import subprocess
import os
from django.db.models.signals import post_save
from django.dispatch import receiver
from django.core.files import File
from pathlib import Path
from .models import Lecture


@receiver(post_save, sender=Lecture)
def handle_video_upload(sender, instance, created, **kwargs):
    """
    Variables:
        - file_relative_path:
            path relative to the project directory
            ex: media/lectures/first_video_2/2020-04-04_16-11-20.mkv

        - file_suffix:
            suffix | file extension
            ex: .mkv

        - file_relative_dir:
            project-related directory, without the file name included
            ex: media/lectures/first_video_2

        - file_name_m3u8:
            name of the file containing the .m3u8 extension
            ex: 2020-04-04_16-11-20.m3u8

        - file_tmp_local_dir:
            temporary directory to store files
            ex: /tmp/media/lectures/first_video_2

        - file_tmp_local_output:
            temporary path of the .m3u8 file, where also
            will have the .ts files
            ex: /tmp/media/lectures/first_video_2/2020-04-04_16-11-20.m3u8

        - file_cloudfront_url:
            url of the file uploaded to the cloudfront
            ex: https://d4fmj82j2soe4.cloudfront.net/media/lectures/first_video_2/2020-04-04_16-11-20.mkv
    """

    file_relative_path = Path(instance.file.name)
    file_suffix = file_relative_path.suffix

    if not file_suffix == '.m3u8' and instance.file_type == "V":
        file_relative_dir = os.path.dirname(instance.file.name)

        file_relative_path_m3u8 = file_relative_path.with_suffix(".m3u8")
        file_name_m3u8 = file_relative_path_m3u8.name

        file_tmp_local_dir = f"/tmp/{file_relative_dir}"
        file_tmp_local_output = f"{file_tmp_local_dir}/{file_name_m3u8}"
        file_cloudfront_url = instance.file.url

        # create the local dir for the files
        subprocess.run(['mkdir', '-p', file_tmp_local_dir])

        # convert a video in HLS (.m3u8 and .ts files)
        subprocess.run([
            "ffmpeg",
            "-i",
            file_cloudfront_url,
            "-f",
            "hls",
            file_tmp_local_output
        ])

        # update the instance file field with the new .m3u8 file
        with open(file_tmp_local_output, "r") as file_object:
            print(file_tmp_local_output)
            print(file_name_m3u8)
            file_m3u8 = File(
                name=file_relative_path_m3u8,
                file=file_object)
            instance.file.save(file_name_m3u8, file_m3u8)
            subprocess.run(["rm", "-r", file_tmp_local_dir])

        print("file_relative_path: ", file_relative_path)

        print("file_suffix: ", file_suffix)
        print("file_relative_dir: ", file_relative_dir)
        print("file_name_m3u8: ", file_name_m3u8)
        print("file_relative_path_m3u8: ", file_relative_path_m3u8)

        print("file_tmp_local_dir:", file_tmp_local_dir)
        print("file_tmp_local_output", file_tmp_local_output)

        print("file_cloudfront_url: ", file_cloudfront_url)