#! /usr/bin/perl
# ex:ts=8 sw=4:
# $OpenBSD: clean-old-distfiles,v 1.3 2012/01/29 14:35:40 espie Exp $
#
# Copyright (c) 2012 Marc Espie <espie@openbsd.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

use strict;
use warnings;
use feature qw(say);
use OpenBSD::Getopt;
use OpenBSD::md5;

sub usage
{
	my $err = shift;
	my $prog = $0;
	$prog =~ s/.*\///;
	$err =~ s/\sat.*//s;
	say STDERR "$prog: $err";
	say STDERR "Usage: $prog [-nv] [-e except] [cutdate]";
	exit 1;
}

our ($opt_v, $opt_n, $opt_e);
eval { getopts('e:vn'); };
if ($@) {
	usage($@);
}

if (@ARGV > 1) {
	usage("too many arguments");
}

sub really_remove
{
	my $file = shift;
	say "rm $file" if $opt_v;
	return if $opt_n;
	if (!unlink $file) {
		say STDERR "Couldn't remove $file: $!";
	}
}

sub remove_file
{
	my ($file, $sha) = @_;
	# let's do i-node caching to avoid doing the same file twice.
	my $basename = $file;
	my $inode;
	$basename =~ s/^.*\///; # remove directory
	$sha =~ m/(..)/;
	my $link = "by_cipher/sha256/$1/$sha/$basename";
	if (-f $link) {
		$inode = (stat _)[1];
		really_remove($link);
	}
	if (-f $file) {
		my $inode2 = (stat _)[1];
		if (defined $inode && $inode2 == $inode) {
			really_remove($file);
		} else {
			my $ck = OpenBSD::sha->new($file);
			if ($ck->stringize eq $sha) {
				really_remove($file);
			} else {
				say STDERR "SHA256 mismatch on $file\n";
			}
	    	}
    	}
}

my $cutdate //=  $ARGV[1];

my $PORTSDIR = $ENV{PORTSDIR} // '/usr/ports';
my $DISTDIR = $ENV{DISTDIR} // "$PORTSDIR/distfiles";
chdir($DISTDIR) or die "Can't chdir to $DISTDIR";

open my $fh, '<', "history" or die "No history to prune";
my $fh2;

unless ($opt_n) {
	open $fh2, '>', "history.new" or die "Can't write new history";
}

my $except = {};

if ($opt_e) {
	open(my $e, '<', $opt_e) or die "Can't read exception file $opt_e: $!";

	while (<$e>) {
		chomp;
		$except->{$_} = 1;
	}
	close $e;
}

while (<$fh>) {
	my ($ts, $file, $sha);
	if (m/^(\d+)\s+SHA256\s*\((.*)\) \= (.*)$/) {
		($ts, $file, $sha) = ($1, $2, $3);
	} else {
		die "Bad history line $_";
	}
	if ($except->{$file} || defined $cutdate && $ts > $cutdate) {
		if ($fh2) {
			print $fh2 $_;
		}
	} else {
		remove_file($file, $sha);
	}
}
close $fh;

if ($fh2) {
	close $fh2;
	unlink('history');
	rename('history.new', 'history');
}