#!/bin/sh

#initializing..

help_text () {
        while IFS= read -r line; do
	    printf "%s\n" "$line"
	done <<-EOF
	Usage:
	    ${0##*/} [ -f <filename> ] [ -s ] [ <m3u8_link> ]
	    ${0##*/} -h
	
	Options:
	    -h show helptext
	    -f filename (default : video)
	    -s select highest resolution automatically
	EOF
}

skip_res=0
file="video"
tmpdir="${XDG_CACHE_HOME:-$HOME/.cache}/hls-temp"
jobdir="${XDG_CACHE_HOME:-$HOME/.cache}/hls-jobs"

while getopts 'fs' OPT; do
        case $OPT in
                f)	file=$OPTARG ;;
                s)	skip_res=1;;
                *|h)
                        help_text
                        exit 0
                        ;;
	esac
done
shift $((OPTIND - 1))

[ -z "$*" ] && printf "\033[1;34mEnter link >\033[0m " && read -r link || link=$* 
trap "rm -rdf $tmpdir $jobdir;exit 0" INT HUP
printf "\033[2K\r\033[1;36mFetching resolutions.."
m3u8_data=$(curl -s "$link")
res_list=$(printf "%s" "$m3u8_data" | sed -nE 's_.*RESOLUTION=.*x([^,]*),.*_\1_p')
highest_res=$(printf "$res_list" | sort -nr | head -1)
[ "$skip_res" -eq 1 ] && printf "\033[2K\r\033[1;36mSelecting highest resolution.." || (printf "" printf "\033[2K\r\033[1;33mRESOLUTIONS >>\n\033[0m$res_list\n\033[1;34mType ur preferred resolution (default: $highest_res) > " && read -r sel_res)
[ -z "$sel_res" ] && sel_res=$highest_res
unset highest_res res_list
url=$(printf "%s" "$m3u8_data" | sed -n "/$sel_res,/{n;p;}" | tr -d '\r')
[ -d "$tmpdir" ] || mkdir -p "$tmpdir"
#check whether the m3u8_data contains uri that starts from http
printf "%s" "$m3u8_data" | grep -q "http" || relative_url=$(printf "%s" "$link" | sed 's_[^/]*$__')
printf "\033[2K\r\033[1;36mFetching Metadata.."
resp="$(curl -s "${relative_url}$url")"
#extract key uri and iv uri from encrypted stream if exists..
key_uri="$(printf "%s" "$resp" | sed -nE 's/^#EXT-X-KEY.*URI="([^"]*)"/\1/p')"
[ -z "$key_uri" ] || iv_uri="$(printf "%s" "$resp" | sed -nE 's/^#EXT-X-IV.*URI="([^"]*)"/\1/p')"
data="$(printf "%s" "$resp" | sed '/#/d')"
printf "%s" "$data" | grep -q "http" && relative_url='' || relative_url=$(printf "%s" "$link" | sed 's_[^/]*$__')
range=$(printf "%s\n" "$data" | wc -l)

#for encrypted stream only
if [ -n "$key_uri" ];then
	#extract key from uri..
	key=$(curl -s "$key_uri" | od -A n -t x1 | tr -d ' |\n')
	#iv from uri
	[ -z "$iv_uri" ] && iv=$(openssl rand -hex 16) || iv=$(curl -s "$iv_uri" | od -A n -t x1 | tr -d ' |\n')
fi

printf "\033[2K\r\033[1;35mpieces : $range\n\033[1;33mDownloading.."
#downloading .ts data asynchronously
for i in $(seq $range); do 
    curl -s "${relative_url}$(printf "%s" "$data" | sed -n "${i}p")" > "$tmpdir/$(printf "%04d" "$i").ts" && printf "\033[2K\r\033[1;32m ✓ $i / $range done" &
    jobs -p > "$jobdir"
    while [ "$(cat "$jobdir" | wc -w)" -ge 35 ];do jobs > "$jobdir";sleep 0.05;done
done
wait

#concatenating all .ts file in one file..
if [ -n "$key_uri" ];then
    #decrypting while concatenating..
    printf "\033[2K\r\033[1;36m Decrypting and Concatenating pieces into single file.."
    for i in "$tmpdir"/*;do
	cat "$i" | openssl aes-128-cbc -d -K "$key" -iv "$iv" -nopad >> "$file.ts"
    done
else
    printf "\033[2K\r\033[1;36m Concatenating pieces into single file.."
    cat "$tmpdir"/* >> "$file.ts"
fi

rm -rdf $tmpdir $jobdir
#conversion of allts file to mp4 video using ffmpeg..
printf "\033[2K\r\033[1;36mEncoding file to mp4 video..\n\033[0m"
ffmpeg -i "$file.ts" -loglevel error -stats -c copy "$file.mp4"

#cleanup..
rm $file.ts
printf "\033[2K\r\033[1;36m Done!!"