PDF generation process

def create_pdf(
    image_paths: List[str],
    output_pdf: str,
    log_callback: Callable[[str], None]
) -> bool:
    """Compiles a list of image paths into a single PDF using img2pdf (if available) or Pillow."""
    if not image_paths:
        log_callback("[WARN] No images to compile into PDF.")
        return False

    final_paths = []
    
    try:
        # Step 1: Convert RGBA images to RGB
        for path in image_paths:
            try:
                with Image.open(path) as img:
                    if img.mode in ("RGBA", "LA") or (img.mode == "P" and "transparency" in img.info):
                        head, tail = os.path.split(path)
                        new_filename = os.path.splitext(tail)[0] + "_converted.jpg"
                        new_path = os.path.join(head, new_filename)
                        img.convert("RGB").save(new_path, "JPEG", quality=90)
                        final_paths.append(new_path)
                    else:
                        final_paths.append(path)
            except Exception:
                final_paths.append(path)
        
        # Step 2: Use img2pdf for fast conversion
        if img2pdf:
            with open(output_pdf, "wb") as f:
                f.write(img2pdf.convert(final_paths, rotation=img2pdf.Rotation.ifvalid))
        else:
            raise ImportError("img2pdf not installed")

        # Step 3: Generate success message with relative path
        try:
            project_root = os.getcwd()
            pdf_root = os.path.join(project_root, PDF_FOLDER_NAME)
            
            if os.path.abspath(output_pdf).startswith(os.path.abspath(pdf_root)):
                logged_path = os.path.relpath(output_pdf, pdf_root)
            else:
                logged_path = os.path.basename(output_pdf)
            logged_path = logged_path.replace("\\", "/")
        except:
            logged_path = os.path.basename(output_pdf)

        log_callback(f"[SUCCESS] PDF Generated: {logged_path}")
        return True

    except Exception as e:
        # Fallback to Pillow method
        log_callback(f"[ERROR] Failed to save PDF (img2pdf): {e}")
        try:
            log_callback("[INFO] Trying alternative method (Pillow)...")
            images = []
            for path in image_paths:
                try:
                    with Image.open(path) as img:
                        if img.mode in ("RGBA", "P"): img = img.convert("RGB")
                        images.append(img.copy())
                except: pass
                
            if images:
                images[0].save(
                    output_pdf,
                    "PDF",
                    resolution=100.0,
                    save_all=True,
                    append_images=images[1:]
                )
                return True
        except Exception as e2:
            log_callback(f"[ERROR] Alternative method failed: {e2}")
        
        return False

def clean_filename(text: str) -> str:
    """Sanitizes the string to create a valid Windows/Linux file name."""
    if not text: return "untitled"
    text = re.sub(r'<[^>]+>', '', text)  # Remove HTML tags
    safe = re.sub(r'[\\/*?:"<>|]', "", text).strip()  # Remove reserved chars
    return safe if safe else "untitled"

def finalize_pdf_flow(
    image_paths: List[str],
    pdf_name: str,
    log_callback: Callable[[str], None],
    temp_dir: Optional[str] = None,
    open_result: bool = True
):
    """Creates PDF, Opens it/Folder (if open_result is True), and Cleans up temp dir."""
    project_root = os.getcwd()
    pdf_dir = os.path.join(project_root, PDF_FOLDER_NAME)
    os.makedirs(pdf_dir, exist_ok=True)
    
    output_pdf = os.path.join(pdf_dir, pdf_name)
    log_callback(f"[INFO] Generating PDF: {pdf_name}")
    
    if create_pdf(image_paths, output_pdf, log_callback):
        if open_result:
            if os.path.exists(output_pdf):
                try: os.startfile(os.path.dirname(output_pdf))
                except: pass
                try: os.startfile(output_pdf)
                except: pass
        log_callback("[DONE] Finished.")
    else:
        log_callback("[ERROR] Could not create PDF.")

    if temp_dir and os.path.exists(temp_dir):
        try:
            shutil.rmtree(temp_dir)
        except: pass

# Folder Names
PDF_FOLDER_NAME = "PDF"             # Output directory name
TEMP_FOLDER_NAME = "temp_manga_images"  # Temporary download directory

# Runtime Flags
OPEN_RESULT_ON_FINISH = True        # Auto-open PDFs after creation