import streamlit as st
from pytube import YouTube
from pytube.exceptions import VideoUnavailable

class YouTubeDownloader:
    @staticmethod
    def run():
        st.header("유튜브(Youtube) 영상 URL로 다운로드")
        url = st.text_input("Enter YouTube URL to download:")
        if url:
            YouTubeDownloader.validate_url(url)
            try:
                with st.expander("preview video"):
                    st.video(url)
                if st.button("Download"):
                    YouTubeDownloader.cleanup()
                    file_ = YouTubeDownloader.download_video(url)
                    if file_:  # file_ 이 None이 아닐 때만 비디오 표시
                        st.video(file_)
                        YouTubeDownloader.helper_message()
            except Exception as e:
                st.error(f"Error: {str(e)}")
        st.markdown("예) https://www.youtube.com/watch?v=hXpNj1ChxRI ")

    @staticmethod
    def download_video(url):
        try:
            with st.spinner("Downloading..."):
                yt = YouTube(url)
                stream = yt.streams.filter(progressive=True, file_extension="mp4").first()
                if stream:
                    local_file = stream.download()
                    st.success("Downloaded")
                    return local_file
                else:
                    st.error("No suitable stream found for this video")
                    return None
        except VideoUnavailable:
            st.error("This video is unavailable")
            return None
        except Exception as e:
            st.error(f"An error occurred: {str(e)}")
            return None

    @staticmethod
    def validate_url(url):
        import validators

        if not validators.url(url):
            st.error("URL이 정상적이지 않습니다.")
            st.stop()

    @classmethod
    def cleanup(cls):
        import pathlib
        import glob

        junks = glob.glob("*.mp4")
        for junk in junks:
            pathlib.Path(junk).unlink()

    @classmethod
    def helper_message(cls):
        st.write(
            "영상 화면 우측 하단 ... 버튼을 클릭하면 다운로드 할 수 있습니다."
        )

if __name__ == "__main__":
    YouTubeDownloader.run()