FFMPEG downloader (#36)

* Add ffmpeg_downloader.py

* Move shared download logic to downloader_core.py

* Added Windows support and some misc cleanup

* Fix issue with copying contents of .dmg files

* Add FFMPEGDownloader to engine_manager.py

src/engines/downloaders/downloader_core.py

@@ -0,0 +1,138 @@
+import logging
+import os
+import shutil
+import tarfile
+import tempfile
+import zipfile
+
+import requests
+from tqdm import tqdm
+
+supported_formats = ['.zip', '.tar.xz', '.dmg']
+logger = logging.getLogger()
+
+
+def download_and_extract_app(remote_url, download_location):
+
+    # Create a temp download directory
+    temp_download_dir = tempfile.mkdtemp()
+    temp_downloaded_file_path = os.path.join(temp_download_dir, os.path.basename(remote_url))
+
+    try:
+        output_dir_name = os.path.basename(remote_url)
+        for fmt in supported_formats:
+            output_dir_name = output_dir_name.split(fmt)[0]
+
+        if os.path.exists(os.path.join(download_location, output_dir_name)):
+            logger.error(f"Engine download for {output_dir_name} already exists")
+            return
+
+        if not os.path.exists(temp_downloaded_file_path):
+            # Make a GET request to the URL with stream=True to enable streaming
+            logger.info(f"Downloading {output_dir_name} from {remote_url}")
+            response = requests.get(remote_url, stream=True)
+
+            # Check if the request was successful
+            if response.status_code == 200:
+                # Get the total file size from the "Content-Length" header
+                file_size = int(response.headers.get("Content-Length", 0))
+
+                # Create a progress bar using tqdm
+                progress_bar = tqdm(total=file_size, unit="B", unit_scale=True)
+
+                # Open a file for writing in binary mode
+                with open(temp_downloaded_file_path, "wb") as file:
+                    for chunk in response.iter_content(chunk_size=1024):
+                        if chunk:
+                            # Write the chunk to the file
+                            file.write(chunk)
+                            # Update the progress bar
+                            progress_bar.update(len(chunk))
+
+                # Close the progress bar
+                progress_bar.close()
+                logger.info(f"Successfully downloaded {os.path.basename(temp_downloaded_file_path)}")
+            else:
+                logger.error(f"Failed to download the file. Status code: {response.status_code}")
+
+        os.makedirs(download_location, exist_ok=True)
+
+        # Extract the downloaded file
+        # Process .tar.xz files
+        if temp_downloaded_file_path.lower().endswith('.tar.xz'):
+            try:
+                with tarfile.open(temp_downloaded_file_path, 'r:xz') as tar:
+                    tar.extractall(path=download_location)
+
+                logger.info(
+                    f'Successfully extracted {os.path.basename(temp_downloaded_file_path)} to {download_location}')
+            except tarfile.TarError as e:
+                logger.error(f'Error extracting {temp_downloaded_file_path}: {e}')
+            except FileNotFoundError:
+                logger.error(f'File not found: {temp_downloaded_file_path}')
+
+        # Process .zip files
+        elif temp_downloaded_file_path.lower().endswith('.zip'):
+            try:
+                with zipfile.ZipFile(temp_downloaded_file_path, 'r') as zip_ref:
+                    zip_ref.extractall(download_location)
+                logger.info(
+                    f'Successfully extracted {os.path.basename(temp_downloaded_file_path)} to {download_location}')
+            except zipfile.BadZipFile as e:
+                logger.error(f'Error: {temp_downloaded_file_path} is not a valid ZIP file.')
+            except FileNotFoundError:
+                logger.error(f'File not found: {temp_downloaded_file_path}')
+
+        # Process .dmg files (macOS only)
+        elif temp_downloaded_file_path.lower().endswith('.dmg'):
+            import dmglib
+            dmg = dmglib.DiskImage(temp_downloaded_file_path)
+            for mount_point in dmg.attach():
+                try:
+                    copy_directory_contents(mount_point, os.path.join(download_location, output_dir_name))
+                    logger.info(f'Successfully copied {os.path.basename(temp_downloaded_file_path)} to {download_location}')
+                except FileNotFoundError:
+                    logger.error(f'Error: The source .app bundle does not exist.')
+                except PermissionError:
+                    logger.error(f'Error: Permission denied to copy {download_location}.')
+                except Exception as e:
+                    logger.error(f'An error occurred: {e}')
+            dmg.detach()
+
+        else:
+            logger.error("Unknown file. Unable to extract binary.")
+
+    except Exception as e:
+        logger.exception(e)
+
+    # remove downloaded file on completion
+    shutil.rmtree(temp_download_dir)
+    return download_location
+
+
+# Function to copy directory contents but ignore symbolic links and hidden files
+def copy_directory_contents(src_dir, dest_dir):
+    try:
+        # Create the destination directory if it doesn't exist
+        os.makedirs(dest_dir, exist_ok=True)
+
+        for item in os.listdir(src_dir):
+            item_path = os.path.join(src_dir, item)
+
+            # Ignore symbolic links
+            if os.path.islink(item_path):
+                continue
+
+            # Ignore hidden files or directories (those starting with a dot)
+            if not item.startswith('.'):
+                dest_item_path = os.path.join(dest_dir, item)
+
+                # If it's a directory, recursively copy its contents
+                if os.path.isdir(item_path):
+                    copy_directory_contents(item_path, dest_item_path)
+                else:
+                    # Otherwise, copy the file
+                    shutil.copy2(item_path, dest_item_path)
+
+    except Exception as e:
+        logger.exception(f"Error copying directory contents: {e}")