#!/usr/bin/env bash
# ipkg-build -- construct a .ipk from a directory
# Waldemar Brodkorb <wbx@openadk.org>
# use cpio instead of tar for uid/gid handling
# Carl Worth <cworth@east.isi.edu>
# based on a script by Steve Redler IV <steve@sr-tech.com>
set -e

version=1.0

ipkg_extract_value() {
	sed -e "s/^[^:]*:[[:space:]]*//"
}

required_field() {
	field=$1

	value=`grep "^$field:" < $CONTROL/control | ipkg_extract_value`
	if [ -z "$value" ]; then
		echo "*** Error: $CONTROL/control is missing field $field" >&2
		return 1
	fi
	echo $value
	return 0
}

disallowed_field() {
	field=$1

	value=`grep "^$field:" < $CONTROL/control | ipkg_extract_value`
	if [ -n "$value" ]; then
		echo "*** Error: $CONTROL/control contains disallowed field $field" >&2
		return 1
	fi
	echo $value
	return 0
}

pkg_appears_sane() {
	local pkg_dir=$1

	local owd=$PWD
	cd $pkg_dir

	PKG_ERROR=0

	tilde_files=`find . -name '*~'`
	if [ -n "$tilde_files" ]; then
	    if [ "$noclean" = "1" ]; then
		echo "*** Warning: The following files have names ending in '~'.
You probably want to remove them: " >&2
		ls -ld $tilde_files
		echo >&2
	    else
		echo "*** Removing the following files: $tilde_files"
		rm -f "$tilde_files"
	    fi
	fi

	if [ ! -f "$CONTROL/control" ]; then
		echo "*** Error: Control file $pkg_dir/$CONTROL/control not found." >&2
		cd $owd
		return 1
	fi

	pkg=`required_field Package`
	[ "$?" -ne 0 ] && PKG_ERROR=1

	version=`required_field Version | sed 's/Version://; s/^.://g;'`
	[ "$?" -ne 0 ] && PKG_ERROR=1

	arch=`required_field Architecture`
	[ "$?" -ne 0 ] && PKG_ERROR=1

	required_field Maintainer >/dev/null
	[ "$?" -ne 0 ] && PKG_ERROR=1

	required_field Description >/dev/null
	[ "$?" -ne 0 ] && PKG_ERROR=1

	section=`required_field Section`
	[ "$?" -ne 0 ] && PKG_ERROR=1
	if [ -z "$section" ]; then
	    echo "The Section field should have one of the following values:" >&2
	    echo "admin, base, boot, comm, editors, extras, games, graphics, kernel, lang, libs, misc, net, scm, text, web, x11" >&2
	fi

	priority=`required_field Priority`
	[ "$?" -ne 0 ] && PKG_ERROR=1
	if [ -z "$priority" ]; then
	    echo "The Priority field should have one of the following values:" >&2
	    echo "required, important, standard, optional, extra." >&2
	    echo "If you don't know which priority value you should be using, then use \`optional'" >&2
	fi

	source=`required_field Source`
	[ "$?" -ne 0 ] && PKG_ERROR=1
	if [ -z "$source" ]; then
	    echo "The Source field contain the URL's or filenames of the source code and any patches" 
	    echo "used to build this package.  Either gnu-style tarballs or Debian source packages "
	    echo "are acceptable.  Relative filenames may be used if they are distributed in the same"
	    echo "directory as the .ipk file."
	fi

	disallowed_filename=`disallowed_field Filename`
	[ "$?" -ne 0 ] && PKG_ERROR=1

	if echo $pkg | grep '[^a-z0-9.+-]'; then
		echo "*** Error: Package name $pkg contains illegal characters, (other than [a-z0-9.+-])" >&2
		PKG_ERROR=1;
	fi

	local bad_fields=`sed -ne 's/^\([^[:space:]][^:[:space:]]\+[[:space:]]\+\)[^:].*/\1/p' < $CONTROL/control | sed -e 's/\\n//'`
	if [ -n "$bad_fields" ]; then
		bad_fields=`echo $bad_fields`
		echo "*** Error: The following fields in $CONTROL/control are missing a ':'" >&2
		echo "	$bad_fields" >&2
		echo "ipkg-build: This may be due to a missing initial space for a multi-line field value" >&2
		PKG_ERROR=1
	fi

	for script in $CONTROL/preinst $CONTROL/postinst $CONTROL/prerm $CONTROL/postrm; do
		if [ -f $script -a ! -x $script ]; then
		    if [ "$noclean" = "1" ]; then
			echo "*** Error: package script $script is not executable" >&2
			PKG_ERROR=1
		    else
			chmod a+x $script
		    fi
		fi
	done

	if [ -f $CONTROL/conffiles ]; then
		for cf in `cat $CONTROL/conffiles`; do
			if [ ! -f ./$cf ]; then
				echo "*** Error: $CONTROL/conffiles mentions conffile $cf which does not exist" >&2
				PKG_ERROR=1
			fi
		done
	fi

	cd $owd
	return $PKG_ERROR
}

###
# ipkg-build "main"
###
noclean=0
usage="Usage: $0 [-C] <pkg_directory> [<destination_directory>]"
while getopts ":h:v" opt; do
    case $opt in
        C ) noclean=1
            ;;
	v ) echo $version
	    exit 0
	    ;;
	h ) 	echo $usage  >&2 ;;
	\? ) 	echo $usage  >&2
	esac
done

shift $(($OPTIND - 1))

# continue on to process additional arguments

case $# in
1)
	dest_dir=$PWD
	;;
2)
	dest_dir=$2
	if [ "$dest_dir" = "." -o "$dest_dir" = "./" ] ; then
	    dest_dir=$PWD
	fi
	;;
*)
	echo $usage >&2
	exit 1 
	;;
esac

pkg_dir=$1

if [ ! -d $pkg_dir ]; then
	echo "*** Error: Directory $pkg_dir does not exist" >&2
	exit 1
fi

# CONTROL is second so that it takes precedence
CONTROL=
[ -d $pkg_dir/DEBIAN ] && CONTROL=DEBIAN
[ -d $pkg_dir/CONTROL ] && CONTROL=CONTROL
if [ -z "$CONTROL" ]; then
	echo "*** Error: Directory $pkg_dir has no CONTROL subdirectory." >&2
	exit 1
fi

if ! pkg_appears_sane $pkg_dir; then
	echo >&2
	echo "ipkg-build: Please fix the above errors and try again." >&2
	exit 1
fi

tmp_dir=$dest_dir/IPKG_BUILD.$$
mkdir $tmp_dir

( cd $pkg_dir && find . | grep -v $CONTROL | \
	sort | cpio --quiet -o -Hustar | gzip -n9 > $tmp_dir/data.tar.gz )

( cd $pkg_dir/$CONTROL && find . | \
	sort | cpio --quiet -o -Hustar | gzip -n9 > $tmp_dir/control.tar.gz )

echo "2.0" > $tmp_dir/debian-binary
pkg_file=$dest_dir/${pkg}_${version}_${arch}.ipk
rm -f $pkg_file
( cd $tmp_dir && tar -czf $pkg_file ./debian-binary ./data.tar.gz ./control.tar.gz )
rm $tmp_dir/debian-binary $tmp_dir/data.tar.gz $tmp_dir/control.tar.gz
rmdir $tmp_dir
echo "Packaged contents of $pkg_dir into $pkg_file"