<?php

# Folder in which current tiles reside
$currentTilesFolder = 'tiles';

# Timeout between requests so script doesnt get blocked
$timeout = 1;

# Init recusrive iterator
$rii = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($currentTilesFolder));

$files = array(); 

# Get only file paths, no folders
foreach ($rii as $file) {

    if ($file->isDir()){ 
        continue;
    }

    $files[] = $file->getPathname(); 
}
// Url format https://a.tile.openstreetmap.org/${z}/${x}/${y}.png;
$downloadUrlPattern = 'https://a.tile.openstreetmap.org/%s/%s/%s';

# Make urself look like a browser
$forge = array(
  'http'=>array(
    'method'=>"GET",
    'header'=>"Accept-language: en\r\n" .
        "User-Agent: Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.102011-10-16 20:23:10\r\n" // i.e. An iPad 
  )
);

$context = stream_context_create($forge);

foreach ($files as $key => $pathName) {
  # Remove current folder name from path to get clean tile path
  $pathName = str_replace($currentTilesFolder, '', $pathName);

  $parts = explode('\\', $pathName);

  # echo $pathName . " \n";
  $parts = array_values(array_filter($parts));

  # print_r($parts);
  list($z, $x, $y) = $parts;

  $downloadUrl = sprintf($downloadUrlPattern, $z, $x, $y);

  $newPath = "cool-tiles/$z/$x/";

  if (!file_exists($newPath)) {
    mkdir($newPath, 0777, true);
  }

  $newPath = $newPath.$y;

  if (!file_exists($newPath)) {

    $newTileContents = file_get_contents($downloadUrl, false, $context);

    file_put_contents($newPath, $newTileContents);

    echo $key . " For url: $downloadUrl new path is: $newPath \n";

    sleep(1);
  } else {

    echo $key . ' '. $newPath . " already downloaded \n";

  }
}