tru

#!/bin/sh
# vi: lbr noet sw=2 ts=2 tw=79 wrap
# SPDX-FileCopyrightText: 2020-2026 David Rabkin
# SPDX-License-Identifier: 0BSD
#
# Removes a torrent and its content, then adds it again to increase the share
# ratio; the name stands for Transmission Remote Updater.
#
# The script uses local variables which are not POSIX but supported by most
# shells. See:
#  https://stackoverflow.com/q/18597697
#  shellcheck disable=SC1091,SC2034,SC2039,SC3043
readonly \
	BASE_APP_VERSION=0.9.20260711 \
	BASE_MIN_VERSION=0.9.20260707
. base.sh

# Validates arguments and runs the remove-then-add cycle.
main() {
	validate "$@"
	process
}

# Removes the existing torrent if present, then re-adds it from the file.
process() {
	local tid
	tid=$(tid) || die
	if [ -n "$tid" ]; then
		xmit --torrent "$tid" --remove-and-delete
		log "$NME $tid is removed from $SER."
	fi
	xmit --add "$TOR"
	tid=$(tid) || die
	log "$NME $tid is added to $SER."
}

# Looks up the torrent ID by the torrent name.
# Word splitting required for AUT:
#  shellcheck disable=SC2086
tid() {
	local out
	out="$(transmission-remote "$SER" $AUT --list 2>&1)" ||
		die "Unable to communicate with $SER: $out"
	out="$(printf %s "$out" | grep "$NME")" || {
		log "There is no $NME in $SER."
		return 0
	}
	[ -n "$out" ] || die "Unexpected empty match for $NME on $SER."
	out="$(printf %s "$out" | awk '{print $1}')" || die Wrong format: "$out"
	[ -n "$out" ] || die Unable to extract the torrent ID: "$out"
	printf %s "$out"
}

# Validates arguments and sets SER, AUT, TOR, and NME. A lone ':' as the second
# argument means no authentication data. Splits host:port into nc parameters,
# then validates the torrent file given as the third argument.
# Word splitting required for prm:
#  shellcheck disable=SC2086
validate() {
	cmd_exists awk nc tr transmission-remote transmission-show || die
	[ "$#" -eq 3 ] || die tru: try tru [host:port user:pass torrent-file]
	[ "$2" != : ] && AUT="--auth $2" || AUT=''
	readonly \
		AUT \
		SER="$1" \
		TOR="$3"
	local out prm
	prm="$(printf %s "$SER" | tr : \ )"
	nc -z $prm >/dev/null 2>&1 || die "$prm" is not available.
	isreadable "$TOR" || die Unable to read "$TOR".
	out="$(transmission-show "$TOR")" || die Unable to read "$TOR": "$out"
	NME="$(printf %s "$out" | grep Name: | head -1 | cut -c 7-)"
	readonly NME
	[ -n "$NME" ] || die Unable to extract name from "$TOR": "$out"
}

# Wraps transmission-remote with cmd_run.
# Word splitting required for AUT:
#  shellcheck disable=SC2086
xmit() {
	cmd_run transmission-remote "$SER" $AUT "$@"
}

# Entry point.
main "$@"