refactor: ColumnWidths holds the column-width rules (H5)

Composer::row uses ColumnWidths::parse; rowWidthsError and its error-state
save/restore are gone. The update width check moves out of
DiviUpdateAbility into ColumnWidths::updateErrors. Behaviour unchanged.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

src/Integrations/Divi/Compose/Composer.php

@@ -24,8 +24,9 @@ use LIT\MCP\Integrations\Divi\Schema\ShortformMap;
  * preset ids. A value that fails there is an error, never stored raw (S13). What Composer
  * writes itself is not client text: the builder version (checked in the constructor), block
  * names (catalog + StructureRules + Block::create), "fullwidth" and column flexTypes built
- * from digits. Design-system names that match several entries are errors listing the ids
- * (ruling S13a: colors/variables in Placeholders, presets in DesignSystem::modulePresetId()).
+ * from digits (ColumnWidths). Design-system names that match several entries are errors
+ * listing the ids (ruling S13a: colors/variables in Placeholders, presets in
+ * DesignSystem::modulePresetId()).
  */
 final class Composer
 {
@@ -36,9 +37,6 @@ final class Composer
     /** Keys of one lit-divi-update change ("id" names the node, read by the ability). */
     private const UPDATE = ['id', 'set', 'attrs', 'preset', 'label'];
 
-    /** Column fractions Divi's flex layout knows besides multiples of 1/24. */
-    private const SPECIAL_WIDTHS = ['1_5', '2_5', '3_5', '4_5', '1_7', '1_9', '1_10', '1_11'];
-
     /** ET_BUILDER_PRODUCT_VERSION, e.g. "5.2.1" – written into every new block. */
     private const VERSION = '/^[0-9][0-9A-Za-z.+-]*$/D';
 
@@ -48,12 +46,6 @@ final class Composer
 
     private const DEFAULT_LEVEL = 'h2';
 
-    /**
-     * The builder's "Column Class" choices (Divi 5.2.1 visual-builder/build/field-library.js):
-     * n_24, the special fractions and "none" (no width class). Ruling S43.
-     */
-    private const COLUMN_CLASSES = ['1_5', '2_5', '3_5', '1_7', '1_9', '1_10', '1_11', 'none'];
-
     /** Advice of the S40 overlap error for new nodes. */
     private const ONE_FORM = 'für diesen Pfad nur Kurzform oder attrs angeben';
 
@@ -342,7 +334,11 @@ final class Composer
     private function row(array $spec, string $path, string $context): Block
     {
         $this->unknownKeys($spec, array_merge(self::COMMON, self::ROW), $path);
-        $widths = $this->widths($spec['columns'] ?? '4_4', $path . '.columns');
+        $parsed = ColumnWidths::parse($spec['columns'] ?? '4_4');
+        if ($parsed['error'] !== null) {
+            $this->errors[$path . '.columns'] = $parsed['error'];
+        }
+        $widths = $parsed['widths'];
         $label = $context === '' ? null : $context . ' – Zeile';
         $attrs = $this->common('divi/row', ['builderVersion' => $this->builderVersion], $spec, $path, $label);
         $row = Block::create('divi/row', $attrs);
@@ -604,111 +600,6 @@ final class Composer
         }
     }
 
-    /**
-     * "1_3,2_3" → flexTypes ["8_24", "16_24"]; the fractions must add up to exactly one row
-     * (exact integer arithmetic over the common denominator, ruling S34 – no float tolerance).
-     *
-     * @return list<string>
-     */
-    private function widths(mixed $columns, string $path): array
-    {
-        $parts = is_string($columns) ? array_map('trim', explode(',', $columns)) : [];
-        $widths = [];
-        $fractions = [];
-        foreach ($parts as $part) {
-            $valid = preg_match('/^(\d{1,2})_(\d{1,2})$/D', $part, $match) === 1
-                && (int) $match[1] >= 1
-                && (int) $match[1] <= (int) $match[2];
-            if (! $valid) {
-                $this->errors[$path] = 'Spaltenaufteilung wie "1_2,1_2" oder "1_3,2_3" erwartet';
-
-                return ['24_24'];
-            }
-
-            [$numerator, $denominator] = [(int) $match[1], (int) $match[2]];
-            if (24 % $denominator === 0) {
-                $widths[] = ($numerator * 24 / $denominator) . '_24';
-            } elseif (in_array($part, self::SPECIAL_WIDTHS, true)) {
-                $widths[] = $part;
-            } else {
-                $this->errors[$path] = sprintf('Spaltenbreite %s gibt es in Divi nicht', $part);
-
-                return ['24_24'];
-            }
-            $fractions[] = [$numerator, $denominator];
-        }
-
-        if ($widths === [] || ! self::sumsToOne($fractions)) {
-            $this->errors[$path] = 'die Spaltenbreiten müssen zusammen eine volle Zeile ergeben (z. B. "1_3,2_3")';
-
-            return ['24_24'];
-        }
-
-        return $widths;
-    }
-
-    /**
-     * Ruling S41: the desktop flexType values of all columns of a row (in order), checked with
-     * the rules of "columns" – valid Divi widths that fill the row exactly. Null when valid,
-     * else the German problem.
-     *
-     * @param list<mixed> $flexTypes
-     */
-    public function rowWidthsError(array $flexTypes): ?string
-    {
-        $saved = $this->errors;
-        $this->errors = [];
-        $valid = $flexTypes !== [] && array_filter(
-            $flexTypes,
-            static fn (mixed $width): bool => is_string($width) && preg_match('/^\d{1,2}_\d{1,2}$/D', $width) === 1
-        ) === $flexTypes;
-        if ($valid) {
-            $this->widths(implode(',', $flexTypes), 'w');
-        }
-
-        $error = $valid ? ($this->errors['w'] ?? null) : 'Spaltenbreiten wie "8_24" erwartet';
-        $this->errors = $saved;
-
-        return $error;
-    }
-
-    /** Ruling S43: whether $width is a column class the Visual Builder offers. */
-    public static function isColumnClass(mixed $width): bool
-    {
-        if (! is_string($width)) {
-            return false;
-        }
-
-        return in_array($width, self::COLUMN_CLASSES, true)
-            || (preg_match('/^([1-9]|1\d|2[0-4])_24$/D', $width) === 1);
-    }
-
-    /**
-     * Whether the fractions add up to exactly 1: numerators scaled to the least common
-     * denominator (denominators are divisors of 24 or 5, 7, 9, 10, 11 – at most 27720).
-     *
-     * @param list<array{int, int}> $fractions [numerator, denominator]
-     */
-    private static function sumsToOne(array $fractions): bool
-    {
-        $common = 1;
-        foreach ($fractions as [, $denominator]) {
-            $common = intdiv($common * $denominator, self::gcd($common, $denominator));
-        }
-
-        $sum = 0;
-        foreach ($fractions as [$numerator, $denominator]) {
-            $sum += $numerator * intdiv($common, $denominator);
-        }
-
-        return $sum === $common;
-    }
-
-    private static function gcd(int $a, int $b): int
-    {
-        return $b === 0 ? $a : self::gcd($b, $a % $b);
-    }
-
     /**
      * @param array<array-key, mixed> $spec
      * @param list<string>            $allowed