# Group files by extension.
# Usage: group_ext [FILES]
function group_ext() {
	local IFS=$'\n'
	local targets=(${@})
	[[ "${targets}" = "" ]] && targets=($(_ls_file))

	process() {
		local ext=${target##*.}
		[[ -d "${target}" ]] && { _iterate_skip "Is a directory."; return 0; }
		[[ "${ext}" = "${target}" ]] && { _iterate_skip "No extension."; return 0; }

		mkdir ${ext} 2> /dev/null

		mv -- ${target} ./${ext}/${target}
	}

	_iterate_targets process ${targets[@]}
}

# Group files and dirs by year.
# Usage: group_year [FILES]
function group_year() {
	local IFS=$'\n'
	local targets=(${@})
	[[ "${targets}" = "" ]] && targets=($(ls))

	process() {
		local year=$(stat --format=%y ${target})
		year=${year%%-*}

		mkdir ${year} 2> /dev/null

		mv -- ${target} ./${year}/${target}
	}

	_iterate_targets process ${targets[@]}
}

# Copy files from current year to the named dir.
function group_year_current() {
	local IFS=$'\n'
	local targets=(${@})
	[[ "${targets}" = "" ]] && targets=($(ls))

	local today="$(date +%Y)"
	mkdir ${today} 2> /dev/null

	process() {
		local year=$(stat --format=%y ${target})
		year=${year%%-*}

		if [[ "${year}" = "${today}" ]]; then
			/usr/bin/env cp -- ${target} ./${today}/
		else
			_iterate_skip
		fi
	}

	_iterate_targets process ${targets[@]}
}