Fix #2100559 [KePubify: Restore 'template for kepubification'](https://bugs.launchpad.net/calibre/+bug/2100559)

src/calibre/devices/kobo/driver.py

@@ -2294,24 +2294,43 @@ class KOBOTOUCH(KOBO):
         debug_print(f'KoboTouch:upload_books - {len(files)} books')
         debug_print('KoboTouch:upload_books - files=', files)
 
-        modify_epub = self.modifying_epub() or self.get_pref('kepubify')
-        def should_modify(name: str) -> bool:
-            ext = '.' + name.rpartition('.')[-1].lower()
-            return ext == EPUB_EXT and modify_epub
+        do_kepubify = self.get_pref('kepubify')
+        template = self.get_pref('template_for_kepubify')
+        modify_css = self.modifying_epub()
+        entries = tuple(zip(files, names, metadata))
+        kepubifiable = set()
+
+        def should_modify(name: str, mi) -> bool:
+            mi.kte_calibre_name = name
+            if not name.lower().endswith(EPUB_EXT):
+                return False
+            if do_kepubify:
+                if not template:
+                    kepubifiable.add(mi.uuid)
+                    return True
+                from calibre.ebooks.metadata.book.formatter import SafeFormat
+                kepubify = SafeFormat().safe_format(template, mi, 'Open With template error', mi)
+                debug_print(f'kepubify_template_result for {mi.title}:', kepubify)
+                if kepubify is not None and kepubify.startswith('PLUGBOARD TEMPLATE ERROR'):
+                    import sys
+                    print(f'kepubify template: {template} returned error', file=sys.stderr)
+                    kepubifiable.add(mi.uuid)
+                    return True
+                return kepubify and kepubify != 'false'
+            return modify_css
 
         self.extra_css, self.extra_sheet = self.get_extra_css()
-        modifiable = {x for x in names if should_modify(x)}
+        modifiable = {mi.uuid for _, name, mi in entries if should_modify(name, mi)}
         self.files_to_rename_to_kepub = set()
         if modifiable:
             i = 0
-            for idx, (file, n, mi) in enumerate(zip(files, names, metadata)):
-                if n not in modifiable:
+            for idx, (file, n, mi) in enumerate(entries):
+                if mi.uuid not in modifiable:
                     continue
                 debug_print('KoboTouch:upload_books: Processing book: {} by {}'.format(mi.title, ' and '.join(mi.authors)))
                 debug_print(f'KoboTouch:upload_books: file={file}, name={n}')
                 self.report_progress(i / float(len(modifiable)), 'Processing book: {} by {}'.format(mi.title, ' and '.join(mi.authors)))
-                mi.kte_calibre_name = n
-                if self.get_pref('kepubify'):
+                if mi.uuid in kepubifiable:
                     self._kepubify(file, n, mi)
                 else:
                     self._modify_epub(file, mi)
@@ -3663,6 +3682,7 @@ class KOBOTOUCH(KOBO):
         c.add_opt('bookstats_timetoread_lower_template', default=None)
 
         c.add_opt('kepubify', default=True)
+        c.add_opt('template_for_kepubify', default=None)
         c.add_opt('modify_css', default=False)
         c.add_opt('per_device_css', default='{}')
         c.add_opt('override_kobo_replace_existing', default=True)  # Overriding the replace behaviour is how the driver has always worked.

src/calibre/devices/kobo/kobotouch_config.py

@@ -155,6 +155,7 @@ class KOBOTOUCHConfig(TabbedDeviceConfig):
         p['modify_css'] = self.modify_css
         p['per_device_css'] = self.per_device_css
         p['kepubify'] = self.kepubify
+        p['template_for_kepubify'] = self.template_for_kepubify
         p['override_kobo_replace_existing'] = self.override_kobo_replace_existing
 
         p['support_newer_firmware'] = self.support_newer_firmware
@@ -359,6 +360,20 @@ class BookUploadsGroupBox(DeviceOptionsGroupBox):
                 ' the Kobo viewer. If you would rather use the legacy viewer for EPUB, disable this option.'
             ), device.get_pref('kepubify'))
 
+        self.template_la = la = QLabel('\xa0\xa0' + _('Template to decide conversion:'))
+        self.kepubify_template_edit = TemplateConfig(
+            device.get_pref('template_for_kepubify'),
+            tooltip=_(
+                'Enter a template to decide if an EPUB book is to be auto converted to KEPUB. '
+                'If the template returns false or no result, the book will not be '
+                'converted to KEPUB. For example to only kepubify books that have the tag "as_kepub", use the template: {0}'
+                ' or to only convert books that do not have the tag as_epub, use the template: {1}'
+                '\n\nIf no template is specified conversion to KEPUB is controlled only by the setting above to use the Kobo viewer. '
+                'Note that the setting above must be enabled for the template to be checked.'
+            ).format(r'{tags:str_in_list(\,,as_kepub,true,false)}', r'{tags:str_in_list(\,,as_epub,false,true)}')
+        )
+        la.setBuddy(self.kepubify_template_edit)
+
         self.override_kobo_replace_existing_checkbox = create_checkbox(
                 _('Do not treat replacements as new books'),
                 _('When a new book is side-loaded, the Kobo firmware imports details of the book into the internal database. '
@@ -371,7 +386,14 @@ class BookUploadsGroupBox(DeviceOptionsGroupBox):
                 )
 
         self.options_layout.addWidget(self.kepubify_checkbox, 0, 0, 1, 2)
-        self.options_layout.addWidget(self.override_kobo_replace_existing_checkbox, 1, 0, 1, 2)
+        self.options_layout.addWidget(self.template_la, 1, 0, 1, 1)
+        self.options_layout.addWidget(self.kepubify_template_edit, 1, 1, 1, 1)
+        self.options_layout.addWidget(self.override_kobo_replace_existing_checkbox, 2, 0, 1, 2)
+        self.update_template_state()
+        self.kepubify_checkbox.toggled.connect(self.update_template_state)
+
+    def update_template_state(self):
+        self.kepubify_template_edit.setEnabled(self.kepubify)
 
     @property
     def override_kobo_replace_existing(self):
@@ -381,6 +403,10 @@ class BookUploadsGroupBox(DeviceOptionsGroupBox):
     def kepubify(self):
         return self.kepubify_checkbox.isChecked()
 
+    @property
+    def template_for_kepubify(self):
+        return (self.kepubify_template_edit.template or '').strip()
+
 
 class HyphenationGroupBox(DeviceOptionsGroupBox):
 

src/calibre/ebooks/oeb/polish/kepubify.py

@@ -553,11 +553,12 @@ def unkepubify_path(path, outpath='', max_workers=0, allow_overwrite=False):
 
 def check_if_css_needs_modification(extra_css: str) -> tuple[bool, bool]:
     remove_widows_and_orphans = remove_at_page_rules = False
+    sheet = None
     if extra_css:
         try:
             sheet = css_parser().parseString(extra_css)
         except Exception:
-            sheet = None
+            pass
         else:
             for rule in sheet.cssRules:
                 if rule.type == CSSRule.PAGE_RULE: