instalee/instalee

#!/bin/sh

## DEFINITIONS
name="$(basename "$0")"
home="$(find "$INSTALEE_HOME" "${XDG_CONFIG_HOME:-$HOME/.config}/$name" "$HOME/.$name" "$PWD" -maxdepth 0 2>/dev/null | head -1)"

highlight() { echo "$1"; }
destress() { echo "$1"; }

# Get the content of a file or the output of its execution
getcontent() { test -x "$1" && "$1" || cat "$1"; }

# Get available package entries for given package
getentries() {
	cat "$home/handlers.available" | while read handler
	do find "$home/packages/$1/" -type f -name "$handler*" 2>/dev/null
	done
}

# Install a package by name
installpkg() {
	test "$1" = "--quiet" && local quiet=true && shift
	local pkgs=$(getentries "$1")
	if test -z "$pkgs"; then
		local handlers=$(find "$home/packages/$1/" -type f -printf "%f\n" 2>/dev/null)
		for handler in $handlers
		do installpkg --quiet "$handler" &&
				echo "$handler" >> "$home/handlers.available" &&
				installpkg "$1" &&
				return $?
		done
		test "$quiet" ||
			echo "No handler available for package '$1'" >&2
		return 2
	fi
	for pkg in $pkgs
	do  highlight "$pkg"
		local name="$(basename $pkg)"
		local base="${name%_*}"

		local ext="${name#$base}"
		local handler="$home/handlers/$base"
		if test -d "$handler"
		then
			local args="$(getcontent "$pkg" | grep . || echo "$1")"
			local install="$(find "$handler" -name "install$ext" | head -1)" &&
				destress " $install $args" &&
				$install $args
		else
			destress " running unhandled $pkg"
			$pkg
		fi
		break
	done
}

## EXECUTION
chmod +rx "$home/handlers" -R

case "$1" in
	(-V|--version|"")
		printf "$0 r%s.%s\n" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"
		echo "Try '$0 --help' or 'man $name' for usage info"
		# TODO license https://www.gnu.org/prep/standards/html_node/_002d_002dversion.html#g_t_002d_002dversion
		exit 0
		;;
	(-h|--help)
		man $name 2>/dev/null || man "$home/$name.1"
		exit $?
		;;
	(-a|--add)
		dir="$home/packages/$2"
		mkdir -p "$dir"
		test $# -gt 3 && echo "$4">"$dir/$3" || $EDITOR "$dir/$3"
		exit $?
		;;
	(-v|--verbose)
		set -x
		shift
		;;
esac

runinstalee() {
	groupfile="$home/groups/$1"
	if test -f "$groupfile"
	then for pkg in $(getcontent "$groupfile")
		do runinstalee "$pkg" ||
			"$home/handlers/$(head -1 handlers.available)/install" "$pkg"
		done
	else installpkg "$1"
	fi
}

exitcode=0
while test $# -gt 0; do
	runinstalee "$1"
	exitcode=$(expr $exitcode \| $?)
	shift
done
exit $exitcode