"""
Script to extract the first 30 seconds from the output video.
This script takes the detection_output_improved.mp4 file and creates a demo video
containing only the first 30 seconds for presentation purposes.
"""

from moviepy import VideoFileClip
import os

def cut_first_30_seconds(input_video_path, output_video_path, duration_to_cut=30):
    """
    Extract the first N seconds from a video and save to a new file.
    This creates a demo clip of the specified duration from the start of the video.
    
    Args:
        input_video_path: Path to the input video file
        output_video_path: Path where the output video will be saved
        duration_to_cut: Number of seconds to extract from the beginning (default: 30)
    """
    # Check if input file exists
    if not os.path.exists(input_video_path):
        print(f"Error: Input video file not found: {input_video_path}")
        return False
    
    print(f"Loading video: {input_video_path}")
    
    # Load the video
    video = VideoFileClip(input_video_path)
    
    # Get the total duration
    total_duration = video.duration
    print(f"Original video duration: {total_duration:.2f} seconds")
    
    # Check if video is long enough
    if total_duration <= duration_to_cut:
        print(f"Error: Video is only {total_duration:.2f} seconds long, cannot cut {duration_to_cut} seconds")
        video.close()
        return False
    
    # Extract the first N seconds (keep only the first duration_to_cut seconds)
    print(f"Extracting first {duration_to_cut} seconds...")
    # In moviepy 2.x, use slicing notation to extract video segment
    cut_video = video[:duration_to_cut]
    
    # Write the output video
    print(f"Saving output video to: {output_video_path}")
    cut_video.write_videofile(output_video_path, codec='libx264', audio_codec='aac')
    
    # Clean up
    cut_video.close()
    video.close()
    
    print(f"Successfully extracted first {duration_to_cut} seconds!")
    print(f"Demo video duration: {cut_video.duration:.2f} seconds")
    return True

if __name__ == "__main__":
    # Define paths
    input_folder = "input and output"
    input_video = os.path.join(input_folder, "detection_output_improved.mp4")
    output_video = os.path.join(input_folder, "detection_output_demo_30sec.mp4")
    
    # Extract the first 30 seconds
    success = cut_first_30_seconds(input_video, output_video, duration_to_cut=30)
    
    if success:
        print("\nDone! Check the 'input and output' folder for 'detection_output_demo_30sec.mp4'")
    else:
        print("\nFailed to process video. Please check the error messages above.")