listed, err := json.Marshal(list)
+	if err != nil {
+		t.Fatal(err)
+	}
+	check("list response", string(listed))
+
+	// The same link under another name is still a duplicate, and its error
+	// names the existing dinner by the household's name.
+	_, err = e.svc.CreateRegular(t.Context(), dinners.NewRegular{Name: ptr("Weeknight chili"), RecipeURL: ptr(link)}, member)
+	var dup *dinners.DuplicateError
+	if !errors.As(err, &dup) || dup.Existing.ID != c.ID {
+		t.Fatalf("same link again: err = %v, want a duplicate of %s", err, c.ID)
+	}
+	check("duplicate error", dup.Error())
+}

internal/dinners/export_test.go

@@ -0,0 +1,23 @@
+package dinners
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+// SetGroundTimeout sets the deadline of grounding by hand until t ends. A
+// test calling it must not run in parallel.
+func SetGroundTimeout(t *testing.T, d time.Duration) {
+	old := groundTimeout
+	groundTimeout = d
+	t.Cleanup(func() { groundTimeout = old })
+}
+
+// RunGroundJob runs the KindGroundDinner handler for p in the caller's
+// goroutine, as the job runner would, and returns the grounding status it
+// reports.
+func (s *Service) RunGroundJob(ctx context.Context, p GroundJob) (string, error) {
+	r, err := s.runGroundJob(ctx, p, nil)
+	return r.GroundingStatus, err
+}

internal/dinners/grounding.go

@@ -0,0 +1,635 @@
+package dinners
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"slices"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/recipes"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+)
+
+// KindGroundDinner is the job that grounds a new Regular in a recipe.
+const KindGroundDinner = "ground_dinner"
+
+// Grounding statuses (the dinners.grounding_status column).
+const (
+	GroundingPending  = "pending"
+	GroundingGrounded = "grounded"
+	GroundingFailed   = "failed"
+	GroundingManual   = "manual"
+)
+
+// Reasons a dinner's background grounding failed, stored in
+// dinners.grounding_error and as the KindGroundDinner job's failure code.
+const (
+	// ReasonNoRecipe: no page the search found holds a usable recipe.
+	ReasonNoRecipe = "no_recipe_found"
+	// ReasonRecipeUnusable: the dinner's recipe_url holds no usable recipe.
+	ReasonRecipeUnusable = "recipe_unusable"
+	// ReasonSearchNotConfigured: recipe search is not set up.
+	ReasonSearchNotConfigured = "search_not_configured"
+	// ReasonSearchFailed: the search provider failed.
+	ReasonSearchFailed = "search_failed"
+	// ReasonAIFailed: normalize_recipe's model provider could not be built
+	// or called.
+	ReasonAIFailed = "ai_failed"
+	// ReasonInterrupted: the server stopped while grounding.
+	ReasonInterrupted = "interrupted"
+	// ReasonGroundingError: any other failure, such as the database's.
+	ReasonGroundingError = "grounding_error"
+)
+
+// Reasons are every grounding failure reason.
+var Reasons = []string{
+	ReasonNoRecipe, ReasonRecipeUnusable, ReasonSearchNotConfigured, ReasonSearchFailed,
+	ReasonAIFailed, ReasonInterrupted, ReasonGroundingError,
+}
+
+// Limits on candidates and on a recipe entered by hand.
+const (
+	MaxCandidates     = 3
+	MaxManualLines    = 100
+	MaxManualLineChar = 500
+	// manualSourcePrefix starts the source_url of a recipe entered by hand,
+	// followed by the recipe's id; it is never a fetchable page.
+	manualSourcePrefix = "mealquest:manual:"
+)
+
+// GroundTimeout bounds grounding a candidate or link by hand, which runs in
+// the request: the page fetch (recipes.Timeout), its photo download and
+// normalize_recipe (harness.DefaultTimeout), with some slack.
+const GroundTimeout = 90 * time.Second
+
+// groundTimeout is GroundTimeout; tests shorten it.
+var groundTimeout = GroundTimeout
+
+// ErrGroundTimeout is returned by Ground when grounding a candidate or link
+// runs past GroundTimeout; the dinner is left as it was.
+var ErrGroundTimeout = errors.New("dinners: grounding the recipe took too long")
+
+// ErrGroundFailed wraps any unexpected failure grounding a dinner by hand.
+// Its text may quote the link and dependency errors, so it is never
+// logged.
+var ErrGroundFailed = errors.New("dinners: grounding the recipe failed")
+
+// ErrArchived is grounding an archived dinner by hand.
+var ErrArchived = errors.New("dinner archived")
+
+// ErrGroundConflict is a candidate or link grounded for a dinner that was
+// renamed or grounded some other way while it was grounding.
+var ErrGroundConflict = errors.New("dinner changed while its recipe was grounding")
+
+// GroundJob is the KindGroundDinner payload: the dinner to ground and its
+// grounding_revision when the job was enqueued.
+type GroundJob struct {
+	DinnerID string `json:"dinner_id"`
+	Revision int64  `json:"revision"`
+}
+
+// groundResult is the KindGroundDinner result: the dinner's grounding
+// status once the job ends. It is not grounded by this job when the dinner
+// was grounded by hand before the job finished, renamed (a later job
+// grounds it) or archived; the job then reports the status it found.
+type groundResult struct {
+	DinnerID        string `json:"dinner_id"`
+	GroundingStatus string `json:"grounding_status"`
+}
+
+func (r groundResult) PublicJSON() ([]byte, error) { return json.Marshal(r) }
+
+// runGroundJob grounds a pending dinner as its creation asked: its
+// recipe_url with GroundURL, else its name with Ground. Success records
+// the recipe and photo with grounding_status grounded, and the recipe's
+// method, minutes and difficulty where a member has not set them; failure
+// records grounding_status failed with its Reason, which is also the job's
+// failure code. A dinner archived, no longer pending, or at a
+// grounding_revision other than p.Revision is not grounded at all, and
+// either result is recorded only while the dinner is still unarchived,
+// pending and at p.Revision: a dinner grounded by hand meanwhile is left as
+// it is, and one renamed or archived meanwhile is left pending — for the
+// job its rename enqueued, or for none. Archiving or renaming the dinner
+// stops the grounding where it is, so no further search, fetch, photo
+// download or model call is made for it.
+func (s *Service) runGroundJob(ctx context.Context, p GroundJob, _ func(groundResult) error) (groundResult, error) {
+	// Tracked before the dinner is read: an archive or rename committed
+	// after the read finds this job to stop.
+	groundCtx, done := s.trackGrounding(ctx, p.DinnerID, p.Revision)
+	defer done()
+	row, err := db.New(s.st.Reader).GetDinner(ctx, p.DinnerID)
+	if err != nil {
+		return groundResult{}, fmt.Errorf("dinners: ground: read %s: %w", p.DinnerID, err)
+	}
+	if row.Status == StatusArchived || row.GroundingStatus != GroundingPending || row.GroundingRevision != p.Revision {
+		return groundResult{DinnerID: row.ID, GroundingStatus: row.GroundingStatus}, nil
+	}
+
+	var gr recipes.Grounded
+	if row.RecipeUrl.Valid {
+		gr, err = s.grounder.GroundURL(groundCtx, row.RecipeUrl.String)
+	} else {
+		gr, err = s.grounder.Ground(groundCtx, row.Name, row.Name)
+	}
+	if err != nil && ctx.Err() == nil && errors.Is(context.Cause(groundCtx), errGroundingStopped) {
+		return s.currentGrounding(ctx, row.ID)
+	}
+	if err != nil {
+		reason := reasonFor(err, row.RecipeUrl.Valid)
+		if ctx.Err() != nil {
+			reason = ReasonInterrupted
+		}
+		// Only the reason is logged: the error may quote a dependency's
+		// response, which jobs never store, return or log.
+		s.logger.InfoContext(ctx, "dinner grounding failed", "dinner_id", row.ID, "reason", reason)
+		write := context.WithoutCancel(ctx)
+		if _, failErr := db.New(s.st.Writer).FailPendingDinnerGrounding(write, db.FailPendingDinnerGroundingParams{
+			GroundingError:    sql.NullString{String: reason, Valid: true},
+			UpdatedAt:         store.Now().String(),
+			ID:                row.ID,
+			GroundingRevision: p.Revision,
+		}); failErr != nil {
+			return groundResult{}, fmt.Errorf("dinners: ground: record failure of %s: %w", row.ID, failErr)
+		}
+		if ctx.Err() != nil {
+			return groundResult{}, ctx.Err()
+		}
+		return groundResult{}, &jobs.Failure{Code: reason}
+	}
+
+	n, err := db.New(s.st.Writer).GroundPendingDinner(ctx, db.GroundPendingDinnerParams{
+		RecipeID:          sql.NullString{String: gr.RecipeID, Valid: true},
+		PhotoID:           sql.NullString{String: gr.PhotoID, Valid: true},
+		Method:            sql.NullString{String: gr.Method, Valid: true},
+		MinutesTotal:      nullInt(gr.MinutesTotal),
+		Difficulty:        sql.NullString{String: gr.Difficulty, Valid: true},
+		UpdatedAt:         store.Now().String(),
+		ID:                row.ID,
+		GroundingRevision: p.Revision,
+	})
+	if err != nil {
+		return groundResult{}, fmt.Errorf("dinners: ground: record %s: %w", row.ID, err)
+	}
+	if n == 0 {
+		return s.currentGrounding(ctx, row.ID)
+	}
+	return groundResult{DinnerID: row.ID, GroundingStatus: GroundingGrounded}, nil
+}
+
+// currentGrounding is the KindGroundDinner result of a job that did not
+// ground dinner id: the grounding status the dinner has now.
+func (s *Service) currentGrounding(ctx context.Context, id string) (groundResult, error) {
+	cur, err := db.New(s.st.Reader).GetDinner(ctx, id)
+	if err != nil {
+		return groundResult{}, fmt.Errorf("dinners: ground: read %s: %w", id, err)
+	}
+	return groundResult{DinnerID: cur.ID, GroundingStatus: cur.GroundingStatus}, nil
+}
+
+// errGroundingStopped is the cause a running KindGroundDinner job's
+// grounding is cancelled with when its dinner is archived or renamed.
+var errGroundingStopped = errors.New("dinners: grounding stopped: dinner archived or renamed")
+
+// runningGrounding is a KindGroundDinner job running for a dinner at
+// revision, with the cancel of its grounding.
+type runningGrounding struct {
+	revision int64
+	cancel   context.CancelCauseFunc
+}
+
+// trackGrounding returns a context for grounding dinnerID at revision that
+// stopGroundings cancels, and the func to call when the job ends.
+func (s *Service) trackGrounding(ctx context.Context, dinnerID string, revision int64) (context.Context, func()) {
+	groundCtx, cancel := context.WithCancelCause(ctx)
+	r := &runningGrounding{revision: revision, cancel: cancel}
+	s.groundingsMu.Lock()
+	if s.groundings[dinnerID] == nil {
+		s.groundings[dinnerID] = make(map[*runningGrounding]struct{})
+	}
+	s.groundings[dinnerID][r] = struct{}{}
+	s.groundingsMu.Unlock()
+	return groundCtx, func() {
+		s.groundingsMu.Lock()
+		delete(s.groundings[dinnerID], r)
+		if len(s.groundings[dinnerID]) == 0 {
+			delete(s.groundings, dinnerID)
+		}
+		s.groundingsMu.Unlock()
+		cancel(nil)
+	}
+}
+
+// stopGroundings cancels, with errGroundingStopped, the grounding of every
+// KindGroundDinner job running for dinnerID at a revision below below. Call
+// it once the change that makes those jobs stale is committed.
+func (s *Service) stopGroundings(dinnerID string, below int64) {
+	s.groundingsMu.Lock()
+	defer s.groundingsMu.Unlock()
+	for r := range s.groundings[dinnerID] {
+		if r.revision < below {
+			r.cancel(errGroundingStopped)
+		}
+	}
+}
+
+// FailInterruptedGroundings fails, with ReasonInterrupted, every unarchived
+// dinner still pending whose KindGroundDinner job is no longer queued or
+// running: a previous process stopped before enqueuing the job or before
+// its handler recorded a result. An archived dinner is left pending, since
+// archiving, not a restart, stopped its grounding. Call it once at boot, after the job runner's
+// Start has failed the jobs that process left running, so no dinner stays
+// pending with nothing left to ground it. It returns how many it failed.
+func (s *Service) FailInterruptedGroundings(ctx context.Context) (int64, error) {
+	n, err := db.New(s.st.Writer).FailOrphanedPendingDinnerGroundings(ctx, db.FailOrphanedPendingDinnerGroundingsParams{
+		GroundingError: sql.NullString{String: ReasonInterrupted, Valid: true},
+		UpdatedAt:      store.Now().String(),
+		Kind:           KindGroundDinner,
+	})
+	if err != nil {
+		return 0, fmt.Errorf("dinners: fail interrupted groundings: %w", err)
+	}
+	if n > 0 {
+		s.logger.WarnContext(ctx, "failed dinner groundings interrupted by restart", "count", n)
+	}
+	return n, nil
+}
+
+// reasonFor is the Reason for a grounding error; fromURL says whether the
+// dinner's recipe_url was grounded rather than its name.
+func reasonFor(err error, fromURL bool) string {
+	var ungroundable *recipes.ErrUngroundable
+	switch {
+	case errors.As(err, &ungroundable) && fromURL:
+		return ReasonRecipeUnusable
+	case errors.As(err, &ungroundable):
+		return ReasonNoRecipe
+	case errors.Is(err, recipes.ErrSearchNotConfigured):
+		return ReasonSearchNotConfigured
+	case errors.Is(err, recipes.ErrSearchFailed):
+		return ReasonSearchFailed
+	case errors.Is(err, recipes.ErrNormalizeFailed):
+		return ReasonAIFailed
+	}
+	return ReasonGroundingError
+}
+
+// Candidate is a recipe page offered to ground a dinner in.
+type Candidate struct {
+	// CandidateID is the page's URL; Fix.CandidateID grounds it.
+	CandidateID string `json:"candidate_id"`
+	Title       string `json:"title"`
+	SiteName    string `json:"site_name"`
+	// PhotoURL is the cached photo of a page already grounded, else null.
+	PhotoURL *string `json:"photo_url"`
+	Minutes  *int    `json:"minutes"`
+}
+
+// Candidates searches for dinner id's name and returns up to MaxCandidates
+// recipe pages to ground it in, best first; the list may be empty. A
+// search that fails wraps recipes.ErrSearchFailed.
+func (s *Service) Candidates(ctx context.Context, id string) ([]Candidate, error) {
+	row, err := s.get(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+	offers, err := s.grounder.Candidates(ctx, row.Name, row.Name, MaxCandidates)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]Candidate, len(offers))
+	for i, o := range offers {
+		out[i] = Candidate{CandidateID: o.URL, Title: o.Title, SiteName: o.SiteName, Minutes: o.Minutes}
+		if o.PhotoID != "" {
+			u := PhotoURL(o.PhotoID)
+			out[i].PhotoURL = &u
+		}
+	}
+	return out, nil
+}
+
+// Fix grounds a dinner by hand: exactly one of a candidate from
+// Candidates, a pasted recipe link or a recipe typed in.
+type Fix struct {
+	CandidateID *string
+	RecipeURL   *string
+	Manual      *ManualRecipe
+}
+
+// ManualRecipe is a recipe typed in by the household.
+type ManualRecipe struct {
+	// Ingredients are the ingredient lines, at least one.
+	Ingredients []string
+	// Steps are the instructions, in order; there may be none.
+	Steps   []string
+	Minutes *int
+	Method  *string
+}
+
+// Ground grounds dinner id as f says, recording updatedBy. A candidate or
+// link is grounded with recipes.Grounder.GroundURL and sets
+// grounding_status grounded, with the recipe's photo, method, minutes and
+// difficulty; one a member changed while it was grounding is kept. A
+// manual recipe is stored as typed — no model runs — and sets
+// grounding_status manual with its method and minutes; it has no photo,
+// and the dinner keeps its difficulty. An invalid f is a *ValidationError
+// and an archived dinner ErrArchived. A failure grounding a candidate or
+// link, or recording it on the dinner, wraps ErrGroundFailed; a page that
+// cannot ground the dinner is also a *recipes.ErrUngroundable. A dinner
+// renamed, archived or grounded some other way while a candidate or link
+// was grounding is ErrGroundConflict or ErrArchived. A missing dinner is
+// ErrNotFound; any other failure, by candidate, link or manual recipe,
+// wraps ErrGroundFailed. None of these changes the dinner.
+func (s *Service) Ground(ctx context.Context, id string, f Fix, updatedBy string) (Dinner, error) {
+	if updatedBy == "" {
+		return Dinner{}, errors.New("dinners: ground: no member to record as updated_by")
+	}
+	link, manual, err := f.validate()
+	if err != nil {
+		return Dinner{}, err
+	}
+	if manual != nil {
+		return s.groundManual(ctx, id, *manual, updatedBy)
+	}
+	cur, err := s.get(ctx, id)
+	if errors.Is(err, ErrNotFound) {
+		return Dinner{}, err
+	}
+	if err != nil {
+		return Dinner{}, fmt.Errorf("%w: dinner %s: %w", ErrGroundFailed, id, err)
+	}
+	if cur.Status == StatusArchived {
+		return Dinner{}, ErrArchived
+	}
+	groundCtx, cancel := context.WithTimeout(ctx, groundTimeout)
+	defer cancel()
+	gr, err := s.grounder.GroundURL(groundCtx, link)
+	if err != nil {
+		if ctx.Err() == nil && errors.Is(groundCtx.Err(), context.DeadlineExceeded) {
+			return Dinner{}, ErrGroundTimeout
+		}
+		return Dinner{}, fmt.Errorf("%w: dinner %s: %w", ErrGroundFailed, id, err)
+	}
+	row, err := db.New(s.st.Writer).GroundDinner(ctx, db.GroundDinnerParams{
+		RecipeID:                  sql.NullString{String: gr.RecipeID, Valid: true},
+		PhotoID:                   sql.NullString{String: gr.PhotoID, Valid: true},
+		Method:                    sql.NullString{String: gr.Method, Valid: true},
+		MinutesTotal:              nullInt(gr.MinutesTotal),
+		Difficulty:                sql.NullString{String: gr.Difficulty, Valid: true},
+		GroundingStatus:           GroundingGrounded,
+		UpdatedBy:                 sql.NullString{String: updatedBy, Valid: true},
+		UpdatedAt:                 store.Now().String(),
+		ID:                        cur.ID,
+		ObservedName:              cur.Name,
+		ObservedNormalizedName:    cur.NormalizedName,
+		ObservedGroundingStatus:   cur.GroundingStatus,
+		ObservedGroundingRevision: cur.GroundingRevision,
+		ObservedRecipeID:          cur.RecipeID,
+		ObservedMethod:            cur.Method,
+		ObservedMinutesTotal:      cur.MinutesTotal,
+		ObservedDifficulty:        cur.Difficulty,
+	})
+	if errors.Is(err, sql.ErrNoRows) {
+		return Dinner{}, s.groundRejected(ctx, id)
+	}
+	if err != nil {
+		return Dinner{}, fmt.Errorf("%w: dinner %s: record: %w", ErrGroundFailed, id, err)
+	}
+	return fromRow(row), nil
+}
+
+// groundRejected is the error for dinner id when it was not as observed
+// before grounding: ErrNotFound, ErrArchived or ErrGroundConflict. Failing
+// to read it wraps ErrGroundFailed.
+func (s *Service) groundRejected(ctx context.Context, id string) error {
+	cur, err := s.get(ctx, id)
+	if errors.Is(err, ErrNotFound) {
+		return err
+	}
+	if err != nil {
+		return fmt.Errorf("%w: dinner %s: %w", ErrGroundFailed, id, err)
+	}
+	if cur.Status == StatusArchived {
+		return ErrArchived
+	}
+	return ErrGroundConflict
+}
+
+// groundManual stores m as dinner id's recipe, with its ingredients and
+// steps, and records it on the dinner, all in one transaction. A missing
+// or archived dinner is ErrNotFound or ErrArchived; any other failure
+// wraps ErrGroundFailed.
+func (s *Service) groundManual(ctx context.Context, id string, m ManualRecipe, updatedBy string) (Dinner, error) {
+	var row db.Dinner
+	err := s.st.WithTx(ctx, func(tx *sql.Tx) error {
+		q := db.New(tx)
+		cur, err := q.GetDinner(ctx, id)
+		if errors.Is(err, sql.ErrNoRows) {
+			return ErrNotFound
+		}
+		if err != nil {
+			return fmt.Errorf("dinners: read %s: %w", id, err)
+		}
+		if cur.Status == StatusArchived {
+			return ErrArchived
+		}
+		ld, err := json.Marshal(manualJSONLD{
+			Context:      "https://schema.org",
+			Type:         "Recipe",
+			Name:         cur.Name,
+			Ingredients:  m.Ingredients,
+			Instructions: m.Steps,
+			TotalTime:    fmt.Sprintf("PT%dM", *m.Minutes),
+		})
+		if err != nil {
+			return fmt.Errorf("dinners: encode manual recipe: %w", err)
+		}
+		now := store.Now().String()
+		recipeID := store.NewID()
+		minutes := sql.NullInt64{Int64: int64(*m.Minutes), Valid: true}
+		method := sql.NullString{String: *m.Method, Valid: true}
+		rec, err := q.CreateManualRecipe(ctx, db.CreateManualRecipeParams{
+			ID:           recipeID,
+			SourceUrl:    manualSourcePrefix + recipeID,
+			Title:        cur.Name,
+			TotalMinutes: minutes,
+			RawJsonld:    string(ld),
+			Method:       method,
+			MinutesTotal: minutes,
+			FetchedAt:    now,
+			CreatedAt:    now,
+			UpdatedAt:    now,
+		})
+		if err != nil {
+			return fmt.Errorf("dinners: store manual recipe: %w", err)
+		}
+		for i, line := range m.Ingredients {
+			if err := q.CreateRecipeIngredient(ctx, db.CreateRecipeIngredientParams{
+				ID:        store.NewID(),
+				RecipeID:  rec.ID,
+				Position:  int64(i),
+				RawText:   line,
+				CreatedAt: now,
+				UpdatedAt: now,
+			}); err != nil {
+				return fmt.Errorf("dinners: store manual ingredient %d: %w", i+1, err)
+			}
+		}
+		for i, text := range m.Steps {
+			if err := q.CreateRecipeStep(ctx, db.CreateRecipeStepParams{
+				ID:        store.NewID(),
+				RecipeID:  rec.ID,
+				Position:  int64(i),
+				Text:      text,
+				CreatedAt: now,
+				UpdatedAt: now,
+			}); err != nil {
+				return fmt.Errorf("dinners: store manual step %d: %w", i+1, err)
+			}
+		}
+		row, err = q.GroundDinner(ctx, db.GroundDinnerParams{
+			RecipeID:                  sql.NullString{String: rec.ID, Valid: true},
+			Method:                    method,
+			MinutesTotal:              minutes,
+			Difficulty:                cur.Difficulty,
+			GroundingStatus:           GroundingManual,
+			UpdatedBy:                 sql.NullString{String: updatedBy, Valid: true},
+			UpdatedAt:                 now,
+			ID:                        cur.ID,
+			ObservedName:              cur.Name,
+			ObservedNormalizedName:    cur.NormalizedName,
+			ObservedGroundingStatus:   cur.GroundingStatus,
+			ObservedGroundingRevision: cur.GroundingRevision,
+			ObservedRecipeID:          cur.RecipeID,
+			ObservedMethod:            cur.Method,
+			ObservedMinutesTotal:      cur.MinutesTotal,
+			ObservedDifficulty:        cur.Difficulty,
+		})
+		if err != nil {
+			return fmt.Errorf("dinners: ground %s: %w", id, err)
+		}
+		return nil
+	})
+	if errors.Is(err, ErrNotFound) || errors.Is(err, ErrArchived) {
+		return Dinner{}, err
+	}
+	if err != nil {
+		return Dinner{}, fmt.Errorf("%w: dinner %s: %w", ErrGroundFailed, id, err)
+	}
+	return fromRow(row), nil
+}
+
+// manualJSONLD is the schema.org Recipe stored as a manual recipe's
+// raw_jsonld, so it reads like a fetched page's.
+type manualJSONLD struct {
+	Context      string   `json:"@context"`
+	Type         string   `json:"@type"`
+	Name         string   `json:"name"`
+	Ingredients  []string `json:"recipeIngredient"`
+	Instructions []string `json:"recipeInstructions"`
+	TotalTime    string   `json:"totalTime"`
+}
+
+// validate checks f and returns the link to ground, or the manual recipe
+// with its lines trimmed.
+func (f Fix) validate() (link string, manual *ManualRecipe, err error) {
+	given := 0
+	for _, set := range []bool{f.CandidateID != nil, f.RecipeURL != nil, f.Manual != nil} {
+		if set {
+			given++
+		}
+	}
+	if given != 1 {
+		return "", nil, invalid("ground", "give exactly one of candidate_id, recipe_url and manual")
+	}
+	switch {
+	case f.CandidateID != nil:
+		u, err := checkRecipeURL(*f.CandidateID)
+		if err != nil {
+			return "", nil, invalid("candidate_id", "is not a candidate from recipe-candidates")
+		}
+		return u.String(), nil, nil
+	case f.RecipeURL != nil:
+		u, err := checkRecipeURL(*f.RecipeURL)
+		if err != nil {
+			return "", nil, err
+		}
+		return u.String(), nil, nil
+	}
+	m, err := f.Manual.validate()
+	if err != nil {
+		return "", nil, err
+	}
+	return "", &m, nil
+}
+
+// validate checks every field of m and returns it with its lines trimmed.
+func (m ManualRecipe) validate() (ManualRecipe, error) {
+	var problems []Problem
+	ings, ingProblem := checkLines(m.Ingredients, 1)
+	if ingProblem != "" {
+		problems = append(problems, Problem{"manual.ingredients", ingProblem})
+	}
+	steps, stepProblem := checkLines(m.Steps, 0)
+	if stepProblem != "" {
+		problems = append(problems, Problem{"manual.steps", stepProblem})
+	}
+	if m.Minutes == nil || *m.Minutes < 1 || *m.Minutes > MaxMinutes {
+		problems = append(problems, Problem{"manual.minutes", fmt.Sprintf("must be 1 to %d", MaxMinutes)})
+	}
+	if m.Method == nil || !slices.Contains(Methods, *m.Method) {
+		problems = append(problems, Problem{"manual.method", "must be one of " + strings.Join(Methods, ", ")})
+	}
+	if problems != nil {
+		return ManualRecipe{}, &ValidationError{Problems: problems}
+	}
+	return ManualRecipe{Ingredients: ings, Steps: steps, Minutes: m.Minutes, Method: m.Method}, nil
+}
+
+// checkLines returns lines trimmed, or why they are refused: fewer than
+// least, more than MaxManualLines, or one blank or over MaxManualLineChar.
+func checkLines(lines []string, least int) ([]string, string) {
+	if len(lines) < least {
+		return nil, fmt.Sprintf("must have at least %d line", least)
+	}
+	if len(lines) > MaxManualLines {
+		return nil, fmt.Sprintf("must have at most %d lines", MaxManualLines)
+	}
+	out := make([]string, len(lines))
+	for i, line := range lines {
+		line = strings.TrimSpace(line)
+		switch {
+		case line == "":
+			return nil, fmt.Sprintf("line %d is blank", i+1)
+		case utf8.RuneCountInString(line) > MaxManualLineChar:
+			return nil, fmt.Sprintf("line %d is over %d characters", i+1, MaxManualLineChar)
+		}
+		out[i] = line
+	}
+	return out, ""
+}
+
+// get reads dinner id, or ErrNotFound.
+func (s *Service) get(ctx context.Context, id string) (db.Dinner, error) {
+	row, err := db.New(s.st.Reader).GetDinner(ctx, id)
+	if errors.Is(err, sql.ErrNoRows) {
+		return db.Dinner{}, ErrNotFound
+	}
+	if err != nil {
+		return db.Dinner{}, fmt.Errorf("dinners: read %s: %w", id, err)
+	}
+	return row, nil
+}
+
+func nullInt(v *int) sql.NullInt64 {
+	if v == nil {
+		return sql.NullInt64{}
+	}
+	return sql.NullInt64{Int64: int64(*v), Valid: true}
+}