#!/bin/sh
set -eu


usage() {
	cat <<-'EOF'
		Usage:
		  aux [FILE...]
		  aux -i
		  aux -h
	EOF
}

help() {
	cat <<-'EOF'


		Options:
		  -i            init a new project repository
		  -h, --help    show this message

		  FILE          specific path to be written


		Hydrate software project with auxiliary files.  If FILE is
		given, restrict effect to those paths.


		Examples:

		  Just run it with default values:

		    $ aux


		  Get only the "tests/assert-shellcheck.sh" file:

		    $ aux tests/assert-shellcheck.sh


		  Start a new project repository in the current directory:

		    $ aux -i
	EOF
}


for flag in "$@"; do
	case "$flag" in
		(--)
			break
			;;
		(--help)
			usage
			help
			exit
			;;
		(*)
			;;
	esac
done

while getopts 'ih' flag; do
	case "$flag" in
		(i)
			git init
			git commit --allow-empty -m 'Initial empty commit'
			touch FIXME
			mkdir -p vendor
			exit
			;;
		(h)
			usage
			help
			exit
			;;
		(*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))

D="${XDG_DATA_HOME:-$HOME/.local/share}"/aux

cp_all() {
	from="$1"
	to="$2"
	mkdir -p "$(dirname "$to")"
	echo "cp '$from' '$to'"
	ifnew "$to" < "$from"
	if [ -x "$from" ]; then
		chmod +x "$to"
	fi
}

cp_if() {
	from="$1"
	to="$2"
	if [ -e "$to" ]; then
		cp_all "$from" "$to"
	fi
}

cp_empty() {
	from="$1"
	to="$2"
	if [ -e "$to" ] && [ ! -s "$to" ]; then
		cp_all "$from" "$to"
	fi
}


if [ $# = 0 ]; then
	for d in "$D"/cases/*/; do
		fn="$(basename "$d")"
		find "$d" -not -type d | while read -r f; do
			"$fn" "$f" "${f#"$D/cases/$fn/"}"
		done
	done
else
	for to in "$@"; do
		find "$D" -not -type d | grep "$to"$ | while read -r from; do
			cp_all "$from" "$to"
		done
	done
fi