# import streamlit as st
# import yt_dlp
# import os
# from pathlib import Path

# # Set page config
# st.set_page_config(page_title="YouTube Video Downloader", page_icon="📺")

# # Set the title of the app
# st.title("YouTube Video Downloader 📺")

# # Create output directory if it doesn't exist
# output_dir = Path("downloads")
# output_dir.mkdir(exist_ok=True)

# # Input field for YouTube video URL
# video_url = st.text_input("Enter YouTube Video URL:", placeholder="https://www.youtube.com/watch?v=...")

# # Function to download video
# def download_video(url):
#     try:
#         ydl_opts = {
#             'format': 'bestvideo+bestaudio/best',
#             'outtmpl': str(output_dir / '%(title)s.%(ext)s'),
#             'merge_output_format': 'webm',
#             # Add these options to mimic browser behavior
#             'quiet': True,
#             'no_warnings': True,
#             'user_agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
#             'referer': 'https://www.youtube.com/',
#             'cookiefile': 'youtube.com_cookies.txt',  # 쿠키 파일 사용
#             'socket_timeout': 30,
#             'http_chunk_size': 10485760,  # 10MB
#         }

#         # Progress placeholder
#         progress_bar = st.progress(0)
#         status_text = st.empty()
        
#         def progress_hook(d):
#             if d['status'] == 'downloading':
#                 try:
#                     progress = d['downloaded_bytes'] / d['total_bytes']
#                     progress_bar.progress(progress)
#                     status_text.text(f"Downloading: {progress:.1%}")
#                 except:
#                     status_text.text("Downloading... (size unknown)")
#             elif d['status'] == 'finished':
#                 progress_bar.progress(1.0)
#                 status_text.text("Processing...")

#         ydl_opts['progress_hooks'] = [progress_hook]
        
#         with yt_dlp.YoutubeDL(ydl_opts) as ydl:
#             info = ydl.extract_info(url, download=True)
#             filename = ydl.prepare_filename(info)
#             return filename

#     except Exception as e:
#         st.error(f"An error occurred: {str(e)}")
#         return None

# # Download button
# if st.button("Download"):
#     if video_url:
#         try:
#             with st.spinner("Preparing download..."):
#                 downloaded_file_path = download_video(video_url)
                
#             if downloaded_file_path and os.path.exists(downloaded_file_path):
#                 with open(downloaded_file_path, 'rb') as file:
#                     st.download_button(
#                         label="Click here to download",
#                         data=file,
#                         file_name=os.path.basename(downloaded_file_path),
#                         mime="application/octet-stream"
#                     )
#                 st.success("✅ Download ready!")
#             else:
#                 st.error("❌ Download failed. Please try again.")
#         except Exception as e:
#             st.error(f"❌ An error occurred: {str(e)}")
#     else:
#         st.warning("⚠️ Please enter a valid YouTube URL.")

# # Help section
# with st.expander("ℹ️ Help & Troubleshooting"):
#     st.markdown("""
#     **If you're experiencing download issues:**
    
#     1. Cookie Authentication Method:
#        - Install a browser extension like "Get cookies.txt"
#        - Visit YouTube and ensure you're logged in
#        - Export cookies to 'youtube.com_cookies.txt'
#        - Place the file in the same directory as this app
    
#     2. Alternative Solutions:
#        - Try different videos
#        - Check if the video is public/not age-restricted
#        - Try again later if YouTube is blocking requests
#     """)


# import streamlit as st
# import yt_dlp
# import os
# from pathlib import Path

# # Set page config
# st.set_page_config(page_title="YouTube Video Downloader", page_icon="📺")

# # Set the title of the app
# st.title("YouTube Video Downloader 📺")

# # Create output directory if it doesn't exist
# output_dir = Path("downloads")
# output_dir.mkdir(exist_ok=True)

# # Check if cookies file exists
# COOKIES_FILE = 'youtube.com_cookies.txt'
# has_cookies = os.path.exists(COOKIES_FILE)

# if has_cookies:
#     st.success("✅ Cookie file detected")
# else:
#     st.warning("⚠️ No cookie file found - Some videos might be restricted")

# # Input field for YouTube video URL
# video_url = st.text_input("Enter YouTube Video URL:", placeholder="https://www.youtube.com/watch?v=...")

# def download_video(url):
#     try:
#         ydl_opts = {
#             'format': 'bestvideo+bestaudio/best',
#             'outtmpl': str(output_dir / '%(title)s.%(ext)s'),
#             'merge_output_format': 'webm',
#             'quiet': True,
#             'no_warnings': True,
#             'user_agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
#             'referer': 'https://www.youtube.com/',
#             'http_chunk_size': 10485760
#         }

#         # Add cookies file if available
#         if has_cookies:
#             ydl_opts['cookiefile'] = COOKIES_FILE

#         # Progress placeholder
#         progress_bar = st.progress(0)
#         status_text = st.empty()
        
#         def progress_hook(d):
#             if d['status'] == 'downloading':
#                 try:
#                     progress = d['downloaded_bytes'] / d['total_bytes']
#                     progress_bar.progress(progress)
#                     status_text.text(f"Downloading: {progress:.1%}")
#                 except:
#                     status_text.text("Downloading... (size unknown)")
#             elif d['status'] == 'finished':
#                 progress_bar.progress(1.0)
#                 status_text.text("Processing...")

#         ydl_opts['progress_hooks'] = [progress_hook]
        
#         with yt_dlp.YoutubeDL(ydl_opts) as ydl:
#             info = ydl.extract_info(url, download=True)
#             filename = ydl.prepare_filename(info)
#             return filename

#     except Exception as e:
#         st.error(f"An error occurred: {str(e)}")
#         return None

# # Download button
# if st.button("Download"):
#     if video_url:
#         try:
#             with st.spinner("Preparing download..."):
#                 downloaded_file_path = download_video(video_url)
                
#             if downloaded_file_path and os.path.exists(downloaded_file_path):
#                 with open(downloaded_file_path, 'rb') as file:
#                     st.download_button(
#                         label="Click here to download",
#                         data=file,
#                         file_name=os.path.basename(downloaded_file_path),
#                         mime="application/octet-stream"
#                     )
#                 st.success("✅ Download ready!")
#             else:
#                 st.error("❌ Download failed. Please try again.")
#         except Exception as e:
#             st.error(f"❌ An error occurred: {str(e)}")
#     else:
#         st.warning("⚠️ Please enter a valid YouTube URL.")

# # Help section
# with st.expander("ℹ️ Help & Information"):
#     st.markdown("""
#     **About Cookie Authentication:**
#     - This app uses cookie authentication to bypass YouTube's bot detection
#     - Cookies help the app behave like a logged-in browser
#     - No personal data is stored or transmitted
    
#     **If downloads fail:**
#     1. Check if the video is public
#     2. Verify the URL is correct
#     3. Try a different video
#     4. Try again later if YouTube is blocking requests
#     """)


import streamlit as st
import yt_dlp
import os
from pathlib import Path
from http.cookiejar import MozillaCookieJar
import random
import time

# Constants
COOKIES_FILE = 'youtube.com_cookies.txt'
OUTPUT_DIR = Path("downloads")

# Set page config
st.set_page_config(page_title="YouTube Video Downloader", page_icon="📺")
st.title("YouTube Video Downloader 📺")

# Create output directory if it doesn't exist
OUTPUT_DIR.mkdir(exist_ok=True)

def get_random_user_agent():
    """랜덤 User-Agent 생성"""
    user_agents = [
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36',
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
        'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36',
        'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36',
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:122.0) Gecko/20100101 Firefox/122.0'
    ]
    return random.choice(user_agents)

def validate_cookies():
    """쿠키 파일 유효성 검사 및 갱신"""
    if not os.path.exists(COOKIES_FILE):
        return False, "Cookie file not found"
    
    try:
        cookie_jar = MozillaCookieJar(COOKIES_FILE)
        cookie_jar.load()
        return True, "Cookies loaded successfully"
    except Exception as e:
        return False, f"Cookie error: {str(e)}"

def download_with_retry(url, ydl_opts, max_retries=3, delay=5):
    """재시도 로직이 포함된 다운로드 함수"""
    for attempt in range(max_retries):
        try:
            # 매 시도마다 새로운 User-Agent 사용
            ydl_opts['headers']['User-Agent'] = get_random_user_agent()
            
            with yt_dlp.YoutubeDL(ydl_opts) as ydl:
                info = ydl.extract_info(url, download=True)
                filename = ydl.prepare_filename(info)
                return filename, info
                
        except yt_dlp.utils.DownloadError as e:
            if "Sign in to confirm you're not a bot" in str(e):
                if attempt < max_retries - 1:
                    st.warning(f"Bot detection encountered. Retrying in {delay} seconds... (Attempt {attempt + 1}/{max_retries})")
                    time.sleep(delay)
                    delay *= 2  # 지수 백오프
                    continue
            raise e
        except Exception as e:
            if attempt < max_retries - 1:
                st.warning(f"Error occurred. Retrying... (Attempt {attempt + 1}/{max_retries})")
                time.sleep(delay)
                continue
            raise e

def download_video(url):
    try:
        ydl_opts = {
            'format': 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best',
            'outtmpl': str(OUTPUT_DIR / '%(title)s.%(ext)s'),
            'merge_output_format': 'mp4',
            
            # 쿠키 및 인증 설정
            'cookiefile': COOKIES_FILE,
            'cookiesfrombrowser': ('chrome',),
            
            # 향상된 옵션
            'quiet': True,
            'no_warnings': True,
            'extract_flat': False,
            'socket_timeout': 30,
            'retries': 10,
            'fragment_retries': 10,
            
            # 향상된 헤더
            'headers': {
                'User-Agent': get_random_user_agent(),
                'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
                'Accept-Language': 'en-US,en;q=0.5',
                'Accept-Encoding': 'gzip, deflate, br',
                'Connection': 'keep-alive',
                'Upgrade-Insecure-Requests': '1',
                'Sec-Fetch-Dest': 'document',
                'Sec-Fetch-Mode': 'navigate',
                'Sec-Fetch-Site': 'none',
                'Sec-Fetch-User': '?1',
                'Cache-Control': 'max-age=0',
            },
            
            # 추가 옵션
            'age_limit': None,
            'geo_bypass': True,
            'geo_bypass_country': 'US',
            'sleep_interval': 2,  # 요청 사이 대기 시간
            'max_sleep_interval': 5,
        }
        
        # 진행 상황 표시
        progress_bar = st.progress(0)
        status_text = st.empty()
        
        def progress_hook(d):
            if d['status'] == 'downloading':
                try:
                    progress = d['downloaded_bytes'] / d['total_bytes']
                    progress_bar.progress(progress)
                    status_text.text(f"Downloading: {progress:.1%} | Speed: {d.get('speed_str', 'N/A')} | ETA: {d.get('eta_str', 'N/A')}")
                except:
                    status_text.text(f"Downloading... Speed: {d.get('speed_str', 'N/A')}")
            elif d['status'] == 'finished':
                progress_bar.progress(1.0)
                status_text.text("Processing...")
                
        ydl_opts['progress_hooks'] = [progress_hook]
        
        return download_with_retry(url, ydl_opts)
            
    except Exception as e:
        raise Exception(f"Download error: {str(e)}")

# 쿠키 상태 확인
cookie_valid, cookie_message = validate_cookies()
if not cookie_valid:
    st.warning(f"⚠️ Cookie Issue: {cookie_message}")
else:
    st.success("✅ Cookies loaded successfully")

# 비디오 URL 입력
video_url = st.text_input("Enter YouTube Video URL:", placeholder="https://www.youtube.com/watch?v=...")

# 다운로드 버튼
if st.button("Download Video"):
    if not video_url:
        st.warning("⚠️ Please enter a valid YouTube URL.")
    elif not cookie_valid:
        st.error("❌ Cannot proceed without valid cookies.")
    else:
        try:
            with st.spinner("Preparing download..."):
                downloaded_file_path, video_info = download_video(video_url)
                
            if downloaded_file_path and os.path.exists(downloaded_file_path):
                file_size = os.path.getsize(downloaded_file_path)
                st.info(f"""
                **Download Complete!**
                - File: {os.path.basename(downloaded_file_path)}
                - Size: {file_size / (1024*1024):.1f} MB
                """)
                
                with open(downloaded_file_path, 'rb') as file:
                    st.download_button(
                        label="💾 Download Video",
                        data=file,
                        file_name=os.path.basename(downloaded_file_path),
                        mime="video/mp4"
                    )
            else:
                st.error("❌ Download failed. Please try again.")
        except Exception as e:
            st.error(f"❌ {str(e)}")

# Help 섹션
with st.expander("ℹ️ Troubleshooting Guide"):
    st.markdown("""
    **If you encounter 'Sign in to confirm you're not a bot' error:**
    
    1. Cookie Solution:
       - Make sure you're logged into YouTube in your browser
       - Install 'Get cookies.txt' or similar extension
       - Export fresh cookies and replace the existing cookie file
       
    2. General Tips:
       - Wait a few minutes between download attempts
       - Try using a different video URL
       - Clear your browser cache before exporting cookies
       
    3. Advanced Tips:
       - The app automatically retries downloads with different settings
       - Each retry uses a different User-Agent to avoid detection
       - Built-in delays help avoid triggering YouTube's protection
    """)