import os
import cv2
from scenedetect import VideoManager, SceneManager
from scenedetect.detectors import ContentDetector
from moviepy.editor import VideoFileClip
from transformers import CLIPProcessor, CLIPModel
import torch
import yt_dlp
from PIL import Image

device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model = CLIPModel.from_pretrained("openai/clip-vit-base-patch32").to(device)
processor = CLIPProcessor.from_pretrained("openai/clip-vit-base-patch32")

def download_video(url):
    ydl_opts = {
        'format': 'bestvideo[height<=1440]+bestaudio/best[height<=1440]',
        'outtmpl': 'downloaded_video.%(ext)s',
        'merge_output_format': 'mp4',
    }
    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        result = ydl.extract_info(url, download=True)
        video_filename = ydl.prepare_filename(result)
        safe_filename = sanitize_filename(video_filename)
        if os.path.exists(video_filename) and video_filename != safe_filename:
            os.rename(video_filename, safe_filename)
        return safe_filename

def sanitize_filename(filename):
    return "".join([c if c.isalnum() or c in " .-_()" else "_" for c in filename])

def find_scenes(video_path):
    video_manager = VideoManager([video_path])
    scene_manager = SceneManager()
    scene_manager.add_detector(ContentDetector(threshold=30))
    video_manager.set_downscale_factor()
    video_manager.start()
    scene_manager.detect_scenes(frame_source=video_manager)
    scene_list = scene_manager.get_scene_list()
    video_manager.release()
    scenes = [(start.get_timecode(), end.get_timecode()) for start, end in scene_list]
    return scenes

def convert_timestamp_to_seconds(timestamp):
    h, m, s = map(float, timestamp.split(':'))
    return int(h) * 3600 + int(m) * 60 + s

def extract_frames(video_path, start_time, end_time):
    frames = []
    start_seconds = convert_timestamp_to_seconds(start_time)
    end_seconds = convert_timestamp_to_seconds(end_time)
    video_clip = VideoFileClip(video_path).subclip(start_seconds, end_seconds)
    for frame_time in range(0, int(video_clip.duration * video_clip.fps), int(video_clip.fps / 2)):
        frame = video_clip.get_frame(frame_time / video_clip.fps)
        frames.append(frame)
    return frames

def analyze_scenes(video_path, scenes, description):
    highest_prob = 0.0
    best_scene = None

    # Tokenize and encode the description text
    text_inputs = processor(text=[description], return_tensors="pt", padding=True).to(device)
    text_features = model.get_text_features(**text_inputs).detach()

    for scene_num, (start_time, end_time) in enumerate(scenes):
        frames = extract_frames(video_path, start_time, end_time)
        if not frames:
            print(f"Scene {scene_num + 1}: Start={start_time}, End={end_time} - No frames extracted")
            continue

        scene_prob = 0.0
        for frame in frames:
            image = Image.fromarray(frame[..., ::-1])
            image_input = processor(images=image, return_tensors="pt").to(device)
            with torch.no_grad():
                image_features = model.get_image_features(**image_input).detach()
                logits_per_image = torch.cosine_similarity(image_features, text_features)
                scene_prob += logits_per_image.item()

        scene_prob /= len(frames)
        print(f"Scene {scene_num + 1}: Start={start_time}, End={end_time}, Probability={scene_prob}")

        if scene_prob > highest_prob:
            highest_prob = scene_prob
            best_scene = (start_time, end_time)

    if best_scene:
        print(f"Best Scene: Start={best_scene[0]}, End={best_scene[1]}, Probability={highest_prob}")
    else:
        print("No suitable scene found")

    return best_scene

def extract_best_scene(video_path, scene):
    if scene is None:
        return None

    start_time, end_time = scene
    start_seconds = convert_timestamp_to_seconds(start_time)
    end_seconds = convert_timestamp_to_seconds(end_time)
    video_clip = VideoFileClip(video_path).subclip(start_seconds, end_seconds)
    return video_clip

def process_video(video_url, description):
    video_path = download_video(video_url)
    scenes = find_scenes(video_path)
    best_scene = analyze_scenes(video_path, scenes, description)
    final_clip = extract_best_scene(video_path, best_scene)

    if final_clip:
        output_dir = "output"
        os.makedirs(output_dir, exist_ok=True)
        final_clip_path = os.path.join(output_dir, "final_clip.mp4")
        final_clip.write_videofile(final_clip_path, codec='libx264', audio_codec='aac')
        return final_clip_path
    return None