feat: sitemap settings singleton with content types and additional addresses

- one settings tile opening the golem15.sitemap.settings singleton
- Files tab (site address, file size, S1 files partial), Additional
  addresses repeater, Content types tab built from signpost at boot
- golem15_sitemap_types; a type switched off leaves the files (reason type)
- a save validates (errors.*) and dispatches a rebuild after commit

models/settings.go

@@ -2,6 +2,7 @@ package models
 
 import (
 	"net/url"
+	"strconv"
 	"strings"
 	"time"
 	"unicode"
@@ -9,7 +10,6 @@ import (
 
 	"git.golem15.com/golem15/summercms/modules/cabana"
 	"git.golem15.com/golem15/summercms/modules/lagoon"
-	"gorm.io/gorm"
 )
 
 // errFrontendURL is the phrase key of the frontend_url refusal.
@@ -95,28 +95,62 @@ func (s Settings) Extra() []ExtraURL { return s.ExtraURLs.Get() }
 
 func (Settings) TableName() string { return "golem15_sitemap_settings" }
 
-// Fillable lists only the settings columns.
+// Fillable lists the columns the settings form edits.
 func (Settings) Fillable() []string {
-	return []string{
-		"frontend_url", "frontend_default_locale", "updates_manifest_path",
-		"enable_priority_tiers", PriorityHomepage, PriorityServices,
-		PriorityBlog, PriorityCategories, PriorityLegal,
-	}
+	return []string{"site_url", "file_size", "extra_urls"}
 }
 
 // Rules is empty: the PHP settings form validated nothing. The one check of
 // the port, on frontend_url, is in BeforeValidate.
 func (Settings) Rules() map[string]string { return map[string]string{} }
 
-// BeforeValidate is the lagoon.HasBeforeValidate hook cabana calls on a
-// settings save, after the fill and before the row is written: a
-// frontend_url that AllowedFrontendURL refuses is a validation error on
-// frontend_url, so the save answers 422 and the row is left as it was.
-func (s Settings) BeforeValidate(*gorm.DB) error {
-	if AllowedFrontendURL(Text(s.FrontendURL)) {
+// The phrase keys of the other settings refusals.
+const (
+	errFileSize  = "golem15.sitemap::lang.errors.file_size"
+	errURLScheme = "golem15.sitemap::lang.errors.url_scheme"
+	errLastmod   = "golem15.sitemap::lang.errors.lastmod"
+)
+
+// Validate answers every problem Problems finds as a validation error on
+// its field; the settings controller calls it before a save, so the save
+// answers 422 and the row is left as it was.
+func (s Settings) Validate() error {
+	problems := s.Problems()
+	if len(problems) == 0 {
 		return nil
 	}
-	return &cabana.ValidationError{Details: map[string]any{"frontend_url": []string{errFrontendURL}}}
+	details := make(map[string]any, len(problems))
+	for field, keys := range problems {
+		details[field] = keys
+	}
+	return &cabana.ValidationError{Details: details}
+}
+
+// Problems lists the settings' refusals by field (UI-SPEC C26): a site
+// address that AllowedFrontendURL refuses (site_url and the Phase 17
+// frontend_url), a file size outside 1..MaxFileSize and an additional
+// address that is not a path or an http(s) URL (extra_urls.<i>.url) or
+// whose lastmod is not a date (extra_urls.<i>.lastmod).
+func (s Settings) Problems() map[string][]string {
+	out := map[string][]string{}
+	if !AllowedFrontendURL(Text(s.SiteURL)) {
+		out["site_url"] = []string{errFrontendURL}
+	}
+	if !AllowedFrontendURL(Text(s.FrontendURL)) {
+		out["frontend_url"] = []string{errFrontendURL}
+	}
+	if s.FileSize < 1 || s.FileSize > MaxFileSize {
+		out["file_size"] = []string{errFileSize}
+	}
+	for i, e := range s.Extra() {
+		if !AllowedAddress(strings.TrimSpace(e.URL)) {
+			out["extra_urls."+strconv.Itoa(i)+".url"] = []string{errURLScheme}
+		}
+		if mod := strings.TrimSpace(e.LastMod); mod != "" && !ValidDate(mod) {
+			out["extra_urls."+strconv.Itoa(i)+".lastmod"] = []string{errLastmod}
+		}
+	}
+	return out
 }
 
 // AllowedFrontendURL reports whether u may be the frontend_url setting: the
@@ -180,3 +214,26 @@ func (s Settings) Priority(key string) string {
 func init() {
 	Register(Settings{})
 }
+
+// dateLayouts are the lastmod forms an additional address may carry.
+var dateLayouts = []string{time.RFC3339Nano, "2006-01-02 15:04:05", "2006-01-02T15:04:05", "2006-01-02"}
+
+// ParseDate reads a lastmod as the settings form or an import gives it
+// (YYYY-MM-DD, "YYYY-MM-DD hh:mm:ss" or RFC 3339; UTC unless it names a
+// zone); nil when empty or unreadable.
+func ParseDate(s string) *time.Time {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return nil
+	}
+	for _, layout := range dateLayouts {
+		if t, err := time.Parse(layout, s); err == nil {
+			t = t.UTC()
+			return &t
+		}
+	}
+	return nil
+}
+
+// ValidDate reports whether s is a lastmod ParseDate reads.
+func ValidDate(s string) bool { return ParseDate(s) != nil }