<?php
/*
 * Return a configuration value or secret.
 *
 * Values come from the environment first (for example Apache SetEnv),
 * then from the .env file, then from $default. The .env file is the one
 * named by the XXX_ENV_FILE environment variable, or else the .env file
 * next to this one. Git does not track .env; see .env.example.
 *
 * Each line of .env is NAME=value. Blank lines and lines that start
 * with # are skipped, and quotes around a value are removed.
 */
function config($key, $default = NULL) {
  static $values = NULL;

  $env = getenv($key);
  if ($env !== FALSE)
    return $env;

  if ($values === NULL) {
    $values = array();
    $file = getenv('XXX_ENV_FILE') ?: __DIR__ . '/.env';
    if (is_readable($file)) {
      foreach (file($file, FILE_IGNORE_NEW_LINES) as $line) {
        $line = trim($line);
        if ($line === '' || $line[0] === '#' || strpos($line, '=') === FALSE)
          continue;
        list($name, $value) = explode('=', $line, 2);
        $name  = trim(preg_replace('/^export\s+/', '', $name));
        $value = trim($value);
        if (strlen($value) >= 2 &&
            ($value[0] === '"' || $value[0] === "'") &&
            substr($value, -1) === $value[0])
          $value = substr($value, 1, -1);
        $values[$name] = $value;
      }
    }
  }

  return array_key_exists($key, $values) ? $values[$key] : $default;
}
?>