Change auto generated filename - php

Question

So I have this PHP-script which is linked to a contact form on one of my clients sites. What the PHP-script does is basically to take all the fields and values and generates a .txt file with the information given in the form. After that the script decides what to name the file depending on what information you add in the field 'forefternamn'.
My question is pretty straight forward. How do I, instead of naming the file after the field, name it with a serial number?
I would like the serial number to start with 1000 on the first submit, then I would just like it to keep going with 1001, 1002, 1003, 1004, etc..
So the files would look like this:
1000.txt
1001.txt
1002.txt
1003.txt
1004.txt
etc...
This is the PHP-script I'm using:
<?php
$nyckel = array(
'privatforetag',
'forefternamn',
'foretagsnamn',
'gatuadress',
'mobil',
'telefon',
'e-post',
'epost',
'kalender-tidig',
'kalender-senast',
'flyttar-fran-gatuadress',
'flyttar-fran-portkod',
'flyttar-fran-postadress',
'boendetyp',
'meter',
'hiss',
'flyttar-till-gatuadress',
'flyttar-till-postnummer',
'flyttar-till-portkod',
'boendetyp2',
'meter2',
'hiss2',
'rum',
'personer',
'kontor',
'moblerat',
'boyta',
'biyta',
'inventarielista',
'packning',
'uppackning',
'inventarie',
'antalflyttlador',
'flyttlada',
'miljostation',
'flyttstad',
'magasinering',
'student',
'ovriginfo',
'rekommenderad',
'hurhittade'
);
foreach ($nyckel as $key) {
if ($_POST[$key]) {
$input .= $_POST[$key]. "\t";
} else {
$input .= "-\t";
}
$thekey .= $key. "\t";
}
$index = 1;
$name = str_replace(" " , "" , $_POST["forefternamn"]);
$filename = $name . $index . ".txt";
while (file_exists($filename)) {
$index++;
$filename = $name .$index. ".txt";
}
$handle = fopen($filename, 'w') or die('Cannot open file: '.$filename);
fwrite($handle, $thekey);
fwrite($handle, PHP_EOL);
fwrite($handle, $input);
fclose($handle);
if (file_exists($filename)) {
echo "<script>window.location = 'www.domain.com'</script>";
}?>

Answer 1

Create a database table with a primary key ID field and a name field. Insert the name into the table and retrieve the generated ID. Use this generated ID to name the file.

Answer 2

How about something like:-
$dir='c:/temp/inv/';
$col=glob( $dir . '*.txt' );
$tmp=array();
foreach( $col as $file ) $tmp[]=intval( pathinfo( $file, PATHINFO_FILENAME ) );
$last=intval( max( $tmp ) );
$next=( $last+1 ).'.txt';
echo $next;
To continue the idea as requested, and to keep in line with the 'racy' ? comment... how about:-
$nyckel = array(
'privatforetag',
'forefternamn',
'foretagsnamn',
/* rest of the elements removed for brevity */
'student',
'ovriginfo',
'rekommenderad',
'hurhittade'
);
/* Helper function to generate next invoice id */
function getnextinvid( $path=false ){
if( $path ){
$col=glob( $path . '*.txt' );
$tmp=array();
foreach( $col as $file ) $tmp[]=intval( pathinfo( $file, PATHINFO_FILENAME ) );
$last=intval( max( $tmp ) );
return $path . ( $last+1 ).'.txt';
}
return false;
}
/* Loop through array to get POSTed values */
$thekey=$input=array();
foreach( $nyckel as $key ) {
$input[]=isset( $_POST[ $key ] ) ? $_POST[ $key ] : '-';
$thekey[]=$key;
}
/* The output filename / invoice should be sequentially numbered */
$output=getnextinvid('c:/temp/inv/');
if( $output ) {
/* write your data to the output file */
$bytes=file_put_contents( $output, implode( "\t", $thekey ) . PHP_EOL . implode( "\t", $input ), FILE_TEXT );
/* Does the new invoice exist? */
$exists=file_exists( $output ) ? true : false;
/* good practice to call this after calls to certain functions */
clearstatcache();
/* Redirect - alternatively use javascript as originally */
if( $exists && $bytes ) header('location: http://www.domain.com');
} else {
echo 'failed';
}