<?php
header('Content-type: application/json');

// Database connection
// http://www.php.net/manual/en/ref.pdo-mysql.php
$pdo = new PDO('mysql:host=tfb-database;dbname=hello_world', 'benchmarkdbuser', 'benchmarkdbpass', [
  PDO::ATTR_PERSISTENT => true,
  PDO::ATTR_EMULATE_PREPARES => false
]);

// Read number of queries to run from URL parameter
$query_count = 1;
if ($_GET['queries'] > 1) {
  $query_count = $_GET['queries'] > 500 ? 500 : $_GET['queries'];
}

// Create an array with the response string.
$arr = [];

// Define query
$statement = $pdo->prepare('SELECT randomNumber FROM World WHERE id = ?');
$updateStatement = $pdo->prepare('UPDATE World SET randomNumber = ? WHERE id = ?');

// For each query, store the result set values in the response array
while (0 < $query_count--) {
  $id = mt_rand(1, 10000);
  $randomNumber = mt_rand(1, 10000);

  $statement->execute( [$id] );
  
  // Store result in array.
  $world = ['id' => $id, 'randomNumber' => $statement->fetchColumn()];
  $world['randomNumber'] = $randomNumber;
  $updateStatement->execute([$randomNumber, $id]);
  
  $arr[] = $world;
}

// Use the PHP standard JSON encoder.
// http://www.php.net/manual/en/function.json-encode.php
echo json_encode($arr);