refactor(converter): deduplicate epub extraction

2 files changed, 36 insertions, 96 deletions

diff --git a/converter/extractors.py b/converter/extractors.py
index 9139626..cd270a1 100644
--- a/converter/extractors.py
+++ b/converter/extractors.py
@@ -43,12 +43,11 @@ def extract_sections(file_path: Path) -> List[Section]:
     one chapter at a time. TXT and PDF files have no chapter structure and
     always yield a single section.
     """
-    extension = file_path.suffix.lower()
-    if extension == ".epub":
+    if file_path.suffix.lower() == ".epub":
         chapters = _extract_epub_chapters(file_path)
-        if len(chapters) > 1:
-            return chapters
-        return [Section(file_path.stem, extract_epub(file_path))]
+        if not chapters:
+            raise RuntimeError("All EPUB extraction methods failed")
+        return chapters
 
     return [Section(file_path.stem, extract_text(file_path))]
 
@@ -199,49 +198,11 @@ def clean_html(html_content: str) -> str:
 
 
 def extract_epub(file_path: Path) -> str:
-    """Extract text from EPUB, trying several methods in order."""
-    methods = [
-        _extract_epub_ebooklib,
-        _extract_epub_zipfile,
-        _extract_epub_manual,
-    ]
-
-    for method in methods:
-        try:
-            text = method(file_path)
-            if text and text.strip():
-                logger.info("EPUB extraction successful (%s): %d characters", method.__name__, len(text))
-                return text
-        except Exception as exc:
-            logger.warning("EPUB method %s failed: %s", method.__name__, exc)
-
-    raise RuntimeError("All EPUB extraction methods failed")
-
-
-def _extract_epub_ebooklib(file_path: Path) -> str:
-    """Extract using ebooklib, following the spine (reading) order."""
-    import ebooklib
-    from ebooklib import epub
-
-    book = epub.read_epub(str(file_path))
-    text_parts = []
-
-    for entry in book.spine:
-        item_id = entry[0] if isinstance(entry, (tuple, list)) else entry
-        try:
-            item = book.get_item_with_id(item_id)
-            if item and item.get_type() == ebooklib.ITEM_DOCUMENT:
-                content = item.get_body_content()
-                if content:
-                    if isinstance(content, bytes):
-                        content = content.decode("utf-8", errors="ignore")
-                    cleaned = clean_html(str(content))
-                    if cleaned.strip():
-                        text_parts.append(cleaned)
-        except Exception as exc:
-            logger.debug("Skipping EPUB spine item %r: %s", item_id, exc)
-
-    return "\n\n".join(text_parts)
+    """Extract the book's text from EPUB, trying several methods in order."""
+    chapters = _extract_epub_chapters(file_path)
+    if not chapters:
+        raise RuntimeError("All EPUB extraction methods failed")
+    return "\n\n".join(section.text for section in chapters)
 
 
 def _natural_key(name: str):
@@ -250,41 +211,6 @@ def _natural_key(name: str):
             for part in re.split(r"(\d+)", name)]
 
 
-def _extract_epub_zipfile(file_path: Path) -> str:
-    """Extract by parsing HTML members of the EPUB zip directly."""
-    text_parts = []
-    with zipfile.ZipFile(file_path, "r") as epub_zip:
-        for file_name in sorted(epub_zip.namelist(), key=_natural_key):
-            if file_name.lower().endswith((".html", ".xhtml", ".htm")):
-                try:
-                    content = epub_zip.read(file_name).decode("utf-8", errors="ignore")
-                    cleaned = clean_html(content)
-                    if cleaned.strip():
-                        text_parts.append(cleaned)
-                except Exception as exc:
-                    logger.debug("Skipping EPUB member %r: %s", file_name, exc)
-    return "\n\n".join(text_parts)
-
-
-def _extract_epub_manual(file_path: Path) -> str:
-    """Last-resort extraction from any markup-looking EPUB member."""
-    skipped_extensions = (".jpg", ".jpeg", ".png", ".gif", ".css", ".js")
-    text_parts = []
-    with zipfile.ZipFile(file_path, "r") as epub_zip:
-        for file_name in sorted(epub_zip.namelist(), key=_natural_key):
-            if file_name.lower().endswith(skipped_extensions):
-                continue
-            try:
-                content = epub_zip.read(file_name).decode("utf-8", errors="ignore")
-                if "<" in content and len(content.strip()) > 100:
-                    cleaned = clean_html(content)
-                    if cleaned:
-                        text_parts.append(cleaned)
-            except Exception as exc:
-                logger.debug("Skipping EPUB member %r: %s", file_name, exc)
-    return "\n\n".join(text_parts)
-
-
 def _extract_txt(file_path: Path) -> str:
     """Extract from TXT, handling BOMs and common encodings (latin-1 is the catch-all).
 
diff --git a/tests/test_extractors.py b/tests/test_extractors.py
index 09b688e..7b307c0 100644
--- a/tests/test_extractors.py
+++ b/tests/test_extractors.py
@@ -35,7 +35,8 @@ class TxtExtractionTests(unittest.TestCase):
                 extract_text(path)
 
 
-def _build_test_epub(path: Path) -> None:
+def _build_test_epub(path: Path, chapters=(("One", "First chapter text."),
+                                            ("Two", "Second chapter text."))) -> None:
     from ebooklib import epub
 
     book = epub.EpubBook()
@@ -43,15 +44,15 @@ def _build_test_epub(path: Path) -> None:
     book.set_title("Test Book")
     book.set_language("en")
 
-    chapter1 = epub.EpubHtml(title="One", file_name="chap1.xhtml", lang="en")
-    chapter1.content = "<html><body><p>First chapter text.</p></body></html>"
-    chapter2 = epub.EpubHtml(title="Two", file_name="chap2.xhtml", lang="en")
-    chapter2.content = "<html><body><p>Second chapter text.</p></body></html>"
+    items = []
+    for index, (title, text) in enumerate(chapters, 1):
+        chapter = epub.EpubHtml(title=title, file_name=f"chap{index}.xhtml", lang="en")
+        chapter.content = f"<html><body><p>{text}</p></body></html>"
+        book.add_item(chapter)
+        items.append(chapter)
 
-    book.add_item(chapter1)
-    book.add_item(chapter2)
-    book.toc = (chapter1, chapter2)
-    book.spine = ["nav", chapter1, chapter2]
+    book.toc = tuple(items)
+    book.spine = ["nav", *items]
     book.add_item(epub.EpubNcx())
     book.add_item(epub.EpubNav())
 
@@ -68,15 +69,16 @@ class EpubExtractionTests(unittest.TestCase):
     def test_ebooklib_extraction(self):
         # Regression test: the ebooklib path used to silently return "" due to
         # isinstance(item, ebooklib.ITEM_DOCUMENT) (an int, not a class).
-        from converter.extractors import _extract_epub_ebooklib
+        from converter.extractors import _read_epub_ebooklib
 
         with tempfile.TemporaryDirectory() as tmp:
             path = Path(tmp) / "book.epub"
             _build_test_epub(path)
-            text = _extract_epub_ebooklib(path)
+            items = _read_epub_ebooklib(path)
 
-        self.assertIn("First chapter text.", text)
-        self.assertIn("Second chapter text.", text)
+        html = "\n".join(content for _, content in items)
+        self.assertIn("First chapter text.", html)
+        self.assertIn("Second chapter text.", html)
 
     def test_epub_extraction_follows_spine_order(self):
         with tempfile.TemporaryDirectory() as tmp:
@@ -123,6 +125,18 @@ class ExtractSectionsTests(unittest.TestCase):
         self.assertEqual(sections[0].title, "book")
         self.assertEqual(sections[0].text, "Hello world.")
 
+    def test_single_chapter_epub_keeps_chapter_title(self):
+        from converter.extractors import extract_sections
+
+        with tempfile.TemporaryDirectory() as tmp:
+            path = Path(tmp) / "book.epub"
+            _build_test_epub(path, chapters=(("Only", "Just one chapter."),))
+            sections = extract_sections(path)
+
+        self.assertEqual(len(sections), 1)
+        self.assertEqual(sections[0].title, "Only")
+        self.assertIn("Just one chapter.", sections[0].text)
+
 
 if __name__ == "__main__":
     unittest.main()