instalee/instalee

#!/bin/sh

## DEFINITIONS
name="$(basename "$0")"
self="$(realpath "$0")"
homedir="$(find "$INSTALEE_HOME" "${XDG_CONFIG_HOME:-$HOME/.config}/$name" "$HOME/.$name" "$(dirname "$0")" "$PWD" -maxdepth 0 2>/dev/null | head -1)"
handlers="$homedir/handlers.available"
packagedir="$homedir/packages"

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

# Get the content of a file or the output of its execution
getcontent() {
	if test -z "$noexec" && test -x "$1"
	then "$1"
	else cat "$1"
	fi
}

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

# Install a package by name
installpkg() {
	test "$1" = "--quiet" && local quiet=true && shift
	local pkgs=$(getentries "$1")
	local pkgdir="$packagedir/$1/"
	if test -z "$pkgs"; then
		local pkghandlers="$(find "$pkgdir" -type f -printf "%f\n" 2>/dev/null)"
		for handler in $pkghandlers
		do installpkg --quiet "$handler" &&
				echo "$handler" >>"$pkghandlers" &&
				installpkg "$1" &&
				return $?
		done
		test "$quiet" ||
			echo "No handler available for package '$1'" >&2
		return 2
	fi
	local pkg
	for pkg in $pkgs
	do	highlight "Installing $(echo ${pkg#$packagedir/} | sed 's|\(.*\)/|\1 via |')"
		set -e
		local name="$(basename $pkg)"
		local base="${name%_*}"
		echo "Dependencies"
		for dependency in $(cat "${pkgdir}depends" "${pkgdir}${base}_depends" 2>/dev/null)
		do runinstalee $dependency | sed 's/^/ /'
		done

		local ext="${name#$base}"
		local handler="$homedir/handlers/$base"
		cd $(mktemp -d --tmpdir=$execdir $pkg.XXXX)
		if test -d "$handler"
		then
			# This declaration needs to be ahead, otherwise it overrides failing exit codes
			local args
			local install
			args="$(getcontent "$pkg")"
			args="${args:-$1}"
			install="$(find "$handler" -name "install$ext" | head -1)"
			destress " $install $args"
			$install $args
		else
			destress " running unhandled $pkg"
			$pkg
		fi
		break
	done
}

## EXECUTION

# TODO getopt
case "$1" in
	(-V|--version|"")
		printf "$name r%s.%s\n" "$(git rev-list --count HEAD 2>/dev/null)" "$(git rev-parse --short HEAD 2>/dev/null)"
		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 $name 2>/dev/null || man "$homedir/$name.1"
		exit $?
		;;
	(-a|--add)
		shift
		if test $# -gt 0
		then packagename=$1; shift
		else printf "Name of the package? "; read packagename
		fi
		dir="$packagedir/$packagename"
		mkdir -p "$dir"
		if test $# -gt 0
		then handler=$1
			 test $# -gt 1 && echo "$2">"$dir/$handler" || ${EDITOR:-vi} "$dir/$handler"
			 exit $?
		else
			while printf "Handler? (Ctrl-C or Ctrl-D to exit, / to list all) " && read handler
			do
				case "$handler" in
				(/*) find "$packagedir" "$homedir/handlers" -type f -not -name "*depends" -printf "%f\n" | sort | uniq | paste -s -d ' ';;
				(*) ${EDITOR:-vi} "$dir/$handler";;
				esac
			done
			exit 0
		fi
		;;
	(-v|--verbose) set -x; shift;;
	(-d|--default) default=true; shift;;
	(-x|--noexec) noexec=true; shift;;
esac
noexec=true

installdefault() {
	local defaulthandler="$(head -1 "$handlers")"
	highlight "Attempting install of $1 via default handler"
	$(test "$noexec" && echo "sh") "$homedir/handlers/$defaulthandler/install" "$1" &&
		$(test "$noexec" && echo "sh") "$self" --add "$1" "$defaulthandler" ""
}

runinstalee() {
	local groupfile="$homedir/groups/$1"
	if test -f "$groupfile"
	then for pkg in $(getcontent "$groupfile")
		do runinstalee "$pkg" || installdefault "$pkg"
		done
	else installpkg "$1" || { test "$default" && installdefault "$1"; }
	fi
}

if ! test -f "$handlers"
then copy="$(find "$homedir" -name "handlers.available.*" -exec sh -c "echo {} | rev | cut -d'.' -f1 | rev | xargs -i% expr $(lsb_release -s -i | tr 'A-Z' 'a-z') : % >/dev/null" \; -a -print)" &&
		test -n "$copy" &&
		echo "Bootstrapping available handlers from $copy" &&
		cp "$copy" "$handlers" || {
			echo "Missing available handlers in $handlers!"
			exit 1
		}
fi

chmod +rx "$homedir/handlers" -R

execdir=/tmp/instalee.$(date +%s)
mkdir -p $execdir
cd $execdir

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