package cabana_test

import (
	"encoding/json"
	"fmt"
	"io/fs"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"testing/fstest"
	"time"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/cabana"
	"git.golem15.com/golem15/summercms/modules/compass"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/party"
)

// catalogDir is the neutral acme.catalog fixture plugin tree of the Phase
// 18.1 cabana features (D-17): the taglist field and the flat reorder. No
// application names appear in framework tests.
const catalogDir = "testdata/catalog"

// catalogBadge is the fixture model of the badges controller: a name, a
// taglist in array mode over a JSON column, a taglist in string mode over a
// string column and a sort column. The table has no parent_id column.
type catalogBadge struct {
	ID        uint                      `gorm:"column:id;primaryKey"`
	Name      string                    `gorm:"column:name"`
	Tags      lagoon.Jsonable[[]string] `gorm:"column:tags;type:text"`
	Keywords  string                    `gorm:"column:keywords"`
	SortOrder int                       `gorm:"column:sort_order"`
}

func (catalogBadge) TableName() string { return "acme_catalog_badges" }
func (catalogBadge) Fillable() []string {
	return []string{"name", "tags", "keywords", "sort_order"}
}
func (catalogBadge) Rules() map[string]string { return map[string]string{"name": "required"} }

// catalogModels are the fixture tables, dropped and recreated per env.
func catalogModels() []any { return []any{&catalogBadge{}} }

// catalogPlugin registers the badges controller.
type catalogPlugin struct{}

func (catalogPlugin) ID() string                   { return "acme.catalog" }
func (catalogPlugin) Requires() []string           { return nil }
func (catalogPlugin) Register(*backpack.App) error { return nil }
func (catalogPlugin) Boot(*backpack.App) error     { return nil }
func (catalogPlugin) AdminFS() fs.FS               { return os.DirFS(catalogDir) }
func (catalogPlugin) AdminControllers() []pact.AdminController {
	return []pact.AdminController{catalogBadges{}}
}
func (catalogPlugin) Permissions() []pact.Permission {
	return []pact.Permission{{Code: "acme.catalog.access", Roles: []string{"developer"}}}
}

// catalogBadges is the badges controller.
type catalogBadges struct{}

func (catalogBadges) ID() string                    { return "acme.catalog.badges" }
func (catalogBadges) ModelName() string             { return "Badge" }
func (catalogBadges) ConfigDir() string             { return "controllers/badges" }
func (catalogBadges) RequiredPermissions() []string { return []string{"acme.catalog.access"} }
func (catalogBadges) NewRecord() any                { return &catalogBadge{} }

// catalogFSPlugin is the acme.catalog fixture served from another tree,
// optionally with another record model and settings pages.
type catalogFSPlugin struct {
	catalogPlugin
	fsys      fs.FS
	newRecord func() any
	settings  []pact.SettingsItem
}

func (p catalogFSPlugin) Settings() []pact.SettingsItem { return p.settings }

func (p catalogFSPlugin) AdminFS() fs.FS { return p.fsys }
func (p catalogFSPlugin) AdminControllers() []pact.AdminController {
	if p.newRecord != nil {
		return []pact.AdminController{catalogBadgesWith{newRecord: p.newRecord}}
	}
	return p.catalogPlugin.AdminControllers()
}

// catalogBadgesWith is the badges controller over another record model.
type catalogBadgesWith struct {
	catalogBadges
	newRecord func() any
}

func (c catalogBadgesWith) NewRecord() any { return c.newRecord() }

// catalogOverlay is the acme.catalog fixture tree with files replaced; an
// empty value removes the file.
func catalogOverlay(t *testing.T, files map[string]string) fstest.MapFS {
	t.Helper()
	out := fstest.MapFS{}
	err := fs.WalkDir(os.DirFS(catalogDir), ".", func(path string, d fs.DirEntry, err error) error {
		if err != nil || d.IsDir() {
			return err
		}
		raw, err := os.ReadFile(filepath.Join(catalogDir, path))
		if err != nil {
			return err
		}
		out[path] = &fstest.MapFile{Data: raw}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	for path, data := range files {
		if data == "" {
			delete(out, path)
			continue
		}
		out[path] = &fstest.MapFile{Data: []byte(data)}
	}
	return out
}

// catalogFile is one file of the fixture tree.
func catalogFile(t *testing.T, path string) string {
	t.Helper()
	raw, err := os.ReadFile(filepath.Join(catalogDir, path))
	if err != nil {
		t.Fatal(err)
	}
	return string(raw)
}

// activateCatalog boots the admin of p without a database.
func activateCatalog(t *testing.T, p party.Plugin) error {
	t.Helper()
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, "app.yaml"), []byte("name: cabana-catalog-boot\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	cfg, err := compass.Open(compass.Options{Dir: dir, Environ: []string{"SUMMER_ENV=development", "SUMMER_ADMIN__JWT__SECRET=" + adminTestSecret}})
	if err != nil {
		t.Fatal(err)
	}
	_, err = cabana.Activate(backpack.New(cfg), []party.Plugin{p})
	return err
}

// newCatalogEnv boots the acme.catalog fixture alone on Postgres and signs
// an administrator in.
func newCatalogEnv(t *testing.T) *conformEnv {
	t.Helper()
	gdb := adminGorm(t)
	if err := gdb.Migrator().DropTable(catalogModels()...); err != nil {
		t.Fatal(err)
	}
	if err := gdb.AutoMigrate(catalogModels()...); err != nil {
		t.Fatal(err)
	}
	login := fmt.Sprintf("catalog-%d", time.Now().UnixNano())
	insertAdmin(t, gdb, login, login+"@example.test", adminTestPassword, true, false)
	h, err := paymentsAssemble(t, gdb, []party.Plugin{catalogPlugin{}})
	if err != nil {
		t.Fatal(err)
	}
	env := &conformEnv{h: h, db: gdb, login: login}
	if rec := env.send(t, http.MethodPost, "/auth/login", map[string]string{"login": login, "password": adminTestPassword}, false); rec.Code != http.StatusOK {
		t.Fatalf("login status=%d body=%s", rec.Code, rec.Body.String())
	}
	return env
}

// storedTagsText is the tags column of badge id as the database holds it.
func storedTagsText(t *testing.T, e *conformEnv, id uint) *string {
	t.Helper()
	var text *string
	if err := e.db.Raw("SELECT tags FROM acme_catalog_badges WHERE id = ?", id).Scan(&text).Error; err != nil {
		t.Fatal(err)
	}
	return text
}

// expectCatalog422 posts body to the badges controller and wants a 422
// whose detail on field contains message.
func expectCatalog422(t *testing.T, e *conformEnv, body map[string]any, field, message string) {
	t.Helper()
	rec := e.send(t, http.MethodPost, "/acme/catalog/badges", body, true)
	if rec.Code != http.StatusUnprocessableEntity {
		t.Fatalf("want 422 on %s, status=%d body=%s", field, rec.Code, rec.Body.String())
	}
	var out struct {
		Error struct {
			Details map[string][]string `json:"details"`
		} `json:"error"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &out); err != nil {
		t.Fatalf("422 body: %v\n%s", err, rec.Body.String())
	}
	msgs := out.Error.Details[field]
	if len(msgs) != 1 || !strings.Contains(msgs[0], message) {
		t.Fatalf("422 details on %s = %v, want %q; body=%s", field, msgs, message, rec.Body.String())
	}
}

// TestTaglistFieldSmoke checks the taglist save path end to end on
// Postgres: an array-mode list is trimmed, emptied of blanks and duplicates
// and stored as exactly that JSON array, the record GET serves the list,
// null stores [], and a value that is not a list of strings is a 422 on the
// field with taglist.invalid (Polish, the request locale of the env). A
// string-mode value is split on its separator, normalised and stored joined
// by it; null stores an empty string. With customTags false a tag outside
// the options is a 422 with taglist.not_allowed naming the tag.
func TestTaglistFieldSmoke(t *testing.T) {
	e := newCatalogEnv(t)
	rec := e.send(t, http.MethodPost, "/acme/catalog/badges", map[string]any{"name": "First", "tags": []any{" alpha ", "beta", "alpha", ""}}, true)
	if rec.Code != http.StatusCreated {
		t.Fatalf("create status=%d body=%s", rec.Code, rec.Body.String())
	}
	id := dataID(t, rec.Body.Bytes())
	if text := storedTagsText(t, e, id); text == nil || *text != `["alpha","beta"]` {
		t.Fatalf("stored tags = %v, want [\"alpha\",\"beta\"]", text)
	}
	show := e.send(t, http.MethodGet, fmt.Sprintf("/acme/catalog/badges/%d", id), nil, true)
	if show.Code != http.StatusOK {
		t.Fatalf("show status=%d body=%s", show.Code, show.Body.String())
	}
	var record struct {
		Data map[string]json.RawMessage `json:"data"`
	}
	if err := json.Unmarshal(show.Body.Bytes(), &record); err != nil {
		t.Fatal(err)
	}
	if got := string(record.Data["tags"]); got != `["alpha","beta"]` {
		t.Fatalf("served tags = %s, want [\"alpha\",\"beta\"]", got)
	}

	expectCatalog422(t, e, map[string]any{"name": "Bad", "tags": "alpha"}, "tags", "Pole tags musi być listą tagów.")
	expectCatalog422(t, e, map[string]any{"name": "Bad", "tags": []any{1}}, "tags", "Pole tags musi być listą tagów.")

	rec = e.send(t, http.MethodPost, "/acme/catalog/badges", map[string]any{"name": "Empty", "tags": nil}, true)
	if rec.Code != http.StatusCreated {
		t.Fatalf("null create status=%d body=%s", rec.Code, rec.Body.String())
	}
	if text := storedTagsText(t, e, dataID(t, rec.Body.Bytes())); text == nil || *text != `[]` {
		t.Fatalf("null stored %v, want []", text)
	}

	// String mode, separator space: split on whitespace, normalised, joined
	// by one space, served as stored.
	rec = e.send(t, http.MethodPost, "/acme/catalog/badges", map[string]any{"name": "Words", "keywords": "x  y x"}, true)
	if rec.Code != http.StatusCreated {
		t.Fatalf("keywords create status=%d body=%s", rec.Code, rec.Body.String())
	}
	id = dataID(t, rec.Body.Bytes())
	var badge catalogBadge
	if err := e.db.First(&badge, id).Error; err != nil {
		t.Fatal(err)
	}
	if badge.Keywords != "x y" {
		t.Fatalf("stored keywords = %q, want \"x y\"", badge.Keywords)
	}
	show = e.send(t, http.MethodGet, fmt.Sprintf("/acme/catalog/badges/%d", id), nil, true)
	if err := json.Unmarshal(show.Body.Bytes(), &record); err != nil {
		t.Fatal(err)
	}
	if got := string(record.Data["keywords"]); got != `"x y"` {
		t.Fatalf("served keywords = %s, want \"x y\"", got)
	}
	rec = e.send(t, http.MethodPut, fmt.Sprintf("/acme/catalog/badges/%d", id), map[string]any{"name": "Words", "keywords": nil}, true)
	if rec.Code != http.StatusOK {
		t.Fatalf("keywords null status=%d body=%s", rec.Code, rec.Body.String())
	}
	if err := e.db.First(&badge, id).Error; err != nil {
		t.Fatal(err)
	}
	if badge.Keywords != "" {
		t.Fatalf("null keywords stored %q, want empty", badge.Keywords)
	}
	expectCatalog422(t, e, map[string]any{"name": "Bad", "keywords": []any{"x"}}, "keywords", "Pole keywords musi być listą tagów.")

	// customTags false: only the options are accepted.
	expectCatalog422(t, e, map[string]any{"name": "Bad", "tags": []any{"alpha", "delta"}}, "tags", "Tag delta jest niedozwolony.")
}

// catalogReorder is the data of the badges reorder routes.
type catalogReorder struct {
	Data struct {
		Flat  bool `json:"flat"`
		Nodes []struct {
			ID        uint   `json:"id"`
			ParentID  *uint  `json:"parent_id"`
			SortOrder int64  `json:"sort_order"`
			Name      string `json:"name"`
		} `json:"nodes"`
	} `json:"data"`
}

// TestReorderFlatSmoke checks the flat reorder routes on Postgres: the GET
// answers flat true with parent_id null on every node, the POST stores the
// submitted sort values (only the sort column) and answers the new order, a
// node with a parent is a 422 on nodes and a missing node a 409. The
// partitioned subtest runs the same rules within one partition.
func TestReorderFlatSmoke(t *testing.T) {
	e := newCatalogEnv(t)
	ids := make([]uint, 0, 3)
	for i, name := range []string{"One", "Two", "Three"} {
		badge := catalogBadge{Name: name, SortOrder: i + 1}
		if err := e.db.Create(&badge).Error; err != nil {
			t.Fatal(err)
		}
		ids = append(ids, badge.ID)
	}
	rec := e.send(t, http.MethodGet, "/acme/catalog/badges/reorder", nil, true)
	if rec.Code != http.StatusOK {
		t.Fatalf("reorder GET status=%d body=%s", rec.Code, rec.Body.String())
	}
	var got catalogReorder
	if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
		t.Fatal(err)
	}
	if !got.Data.Flat || len(got.Data.Nodes) != 3 || got.Data.Nodes[0].Name != "One" {
		t.Fatalf("reorder GET = %s", rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), `"flat":true`) {
		t.Fatalf("reorder GET lacks flat: %s", rec.Body.String())
	}
	for _, node := range got.Data.Nodes {
		if node.ParentID != nil {
			t.Fatalf("flat node %d has parent %d", node.ID, *node.ParentID)
		}
	}

	reversed := []map[string]any{
		{"id": ids[2], "parent_id": nil, "sort_order": 1},
		{"id": ids[1], "parent_id": nil, "sort_order": 2},
		{"id": ids[0], "parent_id": nil, "sort_order": 3},
	}
	rec = e.send(t, http.MethodPost, "/acme/catalog/badges/reorder", map[string]any{"nodes": reversed}, true)
	if rec.Code != http.StatusOK {
		t.Fatalf("reorder POST status=%d body=%s", rec.Code, rec.Body.String())
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
		t.Fatal(err)
	}
	if len(got.Data.Nodes) != 3 || got.Data.Nodes[0].ID != ids[2] || got.Data.Nodes[2].ID != ids[0] || !got.Data.Flat {
		t.Fatalf("reorder POST answer = %s", rec.Body.String())
	}
	for i, id := range []uint{ids[2], ids[1], ids[0]} {
		var badge catalogBadge
		if err := e.db.First(&badge, id).Error; err != nil {
			t.Fatal(err)
		}
		if badge.SortOrder != i+1 {
			t.Fatalf("badge %d sort_order = %d, want %d", id, badge.SortOrder, i+1)
		}
	}

	nested := []map[string]any{
		{"id": ids[0], "parent_id": nil, "sort_order": 1},
		{"id": ids[1], "parent_id": ids[0], "sort_order": 2},
		{"id": ids[2], "parent_id": nil, "sort_order": 3},
	}
	rec = e.send(t, http.MethodPost, "/acme/catalog/badges/reorder", map[string]any{"nodes": nested}, true)
	if rec.Code != http.StatusUnprocessableEntity || !strings.Contains(rec.Body.String(), `"nodes"`) || !strings.Contains(rec.Body.String(), "Kolejność płaska nie ma elementów nadrzędnych.") {
		t.Fatalf("flat parent status=%d body=%s", rec.Code, rec.Body.String())
	}
	rec = e.send(t, http.MethodPost, "/acme/catalog/badges/reorder", map[string]any{"nodes": reversed[:2]}, true)
	if rec.Code != http.StatusConflict {
		t.Fatalf("missing node status=%d body=%s", rec.Code, rec.Body.String())
	}
	t.Run("partitioned", reorderFlatPartition)
}

// shelfPin is the record of the partitioned flat reorder fixture
// (acme.shelf): a name, the shelf it belongs to (the partition) and a sort
// column, and no parent_id column, so its reorder is flat.
type shelfPin struct {
	ID        uint   `gorm:"column:id;primaryKey"`
	Name      string `gorm:"column:name"`
	ShelfID   *uint  `gorm:"column:shelf_id"`
	SortOrder int    `gorm:"column:sort_order"`
}

func (shelfPin) TableName() string        { return "acme_shelf_pins" }
func (shelfPin) Fillable() []string       { return []string{"name", "sort_order"} }
func (shelfPin) Rules() map[string]string { return map[string]string{"name": "required"} }

// shelfShelf is the belongsTo target of the pins' shelf field.
type shelfShelf struct {
	ID    uint   `gorm:"column:id;primaryKey"`
	Title string `gorm:"column:title"`
}

func (shelfShelf) TableName() string { return "acme_shelf_shelves" }

// shelfFS is the acme.shelf fixture tree: the pins controller with a flat
// reorder partitioned by shelf.
var shelfFS = fstest.MapFS{
	"controllers/pins/config_list.yaml":    {Data: []byte("list: ~/plugins/acme/shelf/models/pin/columns.yaml\nmodelClass: Pin\ntitle: Pins\nrecordUrl: acme/shelf/pins/update/:id\nrecordsPerPage: 20\ntoolbar:\n    buttons: [create, reorder]\n")},
	"controllers/pins/config_form.yaml":    {Data: []byte("name: Pin\nform: ~/plugins/acme/shelf/models/pin/fields.yaml\nmodelClass: Pin\ndefaultRedirect: acme/shelf/pins\n")},
	"controllers/pins/config_reorder.yaml": {Data: []byte("title: Reorder pins\nnameFrom: name\nmodelClass: Pin\npartition:\n    column: shelf_id\n    relation: shelf\n    label: Shelf\n")},
	"models/pin/columns.yaml":              {Data: []byte("columns:\n    name:\n        label: Name\n    sort_order:\n        label: Order\n")},
	"models/pin/fields.yaml":               {Data: []byte("fields:\n    name:\n        label: Name\n        type: text\n    shelf:\n        label: Shelf\n        type: relation\n        nameFrom: title\n")},
}

// shelfPlugin registers the pins controller.
type shelfPlugin struct{}

func (shelfPlugin) ID() string                   { return "acme.shelf" }
func (shelfPlugin) Requires() []string           { return nil }
func (shelfPlugin) Register(*backpack.App) error { return nil }
func (shelfPlugin) Boot(*backpack.App) error     { return nil }
func (shelfPlugin) AdminFS() fs.FS               { return shelfFS }
func (shelfPlugin) AdminControllers() []pact.AdminController {
	return []pact.AdminController{shelfPins{}}
}
func (shelfPlugin) Permissions() []pact.Permission {
	return []pact.Permission{{Code: "acme.shelf.access", Roles: []string{"developer"}}}
}

// shelfPins is the pins controller.
type shelfPins struct{}

func (shelfPins) ID() string                    { return "acme.shelf.pins" }
func (shelfPins) ModelName() string             { return "Pin" }
func (shelfPins) ConfigDir() string             { return "controllers/pins" }
func (shelfPins) RequiredPermissions() []string { return []string{"acme.shelf.access"} }
func (shelfPins) NewRecord() any                { return &shelfPin{} }

// AdminFieldRelations binds the shelf relation field, the reorder partition.
func (shelfPins) AdminFieldRelations() []cabana.FieldRelationContract {
	return []cabana.FieldRelationContract{{Field: "shelf", Kind: "belongsTo", NewRelated: func() any { return &shelfShelf{} }, ForeignKey: "shelf_id"}}
}

// newShelfEnv is a logged-in admin over the acme.shelf fixture with fresh
// tables.
func newShelfEnv(t *testing.T) *conformEnv {
	t.Helper()
	gdb := adminGorm(t)
	models := []any{&shelfPin{}, &shelfShelf{}}
	if err := gdb.Migrator().DropTable(models...); err != nil {
		t.Fatal(err)
	}
	if err := gdb.AutoMigrate(models...); err != nil {
		t.Fatal(err)
	}
	login := fmt.Sprintf("shelf-%d", time.Now().UnixNano())
	insertAdmin(t, gdb, login, login+"@example.test", adminTestPassword, true, false)
	h, err := paymentsAssemble(t, gdb, []party.Plugin{shelfPlugin{}})
	if err != nil {
		t.Fatal(err)
	}
	env := &conformEnv{h: h, db: gdb, login: login}
	if rec := env.send(t, http.MethodPost, "/auth/login", map[string]string{"login": login, "password": adminTestPassword}, false); rec.Code != http.StatusOK {
		t.Fatalf("login status=%d body=%s", rec.Code, rec.Body.String())
	}
	return env
}

// reorderFlatPartition checks a partitioned flat reorder on Postgres (plan
// 18.1-06, a subtest of TestReorderFlatSmoke): the GET of one shelf answers flat true with only
// that shelf's pins and the partition options, the POST writes only the sort
// column (the shelf and the other shelf's rows are untouched), a pin of the
// other shelf is the 409 stale set and a parent is a 422 on nodes.
func reorderFlatPartition(t *testing.T) {
	e := newShelfEnv(t)
	top, low := shelfShelf{Title: "Top"}, shelfShelf{Title: "Low"}
	for _, s := range []*shelfShelf{&top, &low} {
		if err := e.db.Create(s).Error; err != nil {
			t.Fatal(err)
		}
	}
	pins := []shelfPin{{Name: "A", ShelfID: &top.ID, SortOrder: 1}, {Name: "B", ShelfID: &top.ID, SortOrder: 2}, {Name: "X", ShelfID: &low.ID, SortOrder: 7}}
	for i := range pins {
		if err := e.db.Create(&pins[i]).Error; err != nil {
			t.Fatal(err)
		}
	}
	a, b, x := pins[0].ID, pins[1].ID, pins[2].ID

	rec := e.send(t, http.MethodGet, fmt.Sprintf("/acme/shelf/pins/reorder?partition=%d", top.ID), nil, true)
	if rec.Code != http.StatusOK {
		t.Fatalf("GET status=%d body=%s", rec.Code, rec.Body.String())
	}
	var got struct {
		Data struct {
			Flat      bool `json:"flat"`
			Partition *struct {
				Label   string `json:"label"`
				Value   *uint  `json:"value"`
				Options []struct {
					Label string `json:"label"`
				} `json:"options"`
			} `json:"partition"`
			Nodes []struct {
				ID       uint  `json:"id"`
				ParentID *uint `json:"parent_id"`
			} `json:"nodes"`
		} `json:"data"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
		t.Fatal(err)
	}
	d := got.Data
	if !d.Flat || d.Partition == nil || d.Partition.Label != "Shelf" || d.Partition.Value == nil || *d.Partition.Value != top.ID || len(d.Partition.Options) != 2 {
		t.Fatalf("GET = %s", rec.Body.String())
	}
	if len(d.Nodes) != 2 || d.Nodes[0].ID != a || d.Nodes[1].ID != b || d.Nodes[0].ParentID != nil || d.Nodes[1].ParentID != nil {
		t.Fatalf("GET nodes = %s", rec.Body.String())
	}

	post := func(nodes ...map[string]any) int {
		return e.send(t, http.MethodPost, "/acme/shelf/pins/reorder", map[string]any{"partition": top.ID, "nodes": nodes}, true).Code
	}
	n := func(id uint, parent any, sort int) map[string]any {
		return map[string]any{"id": id, "parent_id": parent, "sort_order": sort}
	}
	if code := post(n(b, nil, 1), n(a, nil, 2)); code != http.StatusOK {
		t.Fatalf("POST status=%d", code)
	}
	rows := map[uint]shelfPin{}
	var all []shelfPin
	if err := e.db.Find(&all).Error; err != nil {
		t.Fatal(err)
	}
	for _, p := range all {
		rows[p.ID] = p
	}
	if rows[b].SortOrder != 1 || rows[a].SortOrder != 2 || *rows[a].ShelfID != top.ID || *rows[b].ShelfID != top.ID || rows[x].SortOrder != 7 || *rows[x].ShelfID != low.ID {
		t.Fatalf("rows after POST = %+v", rows)
	}
	if code := post(n(b, nil, 1), n(a, nil, 2), n(x, nil, 3)); code != http.StatusConflict {
		t.Fatalf("pin of the other shelf status=%d, want 409", code)
	}
	if code := post(n(b, nil, 1), n(a, b, 2)); code != http.StatusUnprocessableEntity {
		t.Fatalf("parent status=%d, want 422", code)
	}
}