ytdl-chan

#!/bin/bash

usage() {
	bin=$(basename $0)
	echo >&2 "Usage:"
	echo >&2
	echo >&2 "  $bin n_first [ n_last [ delay_sec ] ]"
	echo >&2 "    Download video(s) for youtube channel to the current dir"
	echo >&2 "     (from n_first to n_last) in same order to how they're"
	echo >&2 "     listed in the metadata cache file (e.g. oldest-to-latest)."
	echo >&2 "    Run in an empty dir with any numbers to get more info on how to"
	echo >&2 "     get metadata cache file (list of yt json manifests, one per line)."
	echo >&2 "    Numbers (n_first, n_last) are inclusive, 1-indexed."
	echo >&2
	echo >&2 "  $bin { -n | --pick } n1 [ n2 ... ]"
	echo >&2 "    Download specific video(s), specified by their sequence number(s)."
	echo >&2
	echo >&2 "  $bin { -r | --reverse-sort | --tac }"
	echo >&2 "    Reverse order of lines in the metadata file."
	echo >&2 "    Useful for 'ytuser:chan-name' meta dumps,"
	echo >&2 "     which are usually in latest-to-oldest order."
	echo >&2
	echo >&2 "  $bin { -l | --list }"
	echo >&2 "    List titles from metadata cache file."
	echo >&2
	echo >&2 "  $bin { -i | --info | -m | --meta | -u | --url } n"
	echo >&2 "    Dump metadata for video, specified by its sequence number."
	echo >&2 "    --info dumps pretty version, --meta - pure json, --url - just video URL."
	echo >&2
	echo >&2 "  $bin [ -h | --help ]"
	exit ${1:-0}
}
[[ -z "$1" || "$1" = -h || "$1" = --help ]] && usage


set -o pipefail
trap exit INT
err=
ytdl=yt-dlp
ytdl_opts=( ) # use ~/.config/<ytdl>/config
chan_cache=_meta.json


[[ ! -e "$chan_cache" ]] && {
	echo >&2 "Create '$chan_cache' file with command like this one:"
	echo >&2 "  $ytdl -sj 'ytuser:TheGreatWar' >$chan_cache"
	exit 1
}

[[ "$1" = -l || "$1" = --list ]] && {
	[[ "$#" -ne 1 ]] && usage 1
	jq -r '.fulltitle' "$chan_cache" | cat -n
	exit
}

[[ "$1" = -r || "$1" = --reverse-sort || "$1" = --tac ]] && {
	[[ "$#" -ne 1 ]] && usage 1
	tac "$chan_cache" >"$chan_cache".new && mv "$chan_cache"{.new,}
	exit
}

[[ "$1" = -i || "$1" = --info || "$1" = -m ||
		"$1" = --meta || "$1" = -u || "$1" = --url ]] && {
	[[ "$#" -ne 2 ]] && usage 1
	case "$1" in
		-i|--info) filter=( jq -CS . ) ;;
		-u|--url) filter=( jq -r .webpage_url ) ;;
		*) filter=( cat ) ;;
	esac
	sed -n "$2 p" "$chan_cache" | "${filter[@]}"
	exit
}


sed_exp= delay=0
if [[ "$1" = -n || "$1" = --pick ]] ; then
	[[ "$#" -ge 2 ]] || usage 1
	shift
	for n in "$@"; do sed_exp="${sed_exp}${n}p;"; done
else
	[[ "$#" -le 3 ]] || usage 1
	[[ -z "$2" ]] && sed_exp="$1 p" || sed_exp="$1,$2 p"
	delay=${3:-0}
fi

while read n u; do
	echo " ------ Fetching video $n"
	$ytdl \
			--no-overwrites --restrict-filenames \
			"${ytdl_opts[@]}" -o "$(printf '%03d' $n)__%(title)s.%(ext)s" "$u" \
		|| err="ERROR (last one only): n=$n code=$?"
	[[ ! "$delay" -gt 0 ]] || { echo " --- delay: ${delay}s"; sleep "$delay"; }
done < <(jq -r '.webpage_url' "$chan_cache" | cat -n | sed -n "$sed_exp")

err=${err:-done}
echo " ------ $err"