initial

backend/services/youtube_service.py

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+import re
+import yt_dlp
+
+
+def validate_youtube_url(url):
+    """
+    Validate YouTube URL and extract video ID
+
+    Returns:
+        (bool, str): (is_valid, video_id or error_message)
+    """
+    patterns = [
+        r'(?:youtube\.com\/watch\?v=|youtu\.be\/)([\w-]+)',
+        r'youtube\.com\/embed\/([\w-]+)',
+        r'youtube\.com\/v\/([\w-]+)'
+    ]
+
+    for pattern in patterns:
+        match = re.search(pattern, url)
+        if match:
+            return True, match.group(1)
+
+    return False, "Invalid YouTube URL format"
+
+
+def get_video_duration(url):
+    """
+    Get video duration without downloading
+
+    Returns:
+        int: Duration in seconds, or None if failed
+    """
+    try:
+        ydl_opts = {
+            'quiet': True,
+            'no_warnings': True,
+            'extract_flat': True,
+        }
+        with yt_dlp.YoutubeDL(ydl_opts) as ydl:
+            info = ydl.extract_info(url, download=False)
+            return info.get('duration')
+    except Exception as e:
+        print(f"Error getting video duration: {e}")
+        return None
+
+
+def validate_timestamps(start_time, end_time, video_duration=None):
+    """
+    Validate timestamp range
+
+    Args:
+        start_time: Start time in seconds
+        end_time: End time in seconds
+        video_duration: Optional video duration for validation
+
+    Returns:
+        (bool, str): (is_valid, error_message if invalid)
+    """
+    if start_time < 0:
+        return False, "Start time must be non-negative"
+
+    if end_time <= start_time:
+        return False, "End time must be greater than start time"
+
+    if end_time - start_time > 300:  # 5 minutes
+        return False, "Clip duration cannot exceed 5 minutes"
+
+    if video_duration and end_time > video_duration:
+        return False, f"End time exceeds video duration ({video_duration}s)"
+
+    return True, None