<?php

class dwp_smtp {
  protected static $instance;
  protected $validations;

  function __construct() {
    $this->prepare_settings();
    $check = $this->validate();
    if( is_wp_error( $check ) ) {
      trigger_error($check->get_error_message(), E_USER_WARNING);
    } else {
      add_action( 'phpmailer_init', array( $this, 'mailer') );
    }
    unset($this->validations);
  }

  public static function launch() {
    self::$instance = (defined('GLOBAL_SMTP_DISABLE') && GLOBAL_SMTP_DISABLE ) ? null : new self();
  }

  protected function prepare_settings() {
    $this->validations = new stdClass;
    $this->validations->required = array('GLOBAL_SMTP_HOST','GLOBAL_SMTP_USER','GLOBAL_SMTP_PASSWORD');
    $this->validations->is_email = array('GLOBAL_SMTP_RETURN_PATH','GLOBAL_SMTP_FROM','GLOBAL_SMTP_REPLYTO_FROM');
    $this->validations->not_empty = array('GLOBAL_SMTP_FROM','GLOBAL_SMTP_FROM_NAME');
    $this->validations->is_int = array('GLOBAL_SMTP_PORT','GLOBAL_SMTP_TIMEOUT');
    $this->validations->should_be = array('GLOBAL_SMTP_SECURE' => array('ssl','tls','none'), 'GLOBAL_SMTP_AUTH_TYPE' => array('LOGIN','PLAIN','NTLM') );
    $assume = array(
      'GLOBAL_SMTP_PORT'=> 465,
      'GLOBAL_SMTP_SECURE' => 'ssl',
      'GLOBAL_SMTP_TIMEOUT' => 10,
      'GLOBAL_SMTP_FROM' => get_site_option('admin_email','',true),
      'GLOBAL_SMTP_FROM_NAME' => get_site_option('site_name','WordPress',true),
      'GLOBAL_SMTP_AUTH_TYPE' => 'LOGIN',
    );

    foreach ($assume as $setting => $default) {
      if(!defined($setting)) {
        define($setting, $default);
      }
    }
  }

  protected function validate() {
    foreach ($this->validations->required as $setting) {
      if(!defined($setting)) {
        return new WP_Error( 'multisite-smtp', sprintf( __( '%s is required. Please define this in wp-config.php.', 'multisite-smtp' ), $setting ) );
      }
    }
    foreach ($this->validations->is_email as $setting) {
      if (defined($setting) && !is_email(constant($setting))) {
        return new WP_Error( 'multisite-smtp', sprintf( __( 'Value of %s is not a valid email address. Check wp-config.php, or ensure a valid fallback is available.', 'multisite-smtp' ), $setting ) );
      }
    }
    foreach ($this->validations->not_empty as $setting) {
      if(defined($setting) && constant($setting)=="") {
        return new WP_Error( 'multisite-smtp', sprintf( __( '%s is empty. Check wp-config.php, or ensure a valid fallback is available.', 'multisite-smtp' ), $setting ) );
      }
    }
    foreach ($this->validations->is_int as $setting) {
      if(defined($setting) && !is_int(constant($setting)) ) {
        return new WP_Error( 'multisite-smtp', sprintf( __( '%s should be an integer.', 'multisite-smtp' ), $setting ) );
      }
    }
    foreach ($this->validations->should_be as $setting => $allowed) {
      if(defined($setting) && !in_array(constant($setting), $allowed)) {
        return new WP_Error( 'multisite-smtp', sprintf( __( '%s is invalid. It should be one of these values: "%s"', 'multisite-smtp' ), $setting, implode('" , "',$allowed) ) );
      }
    }
    return true;
  }

  public function mailer( $phpmailer ) {
    if(defined('GLOBAL_SMTP_DEBUG') && GLOBAL_SMTP_DEBUG ) $phpmailer->SMTPDebug = true;
    $phpmailer->Mailer = "smtp";
    $phpmailer->SMTPAuth = true;
    $phpmailer->Host = GLOBAL_SMTP_HOST;
    $phpmailer->Username = GLOBAL_SMTP_USER;
    $phpmailer->Password = GLOBAL_SMTP_PASSWORD;
    $phpmailer->From = GLOBAL_SMTP_FROM;
    $phpmailer->FromName = GLOBAL_SMTP_FROM_NAME;
    $phpmailer->Port = GLOBAL_SMTP_PORT;
    $phpmailer->SMTPSecure = GLOBAL_SMTP_SECURE;
    $phpmailer->AuthType = GLOBAL_SMTP_AUTH_TYPE;
    $phpmailer->Sender = defined('GLOBAL_SMTP_RETURN_PATH') ? GLOBAL_SMTP_RETURN_PATH : GLOBAL_SMTP_FROM;
    if(defined('GLOBAL_SMTP_REPLYTO_FROM')) {
        $phpmailer->AddReplyTo(GLOBAL_SMTP_REPLYTO_FROM, defined('GLOBAL_SMTP_REPLYTO_FROM_NAME') ? GLOBAL_SMTP_REPLYTO_FROM_NAME : GLOBAL_SMTP_FROM_NAME);
    }
  }
}

dwp_smtp::launch();