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