PHP append version to file name if file already exists

avoid_file_overwrites.php

<?php

function AddCopyToFileName(string $file_name): string
{
    $ext = pathinfo($file_name, PATHINFO_EXTENSION);//json
    if (!str_contains($file_name, '_')) {//OG file name, no _2 etc
        $file_name_no_ext = str_replace(".$ext", "", $file_name);//ralphy
        $number = 0;
    } else {
        $number = str_replace(".$ext", "", substr(strrchr($file_name, '_'), 1));
        if (!is_numeric($number)) {
            $number = 0;//File name has multiple _ in it. The last _ did not have a number following it (First copy)
        }
        $file_name_no_ext = str_replace([".$ext", "_{$number}"], "", $file_name);//ralphy
    }
    return $file_name_no_ext . "_" . ($number + 1) . "." . $ext;
}

function doFileNameCopyNumber(string $file_name): string
{
    if (file_exists($file_name)) {//File name exists add copy number onto it and try again
        $new_name = AddCopyToFileName($file_name);// _1 -> _2 etc
        return doFileNameCopyNumber($new_name);//Try again with new name
    }
    return $file_name;//File name does not exist so return it
}

function createFile(string $file_name, mixed $data): string
{
    $fn = doFileNameCopyNumber($file_name);
    $fp = fopen($fn, 'wb');
    fwrite($fp, json_encode($data));
    fclose($fp);
    return $fn;
}

$array = array('id' => 4860, 'name' => 'Ralph', 'age' => 24);

echo createFile('ralphy.json', $array);

Here is what happens on running the script each time:

1. ralphy.json
2. ralphy_1.json
3. ralphy_2.json
4. ralphy_3.json
5. ralphy_4.json
6. ralphy_5.json
7. ralphy_6.json