feat: prompt before overwriting existing books

1 files changed, 61 insertions, 2 deletions

diff --git a/converter/converter.py b/converter/converter.py
index c0e97e4..a58fc33 100644
--- a/converter/converter.py
+++ b/converter/converter.py
@@ -1,5 +1,6 @@
 """Orchestrates book-to-audiobook conversion."""
 
+import glob
 import logging
 import re
 import sys
@@ -39,6 +40,48 @@ def setup_directories() -> None:
         Path(directory).mkdir(parents=True, exist_ok=True)
 
 
+def find_existing_outputs(output_name: str, output_format: str) -> List[Path]:
+    """Return existing output files that a conversion would overwrite.
+
+    Multi-section books (e.g. EPUB chapters) and speed-adjusted copies are
+    named ``{name}_suffix.{ext}``; exact chapter file names are only known
+    after text extraction, so any file matching that pattern counts.
+    """
+    folder = config.AUDIOBOOKS_FOLDER
+    existing: List[Path] = []
+    primary = folder / f"{output_name}.{output_format}"
+    if primary.exists():
+        existing.append(primary)
+    existing.extend(sorted(
+        folder.glob(f"{glob.escape(output_name)}_*.{output_format}")))
+    return existing
+
+
+def prompt_overwrite(existing: List[Path], output_name: str) -> bool:
+    """Ask whether to reconvert a book whose output files already exist.
+
+    All overwrite questions are asked before any conversion starts so the
+    rest of the run is unattended. Returns False when no interactive input
+    is available (stdin closed), keeping existing files safe.
+    """
+    if len(existing) == 1:
+        message = f"{existing[0].name} already exists. Convert anyway and overwrite it?"
+    else:
+        message = (f"{len(existing)} output files for '{output_name}' already exist "
+                   f"(e.g. {existing[0].name}). Convert anyway and overwrite them?")
+    while True:
+        try:
+            answer = input(f"{message} (y/n): ").strip().lower()
+        except EOFError:
+            print("\n[WARNING] No interactive input available; keeping existing output")
+            return False
+        if answer in ("y", "yes"):
+            return True
+        if answer in ("n", "no"):
+            return False
+        print("Please answer 'y' or 'n'.")
+
+
 class AudiobookConverter:
     """Audiobook converter using the Qwen TTS API."""
 
@@ -336,12 +379,28 @@ class AudiobookConverter:
         # Avoid output collisions when two books share a stem (e.g. dune.txt + dune.epub).
         stem_counts: Dict[str, int] = Counter(book_file.stem for book_file in book_files)
 
-        # Convert each book
-        results = {}
+        # Ask every overwrite question up front, before any conversion
+        # starts, so the rest of the run is unattended.
+        planned: List[Tuple[Path, str]] = []
         for book_file in book_files:
             output_name = book_file.stem
             if stem_counts[book_file.stem] > 1:
                 output_name = f"{book_file.stem}_{book_file.suffix.lstrip('.')}"
+            existing = find_existing_outputs(output_name, self.output_format)
+            if existing and not prompt_overwrite(existing, output_name):
+                print(f"[INFO] Skipping {book_file.name} (existing output kept)")
+                continue
+            planned.append((book_file, output_name))
+
+        if not planned:
+            print("[INFO] Nothing to convert (all books skipped)")
+            return True
+
+        print(f"[INFO] Converting {len(planned)} of {len(book_files)} book(s)")
+
+        # Convert each book
+        results = {}
+        for book_file, output_name in planned:
             try:
                 success = self.convert_book(book_file, output_name=output_name)
                 results[book_file.name] = success