#!/usr/bin/perl

use File::Basename;

usage() if @ARGV < 2;

my %builtin = ();
my %directory = ();

my @missing = ();
my @delete = ();

# Get all snapshot files from the built-in database in Stella
# This data comes from 'stella -listrominfo' (first commandline arg)
# We use a hashmap to get constant lookup time
open(INFILE, "$ARGV[0]");
foreach $line (<INFILE>)
{
	if($line =~ /\|/)
	{
		chomp $line;
		($md5, $name, $other) = split (/\|/, $line);
		$key = $name . ".png";
		$builtin{$key} = $key;
	}
}
close(INFILE);

# Get all snapshot files from the actual directory (second commandline arg)
# We use a hashmap to get constant lookup time
opendir(SNAPDIR, $ARGV[1]) or die "Directory '$ARGV[1]' not found\n";
my @files = grep !/^\.\.?$/, readdir SNAPDIR;
close(SNAPDIR);
foreach $file (@files)
{
	($base,$path,$type) = fileparse($file);
	$directory{$base} = $base;
}

# All files in %builtin but not in %directory are 'missing' snapshots
while(($key, $value) = each(%builtin))
{
	if(!defined $directory{$key})
	{
		push(@missing, $key);
	}
}

# All files in %directory but not in %builtin are redundant, and should be deleted
while(($key, $value) = each(%directory))
{
	if(!defined $builtin{$key})
	{
		$file = $ARGV[1] . "/" . $key;
		push(@delete, $file);
	}
}

$size = @missing;
print "Missing snapshots: ($size)\n\n";
if($size > 0)
{
	@missing = sort(@missing);
	foreach $file (@missing)
	{
		print "$file\n";
	}
}

$size = @delete;
print "\n\nExtra snapshots: ($size)\n\n";
if($size > 0)
{
	@delete = sort(@delete);
	foreach $file (@delete)
	{
		print "$file\n";
	}

	print "\nDelete extra snapshots [yN]: ";
	chomp ($input = <STDIN>);
	if($input eq 'y')
	{ 
		foreach $file (@delete)
		{
			$cmd = "rm \"$file\"";
			system($cmd);
		}
	}
}


sub usage {
	print "prune_snapshots.pl [listrominfo data] [snapshot dir]\n";
	exit(0);
}