[BUGFIX] Respect language based style names on reading Word files

Microsoft Office saves Office document with language based style
mappings for default styles. For example, if a german based Word
version is used, it writes following to the `word/styles.xml` in
the container archive (*.docs):

```
<w:style w:type="paragraph" w:styleId="berschrift1">
  <w:name w:val="heading 1"/>
  ....
  </w:style>
```

versus for a english based version it would be:

```
<w:style w:type="paragraph" w:styleId="Heading1">
  <w:name w:val="heading 1"/>
  ...
</w:style>
```

The value of `<w:name />` defines the internal native code
identifier, whereas the `w:styleId` attribute on the outer
`<w:style />` tag would describe the virtual or alias name.

Later parsing of the document structure, for example the
paragraphs, references the alias (`w:styleId`) name of a
style. The reader code uses hardcoded RegEx matchings in
a case-insensitive manner but using the englisch speaking
variant (`Header\s+d`) - on the language based one, which
would not match at all.

Therefore, multiple tasks need to be done and contained
in this change:

* A alias map is implementend and used to register title
  aliases. Along with this corresponding lookup method is
  added.
* Use the lookup method to resolve for alias where the
  hardcoded language RegEx is needed to be used.

Author: sbuerk

src/PhpWord/Reader/Word2007/AbstractPart.php

@@ -28,6 +28,7 @@
 use PhpOffice\PhpWord\Element\TrackChange;
 use PhpOffice\PhpWord\PhpWord;
 use PhpOffice\PhpWord\Shared\XMLReader;
+use PhpOffice\PhpWord\Style;
 
 /**
  * Abstract part reader.
@@ -290,14 +291,20 @@ protected function readParagraph(XMLReader $xmlReader, DOMElement $domNode, $par
     private function getHeadingDepth(?array $paragraphStyle = null)
     {
         if (is_array($paragraphStyle) && isset($paragraphStyle['styleName'])) {
-            if ('Title' === $paragraphStyle['styleName']) {
+            // Title styles have a special handling in the styles.xms loading and registration, therefore we need to
+            // use the alias for it here to properly check for the correct systeling.
+            /** @see Style::addTitleStyle() */
+            /** @see Styles::read() */
+            $checkStyleName = Style::findAliasForStyleName($paragraphStyle['styleName']);
+            // Title does not have a depth, early return.
+            if ('Title' === $checkStyleName) {
                 return 0;
             }
-
             $headingMatches = [];
-            preg_match('/Heading(\d)/', $paragraphStyle['styleName'], $headingMatches);
+            // We need to support here multiple variants: 'Heading 1' , 'Heading_1', 'Heading1'
+            preg_match('/Heading([_\s]*)(\d)/', $checkStyleName, $headingMatches);
             if (!empty($headingMatches)) {
-                return $headingMatches[1];
+                return $headingMatches[2];
             }
         }
 

src/PhpWord/Reader/Word2007/Styles.php

@@ -19,6 +19,7 @@
 
 use PhpOffice\PhpWord\PhpWord;
 use PhpOffice\PhpWord\Shared\XMLReader;
+use PhpOffice\PhpWord\Style;
 use PhpOffice\PhpWord\Style\Language;
 
 /**
@@ -65,8 +66,17 @@ public function read(PhpWord $phpWord): void
             foreach ($nodes as $node) {
                 $type = $xmlReader->getAttribute('w:type', $node);
                 $name = $xmlReader->getAttribute('w:val', $node, 'w:name');
-                if (null === $name) {
-                    $name = $xmlReader->getAttribute('w:styleId', $node);
+                $alias = $xmlReader->getAttribute('w:styleId', $node);
+                if (null === $name && null === $alias) {
+                    // no name or alias, skip it as matching would not possible otherwise.
+                    continue;
+                }
+                if (null === $name && null !== $alias) {
+                    // fully custom style, use alias as name.
+                    $name = $alias;
+                }
+                if (null !== $name && null === $alias) {
+                    $alias = $name;
                 }
                 $headingMatches = [];
                 preg_match('/Heading\s*(\d)/i', $name, $headingMatches);
@@ -76,7 +86,8 @@ public function read(PhpWord $phpWord): void
                         $paragraphStyle = $this->readParagraphStyle($xmlReader, $node);
                         $fontStyle = $this->readFontStyle($xmlReader, $node);
                         if (!empty($headingMatches)) {
-                            $phpWord->addTitleStyle($headingMatches[1], $fontStyle, $paragraphStyle);
+                            $titleStyleName = $phpWord->addTitleStyle($headingMatches[1], $fontStyle, $paragraphStyle)->getStyleName();
+                            Style::addStyleNameAlias($alias, $titleStyleName);
                         } else {
                             if (empty($fontStyle)) {
                                 if (is_array($paragraphStyle)) {

src/PhpWord/Style.php

@@ -35,6 +35,13 @@ class Style
      */
     private static $styles = [];
 
+    /**
+     * Mapping style name to internal code identifier.
+     *
+     * @var array<string, string>
+     */
+    private static $nameToIdentifierMapping = [];
+
     /**
      * Add paragraph style.
      *
@@ -124,6 +131,52 @@ public static function addTableStyle($styleName, $styleTable, $styleFirstRow = n
         return self::setStyleValues($styleName, new Table($styleTable, $styleFirstRow), null);
     }
 
+    /**
+     * Add a styleName to identifier mapping entry.
+     *
+     * @param string $alias
+     * @param string $styleName
+     *
+     * @see self::resolveStyleNameIdentifier()
+     */
+    public static function addStyleNameAlias($alias, $styleName): void
+    {
+        self::$nameToIdentifierMapping[$alias] = $styleName;
+    }
+
+    /**
+     * Find a the correct for a specified $alias. If $alias is a validName, it is returned. Otherwise, it will return
+     * the styleName for the alias if one is found, and a empty string if nothing could be found.
+     *
+     * @param string $alias
+     *
+     * @return string
+     */
+    public static function findStyleNameForAlias($alias)
+    {
+        foreach (self::$nameToIdentifierMapping as $alias => $mappedStyleName) {
+            if ($mappedStyleName === $alias) {
+                return $alias;
+            }
+        }
+
+        return '';
+    }
+
+    /**
+     * Returns the alias for a specific $styleName. If no alias could be found, $styleName is returned.
+     *
+     * @param string $styleName
+     *
+     * @return string
+     */
+    public static function findAliasForStyleName($styleName)
+    {
+        return (isset(self::$nameToIdentifierMapping[$styleName]) && !empty(self::$nameToIdentifierMapping[$styleName]))
+            ? self::$nameToIdentifierMapping[$styleName]
+            : $styleName;
+    }
+
     /**
      * Count styles.
      *
@@ -144,6 +197,7 @@ public static function countStyles()
     public static function resetStyles(): void
     {
         self::$styles = [];
+        self::$nameToIdentifierMapping = [];
     }
 
     /**