#!/usr/bin/perl

use IPC::Run3;
use Digest::SHA1;
use File::Spec;

# config
# $mode: 0 = normal cleardir/wget/hash using $tmpBase
#        1 = calc hash of $htdocsBase
$mode       = 0;
$url        = 'http://10.0.0.253:81';
$tmpBase    = '/mnt/fs2';
$htdocsBase = '/var/www/port81/htdocs';
$cmpHash    = '04e28506af6a4d00f308647dac7c5842bfa79f80';
$sleepSec   = 5;

# global vars
$tmpPath = File::Spec->catfile($tmpBase, "wget");
%hashes = ();

sub ensureEmptyDir
{
    my ($dir) = @_;
    
    die if ($dir eq "" or $dir eq "/");
    if (-d $dir)
    {
        recursiveEmpty($dir, 0);
    }
    else
    {
        mkdir $dir;
    }
}

sub recursiveEmpty
{
        my ($dir, $level) = @_;
	local *DIR;

	opendir DIR, $dir or die "opendir $dir: $!";
	my $found = 0;
	while ($_ = readdir DIR) {
	        next if /^\.{1,2}$/;
	        my $path = File::Spec->catfile($dir, $_);
		unlink $path if -f $path;
		recursiveEmpty($path, $level + 1) if -d $path;
	}
	closedir DIR;
	if ($level >= 1)
	{
		rmdir $dir or print "error - $!";
	}
}

sub recursiveHash
{
    my ($dir, $level, $relDir) = @_;
    local *DIR;
    local *FILE;
    
    opendir DIR, $dir or die "opendir $dir: $!";
    my $found = 0;
    while ($_ = readdir DIR) {
        next if /^\.{1,2}$/;
        next if m/^index\.html?$/im;
        my $path = File::Spec->catfile($dir, $_);
        my $newRelDir = "";
        $newRelDir = $relDir . "/" . $_ if $level >= 1;
        if (-f $path && $level >= 1)
        {
            open(FILE, "<", $path) or die "cannot hash file";
            binmode FILE;
            my $sha1 = Digest::SHA1->new;
            $sha1->addfile(FILE);
            close FILE;
            #print "$newRelDir\n" if ($mode);
            $hashes{$newRelDir} = $sha1->hexdigest;
        }
	recursiveHash($path, $level + 1, $newRelDir) if -d $path;
    }
    closedir DIR;
}

sub runWget()
{
    my ($stdout, $stderr);
    my @args = ("wget", "-nv", "-P", $tmpPath, "-r", $url);
    IPC::Run3::run3(\@args, undef, \$stdout, \$stderr);
    $r = $?;
    open FILE, ">last-stdout" or die;
    print FILE $stdout;
    close FILE;
    open FILE, ">last-stderr" or die;
    print FILE $stderr;
    close FILE;
    return $r;
}

sub runHash()
{
    my ($dir, $level);
    
    if ($mode)
    {
        $dir = $htdocsBase;
        $level = 1;
    }
    else
    {
        $dir = $tmpPath;
        $level = 0;
    }
    %hashes = ();
    recursiveHash($dir, $level, "");
    my $sha1 = Digest::SHA1->new;
    foreach my $path (sort keys %hashes)
    {
        my $d = $hashes{$path};
        $sha1->add($d);
    }
    return $sha1->hexdigest;
}

sub printFlush
{
    my ($txt) = @_;
    print $txt;
    STDOUT->flush;
}

$iter = 1;

if ($mode)
{
    my $r;
    
    $r = runHash();
    print "calculated hash: $r\n";
    exit 0;
}

while(1)
{
    my ($r);

    printFlush("iteration #$iter: cleardir... ");
    ensureEmptyDir($tmpPath);
    printFlush("wget...");
    $r = runWget;
    if ($r)
    {
        print "\nwget returned an error!\n";
        exit 1;
    }
    if (length($cmpHash) >= 1)
    {
        printFlush(" hashing...");
        $r = runHash;
        if (! ((lc $r) eq (lc $cmpHash)))
        {
            print ": SHA1 hash verification failed!\n";
            print "  expected: $cmpHash\n";
            print "calculated: $r\n";
            exit 1;
        }
    }
    print ": OK\n";
    $iter++;
    sleep($sleepSec);
}