yt_download

#!/usr/bin/env bash

#============================================|
#	Downloads youtube audio
#	created by: Joao Mauricio
#	github: github.com/jean0t
#	version: 1.4
#============================================|
#	Changelog
#
#	1.0:
#		- Downloads and extracts audios
#		  from youtube videos
#
#	1.1:
#		- Test if there are links
#		  to download
#
#	1.2:
#		- Test if the link passed is
#		  a valid youtube link
#
#	1.3:
#		- More organized code with
#		  functions and a menu to
#		  interact with the user.
#
#		- Now provides info about
#		  the app with parameters
#
#		fixed:
#			- download of multiple
#			  songs in a playlist
#			  without explicit allowing. 
#
#	1.4:
#		- Added support to download audio
#		  from a playlist.
#============================================|

# VERIFICATIONS

# Do not allow root to run
[[ "$UID" -eq '0' ]] && { echo 'Do not run as root' ; exit 1 ; }

# test if the necessary module exist
[[ $( type -p yt-dlp ) ]] || { echo 'yt-dlp not found.' ; exit 1 ; }

# Test internet conection
[[ $( ping -c1 8.8.8.8 ) ]] || { echo 'You need internet conection to run the script' ; exit 1 ; }

# test if the directory exists
[[ ! -e "$HOME/Downloads/Youtube_Download" ]] \
&& { echo 'created directory ~Downloads/Youtube_Download' ; mkdir -p "$HOME/Downloads/Youtube_Download" ; }

#============================================| GLOBAL VARIABLES

version='1.4'
output_directory="$HOME/Downloads/Youtube_Download/%(title)s.%(ext)s"

#============================================| FUNCTIONS

function version() {
	echo "version ${version}"
}

function help() {
	cat <<'EOF'
usage: ./yt_download [OPTIONS] LINK

	OPTIONS:
		-a|--audio		Downloads the audio of the video

		-pa|--playlist-audio	Downloads the audio of all videos in a playlist

		-h|--help 		Gets info about the software

		-v|--version		Gets the current version


	REASON OF COMMON ISSUES:
		- Absence of ffmpeg on the system
		- Absence of the module mutagen
EOF
}

# accepts 2 parameters, first is the link, second is the confirmation if it will 
# download the playlist or not
function download_audio() {

	# test if there are parameters
	[[ $# -eq 0 ]] && { echo 'you need to pass an youtube link to download' ; exit 1 ; }

	# test if the link is valid
	local youtube_regex='^(https?\:\/\/)?(www\.youtube\.com|youtu\.?be)\/.+$'
	[[ $1 =~ $youtube_regex ]] || { echo 'It is not a valid link, please provide a https://youtube.com/...' ; exit 1 ; }


	echo 'Starting the download...'
	if yt-dlp -x -f bestaudio -o "$output_directory" --embed-thumbnail --"${2}"-playlist "$1" >&- 2>&- ; then
		echo 'Download was successful, saved in:'
		echo "$HOME/Downloads/Youtube_Download"
		exit 0
	else
		echo $'\E[31;1mAn error has occurred.\E[0m\nUse -h or --help to know more.'
		exit 1
	fi
}

#============================================|START THE PROGRAM


case "$1" in
	-pa|--playlist-audio)
		shift
		download_audio "$1" "yes"
	;;

	-a|--audio)
		shift
		download_audio "$1" "no"
		;;

	-v|--version)
		version
		;;

	-h|--help|*)
		help
		;;

esac