feat: SEO change history

2026-10-27 10:45:30 +01:00
parent 9f1082d62d
commit e8a6b9fc77
21 changed files with 1070 additions and 26 deletions
--- a/admin_navigation.go
+++ b/admin_navigation.go
@@ -24,6 +24,13 @@ func (*Plugin) Navigation() []pact.NavigationItem {
 				Permissions: []string{controllers.PermissionManage},
 				Controller:  controllers.RulesControllerID,
 			},
+			{
+				Code:        "history",
+				Label:       "golem15.seo::lang.nav.history",
+				Icon:        "clock",
+				Permissions: []string{controllers.PermissionManage},
+				Controller:  controllers.HistoryControllerID,
+			},
 		},
 	}}
 }
--- a/classes/entries.go
+++ b/classes/entries.go
@@ -129,7 +129,7 @@ func (s *Service) SaveRecord(ctx context.Context, db *gorm.DB, in RecordWrite) (
 	for locale, e := range existing {
 		before[locale] = e
 	}
-	urls := s.recordURLs(ctx, in.Type.Key, in.ID)
+	described := s.recordLocales(ctx, in.Type.Key, in.ID)
 	touched := map[string]models.Entry{}
 	for column, perLocale := range in.Values {
 		for locale, value := range perLocale {
@@ -153,8 +153,8 @@ func (s *Service) SaveRecord(ctx context.Context, db *gorm.DB, in RecordWrite) (
 			continue
 		}
 		e.TypeKey = in.Type.Key
-		if u, ok := urls[locale]; ok {
-			e.URL = u
+		if l, ok := described[locale]; ok {
+			e.URL = l.URL
 		}
 		if e.ID == 0 {
 			if err := db.Create(&e).Error; err != nil {
@@ -164,10 +164,37 @@ func (s *Service) SaveRecord(ctx context.Context, db *gorm.DB, in RecordWrite) (
 			return nil, nil, err
 		}
 		after[locale] = e
+		var old map[string]any
+		if stored {
+			old = entryValues(existing[locale])
+		}
+		if err := s.Record(ctx, db, Change{
+			Kind:      models.SubjectEntry,
+			SubjectID: EntrySubject(modelType, in.ID, locale),
+			What:      s.recordWhat(in.Type, in.ID, described[locale], locale),
+			Before:    old,
+			After:     entryValues(e),
+		}); err != nil {
+			return nil, nil, err
+		}
 	}
 	return before, after, nil
 }

+// recordWhat is the history description of a record's SEO in a locale:
+// "SEO of <type> “<title>” (<locale>)".
+func (s *Service) recordWhat(typ pact.MenuItemType, id string, l pact.ContentLocale, locale string) string {
+	title := l.Title
+	if strings.TrimSpace(title) == "" {
+		title = "#" + id
+	}
+	return s.Phrase("golem15.seo::lang.history.what_record", map[string]string{
+		"type":   s.Phrase(typ.Label, nil),
+		"title":  title,
+		"locale": locale,
+	})
+}
+
 // entryEmpty reports whether no editable column of e carries a value.
 func entryEmpty(e models.Entry) bool {
 	for _, column := range EntryColumns {
@@ -178,10 +205,10 @@ func entryEmpty(e models.Entry) bool {
 	return len(e.Data) == 0
 }

-// recordURLs returns the record's public path per locale through its
-// content descriptor; an error or a missing registry answers none.
-func (s *Service) recordURLs(ctx context.Context, key, id string) map[string]string {
-	out := map[string]string{}
+// recordLocales describes the record per locale through its content
+// descriptor; an error or a missing registry answers none.
+func (s *Service) recordLocales(ctx context.Context, key, id string) map[string]pact.ContentLocale {
+	out := map[string]pact.ContentLocale{}
 	reg := s.Registry()
 	if reg == nil {
 		return out
@@ -191,7 +218,7 @@ func (s *Service) recordURLs(ctx context.Context, key, id string) map[string]str
 		return out
 	}
 	for _, l := range rec.Locales {
-		out[l.Locale] = l.URL
+		out[l.Locale] = l
 	}
 	return out
 }
--- a/classes/history.go
+++ b/classes/history.go
@@ -0,0 +1,260 @@
+package classes
+
+import (
+	"context"
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+
+	"git.golem15.com/golem15/sm-seo-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/bouncer"
+	"git.golem15.com/golem15/summercms/modules/pact"
+	"git.golem15.com/golem15/summercms/modules/phrasebook"
+	"gorm.io/gorm"
+)
+
+type viaKey struct{}
+
+// WithVia marks ctx as a write through via (import, auto, undo), which
+// history records instead of admin or mcp.
+func WithVia(ctx context.Context, via string) context.Context {
+	return context.WithValue(ctx, viaKey{}, via)
+}
+
+// ViaOf is the writer history records for ctx: a WithVia mark, else mcp
+// when an MCP dispatch for the backend guard carries the request
+// (see mcpPrincipal), else admin.
+func ViaOf(ctx context.Context) string {
+	if v, ok := ctx.Value(viaKey{}).(string); ok && v != "" {
+		return v
+	}
+	if _, ok := mcpPrincipal(ctx); ok {
+		return models.ViaMCP
+	}
+	return models.ViaAdmin
+}
+
+// mcpPrincipal returns the principal of an MCP dispatch for the backend
+// guard, which the MCP module attaches to the requests it builds.
+func mcpPrincipal(ctx context.Context) (*bouncer.Principal, bool) {
+	d, ok := bouncer.Dispatched(ctx, "backend")
+	if !ok {
+		return nil, false
+	}
+	return d.Principal, true
+}
+
+// Change is one changed object for history. Before and After hold the
+// object's values; Record keeps only the fields whose value changed. A
+// created object has a nil Before, a deleted one a nil After.
+type Change struct {
+	Kind      string
+	SubjectID string
+	What      string
+	Before    map[string]any
+	After     map[string]any
+}
+
+// diffValues keeps the keys whose value differs between before and after;
+// nil before or after keeps every key of the other side.
+func diffValues(before, after map[string]any) (b, a map[string]any) {
+	if before == nil || after == nil {
+		return before, after
+	}
+	b, a = map[string]any{}, map[string]any{}
+	keys := map[string]bool{}
+	for k := range before {
+		keys[k] = true
+	}
+	for k := range after {
+		keys[k] = true
+	}
+	for k := range keys {
+		bv, av := before[k], after[k]
+		if !reflect.DeepEqual(plainValue(bv), plainValue(av)) {
+			b[k], a[k] = plainValue(bv), plainValue(av)
+		}
+	}
+	return b, a
+}
+
+// plainValue turns a model value into a JSON-friendly one: pointers are
+// dereferenced, times formatted, and SQL valuers (jsonable columns) read
+// through their stored JSON.
+func plainValue(v any) any {
+	switch val := v.(type) {
+	case nil:
+		return nil
+	case string, bool, float64, int, int64, uint, uint64:
+		return val
+	case time.Time:
+		return val.UTC().Format(time.RFC3339)
+	case *time.Time:
+		if val == nil {
+			return nil
+		}
+		return val.UTC().Format(time.RFC3339)
+	case json.Number:
+		return val.String()
+	case driver.Valuer:
+		raw, err := val.Value()
+		if err != nil || raw == nil {
+			return nil
+		}
+		if s, ok := raw.(string); ok {
+			var decoded any
+			if json.Unmarshal([]byte(s), &decoded) == nil {
+				return decoded
+			}
+			return s
+		}
+		return plainValue(raw)
+	}
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Pointer {
+		if rv.IsNil() {
+			return nil
+		}
+		return plainValue(rv.Elem().Interface())
+	}
+	raw, err := json.Marshal(v)
+	if err != nil {
+		return fmt.Sprint(v)
+	}
+	var decoded any
+	if json.Unmarshal(raw, &decoded) != nil {
+		return fmt.Sprint(v)
+	}
+	return decoded
+}
+
+// ChangesValues turns a save's record changes into before and after maps:
+// the attribute name, with ".<locale>" for a translated value.
+func ChangesValues(changes []pact.RecordChange, created bool) (before, after map[string]any) {
+	after = map[string]any{}
+	if !created {
+		before = map[string]any{}
+	}
+	for _, c := range changes {
+		key := c.Attribute
+		if c.Locale != "" {
+			key += "." + c.Locale
+		}
+		if before != nil {
+			before[key] = plainValue(c.Old)
+		}
+		after[key] = plainValue(c.New)
+	}
+	return before, after
+}
+
+// author returns the author of a write: the backend principal's id and a
+// label (the administrator's name or login; "MCP: <label>" through MCP).
+func (s *Service) author(ctx context.Context, db *gorm.DB, via string) (*uint, string) {
+	p, ok := mcpPrincipal(ctx)
+	if !ok {
+		p, _ = bouncer.User(ctx)
+	}
+	if p == nil || p.ID == 0 {
+		return nil, ""
+	}
+	id := p.ID
+	var row struct {
+		FirstName string
+		LastName  string
+		Login     string
+	}
+	label := fmt.Sprintf("#%d", id)
+	if err := db.Raw(`SELECT first_name, last_name, login FROM backend_users WHERE id = ?`, id).Scan(&row).Error; err == nil {
+		if name := strings.TrimSpace(row.FirstName + " " + row.LastName); name != "" {
+			label = name
+		} else if row.Login != "" {
+			label = row.Login
+		}
+	}
+	if via == models.ViaMCP {
+		label = "MCP: " + label
+	}
+	return &id, label
+}
+
+// Record appends one history row per change whose values differ, inside
+// db (the caller's transaction): author and via from ctx, What as given,
+// before and after of the changed fields only.
+func (s *Service) Record(ctx context.Context, db *gorm.DB, changes ...Change) error {
+	via := ViaOf(ctx)
+	var authorID *uint
+	var authorLabel string
+	authored := false
+	for _, c := range changes {
+		before, after := diffValues(c.Before, c.After)
+		if c.Before != nil && c.After != nil && len(after) == 0 {
+			continue
+		}
+		if !authored {
+			authorID, authorLabel = s.author(ctx, db, via)
+			authored = true
+		}
+		row := models.Revision{
+			AuthorID:    authorID,
+			AuthorLabel: authorLabel,
+			Via:         via,
+			SubjectKind: c.Kind,
+			SubjectID:   c.SubjectID,
+			What:        c.What,
+			Before:      models.JSONMap(before),
+			After:       models.JSONMap(after),
+			CreatedAt:   time.Now().UTC(),
+		}
+		if err := db.Create(&row).Error; err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// translator returns the application translator, nil when none.
+func (s *Service) translator() *phrasebook.Translator {
+	if s == nil || s.app == nil {
+		return nil
+	}
+	tr, _ := s.app.Lookup[*phrasebook.Translator]()
+	return tr
+}
+
+// Phrase renders a phrase key with params in the application's default
+// admin locale (history descriptions are stored as text, so the list can
+// search them).
+func (s *Service) Phrase(key string, params map[string]string) string {
+	tr := s.translator()
+	if tr == nil {
+		return key
+	}
+	return tr.GetIn(tr.Locale(), key, params)
+}
+
+// EntrySubject is the subject id of a record's entry in a locale.
+func EntrySubject(modelType, recordID, locale string) string {
+	return modelType + "|" + recordID + "|" + locale
+}
+
+// entryValues are the editable values of an entry for history.
+func entryValues(e models.Entry) map[string]any {
+	out := map[string]any{}
+	for _, column := range EntryColumns {
+		out[column] = entryValue(e, column)
+	}
+	return out
+}
+
+// RuleValues are a rule's values for history.
+func RuleValues(r models.Rule) map[string]any {
+	out := map[string]any{"url": r.URL, "match": r.Match, "note": r.Note}
+	for _, p := range models.RuleProperties {
+		out[p.Column] = r.Value(p.Column)
+	}
+	return out
+}
--- a/classes/service.go
+++ b/classes/service.go
@@ -24,16 +24,13 @@ type Service struct {
 	app *backpack.App
 }

-// NewService returns the service of a booted application. It needs the
-// application's database; the signpost registry is optional (without it no
-// content type takes part).
+// NewService returns the service of a booted application. The database
+// and the signpost registry are looked up when used, so a binary that runs
+// a console command without a database still boots.
 func NewService(app *backpack.App) (*Service, error) {
 	if app == nil {
 		return nil, ErrNotBooted
 	}
-	if db, ok := app.Lookup[*gorm.DB](); !ok || db == nil {
-		return nil, errors.New("database is not configured")
-	}
 	return &Service{app: app}, nil
 }

--- a/classes/type_settings.go
+++ b/classes/type_settings.go
@@ -41,3 +41,13 @@ func (s *Service) SaveTypeSetting(_ context.Context, db *gorm.DB, row models.Typ
 		DoUpdates: clause.AssignmentColumns([]string{"inject", "title_template", "description_template", "robots"}),
 	}).Create(&row).Error
 }
+
+// TypeSettingValues are a type settings row's values for history.
+func TypeSettingValues(row models.TypeSetting) map[string]any {
+	return map[string]any{
+		"inject":               row.Inject,
+		"title_template":       row.TitleTemplate,
+		"description_template": row.DescriptionTemplate,
+		"robots":               row.Robots,
+	}
+}
--- a/controllers/admin_registry.go
+++ b/controllers/admin_registry.go
@@ -30,6 +30,7 @@ func AdminControllers(app func() *backpack.App) []pact.AdminController {
 	return []pact.AdminController{
 		settingsAdminController{app: app},
 		rulesAdminController{app: app},
+		historyAdminController{app: app},
 	}
 }

--- a/controllers/history.go
+++ b/controllers/history.go
@@ -0,0 +1,241 @@
+package controllers
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"sort"
+	"strings"
+
+	"git.golem15.com/golem15/sm-seo-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/backpack"
+	"git.golem15.com/golem15/summercms/modules/pact"
+	"gorm.io/gorm"
+)
+
+// HistoryControllerID is the history screen (UI-SPEC C12).
+const HistoryControllerID = "golem15.seo.history"
+
+// errHistoryReadOnly refuses writes through the history form.
+var errHistoryReadOnly = errors.New("golem15.seo: history is read-only")
+
+// historyAdminController lists and previews the SEO change history
+// (D-13). History is written by the plugin's service only: the form saves
+// and deletes nothing. Undo arrives as record actions with the management
+// API.
+type historyAdminController struct {
+	app func() *backpack.App
+}
+
+func (historyAdminController) ID() string        { return HistoryControllerID }
+func (historyAdminController) ModelName() string { return `Golem15\SEO\Models\Revision` }
+func (historyAdminController) ConfigDir() string { return "controllers/history" }
+func (historyAdminController) NewRecord() any    { return &models.Revision{} }
+func (historyAdminController) RequiredPermissions() []string {
+	return []string{PermissionManage}
+}
+
+// FormBeforeCreate refuses: history is written by the service only.
+func (historyAdminController) FormBeforeCreate(context.Context, any) error {
+	return errHistoryReadOnly
+}
+
+// FormBeforeUpdate refuses: history is never edited.
+func (historyAdminController) FormBeforeUpdate(context.Context, any) error {
+	return errHistoryReadOnly
+}
+
+// FormBeforeDelete refuses: history is never deleted from the admin.
+func (historyAdminController) FormBeforeDelete(context.Context, any) error {
+	return errHistoryReadOnly
+}
+
+// viaLabel is the phrase key of a writer.
+func viaLabel(via string) string {
+	return "golem15.seo::lang.history.via_" + via
+}
+
+// fieldLabel is the label of a changed field: the SEO tab's and the rule
+// form's phrase for known columns ("title.pl" keeps its locale), else the
+// field name.
+func fieldLabel(ctx context.Context, tr phraser, key string) string {
+	base, locale, _ := strings.Cut(key, ".")
+	label := key
+	for _, p := range models.RuleProperties {
+		if p.Column == base {
+			label = tr(ctx, p.Label, nil)
+			if locale != "" {
+				label += " (" + locale + ")"
+			}
+			break
+		}
+	}
+	return label
+}
+
+// phraser translates a key with params.
+type phraser func(ctx context.Context, key string, params map[string]string) string
+
+// displayValue is a stored history value as text.
+func displayValue(v any) string {
+	switch val := v.(type) {
+	case nil:
+		return ""
+	case string:
+		return val
+	case bool:
+		if val {
+			return "true"
+		}
+		return "false"
+	}
+	raw, err := json.Marshal(v)
+	if err != nil {
+		return fmt.Sprint(v)
+	}
+	return string(raw)
+}
+
+// changedKeys lists the keys of a revision's before and after in order.
+func changedKeys(r *models.Revision) []string {
+	keys := map[string]bool{}
+	for k := range r.Before {
+		keys[k] = true
+	}
+	for k := range r.After {
+		keys[k] = true
+	}
+	out := make([]string, 0, len(keys))
+	for k := range keys {
+		out = append(out, k)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// ListExtendRecords fills the via label, the one-line change summary and
+// the short batch id of each row.
+func (c historyAdminController) ListExtendRecords(ctx context.Context, _ *gorm.DB, records []any) error {
+	tr := translator(c.app)
+	phrase := func(ctx context.Context, key string, params map[string]string) string {
+		return Phrase(ctx, tr, key, params)
+	}
+	for _, record := range records {
+		r, ok := record.(*models.Revision)
+		if !ok || r == nil {
+			continue
+		}
+		r.ViaLabel = phrase(ctx, viaLabel(r.Via), nil)
+		if r.BatchID != nil {
+			r.Batch = *r.BatchID
+			if len(r.Batch) > 8 {
+				r.Batch = r.Batch[:8]
+			}
+		}
+		keys := changedKeys(r)
+		switch {
+		case len(r.Before) == 0 && len(r.After) > 0 && r.SubjectKind != models.SubjectSettings:
+			r.Change = phrase(ctx, "golem15.seo::lang.history.created", nil)
+		case len(r.After) == 0 && len(r.Before) > 0:
+			r.Change = phrase(ctx, "golem15.seo::lang.history.deleted", nil)
+		case len(keys) == 1:
+			if tr != nil {
+				r.Change = tr.Choice(ctx, "golem15.seo::lang.history.change_cell", 1, map[string]string{
+					"field":  fieldLabel(ctx, phrase, keys[0]),
+					"before": displayValue(r.Before[keys[0]]),
+					"after":  displayValue(r.After[keys[0]]),
+				})
+			}
+		default:
+			if tr != nil {
+				r.Change = tr.Choice(ctx, "golem15.seo::lang.history.change_cell", len(keys), map[string]string{
+					"count": fmt.Sprint(len(keys)),
+				})
+			}
+		}
+	}
+	return nil
+}
+
+// ListRowStates marks undone changes disabled (label history.state_undone).
+func (historyAdminController) ListRowStates(_ context.Context, _ *gorm.DB, records []any) ([][]pact.RowState, error) {
+	out := make([][]pact.RowState, len(records))
+	for i, record := range records {
+		if r, ok := record.(*models.Revision); ok && r != nil && r.UndoneAt != nil {
+			out[i] = []pact.RowState{pact.RowStateDisabled}
+		}
+	}
+	return out, nil
+}
+
+// FilterOptions serves the via filter's choices.
+func (historyAdminController) FilterOptions(scope string) []pact.Option {
+	if scope != models.FilterVia {
+		return nil
+	}
+	out := make([]pact.Option, 0, len(models.Vias))
+	for _, v := range models.Vias {
+		out = append(out, pact.Option{Value: v, Label: viaLabel(v)})
+	}
+	return out
+}
+
+// diffRow is one row of the P5 history diff.
+type diffRow struct {
+	Field   string
+	Before  string
+	After   string
+	Mono    bool
+	Created bool
+	Deleted bool
+}
+
+// diffView is the view model of the P5 history diff partial.
+type diffView struct {
+	Rows []diffRow
+}
+
+// PartialData serves the P5 diff of a change: one row per changed field,
+// URL values in monospace, created and deleted markers.
+func (c historyAdminController) PartialData(ctx context.Context, name string, record any) (any, error) {
+	if name != "history_diff" {
+		return nil, nil
+	}
+	r, ok := record.(*models.Revision)
+	if !ok || r == nil {
+		return diffView{}, nil
+	}
+	tr := translator(c.app)
+	phrase := func(ctx context.Context, key string, params map[string]string) string {
+		return Phrase(ctx, tr, key, params)
+	}
+	view := diffView{}
+	for _, key := range changedKeys(r) {
+		base, _, _ := strings.Cut(key, ".")
+		_, inBefore := r.Before[key]
+		_, inAfter := r.After[key]
+		view.Rows = append(view.Rows, diffRow{
+			Field:   fieldLabel(ctx, phrase, key),
+			Before:  displayValue(r.Before[key]),
+			After:   displayValue(r.After[key]),
+			Mono:    base == "url" || base == "canonical" || base == "og_image" || base == "default_og_image",
+			Created: !inBefore || len(r.Before) == 0,
+			Deleted: !inAfter || len(r.After) == 0,
+		})
+	}
+	return view, nil
+}
+
+var (
+	_ pact.AdminController   = historyAdminController{}
+	_ pact.AdminPermissioned = historyAdminController{}
+	_ pact.AdminRecordSource = historyAdminController{}
+	_ pact.FormBeforeCreate  = historyAdminController{}
+	_ pact.FormBeforeUpdate  = historyAdminController{}
+	_ pact.FormBeforeDelete  = historyAdminController{}
+	_ pact.ListExtendRecords = historyAdminController{}
+	_ pact.ListRowStates     = historyAdminController{}
+	_ pact.FilterOptions     = historyAdminController{}
+	_ pact.AdminPartialData  = historyAdminController{}
+)
--- a/controllers/history/_history_diff.htm
+++ b/controllers/history/_history_diff.htm
@@ -0,0 +1,10 @@
+{{- if .Data.Rows -}}
+<table class="summer-table">
+<thead><tr><th>{{ trans "golem15.seo::lang.history.diff_field" }}</th><th>{{ trans "golem15.seo::lang.history.diff_before" }}</th><th>{{ trans "golem15.seo::lang.history.diff_after" }}</th></tr></thead>
+<tbody>
+{{- range .Data.Rows -}}
+<tr><td>{{ .Field }}</td><td>{{ if and .Created (not .Before) }}<span class="summer-table__sub">{{ trans "golem15.seo::lang.history.created" }}</span>{{ else if .Mono }}<code>{{ .Before }}</code>{{ else }}{{ .Before }}{{ end }}</td><td>{{ if and .Deleted (not .After) }}<span class="summer-table__sub">{{ trans "golem15.seo::lang.history.deleted" }}</span>{{ else if .Mono }}<code>{{ .After }}</code>{{ else }}{{ .After }}{{ end }}</td></tr>
+{{- end -}}
+</tbody>
+</table>
+{{- end -}}
--- a/controllers/history/config_filter.yaml
+++ b/controllers/history/config_filter.yaml
@@ -0,0 +1,11 @@
+# History filters (UI-SPEC C12): writer and date.
+scopes:
+    via:
+        label: golem15.seo::lang.history.filter_via
+        modelClass: Golem15\SEO\Models\Revision
+        nameFrom: via
+        scope: FilterVia
+    created_at:
+        label: golem15.seo::lang.history.filter_when
+        type: daterange
+        column: created_at
--- a/controllers/history/config_form.yaml
+++ b/controllers/history/config_form.yaml
@@ -0,0 +1,8 @@
+# History preview (UI-SPEC C12): read-only with the P5 diff.
+name: golem15.seo::lang.history.name
+form: ~/plugins/golem15/seo/models/revision/fields.yaml
+modelClass: Golem15\SEO\Models\Revision
+defaultRedirect: golem15/seo/history
+
+messages:
+    preview: golem15.seo::lang.history.preview
--- a/controllers/history/config_list.yaml
+++ b/controllers/history/config_list.yaml
@@ -0,0 +1,22 @@
+# History list (UI-SPEC C12): newest first, read-only, undone rows
+# disabled.
+list: ~/plugins/golem15/seo/models/revision/columns.yaml
+modelClass: Golem15\SEO\Models\Revision
+title: golem15.seo::lang.history.list_title
+recordUrl: golem15/seo/history/preview/:id
+noRecordsMessage: golem15.seo::lang.history.list_empty
+recordsPerPage: 50
+showSetup: true
+filter: config_filter.yaml
+
+defaultSort:
+    column: created_at
+    direction: desc
+
+toolbar:
+    search:
+        prompt: backend::lang.list.search_prompt
+
+messages:
+    empty: golem15.seo::lang.history.list_empty
+    rowStateDisabled: golem15.seo::lang.history.state_undone
--- a/controllers/rules.go
+++ b/controllers/rules.go
@@ -2,8 +2,10 @@ package controllers

 import (
 	"context"
+	"strconv"
 	"strings"

+	"git.golem15.com/golem15/sm-seo-plugin/classes"
 	"git.golem15.com/golem15/sm-seo-plugin/models"
 	"git.golem15.com/golem15/summercms/modules/backpack"
 	"git.golem15.com/golem15/summercms/modules/pact"
@@ -48,6 +50,29 @@ func (c rulesAdminController) check(ctx context.Context, model any) error {
 	return problemsError(ctx, translator(c.app), r.Problems(db))
 }

+// FormAfterDelete records the deleted rule in history inside the delete's
+// transaction, so its values can be restored.
+func (c rulesAdminController) FormAfterDelete(ctx context.Context, model any) error {
+	r, ok := model.(*models.Rule)
+	if !ok || r == nil {
+		return nil
+	}
+	svc, err := classes.NewService(appOf(c.app))
+	if err != nil {
+		return err
+	}
+	db, err := database(ctx, c.app)
+	if err != nil {
+		return err
+	}
+	return svc.Record(ctx, db, classes.Change{
+		Kind:      models.SubjectRule,
+		SubjectID: strconv.FormatUint(uint64(r.ID), 10),
+		What:      svc.Phrase("golem15.seo::lang.history.what_rule", map[string]string{"url": r.URL}),
+		Before:    classes.RuleValues(*r),
+	})
+}
+
 // ListExtendRecords fills the overrides column: the translated labels of
 // the properties each rule sets, comma-joined.
 func (c rulesAdminController) ListExtendRecords(ctx context.Context, _ *gorm.DB, records []any) error {
@@ -87,4 +112,5 @@ var (
 	_ pact.FormBeforeUpdate  = rulesAdminController{}
 	_ pact.ListExtendRecords = rulesAdminController{}
 	_ pact.FilterOptions     = rulesAdminController{}
+	_ pact.FormAfterDelete   = rulesAdminController{}
 )
--- a/extensions.go
+++ b/extensions.go
@@ -7,6 +7,7 @@ import (

 	"git.golem15.com/golem15/sm-seo-plugin/classes"
 	"git.golem15.com/golem15/sm-seo-plugin/controllers"
+	"git.golem15.com/golem15/sm-seo-plugin/models"
 	"git.golem15.com/golem15/summercms/modules/pact"
 	"git.golem15.com/golem15/summercms/modules/signpost"
 )
@@ -36,9 +37,37 @@ func (p *Plugin) AdminActionExtensions() []pact.AdminActionExtension {
 	if form := p.typeSettingsTabs(types); form != nil {
 		out = append(out, pact.AdminActionExtension{Controller: controllers.SettingsControllerID, Form: form})
 	}
+	out = append(out, pact.AdminActionExtension{Controller: controllers.RulesControllerID, Form: p.ruleHistory()})
 	return out
 }

+// ruleHistory is a field-less extension on the plugin's own rules
+// controller: its Save sees the save's changes inside the save transaction
+// and records them in history (deletes are recorded by the controller).
+func (p *Plugin) ruleHistory() *pact.AdminFormExtension {
+	return &pact.AdminFormExtension{
+		Permissions: []string{controllers.PermissionManage},
+		Save: func(ctx context.Context, in pact.AdminFormSave) (pact.AdminFormSaveResult, error) {
+			svc := p.Service()
+			if svc == nil {
+				return pact.AdminFormSaveResult{}, classes.ErrNotBooted
+			}
+			before, after := classes.ChangesValues(in.Changes, in.Created)
+			url := ""
+			if r, ok := in.Record.(*models.Rule); ok && r != nil {
+				url = r.URL
+			}
+			return pact.AdminFormSaveResult{}, svc.Record(ctx, in.DB, classes.Change{
+				Kind:      models.SubjectRule,
+				SubjectID: in.ID,
+				What:      svc.Phrase("golem15.seo::lang.history.what_rule", map[string]string{"url": url}),
+				Before:    before,
+				After:     after,
+			})
+		},
+	}
+}
+
 func (p *Plugin) registry() *signpost.Registry {
 	if p == nil || p.app == nil {
 		return nil
--- a/extensions_settings.go
+++ b/extensions_settings.go
@@ -108,18 +108,23 @@ func typeSettingsDocument(types []pact.MenuItemType) ([]byte, error) {
 	})
 }

-// typeSettingsTabs is the form extension on the SEO settings controller
-// that adds the per-type tabs; nil when no content type is registered.
+// typeSettingsTabs is the plugin's form extension on its own settings
+// controller: it adds the per-type tabs (none when no content type is
+// registered) and records every settings save in history.
 func (p *Plugin) typeSettingsTabs(types []pact.MenuItemType) *pact.AdminFormExtension {
-	if len(types) == 0 {
-		return nil
-	}
-	doc, err := typeSettingsDocument(types)
-	if err != nil {
-		pluginLog.Error("golem15.seo: per-type settings tabs", "error", err)
-		return nil
+	var doc []byte
+	if len(types) > 0 {
+		var err error
+		if doc, err = typeSettingsDocument(types); err != nil {
+			pluginLog.Error("golem15.seo: per-type settings tabs", "error", err)
+			return nil
+		}
 	}
 	fields := typeSettingsFields(types)
+	labels := map[string]string{}
+	for _, typ := range types {
+		labels[typ.Key] = typ.Label
+	}
 	return &pact.AdminFormExtension{
 		FieldsYAML:  doc,
 		Permissions: []string{controllers.PermissionManage},
@@ -139,7 +144,21 @@ func (p *Plugin) typeSettingsTabs(types []pact.MenuItemType) *pact.AdminFormExte
 			return out, nil
 		},
 		Save: func(ctx context.Context, in pact.AdminFormSave) (pact.AdminFormSaveResult, error) {
-			return pact.AdminFormSaveResult{}, p.saveTypeSettings(ctx, in, fields)
+			svc := p.Service()
+			if svc == nil {
+				return pact.AdminFormSaveResult{}, classes.ErrNotBooted
+			}
+			before, after := classes.ChangesValues(in.Changes, in.Created)
+			if err := svc.Record(ctx, in.DB, classes.Change{
+				Kind:      models.SubjectSettings,
+				SubjectID: in.ID,
+				What:      svc.Phrase("golem15.seo::lang.history.what_settings", nil),
+				Before:    before,
+				After:     after,
+			}); err != nil {
+				return pact.AdminFormSaveResult{}, err
+			}
+			return pact.AdminFormSaveResult{}, p.saveTypeSettings(ctx, in, fields, labels)
 		},
 	}
 }
@@ -161,7 +180,7 @@ func typeSettingValue(row models.TypeSetting, column string) any {

 // saveTypeSettings stores the submitted per-type values through the
 // service; a template with an unknown placeholder refuses the save.
-func (p *Plugin) saveTypeSettings(ctx context.Context, in pact.AdminFormSave, fields []typeField) error {
+func (p *Plugin) saveTypeSettings(ctx context.Context, in pact.AdminFormSave, fields []typeField, labels map[string]string) error {
 	svc := p.Service()
 	if svc == nil {
 		return classes.ErrNotBooted
@@ -208,10 +227,23 @@ func (p *Plugin) saveTypeSettings(ctx context.Context, in pact.AdminFormSave, fi
 	if len(refusals) > 0 {
 		return refusals
 	}
-	for _, row := range changed {
+	for key, row := range changed {
+		old, ok := rows[key]
+		if !ok {
+			old = models.DefaultTypeSetting(key)
+		}
 		if err := svc.SaveTypeSetting(ctx, in.DB, row); err != nil {
 			return err
 		}
+		if err := svc.Record(ctx, in.DB, classes.Change{
+			Kind:      models.SubjectSettings,
+			SubjectID: "type:" + key,
+			What:      svc.Phrase("golem15.seo::lang.history.what_settings", nil) + " – " + svc.Phrase(labels[key], nil),
+			Before:    classes.TypeSettingValues(old),
+			After:     classes.TypeSettingValues(row),
+		}); err != nil {
+			return err
+		}
 	}
 	return nil
 }
--- a/lang/en/lang.yaml
+++ b/lang/en/lang.yaml
@@ -3,6 +3,7 @@ plugin:
    description: Search engine metadata for every content type, URL rules and global SEO settings.
 nav:
    seo: SEO
+    history: History
    rules: URL rules
 permissions:
    tab: SEO
@@ -113,3 +114,36 @@ rules:
    delete_selected_confirm:
        one: Delete :count URL rule? You can undo it in History.
        other: Delete :count URL rules? You can undo it in History.
+history:
+    list_title: History
+    name: Change
+    when: When
+    who: Who
+    via: Via
+    what: What
+    change: Change
+    batch: Batch
+    via_admin: Admin
+    via_mcp: MCP
+    via_import: Import
+    via_auto: Automatic
+    via_undo: Undo
+    what_record: SEO of :type “:title” (:locale)
+    what_rule: URL rule “:url”
+    what_redirect: Redirect “:url”
+    what_robots: robots.txt
+    what_settings: SEO settings
+    change_cell:
+        one: ':field: :before → :after'
+        other: ':count fields changed'
+    created: (created)
+    deleted: (deleted)
+    state_undone: Undone
+    filter_via: Via
+    filter_when: When
+    filter_who: Who
+    preview: Change details
+    diff_field: Field
+    diff_before: Before
+    diff_after: After
+    list_empty: No SEO changes recorded yet. Every change from the admin, MCP or an import appears here and can be undone.
--- a/lang/pl/lang.yaml
+++ b/lang/pl/lang.yaml
@@ -3,6 +3,7 @@ plugin:
    description: Metadane dla wyszukiwarek we wszystkich typach treści, reguły adresów i globalne ustawienia SEO.
 nav:
    seo: SEO
+    history: Historia zmian
    rules: Reguły adresów
 permissions:
    tab: SEO
@@ -115,3 +116,38 @@ rules:
        few: Usunąć :count reguły adresów? Możesz to cofnąć w Historii zmian.
        many: Usunąć :count reguł adresów? Możesz to cofnąć w Historii zmian.
        other: Usunąć :count reguły adresu? Możesz to cofnąć w Historii zmian.
+history:
+    list_title: Historia zmian
+    name: Zmiana
+    when: Kiedy
+    who: Kto
+    via: Skąd
+    what: Czego dotyczy
+    change: Zmiana
+    batch: Partia
+    via_admin: Panel
+    via_mcp: MCP
+    via_import: Import
+    via_auto: Automatycznie
+    via_undo: Cofnięcie
+    what_record: 'SEO: :type „:title” (:locale)'
+    what_rule: Reguła adresu „:url”
+    what_redirect: Przekierowanie „:url”
+    what_robots: robots.txt
+    what_settings: Ustawienia SEO
+    change_cell:
+        one: ':field: :before → :after'
+        few: Zmieniono :count pola
+        many: Zmieniono :count pól
+        other: Zmieniono :count pola
+    created: (utworzono)
+    deleted: (usunięto)
+    state_undone: Cofnięte
+    filter_via: Skąd
+    filter_when: Kiedy
+    filter_who: Kto
+    preview: Szczegóły zmiany
+    diff_field: Pole
+    diff_before: Przed
+    diff_after: Po
+    list_empty: Nie zarejestrowano jeszcze zmian SEO. Każda zmiana z panelu, MCP lub importu pojawi się tutaj i będzie można ją cofnąć.
--- a/models/revision.go
+++ b/models/revision.go
@@ -0,0 +1,91 @@
+package models
+
+import (
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// The writers of a history entry (D-13).
+const (
+	ViaAdmin  = "admin"
+	ViaMCP    = "mcp"
+	ViaImport = "import"
+	ViaAuto   = "auto"
+	ViaUndo   = "undo"
+)
+
+// The subjects of a history entry.
+const (
+	SubjectEntry    = "entry"
+	SubjectRule     = "rule"
+	SubjectRedirect = "redirect"
+	SubjectRobots   = "robots"
+	SubjectSettings = "settings"
+	SubjectNotFound = "notfound"
+)
+
+// Revision is one recorded SEO change on golem15_seo_revisions (D-13): who
+// made it (AuthorID and AuthorLabel, the label kept when the administrator
+// is gone), through what (Via), on which object (SubjectKind and
+// SubjectID: an entry as "<model type>|<record id>|<locale>", a rule by
+// id, settings as "1" or "type:<key>"), a readable description (What) and
+// the changed fields only, before and after. A created object has no
+// Before and a deleted one no After. BatchID groups the changes of one
+// batch; UndoneAt marks an undone change.
+type Revision struct {
+	ID          uint       `gorm:"column:id;primaryKey"`
+	BatchID     *string    `gorm:"column:batch_id"`
+	AuthorID    *uint      `gorm:"column:author_id"`
+	AuthorLabel string     `gorm:"column:author_label"`
+	Via         string     `gorm:"column:via"`
+	SubjectKind string     `gorm:"column:subject_kind"`
+	SubjectID   string     `gorm:"column:subject_id"`
+	What        string     `gorm:"column:what"`
+	Before      JSONMap    `gorm:"column:before"`
+	After       JSONMap    `gorm:"column:after"`
+	UndoneAt    *time.Time `gorm:"column:undone_at"`
+	UndoneByID  *uint      `gorm:"column:undone_by_id"`
+	CreatedAt   time.Time  `gorm:"column:created_at"`
+	// Change is the list's summary of the changed fields and ViaLabel the
+	// via column's label, filled by the history controller.
+	Change   string `gorm:"-:all;column:change"`
+	ViaLabel string `gorm:"-:all;column:via_label"`
+	Batch    string `gorm:"-:all;column:batch"`
+}
+
+func (Revision) TableName() string { return "golem15_seo_revisions" }
+
+// Fillable is empty: history is written by the service only.
+func (Revision) Fillable() []string { return []string{} }
+
+// Rules is empty: history is never edited.
+func (Revision) Rules() map[string]string { return map[string]string{} }
+
+// FilterVia is the history list's via filter scope.
+const FilterVia = "FilterVia"
+
+// Vias lists the writers in display order.
+var Vias = []string{ViaAdmin, ViaMCP, ViaImport, ViaAuto, ViaUndo}
+
+func init() {
+	Register(Revision{})
+}
+
+// FilterScopes lists the history list's filter scopes.
+func (Revision) FilterScopes() []string { return []string{FilterVia} }
+
+// FilterScope narrows the history list to one writer; an unknown value
+// matches nothing.
+func (Revision) FilterScope(name string, db *gorm.DB, value any) *gorm.DB {
+	if db == nil || name != FilterVia {
+		return db
+	}
+	s, _ := value.(string)
+	for _, v := range Vias {
+		if v == s {
+			return db.Where("golem15_seo_revisions.via = ?", s)
+		}
+	}
+	return db.Where("1 = 0")
+}
--- a/models/revision/columns.yaml
+++ b/models/revision/columns.yaml
@@ -0,0 +1,28 @@
+# History list columns (UI-SPEC C12). via_label, change and batch are
+# filled by the controller's ListExtendRecords.
+columns:
+    created_at:
+        label: golem15.seo::lang.history.when
+        type: datetime
+        sortable: true
+    author_label:
+        label: golem15.seo::lang.history.who
+        type: text
+        searchable: true
+    via_label:
+        label: golem15.seo::lang.history.via
+        type: text
+        sortable: false
+    what:
+        label: golem15.seo::lang.history.what
+        type: text
+        searchable: true
+    change:
+        label: golem15.seo::lang.history.change
+        type: text
+        sortable: false
+    batch:
+        label: golem15.seo::lang.history.batch
+        type: text
+        sortable: false
+        invisible: true
--- a/models/revision/fields.yaml
+++ b/models/revision/fields.yaml
@@ -0,0 +1,28 @@
+# History preview (UI-SPEC C12): read-only fields, then the P5 diff.
+fields:
+    created_at:
+        label: golem15.seo::lang.history.when
+        type: text
+        span: left
+        context: preview
+    author_label:
+        label: golem15.seo::lang.history.who
+        type: text
+        span: right
+        context: preview
+    via:
+        label: golem15.seo::lang.history.via
+        type: text
+        span: left
+        context: preview
+    what:
+        label: golem15.seo::lang.history.what
+        type: text
+        span: right
+        context: preview
+    _history_diff:
+        label: golem15.seo::lang.history.change
+        type: partial
+        path: history_diff
+        span: full
+        context: preview
--- a/seo_tab_test.go
+++ b/seo_tab_test.go
@@ -1,12 +1,16 @@
 package seo_test

 import (
+	"encoding/json"
+	"fmt"
 	"net/http"
 	"net/url"
 	"strings"
 	"testing"

 	seo "git.golem15.com/golem15/sm-seo-plugin"
+	"git.golem15.com/golem15/sm-seo-plugin/classes"
+	"git.golem15.com/golem15/summercms/modules/bouncer"
 )

 // seoTabLabel is the English label of seo.TabSEO.
@@ -124,3 +128,96 @@ func TestSEOTabPermission(t *testing.T) {
 		t.Fatalf("editor show carries SEO values: %s", show.Body.String())
 	}
 }
+
+// revisionRow is a history row as the tests read it.
+type revisionRow struct {
+	Via         string
+	SubjectKind string
+	SubjectID   string
+	What        string
+	AuthorLabel string
+	Before      string
+	After       string
+}
+
+func (e *testEnv) revisions(t *testing.T, kind string) []revisionRow {
+	t.Helper()
+	var rows []revisionRow
+	if err := e.db.Raw(`SELECT via, subject_kind, subject_id, what, author_label, COALESCE(before::text, '') AS before, COALESCE(after::text, '') AS after
+		FROM golem15_seo_revisions WHERE subject_kind = ? ORDER BY id`, kind).Scan(&rows).Error; err != nil {
+		t.Fatal(err)
+	}
+	return rows
+}
+
+// TestHistoryRecordsAdminWrite checks D-13 for admin writes: an SEO tab
+// save writes one revision with via admin, the author and the changed
+// field before and after; an unchanged save writes none; rule create,
+// update and delete and a settings save are recorded too, and the history
+// list and preview serve them.
+func TestHistoryRecordsAdminWrite(t *testing.T) {
+	env := bootEnv(t)
+	token := env.admin(t, true)
+	id := env.createPage(t, token, map[string]any{"title": "About", "slug": "about", "published": true, "seo_title": map[string]any{"en": "First"}})
+	env.expect(t, http.StatusOK, http.MethodPut, adminAPI("/acme/pages/pages/"+id), token, map[string]any{
+		"title": "About", "slug": "about", "published": true, "seo_title": map[string]any{"en": "Second"},
+	})
+	env.expect(t, http.StatusOK, http.MethodPut, adminAPI("/acme/pages/pages/"+id), token, map[string]any{
+		"title": "About", "slug": "about", "published": true, "seo_title": map[string]any{"en": "Second"},
+	})
+	rows := env.revisions(t, "entry")
+	if len(rows) != 2 {
+		t.Fatalf("entry revisions = %+v, want create and one change", rows)
+	}
+	last := rows[1]
+	if last.Via != "admin" || last.SubjectID != pagesModel+"|"+id+"|en" || !strings.Contains(last.What, "About") || !strings.Contains(last.What, "(en)") || last.AuthorLabel == "" {
+		t.Fatalf("revision = %+v", last)
+	}
+	if !jsonContains(last.Before, `"title": "First"`) || !jsonContains(last.After, `"title": "Second"`) || strings.Contains(last.After, "description") {
+		t.Fatalf("revision before/after = %s / %s, want the title only", last.Before, last.After)
+	}
+
+	rec := env.expect(t, http.StatusCreated, http.MethodPost, adminAPI("/golem15/seo/rules"), token, map[string]any{"url": "/landing", "match": "exact", "title": "Landing"})
+	var created struct {
+		Data struct {
+			ID json.Number `json:"id"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), &created); err != nil {
+		t.Fatal(err)
+	}
+	ruleID := created.Data.ID.String()
+	env.expect(t, http.StatusOK, http.MethodPut, adminAPI("/golem15/seo/rules/"+ruleID), token, map[string]any{"url": "/landing", "match": "exact", "title": "Landing page"})
+	env.expect(t, http.StatusOK, http.MethodDelete, adminAPI("/golem15/seo/rules/"+ruleID), token, nil)
+	rules := env.revisions(t, "rule")
+	if len(rules) != 3 || rules[0].Before != "{}" || !jsonContains(rules[1].After, `"title": "Landing page"`) || rules[2].After != "{}" || !jsonContains(rules[2].Before, `"url": "/landing"`) {
+		t.Fatalf("rule revisions = %+v", rules)
+	}
+
+	env.expect(t, http.StatusOK, http.MethodPut, adminAPI("/golem15/seo/settings/1"), token, map[string]any{"twitter_site": "@acme", "type_acme_page_robots": "noindex,follow"})
+	settings := env.revisions(t, "settings")
+	if len(settings) != 2 || !jsonContains(settings[0].After, `"twitter_site": "@acme"`) || settings[1].SubjectID != "type:"+pagesTypeKey {
+		t.Fatalf("settings revisions = %+v", settings)
+	}
+
+	list := env.expect(t, http.StatusOK, http.MethodGet, adminAPI("/golem15/seo/history"), token, nil)
+	if !strings.Contains(list.Body.String(), "SEO title: First → Second") || !strings.Contains(list.Body.String(), `"via_label":"Admin"`) {
+		t.Fatalf("history list = %s", list.Body.String())
+	}
+	var firstID uint
+	if err := env.db.Raw(`SELECT id FROM golem15_seo_revisions WHERE subject_kind = 'entry' ORDER BY id DESC LIMIT 1`).Scan(&firstID).Error; err != nil {
+		t.Fatal(err)
+	}
+	partial := env.expect(t, http.StatusOK, http.MethodGet, adminAPI(fmt.Sprintf("/golem15/seo/history/partials/history_diff?id=%d", firstID)), token, nil)
+	if !strings.Contains(partial.Body.String(), "Second") {
+		t.Fatalf("history diff partial = %s", partial.Body.String())
+	}
+
+	mcp := bouncer.WithDispatch(t.Context(), &bouncer.Dispatch{Guards: []string{"backend"}, Principal: &bouncer.Principal{ID: 1, Backend: true}})
+	if got := classes.ViaOf(mcp); got != "mcp" {
+		t.Fatalf("ViaOf(MCP dispatch) = %q, want mcp", got)
+	}
+	if got := classes.ViaOf(classes.WithVia(mcp, "import")); got != "import" {
+		t.Fatalf("ViaOf(WithVia import) = %q", got)
+	}
+}
--- a/updates/202610270002_create_golem15_seo_revisions.go
+++ b/updates/202610270002_create_golem15_seo_revisions.go
@@ -0,0 +1,49 @@
+package updates
+
+import (
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+// createRevisions creates golem15_seo_revisions: the SEO change history
+// (D-13) with author, via, subject, a readable description and the changed
+// fields before and after; undo marks a change undone.
+var createRevisions = []*gormigrate.Migration{
+	{
+		ID: "202610270002_create_golem15_seo_revisions",
+		Migrate: func(tx *gorm.DB) error {
+			for _, stmt := range []string{
+				`CREATE TABLE golem15_seo_revisions (
+	id BIGSERIAL PRIMARY KEY,
+	batch_id TEXT NULL,
+	author_id BIGINT NULL,
+	author_label TEXT NOT NULL DEFAULT '',
+	via TEXT NOT NULL,
+	subject_kind TEXT NOT NULL,
+	subject_id TEXT NOT NULL DEFAULT '',
+	what TEXT NOT NULL DEFAULT '',
+	before jsonb NULL,
+	after jsonb NULL,
+	undone_at TIMESTAMP(0) NULL,
+	undone_by_id BIGINT NULL,
+	created_at TIMESTAMP(0) NOT NULL DEFAULT NOW()
+)`,
+				`CREATE INDEX golem15_seo_revisions_subject ON golem15_seo_revisions (subject_kind, subject_id)`,
+				`CREATE INDEX golem15_seo_revisions_created ON golem15_seo_revisions (created_at DESC)`,
+				`CREATE INDEX golem15_seo_revisions_batch ON golem15_seo_revisions (batch_id) WHERE batch_id IS NOT NULL`,
+			} {
+				if err := tx.Exec(stmt).Error; err != nil {
+					return err
+				}
+			}
+			return nil
+		},
+		Rollback: func(tx *gorm.DB) error {
+			return tx.Exec(`DROP TABLE IF EXISTS golem15_seo_revisions`).Error
+		},
+	},
+}
+
+func init() {
+	Register(createRevisions...)
+}