Commit

src/core/workers.py

@@ -54,6 +54,24 @@ from ..utils.text_utils import (
 )
 from ..config.constants import *
 
+def robust_clean_name(name):
+    """A more robust function to remove illegal characters for filenames and folders."""
+    if not name:
+        return ""
+    # Removes illegal characters for Windows, macOS, and Linux: < > : " / \ | ? *
+    # Also removes control characters (ASCII 0-31) which are invisible but invalid.
+    illegal_chars_pattern = r'[\x00-\x1f<>:"/\\|?*]'
+    cleaned_name = re.sub(illegal_chars_pattern, '', name)
+    
+    # Remove leading/trailing spaces or periods, which can cause issues.
+    cleaned_name = cleaned_name.strip(' .')
+    
+    # If the name is empty after cleaning (e.g., it was only illegal chars),
+    # provide a safe fallback name.
+    if not cleaned_name:
+        return "untitled_folder" # Or "untitled_file" depending on context
+    return cleaned_name
+
 class PostProcessorSignals (QObject ):
     progress_signal =pyqtSignal (str )
     file_download_status_signal =pyqtSignal (bool )
@@ -64,7 +82,6 @@ class PostProcessorSignals (QObject ):
     worker_finished_signal = pyqtSignal(tuple)
 
 class PostProcessorWorker:
-
     def __init__(self, post_data, download_root, known_names,
                  filter_character_list, emitter,
                  unwanted_keywords, filter_mode, skip_zip,
@@ -104,7 +121,10 @@ class PostProcessorWorker:
                  text_export_format='txt',
                  single_pdf_mode=False,
                  project_root_dir=None,
-                 processed_post_ids=None
+                 processed_post_ids=None,
+                 multipart_scope='both', 
+                 multipart_parts_count=4, 
+                 multipart_min_size_mb=100 
                  ):
         self.post = post_data
         self.download_root = download_root
@@ -166,7 +186,9 @@ class PostProcessorWorker:
         self.single_pdf_mode = single_pdf_mode
         self.project_root_dir = project_root_dir
         self.processed_post_ids = processed_post_ids if processed_post_ids is not None else []
-
+        self.multipart_scope = multipart_scope 
+        self.multipart_parts_count = multipart_parts_count 
+        self.multipart_min_size_mb = multipart_min_size_mb 
         if self.compress_images and Image is None:
             self.logger("⚠️ Image compression disabled: Pillow library not found.")
             self.compress_images = False
@@ -201,7 +223,7 @@ class PostProcessorWorker:
             return self .dynamic_filter_holder .get_filters ()
         return self .filter_character_list_objects_initial 
     
-    def _download_single_file(self, file_info, target_folder_path, headers, original_post_id_for_log, skip_event,
+    def _download_single_file(self, file_info, target_folder_path, post_page_url, original_post_id_for_log, skip_event,
                                 post_title="", file_index_in_post=0, num_files_in_this_post=1,
                                 manga_date_file_counter_ref=None,
                                 forced_filename_override=None,
@@ -215,6 +237,11 @@ class PostProcessorWorker:
         if self.check_cancel() or (skip_event and skip_event.is_set()):
             return 0, 1, "", False, FILE_DOWNLOAD_STATUS_SKIPPED, None
 
+        file_download_headers = {
+            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36',
+            'Referer': post_page_url
+        }
+
         file_url = file_info.get('url')
         cookies_to_use_for_file = None
         if self.use_cookie:
@@ -233,34 +260,28 @@ class PostProcessorWorker:
                         self.logger(f"   -> Skip File (Keyword in Original Name '{skip_word}'): '{api_original_filename}'. Scope: {self.skip_words_scope}")
                         return 0, 1, api_original_filename, False, FILE_DOWNLOAD_STATUS_SKIPPED, None
 
-            cleaned_original_api_filename = clean_filename(api_original_filename)
+            cleaned_original_api_filename = robust_clean_name(api_original_filename)
             original_filename_cleaned_base, original_ext = os.path.splitext(cleaned_original_api_filename)
             if not original_ext.startswith('.'): original_ext = '.' + original_ext if original_ext else ''
 
             if self.manga_mode_active:
                 if self.manga_filename_style == STYLE_ORIGINAL_NAME:
-                    # Get the post's publication or added date
                     published_date_str = self.post.get('published')
                     added_date_str = self.post.get('added')
-                    formatted_date_str = "nodate"  # Fallback if no date is found
-
+                    formatted_date_str = "nodate"
                     date_to_use_str = published_date_str or added_date_str
-
                     if date_to_use_str:
                         try:
-                            # Extract just the YYYY-MM-DD part from the timestamp
                             formatted_date_str = date_to_use_str.split('T')[0]
                         except Exception:
                             self.logger(f"     ⚠️ Could not parse date '{date_to_use_str}'. Using 'nodate' prefix.")
                     else:
                         self.logger(f"     ⚠️ Post ID {original_post_id_for_log} has no date. Using 'nodate' prefix.")
-
-                    # Combine the date with the cleaned original filename
                     filename_to_save_in_main_path = f"{formatted_date_str}_{cleaned_original_api_filename}"
                     was_original_name_kept_flag = True
                 elif self.manga_filename_style == STYLE_POST_TITLE:
                     if post_title and post_title.strip():
-                        cleaned_post_title_base = clean_filename(post_title.strip())
+                        cleaned_post_title_base = robust_clean_name(post_title.strip())
                         if num_files_in_this_post > 1:
                             if file_index_in_post == 0:
                                 filename_to_save_in_main_path = f"{cleaned_post_title_base}{original_ext}"
@@ -281,7 +302,7 @@ class PostProcessorWorker:
                             manga_date_file_counter_ref[0] += 1
                         base_numbered_name = f"{counter_val_for_filename:03d}"
                         if self.manga_date_prefix and self.manga_date_prefix.strip():
-                            cleaned_prefix = clean_filename(self.manga_date_prefix.strip())
+                            cleaned_prefix = robust_clean_name(self.manga_date_prefix.strip())
                             if cleaned_prefix:
                                 filename_to_save_in_main_path = f"{cleaned_prefix} {base_numbered_name}{original_ext}"
                             else:
@@ -298,7 +319,7 @@ class PostProcessorWorker:
                         with counter_lock:
                             counter_val_for_filename = manga_global_file_counter_ref[0]
                             manga_global_file_counter_ref[0] += 1
-                        cleaned_post_title_base_for_global = clean_filename(post_title.strip() if post_title and post_title.strip() else "post")
+                        cleaned_post_title_base_for_global = robust_clean_name(post_title.strip() if post_title and post_title.strip() else "post")
                         filename_to_save_in_main_path = f"{cleaned_post_title_base_for_global}_{counter_val_for_filename:03d}{original_ext}"
                     else:
                         self.logger(f"⚠️ Manga Title+GlobalNum Mode: Counter ref not provided or malformed for '{api_original_filename}'. Using original. Ref: {manga_global_file_counter_ref}")
@@ -330,8 +351,8 @@ class PostProcessorWorker:
                         self.logger(f"     ⚠️ Post ID {original_post_id_for_log} missing both 'published' and 'added' dates for STYLE_DATE_POST_TITLE. Using 'nodate'.")
 
                     if post_title and post_title.strip():
-                        temp_cleaned_title = clean_filename(post_title.strip())
-                        if not temp_cleaned_title or temp_cleaned_title.startswith("untitled_file"):
+                        temp_cleaned_title = robust_clean_name(post_title.strip())
+                        if not temp_cleaned_title or temp_cleaned_title.startswith("untitled_folder"):
                             self.logger(f"⚠️ Manga mode (Date+PostTitle Style): Post title for post {original_post_id_for_log} ('{post_title}') was empty or generic after cleaning. Using 'post' as title part.")
                             cleaned_post_title_for_filename = "post"
                         else:
@@ -414,8 +435,7 @@ class PostProcessorWorker:
             final_save_path_check = os.path.join(target_folder_path, filename_to_save_in_main_path)
             if os.path.exists(final_save_path_check):
                 try:
-                    # Use a HEAD request to get the expected size without downloading the body
-                    with requests.head(file_url, headers=headers, timeout=15, cookies=cookies_to_use_for_file, allow_redirects=True) as head_response:
+                    with requests.head(file_url, headers=file_download_headers, timeout=15, cookies=cookies_to_use_for_file, allow_redirects=True) as head_response:
                         head_response.raise_for_status()
                         expected_size = int(head_response.headers.get('Content-Length', -1))
                     
@@ -423,26 +443,21 @@ class PostProcessorWorker:
 
                     if expected_size != -1 and actual_size == expected_size:
                         self.logger(f"   -> Skip (File Exists & Complete): '{filename_to_save_in_main_path}' is already on disk with the correct size.")
-                        
-                        # We still need to add its hash to the session to prevent duplicates in other modes
-                        # This is a quick hash calculation for the already existing file
                         try:
                             md5_hasher = hashlib.md5()
                             with open(final_save_path_check, 'rb') as f_verify:
                                 for chunk in iter(lambda: f_verify.read(8192), b""):
                                     md5_hasher.update(chunk)
-                            
                             with self.downloaded_hash_counts_lock:
                                 self.downloaded_hash_counts[md5_hasher.hexdigest()] += 1
                         except Exception as hash_exc:
                              self.logger(f"   ⚠️ Could not hash existing file '{filename_to_save_in_main_path}' for session: {hash_exc}")
-
                         return 0, 1, filename_to_save_in_main_path, was_original_name_kept_flag, FILE_DOWNLOAD_STATUS_SKIPPED, None
                     else:
                         self.logger(f"   ⚠️ File '{filename_to_save_in_main_path}' exists but is incomplete (Expected: {expected_size}, Actual: {actual_size}). Re-downloading.")
-
                 except requests.RequestException as e:
                     self.logger(f"   ⚠️ Could not verify size of existing file '{filename_to_save_in_main_path}': {e}. Proceeding with download.")
+        
         retry_delay = 5
         downloaded_size_bytes = 0
         calculated_file_hash = None
@@ -463,13 +478,30 @@ class PostProcessorWorker:
                     self.logger(f"   Retrying download for '{api_original_filename}' (Overall Attempt {attempt_num_single_stream + 1}/{max_retries + 1})...")
                     time.sleep(retry_delay * (2 ** (attempt_num_single_stream - 1)))
                 self._emit_signal('file_download_status', True)
-                response = requests.get(file_url, headers=headers, timeout=(15, 300), stream=True, cookies=cookies_to_use_for_file)
+                response = requests.get(file_url, headers=file_download_headers, timeout=(15, 300), stream=True, cookies=cookies_to_use_for_file)
+              
                 response.raise_for_status()
                 total_size_bytes = int(response.headers.get('Content-Length', 0))
-                num_parts_for_file = min(self.num_file_threads, MAX_PARTS_FOR_MULTIPART_DOWNLOAD)
+                num_parts_for_file = min(self.multipart_parts_count, MAX_PARTS_FOR_MULTIPART_DOWNLOAD)
+           
+                file_is_eligible_by_scope = False
+                if self.multipart_scope == 'videos':
+                    if is_video(api_original_filename):
+                        file_is_eligible_by_scope = True
+                elif self.multipart_scope == 'archives':
+                    if is_archive(api_original_filename):
+                        file_is_eligible_by_scope = True
+                elif self.multipart_scope == 'both':
+                    if is_video(api_original_filename) or is_archive(api_original_filename):
+                        file_is_eligible_by_scope = True
+
+                min_size_in_bytes = self.multipart_min_size_mb * 1024 * 1024
+
                 attempt_multipart = (self.allow_multipart_download and MULTIPART_DOWNLOADER_AVAILABLE and
-                                     num_parts_for_file > 1 and total_size_bytes > MIN_SIZE_FOR_MULTIPART_DOWNLOAD and
+                                     file_is_eligible_by_scope and
+                                     num_parts_for_file > 1 and total_size_bytes > min_size_in_bytes and 
                                      'bytes' in response.headers.get('Accept-Ranges', '').lower())
+          
                 if self._check_pause(f"Multipart decision for '{api_original_filename}'"): break
 
                 if attempt_multipart:
@@ -478,7 +510,7 @@ class PostProcessorWorker:
                         response_for_this_attempt = None
                     mp_save_path_for_unique_part_stem_arg = os.path.join(target_folder_path, f"{unique_part_file_stem_on_disk}{temp_file_ext_for_unique_part}")
                     mp_success, mp_bytes, mp_hash, mp_file_handle = download_file_in_parts(
-                        file_url, mp_save_path_for_unique_part_stem_arg, total_size_bytes, num_parts_for_file, headers, api_original_filename,
+                        file_url, mp_save_path_for_unique_part_stem_arg, total_size_bytes, num_parts_for_file, file_download_headers, api_original_filename,
                         emitter_for_multipart=self.emitter, cookies_for_chunk_session=cookies_to_use_for_file,
                         cancellation_event=self.cancellation_event, skip_event=skip_event, logger_func=self.logger,
                         pause_event=self.pause_event
@@ -487,7 +519,7 @@ class PostProcessorWorker:
                         download_successful_flag = True
                         downloaded_size_bytes = mp_bytes
                         calculated_file_hash = mp_hash
-                        downloaded_part_file_path = mp_save_path_for_unique_part_stem_arg + ".part"
+                        downloaded_part_file_path = mp_save_path_for_unique_part_stem_arg
                         if mp_file_handle: mp_file_handle.close()
                         break
                     else:
@@ -553,12 +585,15 @@ class PostProcessorWorker:
                 if isinstance(e, requests.exceptions.ConnectionError) and ("Failed to resolve" in str(e) or "NameResolutionError" in str(e)):
                     self.logger("   💡 This looks like a DNS resolution problem. Please check your internet connection, DNS settings, or VPN.")
             except requests.exceptions.RequestException as e:
-                self.logger(f"   ❌ Download Error (Non-Retryable): {api_original_filename}. Error: {e}")
-                last_exception_for_retry_later = e
-                is_permanent_error = True
-                if ("Failed to resolve" in str(e) or "NameResolutionError" in str(e)):
-                    self.logger("   💡 This looks like a DNS resolution problem. Please check your internet connection, DNS settings, or VPN.")
-                break
+                if e.response is not None and e.response.status_code == 403:
+                    self.logger(f"   ⚠️ Download Error (403 Forbidden): {api_original_filename}. This often requires valid cookies.")
+                    self.logger(f"      Will retry... Check your 'Use Cookie' settings if this persists.")
+                    last_exception_for_retry_later = e
+                else:
+                    self.logger(f"   ❌ Download Error (Non-Retryable): {api_original_filename}. Error: {e}")
+                    last_exception_for_retry_later = e
+                    is_permanent_error = True
+                    break
             except Exception as e:
                 self.logger(f"   ❌ Unexpected Download Error: {api_original_filename}: {e}\n{traceback.format_exc(limit=2)}")
                 last_exception_for_retry_later = e
@@ -635,26 +670,22 @@ class PostProcessorWorker:
                 self.logger(f"   🔄 Compressing '{api_original_filename}' to WebP...")
                 try:
                     with Image.open(downloaded_part_file_path) as img:
-                        # Convert to RGB to avoid issues with paletted images or alpha channels in WebP
                         if img.mode not in ('RGB', 'RGBA'):
                             img = img.convert('RGBA')
                         
-                        # Use an in-memory buffer to save the compressed image
                         output_buffer = BytesIO()
                         img.save(output_buffer, format='WebP', quality=85)
                         
-                        # This buffer now holds the compressed data
                         data_to_write_io = output_buffer
                         
-                        # Update the filename to use the .webp extension
                         base, _ = os.path.splitext(filename_to_save_in_main_path)
                         filename_to_save_in_main_path = f"{base}.webp"
                         self.logger(f"   ✅ Compression successful. New size: {len(data_to_write_io.getvalue()) / (1024*1024):.2f} MB")
 
                 except Exception as e_compress:
                     self.logger(f"   ⚠️ Failed to compress '{api_original_filename}': {e_compress}. Saving original file instead.")
-                    data_to_write_io = None # Ensure we fall back to saving the original
-
+                    data_to_write_io = None
+            
             effective_save_folder = target_folder_path
             base_name, extension = os.path.splitext(filename_to_save_in_main_path)
             counter = 1
@@ -671,17 +702,14 @@ class PostProcessorWorker:
 
             try:
                 if data_to_write_io:
-                    # Write the compressed data from the in-memory buffer
                     with open(final_save_path, 'wb') as f_out:
                         f_out.write(data_to_write_io.getvalue())
-                    # Clean up the original downloaded part file
                     if downloaded_part_file_path and os.path.exists(downloaded_part_file_path):
                         try:
                             os.remove(downloaded_part_file_path)
                         except OSError as e_rem:
                             self.logger(f"  -> Failed to remove .part after compression: {e_rem}")
                 else:
-                    # No compression was done, just rename the original file
                     if downloaded_part_file_path and os.path.exists(downloaded_part_file_path):
                         time.sleep(0.1)
                         os.rename(downloaded_part_file_path, final_save_path)
@@ -728,7 +756,7 @@ class PostProcessorWorker:
                         self.logger(f"   -> Failed to remove partially saved file: {final_save_path}")
 
                 permanent_failure_details = {
-                    'file_info': file_info, 'target_folder_path': target_folder_path, 'headers': headers,
+                    'file_info': file_info, 'target_folder_path': target_folder_path, 'headers': file_download_headers,
                     'original_post_id_for_log': original_post_id_for_log, 'post_title': post_title,
                     'file_index_in_post': file_index_in_post, 'num_files_in_this_post': num_files_in_this_post,
                     'forced_filename_override': filename_to_save_in_main_path,
@@ -742,7 +770,7 @@ class PostProcessorWorker:
             details_for_failure = {
                 'file_info': file_info, 
                 'target_folder_path': target_folder_path, 
-                'headers': headers,
+                'headers': file_download_headers,
                 'original_post_id_for_log': original_post_id_for_log, 
                 'post_title': post_title,
                 'file_index_in_post': file_index_in_post, 
@@ -1044,7 +1072,7 @@ class PostProcessorWorker:
                     determined_post_save_path_for_history = os.path.join(determined_post_save_path_for_history, base_folder_names_for_post_content[0])
 
             if not self.extract_links_only and self.use_post_subfolders:
-                cleaned_post_title_for_sub = clean_folder_name(post_title)
+                cleaned_post_title_for_sub = robust_clean_name(post_title)
                 post_id_for_fallback = self.post.get('id', 'unknown_id')
 
                 if not cleaned_post_title_for_sub or cleaned_post_title_for_sub == "untitled_folder":
@@ -1626,7 +1654,7 @@ class PostProcessorWorker:
                             self._download_single_file,
                             file_info=file_info_to_dl,
                             target_folder_path=current_path_for_file_instance,
-                            headers=headers, original_post_id_for_log=post_id, skip_event=self.skip_current_file_flag,
+                            post_page_url=post_page_url,  original_post_id_for_log=post_id, skip_event=self.skip_current_file_flag,
                             post_title=post_title, manga_date_file_counter_ref=manga_date_counter_to_pass,
                             manga_global_file_counter_ref=manga_global_counter_to_pass, folder_context_name_for_history=folder_context_for_file,
                             file_index_in_post=file_idx, num_files_in_this_post=len(files_to_download_info_list)
@@ -1783,6 +1811,8 @@ class DownloadThread(QThread):
                  remove_from_filename_words_list=None,
                  manga_date_prefix='',
                  allow_multipart_download=True,
+                 multipart_parts_count=4, 
+                 multipart_min_size_mb=100, 
                  selected_cookie_file=None,
                  override_output_dir=None,
                  app_base_dir=None,
@@ -1845,6 +1875,8 @@ class DownloadThread(QThread):
         self.remove_from_filename_words_list = remove_from_filename_words_list
         self.manga_date_prefix = manga_date_prefix
         self.allow_multipart_download = allow_multipart_download
+        self.multipart_parts_count = multipart_parts_count 
+        self.multipart_min_size_mb = multipart_min_size_mb 
         self.selected_cookie_file = selected_cookie_file
         self.app_base_dir = app_base_dir
         self.cookie_text = cookie_text
@@ -1986,6 +2018,8 @@ class DownloadThread(QThread):
                         'text_only_scope': self.text_only_scope,
                         'text_export_format': self.text_export_format,
                         'single_pdf_mode': self.single_pdf_mode,
+                        'multipart_parts_count': self.multipart_parts_count, 
+                        'multipart_min_size_mb': self.multipart_min_size_mb, 
                         'project_root_dir': self.project_root_dir,
                     }
 

src/ui/dialogs/MultipartScopeDialog.py

@@ -0,0 +1,118 @@
+# multipart_scope_dialog.py
+from PyQt5.QtWidgets import (
+    QDialog, QVBoxLayout, QGroupBox, QRadioButton, QDialogButtonBox, QButtonGroup,
+    QLabel, QLineEdit, QHBoxLayout, QFrame
+)
+from PyQt5.QtGui import QIntValidator
+from PyQt5.QtCore import Qt
+
+# It's good practice to get this constant from the source
+# but for this example, we will define it here.
+MAX_PARTS = 16 
+
+class MultipartScopeDialog(QDialog):
+    """
+    A dialog to let the user select the scope, number of parts, and minimum size for multipart downloads.
+    """
+    SCOPE_VIDEOS = 'videos'
+    SCOPE_ARCHIVES = 'archives'
+    SCOPE_BOTH = 'both'
+
+    def __init__(self, current_scope='both', current_parts=4, current_min_size_mb=100, parent=None):
+        super().__init__(parent)
+        self.setWindowTitle("Multipart Download Options")
+        self.setWindowFlags(self.windowFlags() & ~Qt.WindowContextHelpButtonHint)
+        self.setMinimumWidth(350)
+
+        # Main Layout
+        layout = QVBoxLayout(self)
+
+        # --- Options Group for Scope ---
+        self.options_group_box = QGroupBox("Apply multipart downloads to:")
+        options_layout = QVBoxLayout()
+        # ... (Radio buttons and button group code remains unchanged) ...
+        self.radio_videos = QRadioButton("Videos Only")
+        self.radio_archives = QRadioButton("Archives Only (.zip, .rar, etc.)")
+        self.radio_both = QRadioButton("Both Videos and Archives")
+
+        if current_scope == self.SCOPE_VIDEOS:
+            self.radio_videos.setChecked(True)
+        elif current_scope == self.SCOPE_ARCHIVES:
+            self.radio_archives.setChecked(True)
+        else:
+            self.radio_both.setChecked(True)
+
+        self.button_group = QButtonGroup(self)
+        self.button_group.addButton(self.radio_videos)
+        self.button_group.addButton(self.radio_archives)
+        self.button_group.addButton(self.radio_both)
+
+        options_layout.addWidget(self.radio_videos)
+        options_layout.addWidget(self.radio_archives)
+        options_layout.addWidget(self.radio_both)
+        self.options_group_box.setLayout(options_layout)
+        layout.addWidget(self.options_group_box)
+
+        # --- START: MODIFIED Download Settings Group ---
+        self.settings_group_box = QGroupBox("Download settings:")
+        settings_layout = QVBoxLayout()
+
+        # Layout for Parts count
+        parts_layout = QHBoxLayout()
+        self.parts_label = QLabel("Number of download parts per file:")
+        self.parts_input = QLineEdit(str(current_parts))
+        self.parts_input.setValidator(QIntValidator(2, MAX_PARTS, self))
+        self.parts_input.setFixedWidth(40)
+        self.parts_input.setToolTip(f"Set the number of concurrent connections per file (2-{MAX_PARTS}).")
+        parts_layout.addWidget(self.parts_label)
+        parts_layout.addStretch()
+        parts_layout.addWidget(self.parts_input)
+        settings_layout.addLayout(parts_layout)
+
+        # Layout for Minimum Size
+        size_layout = QHBoxLayout()
+        self.size_label = QLabel("Minimum file size for multipart (MB):")
+        self.size_input = QLineEdit(str(current_min_size_mb))
+        self.size_input.setValidator(QIntValidator(10, 10000, self)) # Min 10MB, Max ~10GB
+        self.size_input.setFixedWidth(40)
+        self.size_input.setToolTip("Files smaller than this will use a normal, single-part download.")
+        size_layout.addWidget(self.size_label)
+        size_layout.addStretch()
+        size_layout.addWidget(self.size_input)
+        settings_layout.addLayout(size_layout)
+
+        self.settings_group_box.setLayout(settings_layout)
+        layout.addWidget(self.settings_group_box)
+        # --- END: MODIFIED Download Settings Group ---
+
+        # OK and Cancel Buttons
+        self.button_box = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel)
+        self.button_box.accepted.connect(self.accept)
+        self.button_box.rejected.connect(self.reject)
+        layout.addWidget(self.button_box)
+
+        self.setLayout(layout)
+
+    def get_selected_scope(self):
+        # ... (This method remains unchanged) ...
+        if self.radio_videos.isChecked():
+            return self.SCOPE_VIDEOS
+        if self.radio_archives.isChecked():
+            return self.SCOPE_ARCHIVES
+        return self.SCOPE_BOTH
+
+    def get_selected_parts(self):
+        # ... (This method remains unchanged) ...
+        try:
+            parts = int(self.parts_input.text())
+            return max(2, min(parts, MAX_PARTS))
+        except (ValueError, TypeError):
+            return 4
+
+    def get_selected_min_size(self):
+        """Returns the selected minimum size in MB as an integer."""
+        try:
+            size = int(self.size_input.text())
+            return max(10, min(size, 10000)) # Enforce valid range
+        except (ValueError, TypeError):
+            return 100 # Return a safe default

src/ui/dialogs/SinglePDF.py

@@ -3,8 +3,27 @@ import re
 try:
     from fpdf import FPDF
     FPDF_AVAILABLE = True
+
+    # --- FIX: Move the class definition inside the try block ---
+    class PDF(FPDF):
+        """Custom PDF class to handle headers and footers."""
+        def header(self):
+            pass 
+
+        def footer(self):
+            self.set_y(-15)
+            if self.font_family:
+                 self.set_font(self.font_family, '', 8)
+            else:
+                 self.set_font('Arial', '', 8)
+            self.cell(0, 10, 'Page ' + str(self.page_no()), 0, 0, 'C')
+
 except ImportError:
     FPDF_AVAILABLE = False
+    # If the import fails, FPDF and PDF will not be defined,
+    # but the program won't crash here.
+    FPDF = None 
+    PDF = None
 
 def strip_html_tags(text):
     if not text:
@@ -12,19 +31,6 @@ def strip_html_tags(text):
     clean = re.compile('<.*?>')
     return re.sub(clean, '', text)
 
-class PDF(FPDF):
-    """Custom PDF class to handle headers and footers."""
-    def header(self):
-        pass 
-
-    def footer(self):
-        self.set_y(-15)
-        if self.font_family:
-             self.set_font(self.font_family, '', 8)
-        else:
-             self.set_font('Arial', '', 8)
-        self.cell(0, 10, 'Page ' + str(self.page_no()), 0, 0, 'C')
-
 def create_single_pdf_from_content(posts_data, output_filename, font_path, logger=print):
     """
     Creates a single, continuous PDF, correctly formatting both descriptions and comments.
@@ -68,7 +74,7 @@ def create_single_pdf_from_content(posts_data, output_filename, font_path, logge
                 pdf.ln(10)
 
         pdf.set_font(default_font_family, 'B', 16)
-        pdf.multi_cell(w=0, h=10, text=post.get('title', 'Untitled Post'), align='L')
+        pdf.multi_cell(w=0, h=10, txt=post.get('title', 'Untitled Post'), align='L')
         pdf.ln(5)
 
         if 'comments' in post and post['comments']:
@@ -89,7 +95,7 @@ def create_single_pdf_from_content(posts_data, output_filename, font_path, logge
                 pdf.ln(10)
 
                 pdf.set_font(default_font_family, '', 11)
-                pdf.multi_cell(0, 7, body)
+                pdf.multi_cell(w=0, h=7, txt=body)
                 
                 if comment_index < len(comments_list) - 1:
                     pdf.ln(3)
@@ -97,7 +103,7 @@ def create_single_pdf_from_content(posts_data, output_filename, font_path, logge
                     pdf.ln(3)
         elif 'content' in post:
             pdf.set_font(default_font_family, '', 12)
-            pdf.multi_cell(w=0, h=7, text=post.get('content', 'No Content'))
+            pdf.multi_cell(w=0, h=7, txt=post.get('content', 'No Content'))
     
     try:
         pdf.output(output_filename)
@@ -105,4 +111,4 @@ def create_single_pdf_from_content(posts_data, output_filename, font_path, logge
         return True
     except Exception as e:
         logger(f"❌ A critical error occurred while saving the final PDF: {e}")
-        return False
+        return False

src/ui/main_window.py

@@ -58,6 +58,7 @@ from .dialogs.MoreOptionsDialog import MoreOptionsDialog
 from .dialogs.SinglePDF import create_single_pdf_from_content
 from .dialogs.SupportDialog import SupportDialog
 from .dialogs.KeepDuplicatesDialog import KeepDuplicatesDialog
+from .dialogs.MultipartScopeDialog import MultipartScopeDialog
 
 class DynamicFilterHolder:
     """A thread-safe class to hold and update character filters during a download."""
@@ -222,6 +223,9 @@ class DownloaderApp (QWidget ):
         self.only_links_log_display_mode = LOG_DISPLAY_LINKS
         self.mega_download_log_preserved_once = False
         self.allow_multipart_download_setting = False
+        self.multipart_scope = 'both'
+        self.multipart_parts_count = 4     
+        self.multipart_min_size_mb = 100 
         self.use_cookie_setting = False
         self.scan_content_images_setting = self.settings.value(SCAN_CONTENT_IMAGES_KEY, False, type=bool)
         self.cookie_text_setting = ""
@@ -236,7 +240,8 @@ class DownloaderApp (QWidget ):
         self.session_temp_files = []
         self.single_pdf_mode = False
         self.save_creator_json_enabled_this_session = True 
-        
+        self.is_single_post_session = False 
+
         print(f"ℹ️ Known.txt will be loaded/saved at: {self.config_file}")
 
         try:
@@ -267,7 +272,7 @@ class DownloaderApp (QWidget ):
         self.download_location_label_widget = None
         self.remove_from_filename_label_widget = None
         self.skip_words_label_widget = None
-        self.setWindowTitle("Kemono Downloader v6.2.1")
+        self.setWindowTitle("Kemono Downloader v6.3.0")
         setup_ui(self)
         self._connect_signals()
         self.log_signal.emit("ℹ️ Local API server functionality has been removed.")
@@ -2689,16 +2694,13 @@ class DownloaderApp (QWidget ):
         url_text =self .link_input .text ().strip ()if self .link_input else ""
         _ ,_ ,post_id =extract_post_info (url_text )
 
-        # --- START: MODIFIED LOGIC ---
         is_creator_feed =not post_id if url_text else False 
         is_single_post = bool(post_id)
         is_favorite_mode_on =self .favorite_mode_checkbox .isChecked ()if self .favorite_mode_checkbox else False 
 
-        # If the download queue contains items selected from the popup, treat it as a single-post context for UI purposes.
         if self.favorite_download_queue and all(item.get('type') == 'single_post_from_popup' for item in self.favorite_download_queue):
             is_single_post = True
 
-        # Allow Manga Mode checkbox for any valid URL (creator or single post) or if single posts are queued.
         can_enable_manga_checkbox = (is_creator_feed or is_single_post) and not is_favorite_mode_on
         
         if self .manga_mode_checkbox :
@@ -2709,12 +2711,10 @@ class DownloaderApp (QWidget ):
 
         manga_mode_effectively_on = can_enable_manga_checkbox and checked
 
-        # If it's a single post context, prevent sequential styles from being selected as they don't apply.
         sequential_styles = [STYLE_DATE_BASED, STYLE_POST_TITLE_GLOBAL_NUMBERING]
         if is_single_post and self.manga_filename_style in sequential_styles:
-            self.manga_filename_style = STYLE_POST_TITLE # Default to a safe, non-sequential style
+            self.manga_filename_style = STYLE_POST_TITLE 
             self._update_manga_filename_style_button_text()
-        # --- END: MODIFIED LOGIC ---
 
         if self .manga_rename_toggle_button :
             self .manga_rename_toggle_button .setVisible (manga_mode_effectively_on and not (is_only_links_mode or is_only_archives_mode or is_only_audio_mode ))
@@ -2748,11 +2748,9 @@ class DownloaderApp (QWidget ):
                 self .manga_date_prefix_input .setMaximumWidth (16777215 )
                 self .manga_date_prefix_input .setMinimumWidth (0 )
 
-        if hasattr (self ,'multipart_toggle_button'):
-
-            hide_multipart_button_due_mode =is_only_links_mode or is_only_archives_mode or is_only_audio_mode 
-            hide_multipart_button_due_manga_mode =manga_mode_effectively_on 
-            self .multipart_toggle_button .setVisible (not (hide_multipart_button_due_mode or hide_multipart_button_due_manga_mode ))
+        if hasattr(self, 'multipart_toggle_button'):
+            hide_multipart_button_due_mode = is_only_links_mode or is_only_archives_mode or is_only_audio_mode
+            self.multipart_toggle_button.setVisible(not hide_multipart_button_due_mode)
 
         self ._update_multithreading_for_date_mode ()
 
@@ -2953,9 +2951,6 @@ class DownloaderApp (QWidget ):
         
         service, user_id, post_id_from_url = extract_post_info(api_url)
 
-        # --- START: MODIFIED SECTION ---
-        # This check is now smarter. It only triggers the error if the item from the queue
-        # was supposed to be a post ('single_post_from_popup', etc.) but couldn't be parsed.
         if direct_api_url and not post_id_from_url and item_type_from_queue and 'post' in item_type_from_queue:
             self.log_signal.emit(f"❌ CRITICAL ERROR: Could not parse post ID from the queued POST URL: {api_url}")
             self.log_signal.emit("   Skipping this item. This might be due to an unsupported URL format or a temporary issue.")
@@ -2966,50 +2961,55 @@ class DownloaderApp (QWidget ):
                 kept_original_names_list=[]
             )
             return False
-        # --- END: MODIFIED SECTION ---
 
         if not service or not user_id:
             QMessageBox.critical(self, "Input Error", "Invalid or unsupported URL format.")
             return False
 
         self.save_creator_json_enabled_this_session = self.settings.value(SAVE_CREATOR_JSON_KEY, True, type=bool)
+        self.is_single_post_session = bool(post_id_from_url) 
 
-        creator_profile_data = {}
-        if self.save_creator_json_enabled_this_session:
-            creator_name_for_profile = None
-            if self.is_processing_favorites_queue and self.current_processing_favorite_item_info:
-                creator_name_for_profile = self.current_processing_favorite_item_info.get('name_for_folder')
-            else:
-                creator_key = (service.lower(), str(user_id))
-                creator_name_for_profile = self.creator_name_cache.get(creator_key)
+        if not self.is_single_post_session:
+            self.save_creator_json_enabled_this_session = self.settings.value(SAVE_CREATOR_JSON_KEY, True, type=bool)
 
-            if not creator_name_for_profile:
-                creator_name_for_profile = f"{service}_{user_id}"
-                self.log_signal.emit(f"⚠️ Creator name not in cache. Using '{creator_name_for_profile}' for profile file.")
+            creator_profile_data = {}
+            if self.save_creator_json_enabled_this_session:
+                creator_name_for_profile = None
+                if self.is_processing_favorites_queue and self.current_processing_favorite_item_info:
+                    creator_name_for_profile = self.current_processing_favorite_item_info.get('name_for_folder')
+                else:
+                    creator_key = (service.lower(), str(user_id))
+                    creator_name_for_profile = self.creator_name_cache.get(creator_key)
 
-            creator_profile_data = self._setup_creator_profile(creator_name_for_profile, self.session_file_path)
-        
-            current_settings = self._get_current_ui_settings_as_dict(api_url_override=api_url, output_dir_override=effective_output_dir_for_run)
-            creator_profile_data['settings'] = current_settings
-        
-            creator_profile_data.setdefault('creator_url', [])
-            if api_url not in creator_profile_data['creator_url']:
-                creator_profile_data['creator_url'].append(api_url)
+                if not creator_name_for_profile:
+                    creator_name_for_profile = f"{service}_{user_id}"
+                    self.log_signal.emit(f"⚠️ Creator name not in cache. Using '{creator_name_for_profile}' for profile file.")
 
-            creator_profile_data.setdefault('processed_post_ids', [])
-            self._save_creator_profile(creator_name_for_profile, creator_profile_data, self.session_file_path)
-            self.log_signal.emit(f"✅ Profile for '{creator_name_for_profile}' loaded/created. Settings saved.")
+                creator_profile_data = self._setup_creator_profile(creator_name_for_profile, self.session_file_path)
+            
+                current_settings = self._get_current_ui_settings_as_dict(api_url_override=api_url, output_dir_override=effective_output_dir_for_run)
+                creator_profile_data['settings'] = current_settings
+            
+                creator_profile_data.setdefault('creator_url', [])
+                if api_url not in creator_profile_data['creator_url']:
+                    creator_profile_data['creator_url'].append(api_url)
+
+                if self.active_update_profile:
+                    self.log_signal.emit("   Update session active: Loading existing processed post IDs to find new content.")
+                    profile_processed_ids = set(creator_profile_data.get('processed_post_ids', []))
+                
+                elif not is_restore:
+                    self.log_signal.emit("   Fresh download session: Clearing previous post history for this creator to re-download all.")
+                    if 'processed_post_ids' in creator_profile_data:
+                        creator_profile_data['processed_post_ids'] = []
+
+                creator_profile_data.setdefault('processed_post_ids', [])
+                self._save_creator_profile(creator_name_for_profile, creator_profile_data, self.session_file_path)
+                self.log_signal.emit(f"✅ Profile for '{creator_name_for_profile}' loaded/created. Settings saved.")
         
         profile_processed_ids = set()
 
-        if self.active_update_profile:
-            self.log_signal.emit("   Update session active: Loading existing processed post IDs to find new content.")
-            profile_processed_ids = set(creator_profile_data.get('processed_post_ids', []))
         
-        elif not is_restore:
-            self.log_signal.emit("   Fresh download session: Clearing previous post history for this creator to re-download all.")
-            if 'processed_post_ids' in creator_profile_data:
-                creator_profile_data['processed_post_ids'] = []
 
         session_processed_ids = set(processed_post_ids_for_restore)
         combined_processed_ids = session_processed_ids.union(profile_processed_ids)
@@ -3453,6 +3453,9 @@ class DownloaderApp (QWidget ):
             'num_file_threads_for_worker': effective_num_file_threads_per_worker,
             'manga_date_file_counter_ref': manga_date_file_counter_ref_for_thread,
             'allow_multipart_download': allow_multipart,
+            'multipart_scope': self.multipart_scope,
+            'multipart_parts_count': self.multipart_parts_count,
+            'multipart_min_size_mb': self.multipart_min_size_mb,
             'cookie_text': cookie_text_from_input,
             'selected_cookie_file': selected_cookie_file_path_for_backend,
             'manga_global_file_counter_ref': manga_global_file_counter_ref_for_thread,
@@ -3497,7 +3500,7 @@ class DownloaderApp (QWidget ):
                     'manga_mode_active', 'unwanted_keywords', 'manga_filename_style', 'scan_content_for_images',
                     'allow_multipart_download', 'use_cookie', 'cookie_text', 'app_base_dir', 'selected_cookie_file', 'override_output_dir', 'project_root_dir',
                     'text_only_scope', 'text_export_format',
-                    'single_pdf_mode',
+                    'single_pdf_mode','multipart_parts_count', 'multipart_min_size_mb', 
                     'use_date_prefix_for_subfolder','keep_in_post_duplicates', 'keep_duplicates_mode',
                     'keep_duplicates_limit', 'downloaded_hash_counts', 'downloaded_hash_counts_lock',
                     'processed_post_ids'
@@ -3514,7 +3517,6 @@ class DownloaderApp (QWidget ):
             self.is_paused = False
         return True
 
-
     def restore_download(self):
         """Initiates the download restoration process."""
         if self._is_download_active():
@@ -3960,8 +3962,8 @@ class DownloaderApp (QWidget ):
         self.log_signal.emit("="*40)
 
     def _add_to_history_candidates(self, history_data):
-        """Adds processed post data to the history candidates list and updates the creator profile."""
-        if self.save_creator_json_enabled_this_session:
+        """Adds processed post data to the history candidates list and updates the creator profile."""        
+        if self.save_creator_json_enabled_this_session and not self.is_single_post_session:
             post_id = history_data.get('post_id')
             service = history_data.get('service')
             user_id = history_data.get('user_id')
@@ -3969,7 +3971,6 @@ class DownloaderApp (QWidget ):
                 creator_key = (service.lower(), str(user_id))
                 creator_name = self.creator_name_cache.get(creator_key, f"{service}_{user_id}")
                 
-                # Load the profile data before using it to prevent NameError
                 profile_data = self._setup_creator_profile(creator_name, self.session_file_path)
                 
                 if post_id not in profile_data.get('processed_post_ids', []):
@@ -3982,6 +3983,7 @@ class DownloaderApp (QWidget ):
             history_data['creator_name'] = self.creator_name_cache.get(creator_key, history_data.get('user_id','Unknown'))
             self.download_history_candidates.append(history_data)
 
+
     def _finalize_download_history (self ):
         """Processes candidates and selects the final 3 history entries.
         Only updates final_download_history_entries if new candidates are available.
@@ -4553,44 +4555,51 @@ class DownloaderApp (QWidget ):
             self .active_retry_futures_map [future ]=job_details 
             self .active_retry_futures .append (future )
 
-    def _execute_single_file_retry (self ,job_details ,common_args ):
-        """Executes a single file download retry attempt."""
-        dummy_post_data ={'id':job_details ['original_post_id_for_log'],'title':job_details ['post_title']}
+    def _execute_single_file_retry(self, job_details, common_args):
+        """
+        Executes a single file download retry attempt. This function is called by the retry thread pool.
+        """
+        # This worker is temporary and only for this retry task.
+        # It needs dummy post data to initialize.
+        dummy_post_data = {'id': job_details['original_post_id_for_log'], 'title': job_details['post_title']}
 
-        ppw_init_args ={
-        **common_args ,
-        'post_data':dummy_post_data ,
-        'service':job_details .get ('service','unknown_service'),
-        'user_id':job_details .get ('user_id','unknown_user'),
-        'api_url_input':job_details .get ('api_url_input',''),
-        'manga_mode_active':job_details .get ('manga_mode_active_for_file',False ),
-        'manga_filename_style':job_details .get ('manga_filename_style_for_file',STYLE_POST_TITLE ),
-        'scan_content_for_images':common_args .get ('scan_content_for_images',False ),
-        'use_cookie':common_args .get ('use_cookie',False ),
-        'cookie_text':common_args .get ('cookie_text',""),
-        'selected_cookie_file':common_args .get ('selected_cookie_file',None ),
-        'app_base_dir':common_args .get ('app_base_dir',None ),
+        # Reconstruct the post_page_url, which is needed by the download function
+        service = job_details.get('service', 'unknown_service')
+        user_id = job_details.get('user_id', 'unknown_user')
+        post_id = job_details.get('original_post_id_for_log', 'unknown_id')
+        api_url_input = job_details.get('api_url_input', '')
+        parsed_api_url = urlparse(api_url_input)
+        api_domain = parsed_api_url.netloc if parsed_api_url.netloc else self._get_domain_for_service(service)
+        post_page_url = f"https://{api_domain}/{service}/user/{user_id}/post/{post_id}"
+
+        # Prepare all arguments for the PostProcessorWorker
+        ppw_init_args = {
+            **common_args,
+            'post_data': dummy_post_data,
+            'service': service,
+            'user_id': user_id,
+            'api_url_input': api_url_input
         }
-        worker =PostProcessorWorker (**ppw_init_args )
 
-        dl_count ,skip_count ,filename_saved ,original_kept ,status ,_ =worker ._download_single_file (
-        file_info =job_details ['file_info'],
-        target_folder_path =job_details ['target_folder_path'],
-        headers =job_details ['headers'],
-        original_post_id_for_log =job_details ['original_post_id_for_log'],
-        skip_event =None ,
-        post_title =job_details ['post_title'],
-        file_index_in_post =job_details ['file_index_in_post'],
-        num_files_in_this_post =job_details ['num_files_in_this_post'],
-        forced_filename_override =job_details .get ('forced_filename_override')
+        worker = PostProcessorWorker(**ppw_init_args)
+
+        # Call the download method with the corrected arguments
+        dl_count, skip_count, filename_saved, original_kept, status, _ = worker._download_single_file(
+            file_info=job_details['file_info'],
+            target_folder_path=job_details['target_folder_path'],
+            post_page_url=post_page_url, # Using the correct argument
+            original_post_id_for_log=job_details['original_post_id_for_log'],
+            skip_event=None,
+            post_title=job_details['post_title'],
+            file_index_in_post=job_details['file_index_in_post'],
+            num_files_in_this_post=job_details['num_files_in_this_post'],
+            forced_filename_override=job_details.get('forced_filename_override')
         )
 
+        is_successful_download = (status == FILE_DOWNLOAD_STATUS_SUCCESS)
+        is_resolved_as_skipped = (status == FILE_DOWNLOAD_STATUS_SKIPPED)
 
-
-        is_successful_download =(status ==FILE_DOWNLOAD_STATUS_SUCCESS )
-        is_resolved_as_skipped =(status ==FILE_DOWNLOAD_STATUS_SKIPPED )
-
-        return is_successful_download or is_resolved_as_skipped 
+        return is_successful_download or is_resolved_as_skipped
 
     def _handle_retry_future_result (self ,future ):
         self .processed_retry_count +=1 
@@ -4937,14 +4946,15 @@ class DownloaderApp (QWidget ):
         with QMutexLocker (self .prompt_mutex ):self ._add_character_response =result 
         self .log_signal .emit (f"    Main thread received character prompt response: {'Action resulted in addition/confirmation'if result else 'Action resulted in no addition/declined'}")
 
-    def _update_multipart_toggle_button_text (self ):
-        if hasattr (self ,'multipart_toggle_button'):
-            if self .allow_multipart_download_setting :
-                self .multipart_toggle_button .setText (self ._tr ("multipart_on_button_text","Multi-part: ON"))
-                self .multipart_toggle_button .setToolTip (self ._tr ("multipart_on_button_tooltip","Tooltip for multipart ON"))
-            else :
-                self .multipart_toggle_button .setText (self ._tr ("multipart_off_button_text","Multi-part: OFF"))
-                self .multipart_toggle_button .setToolTip (self ._tr ("multipart_off_button_tooltip","Tooltip for multipart OFF"))
+    def _update_multipart_toggle_button_text(self):
+        if hasattr(self, 'multipart_toggle_button'):
+            if self.allow_multipart_download_setting:
+                scope_text = self.multipart_scope.capitalize()
+                self.multipart_toggle_button.setText(self._tr("multipart_on_button_text", f"Multi-part: {scope_text}"))
+                self.multipart_toggle_button.setToolTip(self._tr("multipart_on_button_tooltip", f"Multipart download is ON. Applied to: {scope_text} files. Click to change."))
+            else:
+                self.multipart_toggle_button.setText(self._tr("multipart_off_button_text", "Multi-part: OFF"))
+                self.multipart_toggle_button.setToolTip(self._tr("multipart_off_button_tooltip", "Multipart download is OFF. Click to enable and set options."))
 
     def _update_error_button_count(self):
         """Updates the Error button text to show the count of failed files."""
@@ -4959,36 +4969,25 @@ class DownloaderApp (QWidget ):
         else:
             self.error_btn.setText(base_text)
 
-    def _toggle_multipart_mode (self ):
-        if not self .allow_multipart_download_setting :
-            msg_box =QMessageBox (self )
-            msg_box .setIcon (QMessageBox .Warning )
-            msg_box .setWindowTitle ("Multi-part Download Advisory")
-            msg_box .setText (
-            "<b>Multi-part download advisory:</b><br><br>"
-            "<ul>"
-            "<li>Best suited for <b>large files</b> (e.g., single post videos).</li>"
-            "<li>When downloading a full creator feed with many small files (like images):"
-            "<ul><li>May not offer significant speed benefits.</li>"
-            "<li>Could potentially make the UI feel <b>choppy</b>.</li>"
-            "<li>May <b>spam the process log</b> with rapid, numerous small download messages.</li></ul></li>"
-            "<li>Consider using the <b>'Videos' filter</b> if downloading a creator feed to primarily target large files for multi-part.</li>"
-            "</ul><br>"
-            "Do you want to enable multi-part download?"
-            )
-            proceed_button =msg_box .addButton ("Proceed Anyway",QMessageBox .AcceptRole )
-            cancel_button =msg_box .addButton ("Cancel",QMessageBox .RejectRole )
-            msg_box .setDefaultButton (proceed_button )
-            msg_box .exec_ ()
-
-            if msg_box .clickedButton ()==cancel_button :
-                self .log_signal .emit ("ℹ️ Multi-part download enabling cancelled by user.")
-                return 
-
-        self .allow_multipart_download_setting =not self .allow_multipart_download_setting 
-        self ._update_multipart_toggle_button_text ()
-        self .settings .setValue (ALLOW_MULTIPART_DOWNLOAD_KEY ,self .allow_multipart_download_setting )
-        self .log_signal .emit (f"ℹ️ Multi-part download set to: {'Enabled'if self .allow_multipart_download_setting else 'Disabled'}")
+    def _toggle_multipart_mode(self):
+        """
+        Opens the Multipart Scope Dialog and updates settings based on user choice.
+        """
+        current_scope = self.multipart_scope if self.allow_multipart_download_setting else 'both'
+        dialog = MultipartScopeDialog(current_scope, self.multipart_parts_count, self.multipart_min_size_mb, self)
+        
+        if dialog.exec_() == QDialog.Accepted:
+            self.multipart_scope = dialog.get_selected_scope()
+            self.multipart_parts_count = dialog.get_selected_parts()
+            self.multipart_min_size_mb = dialog.get_selected_min_size() # Get the new value
+            self.allow_multipart_download_setting = True
+            self.log_signal.emit(f"ℹ️ Multi-part download enabled: Scope='{self.multipart_scope.capitalize()}', Parts={self.multipart_parts_count}, Min Size={self.multipart_min_size_mb} MB")
+        else:
+            self.allow_multipart_download_setting = False
+            self.log_signal.emit("ℹ️ Multi-part download setting remains OFF.")
+            
+        self._update_multipart_toggle_button_text()
+        self.settings.setValue(ALLOW_MULTIPART_DOWNLOAD_KEY, self.allow_multipart_download_setting)
 
     def _open_known_txt_file (self ):
         if not os .path .exists (self .config_file ):