#!/usr/bin/env bash
#
# --- T2-COPYRIGHT-NOTE-BEGIN ---
# T2 SDE: scripts/Create-PkgUpdPatch
# Copyright (C) 2004 - 2023 The T2 SDE Project
# 
# This Copyright note is generated by scripts/Create-CopyPatch,
# more information can be found in the files COPYING and README.
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2.
# --- T2-COPYRIGHT-NOTE-END ---

pkg="$1"; shift
ver="$1"; shift

if [ -z "$ver" ]; then
	ver=${pkg/*-/}
	pkg=${pkg%-$ver}
fi

if [ -z "$pkg" -o -z "$ver" ]; then
	echo "Usage: $0 pkg ver"
	echo "   or: $0 pkg-ver"
	exit
fi

pkg=`echo $pkg | tr A-Z a-z`

echo "[ $pkg ]" >&2
pkgdir=`echo package/*/$pkg`

if [ ! -d "$pkgdir" ]; then
	echo "Can't find package for '$x'!" >&2
else
	oldver="`egrep "^\[(V|VER|VERSION)\] " $pkgdir/$pkg.desc |
			sed 's, ,\t,g; s,\t\t*,\t,g' | cut -f2`"
	tmpfile=`mktemp` tmpfile2=`mktemp`
	echo "Update patch for $pkg ($pkgdir): $oldver -> $ver"

	# [V]
 	expression="-e 's@^\[\(V\|VER\|VERSION\)\].*@[\1] $ver@'"
	# file at [D]
	expression="$expression -e '/^\[\(D\|DOWN\|DOWNLOAD\)\]/ s@${oldver//./\\.}@$ver@g;'"

	# detect download location structure
	sed -n -e 's,^\[\(D\|DOWN\|DOWNLOAD\)\].*[ \t]\([^ \t]*\)[ \t]*$,\2,p' $pkgdir/$pkg.desc > $tmpfile

	oldver2=${oldver%.*}
	ver2=${ver%.*}
	[ "$oldver2" == "$oldver" -o "$ver2" == "$ver" ] && oldver2= ver2=
	if grep -q "/$oldver/$" $tmpfile; then
		# $ver -> /$ver/
		oldver="${oldver//./\\.}"
		expression="$expression -e '/^\[\(D\|DOWN\|DOWNLOAD\)\]/ s@/$oldver/[^ \t]*\$@/$ver/@g;'"
	elif [ "$oldver" != "${oldver//-/}" ] && grep -q "/${oldver//-/}/\$" $tmpfile; then
		# $ver-$extra -> /$ver/
		oldver="${oldver%%-*}" oldver="${oldver//./\\.}"
		ver="${ver%%-*}"
		expression="$expression -e '/^\[\(D\|DOWN\|DOWNLOAD\)\]/ s@/$oldver/[^ \t]*\$@/$ver/@g;'"
	else
		# $ver.$extra -> /$ver/
		oldver="${oldver%%-*}"
		ver="${ver%%-*}"

		oldauxver=
		auxver=
		pattern="[^\.]*"
		while [ "${oldver#$oldauxver}" ]; do
			eval $(echo "$oldver $ver" | sed -e "s,\($pattern\).* \($pattern\).*,oldauxver='\1' auxver='\2',")
			if grep -q "/$oldauxver/\$" $tmpfile; then
				oldver="${oldauxver%%-*}" oldauxver="${oldauxver//./\\.}"
				ver="${auxver%%-*}"
				expression="$expression -e '/^\[\(D\|DOWN\|DOWNLOAD\)\]/ s@/$oldver/[^ \t]*\$@/$ver/@g;'"
				break
			fi
			pattern="$pattern\.\?[^\.]*"
		done
	fi

	# leading short, major version directory, too
	if [ "$oldver2" ]; then
		oldver2="${oldver2//./\\.}"
		expression="$expression -e '/^\[\(D\|DOWN\|DOWNLOAD\)\]/ s@/$oldver2/@/$ver2/@g;'"
	fi

	# checksum at [D]
	expression="$expression -e 's,^\[\(D\|DOWN\|DOWNLOAD\)\] [^ ]\+,[\1] 0,'"

	eval "sed $expression $pkgdir/$pkg.desc" > $tmpfile
	diff -u ./$pkgdir/$pkg.desc $tmpfile | tee $tmpfile2
	[ -s $tmpfile2 ] || echo "Patch for '$x' is empty!" >&2
	rm -f $tmpfile $tmpfile2
fi
echo