#!/usr/bin/perl

if ($#ARGV != 2) {
	warn "Usage: $0 <changelog> <to> <range>\n";
	die  "       $0 debian.master/changelog v3.2.3 v3.2.2..v3.2.3\n";
}
my ($changelog, $to, $range) = @ARGV;

my @changes = ();

push(@changes, "\n");
push(@changes, "  [ Upstream Kernel Changes ]\n\n");
push(@changes, "  * rebase to $to\n");

open(LOG, "git log '$range'|") || die "$0: git log failed: - $!\n";
while (<LOG>) {
	if (m@BugLink: .*launchpad.net/.*/([0-9]+)\s$@) {
		push(@changes, "    - LP: #$1\n");
	}
}
close(LOG);

open(CHANGELOG, "< $changelog") or die "Cannot open changelog";
open(NEW, "> $changelog.new") or die "Cannot open new changelog";

$printed = 3;
while (<CHANGELOG>) {
	if (/^  CHANGELOG: /) {
		$printed--;
		print NEW;
		if ($printed == 0) {
			print NEW @changes;
		}
		next;
	}
	print NEW;
}

close(NEW);
close(CHANGELOG);

rename("$changelog.new", "$changelog");