#!/bin/sh
#
#  scratchpkg
#
#  Copyright (c) 2018 by Emmett1  (emmett1.2miligrams@gmail.com)
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <https://www.gnu.org/licenses/>.
#

trap "interrupted" 1 2 3 15

export LC_ALL=C

interrupted() {
	echo
	ret 1
}

msg() {
	echo "==> $1"
}

msg2() {
	echo " -> $1"
}

msgerr() {
	echo "==> ERROR: $1" >&2
}

msgwarn() {
	echo "==> WARNING: $1" >&2
}

help() {
	cat << EOF
Usage:
  $(basename $0) [ <options> <package.spkg.txz> ]

Options:
  -u, --upgrade              upgrade package
  -r, --reinstall            reinstall package
  -c, --ignore-conflict      ignore conflict when installing package
  -v, --verbose              print files installed
  -h, --help                 show this help message
      --no-backup            skip backup when upgrading package
      --print-dbdir          print package database path
      --root=<path>          install to custom root directory
      
EOF
}

extract_opts() {
	while [ "$1" ]; do
		case $1 in
			--*) opts="$opts $1";;
			-*) char=${#1}; count=1
			    while [ "$count" != "$char" ]; do
			        count=$((count+1))
			        opts="$opts -$(echo $1 | cut -c $count)"
			   done;;
			*) opts="$opts $1"
		esac
		shift
	done
	echo $opts
}

parse_opts() {
	if [ -z "$1" ]; then
		SHOWHELP=yes
	else
		while [ "$1" ]; do
			case $1 in
			-u |           --upgrade) UPGRADE_PKG=yes ;;
			-r |         --reinstall) REINSTALL_PKG=yes ;;
			-c |   --ignore-conflict) IGNORE_CONFLICT=yes ;;
			-v |           --verbose) VERBOSE_INSTALL="-v" ;;
			-h |              --help) SHOWHELP=yes ;;
			             --no-backup) NO_BACKUP=yes ;;
			           --print-dbdir) PRINTDBDIR=yes ;;
			                --root=*) ROOT_DIR="${1#*=}" ;;
			            *.spkg.tar.*) PKGNAME="$(realpath $1)" ;;
			                       *) msg "Invalid option! ($1)"; exit 1 ;;
			esac
			shift
		done
	fi
}

ret() {
	# remove lock and all tmp files on exit
	rm -f "$ROOT_DIR/$LOCK_FILE" "$TMP_PKGADD" "$TMP_PKGINSTALL" "$TMP_CONFLICT"
	exit $1
}

isinstalled() {
	if [ -s "$ROOT_DIR/$PKGDB_DIR/$1" ]; then
		return 0
	else
		return 1
	fi
}

parse_opts $(extract_opts "$@")

SCRATCHPKG_DIR="var/lib/scratchpkg"
PKGDB_DIR="$SCRATCHPKG_DIR/db"
PKGDBPERMS_DIR="$PKGDB_DIR.perms"
LOCK_FILE="$SCRATCHPKG_DIR/spkg.lock"

ROOT_DIR="${ROOT_DIR%/}" # remove trailing slash

[ "$PRINTDBDIR" ] && {
	echo "$ROOT_DIR/$PKGDB_DIR"
	exit 0
}

# show help page
[ "$SHOWHELP" ] || [ -z "$PKGNAME" ] && {
	help
	exit 0
}

[ -d "$ROOT_DIR/$PKGDB_DIR" ] || {
	msgerr "Package's database directory does not exist: $ROOT_DIR/$PKGDB_DIR"
	exit 1
}

# check for root access
[ "$(id -u)" = "0" ] || {
	msgerr "Installing packages requires root access!"
	exit 1
}

# check for lock file
[ -f "$ROOT_DIR/$LOCK_FILE" ] && {
	msgerr "Cannot install/remove package simultaneously."
	msgerr "remove '$ROOT_DIR/$LOCK_FILE' if no install/remove package process running."
	exit 1
}

touch "$ROOT_DIR/$LOCK_FILE" 2>/dev/null || {
	msgerr "Cannot create lock file in '$ROOT_DIR/$LOCK_FILE'."
	exit 1
}

BASEPKGNAME=$(basename $PKGNAME)

# check existence of package file
[ -f "$PKGNAME" ] || {
	msgerr "Package '$1' does not exist!"
	ret 1
}

noextname=${BASEPKGNAME%*.spkg.tar.*}
release=${noextname##*-}
noextname=${noextname%-*}
version=${noextname##*-}
name=${noextname%-*}

# get package information if installed
if isinstalled $name; then
	iversion=$(head -n1 $ROOT_DIR/$PKGDB_DIR/$name | awk '{print $1}')
	irelease=$(head -n1 $ROOT_DIR/$PKGDB_DIR/$name | awk '{print $2}')
	ALREADYINSTALLED=yes
fi

if [ "$ALREADYINSTALLED" = "yes" ] && [ ! "$UPGRADE_PKG" ] && [ ! "$REINSTALL_PKG" ]; then
	echo "Package '$name' already installed. ($iversion-$irelease)"
	ret 0
fi

# cant reinstall if not installed and cant upgrade if up-to-date
if [ "$UPGRADE_PKG" ] || [ "$REINSTALL_PKG" ]; then	
	if [ "$ALREADYINSTALLED" != "yes" ]; then
		msgerr "Package '$name' not installed."
		ret 1
	fi
	if [ "$UPGRADE_PKG" ]; then	
		if [ "$version-$release" = "$iversion-$irelease" ]; then
			echo "Package '$name' is up-to-date. ($iversion-$irelease)"
			ret 0
		fi
	fi
fi

TMP_PKGADD="$ROOT_DIR/$SCRATCHPKG_DIR/.tmp_pkgadd"
TMP_PKGINSTALL="$ROOT_DIR/$SCRATCHPKG_DIR/.tmp_pkginstall"
TMP_CONFLICT="$ROOT_DIR/$SCRATCHPKG_DIR/.tmp_conflict"

# check integrity of package and save list file/dirs to install in the meantime
tar -tvf $PKGNAME > $TMP_PKGADD 2>/dev/null || {
	msgerr "Package '$1' is corrupted!"
	ret 1
}

# set operation whether install/upgrade/reinstall
# install is default
opr=install
[ "$UPGRADE_PKG" ] && opr=upgrade
[ "$REINSTALL_PKG" ] && opr=reinstall
echo "$opr: $name-$version-$release..."

# check for file conflict
if [ ! "$IGNORE_CONFLICT" ]; then
	grep -v '/$' "$TMP_PKGADD" | awk '{print $6}' | while read -r line; do
		if [ "$line" = "${line%.*}.spkgnew" ]; then
			line=${line%.*}
		fi
		if [ -e "$ROOT_DIR/$line" ] || [ -L "$ROOT_DIR/$line" ]; then
			if [ "$UPGRADE_PKG" ] || [ "$REINSTALL_PKG" ]; then
				if ! grep -Fqx "$line" "$ROOT_DIR/$PKGDB_DIR/$name"; then
					_f=$(grep -x ^"$line"$ $ROOT_DIR/$PKGDB_DIR/* | cut -d : -f1 | awk -F / '{print $(NF)}' | head -n1 | grep -vx $name)
					_f=${_f:-(none)}
					echo "$_f $line"
					touch "$TMP_CONFLICT"
				fi
			else
				_f=$(grep -x ^"$line"$ $ROOT_DIR/$PKGDB_DIR/* | cut -d : -f1 | awk -F / '{print $(NF)}' | head -n1)
				_f=${_f:-(none)}
				echo "$_f $line"
				touch "$TMP_CONFLICT"
			fi
		fi
	done
	
	if [ -e "$TMP_CONFLICT" ]; then
		msgerr "File conflict found!"
		ret 1
	fi
fi

rm -f $TMP_PKGINSTALL

# extract package into ROOT_DIR
tar -xvhpf "$PKGNAME" -C "$ROOT_DIR"/ | while read -r line; do
	if [ "$line" = "${line%.*}.spkgnew" ]; then
		line=${line%.*}
		if [ "$UPGRADE_PKG" ] || [ "$REINSTALL_PKG" ]; then
			if [ ! -e "$ROOT_DIR/$line" ] || [ "$NO_BACKUP" = yes ]; then
				mv "$ROOT_DIR/$line".spkgnew "$ROOT_DIR/$line"
			fi
		else
			mv "$ROOT_DIR/$line".spkgnew "$ROOT_DIR/$line"
		fi
	fi
	[ "$VERBOSE_INSTALL" ] && echo "extracted '$line'"
	echo "$line" >> $TMP_PKGINSTALL
done

# remove old files from old package that not exist in new package
if [ "$UPGRADE_PKG" ] || [ "$REINSTALL_PKG" ]; then
	tail -n+2 "$ROOT_DIR/$PKGDB_DIR/$name" | tac | while read -r line; do
		case $line in
			*/) grep "^$line$" $ROOT_DIR/$PKGDB_DIR/* "$TMP_PKGINSTALL" 2>/dev/null | grep -qv "$ROOT_DIR/$PKGDB_DIR/$name" || rmdir $([ "$VERBOSE_INSTALL" ] && echo -v) "$ROOT_DIR/$line";;
			 *) grep -q "^$line$" "$TMP_PKGINSTALL" || rm $([ "$VERBOSE_INSTALL" ] && echo -v) "$ROOT_DIR/$line";;
		esac
	done
fi

# register package into database
echo "$version $release" > "$ROOT_DIR/$PKGDB_DIR/$name"
cat "$TMP_PKGINSTALL" >> "$ROOT_DIR/$PKGDB_DIR/$name"
mkdir -p "$ROOT_DIR/$PKGDBPERMS_DIR"
rm -f "$ROOT_DIR/$PKGDBPERMS_DIR/$name"
grep '/$' $TMP_PKGADD | while read -r perms own junk1 junk2 junk3 dir junk4; do
	if [ "$perms" != drwxr-xr-x ] || [ "$own" != root/root ]; then
		echo "$perms $own $dir" >> "$ROOT_DIR/$PKGDBPERMS_DIR/$name"
		[ -s "$ROOT_DIR/$PKGDBPERMS_DIR/$name" ] || rm "$ROOT_DIR/$PKGDBPERMS_DIR/$name"
	fi
done

# running ldconfig
if [ -x "$ROOT_DIR"/sbin/ldconfig ]; then
	"$ROOT_DIR"/sbin/ldconfig -r "$ROOT_DIR"/
fi

ret 0