[themes] make a build_tag function which themes can override, see #1328

core/themelet.php

@@ -28,6 +28,13 @@ private function get_common(): Themelet
         return self::$common;
     }
 
+    public function build_tag(string $tag, bool $show_underscores = true, bool $show_category = true): HTMLElement
+    {
+        $c = self::get_common();
+        assert(is_a($c, CommonElementsTheme::class));
+        return $c->build_tag($tag, $show_underscores, $show_category);
+    }
+
     public function build_thumb(Image $image): HTMLElement
     {
         $c = self::get_common();

ext/common_elements/theme.php

@@ -10,6 +10,31 @@
 
 class CommonElementsTheme extends Themelet
 {
+    public function build_tag(string $tag, bool $show_underscores = true, bool $show_category = true): HTMLElement
+    {
+        $props = [
+            "href" => search_link([$tag]),
+            "class" => "tag",
+            "title" => "View all posts tagged $tag"
+        ];
+        $body = $tag;
+
+        if (Extension::is_enabled(TagCategoriesInfo::KEY)) {
+            $category = TagCategories::getTagCategory($tag);
+            if (!is_null($category)) {
+                $tag_category_dict = TagCategories::getKeyedDict();
+                $props["class"] = "tag tag_category_$category";
+                $props["style"] = "color:".$tag_category_dict[$category]['color'].";";
+
+                if ($show_category === false) {
+                    $body = TagCategories::getTagBody($tag);
+                }
+            }
+        }
+
+        return A($props, $show_underscores ? str_replace("_", " ", $body) : $body);
+    }
+
     /**
      * Generic thumbnail code; returns HTML rather than adding
      * a block since thumbs tend to go inside blocks...

ext/post_tags/theme.php

@@ -31,11 +31,7 @@ public function get_tag_editor_html(Image $image): HTMLElement
 
         $tag_links = [];
         foreach ($image->get_tag_array() as $tag) {
-            $tag_links[] = A([
-                "href" => search_link([$tag]),
-                "class" => "tag",
-                "title" => "View all posts tagged $tag"
-            ], $tag);
+            $tag_links[] = $this->build_tag($tag);
         }
 
         return SHM_POST_INFO(

ext/tag_categories/main.php

@@ -131,6 +131,26 @@ public static function getKeyedDict(): array
         return $tc_keyed_dict;
     }
 
+    public static function getTagCategory(string $tag): ?string
+    {
+        $tag_category_dict = static::getKeyedDict();
+        $tag_split = explode(':', $tag, 2);
+        if (count($tag_split) > 1 && array_key_exists($tag_split[0], $tag_category_dict)) {
+            return $tag_split[0];
+        }
+        return null;
+    }
+
+    public static function getTagBody(string $tag): string
+    {
+        $tag_category_dict = static::getKeyedDict();
+        $tag_split = explode(':', $tag, 2);
+        if (count($tag_split) > 1 && array_key_exists($tag_split[0], $tag_category_dict)) {
+            return $tag_split[1];
+        }
+        return $tag;
+    }
+
     public static function getTagHtml(string $h_tag, string $extra_text = ''): string
     {
         $h_tag_no_underscores = str_replace("_", " ", $h_tag);