<?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;
}

/*
 * The address of the site comes from SITE_URL, never from the Host
 * header, which the browser controls. site_url() gives the scheme, host
 * and port (for example "https://xxx.org.za"), and site_host() gives the
 * host. Both are empty if SITE_URL has no host.
 */
function site_url_parts() {
  $site = parse_url(trim((string)config('SITE_URL', '')));
  return is_array($site) && !empty($site['host']) ? $site : array();
}

function site_host() {
  return site_url_parts()['host'] ?? '';
}

function site_url($scheme = NULL) {
  $site = site_url_parts();
  if (!$site)
    return '';
  $port = isset($site['port']) ? ':' . $site['port'] : '';
  return ($scheme ?? $site['scheme'] ?? 'https') . '://' . $site['host'] . $port;
}

// An address at the site's host, such as "editor@xxx.org.za"
function site_email($name) {
  return $name . '@' . site_host();
}

// The cookie domain: the site's host and its subdomains
function cookie_domain() {
  return site_host() === '' ? '' : '.' . site_host();
}

/*
 * Send a plain HTTP request to the same page over HTTPS, and stop.
 * Without SITE_URL, the page refuses plain HTTP.
 */
function require_https() {
  if (isset($_SERVER['HTTPS']))
    return;
  if (site_url() === '') {
    http_response_code(403);
    echo "This page needs HTTPS.\n";
  } else {
    header('Location: ' . site_url('https') . $_SERVER['REQUEST_URI']);
  }
  exit;
}

// Always log PHP errors; show them only if DISPLAY_ERRORS is set (for development)
ini_set('log_errors', '1');
ini_set('display_errors', (string)config('DISPLAY_ERRORS', '0'));
?>