#!/usr/bin/perl

use strict;
use File::Which;

my $exe_path = which 'parted';
if(!$exe_path) {
	print "This program requires the parted program to be installed and in your path\n";
	exit(-1);
}


$exe_path = which 'hdparm';
if(!$exe_path) {
	print "This program requires the hdparm program to be installed and in your path\n";
	exit(-1);
}

if(!$ARGV[0] || ! -b $ARGV[0]) {
	print "Usage is:\n";
	print "	$0 /dev/sdX\n";
	exit(-1);
}

open INFO,"parted $ARGV[0] print|" or die "Error running parted $ARGV[0] print: $!\n";
print "ARE YOU SURE YOU WANT TO ERASE THE FOLLOWING DRIVE:\n\n";
while(<INFO>) {
	print;
}
close INFO;
print "\nTYPE \"YES\" TO COMPLETELY ERASE THE DRIVE SHOWN ABOVE:\n";
my $reply=<STDIN>;
chomp $reply;
if($reply ne "YES") {
	print "\nAborting...\n";
	exit(-1);
}

open INFO,"hdparm -I $ARGV[0]|" or die "Error running hdparm -I $ARGV[0]: $!\n";
my $sectors;
while(my $line=<INFO>) {
	chomp $line;
	if ($line =~ /LBA48  user addressable sectors:\s+(\d+)/) {
		$sectors=$1;
	}
}
close INFO;

if(!$sectors) {
	print "Unable to determine the number of sectors\n";
	exit(-1);
}

open MOUNTS,"/proc/mounts" or die "Error opening /proc/mounts: $!\n";
while(my $line=<MOUNTS>) {
	if ($line =~ /^$ARGV[0]/) {
		print "Error - possible mounted disk detected:\n";
		print $line;
		exit(-1);
	}
}

print "Issuing TRIM commands\n";
open TRIM,"|hdparm --trim-sector-ranges-stdin --please-destroy-my-drive $ARGV[0]" or die "Unable to run hdparm --trim-sector-ranges-stdin --please-destroy-my-drive $ARGV[0]: $!\n";
for(my $i=0; $i < $sectors; $i+=65535) {
	my $length=$sectors-$i;
	$length=65535 if $length > 65535;
	print TRIM "$i:$length\n";
}
close TRIM;

print "Syncing\n";
system("sync");