<?php

namespace MailPoet\Router\Endpoints;

use MailPoet\Config\AccessControl;
use MailPoet\Models\Newsletter;
use MailPoet\Models\SendingQueue;
use MailPoet\Models\Subscriber;
use MailPoet\Newsletter\Url as NewsletterUrl;
use MailPoet\Newsletter\ViewInBrowser as NewsletterViewInBrowser;
use MailPoet\Settings\SettingsController;
use MailPoet\Subscribers\LinkTokens;
use MailPoet\WP\Emoji;
use MailPoet\WP\Functions as WPFunctions;

class ViewInBrowser {
  const ENDPOINT = 'view_in_browser';
  const ACTION_VIEW = 'view';
  public $allowedActions = [self::ACTION_VIEW];
  public $permissions = [
    'global' => AccessControl::NO_ACCESS_RESTRICTION,
  ];
  /** @var AccessControl */
  private $accessControl;

  /** @var SettingsController */
  private $settings;

  /** @var LinkTokens */
  private $linkTokens;

  /** @var Emoji */
  private $emoji;

  public function __construct(AccessControl $accessControl, SettingsController $settings, LinkTokens $linkTokens, Emoji $emoji) {
    $this->accessControl = $accessControl;
    $this->settings = $settings;
    $this->linkTokens = $linkTokens;
    $this->emoji = $emoji;
  }

  public function view($data) {
    $data = $this->_processBrowserPreviewData($data);
    $viewInBrowser = new NewsletterViewInBrowser($this->emoji, (bool)$this->settings->get('tracking.enabled'));
    return $this->_displayNewsletter($viewInBrowser->view($data));
  }

  public function _processBrowserPreviewData(array $data) {
    $data = NewsletterUrl::transformUrlDataObject($data);
    return $this->_validateBrowserPreviewData($data) ?: $this->_abort();
  }

  /**
   * @param array $data
   * @return array|false
   */
  public function _validateBrowserPreviewData(array $data) {
    // either newsletter ID or hash must be defined, and newsletter must exist
    if (empty($data['newsletter_id']) && empty($data['newsletter_hash'])) {
      return false;
    }

    $data['newsletter'] = (!empty($data['newsletter_hash']))
      ? Newsletter::getByHash($data['newsletter_hash'])
      : Newsletter::findOne($data['newsletter_id']);
    if (!$data['newsletter']) {
      return false;
    }

    // subscriber is optional; if exists, token must validate
    $data['subscriber'] = !empty($data['subscriber_id']) ? Subscriber::findOne($data['subscriber_id']) : false;
    if ($data['subscriber']) {
      if (empty($data['subscriber_token']) || !$this->linkTokens->verifyToken($data['subscriber'], $data['subscriber_token'])) {
        return false;
      }
    } else if (!$data['subscriber'] && !empty($data['preview'])) {
      // if this is a preview and subscriber does not exist,
      // attempt to set subscriber to the current logged-in WP user
      $data['subscriber'] = Subscriber::getCurrentWPUser();
    }

    // if newsletter hash is not provided but newsletter ID is defined then subscriber must exist
    if (empty($data['newsletter_hash']) && $data['newsletter_id'] && !$data['subscriber']) {
      return false;
    }

    // queue is optional; try to find it if it's not defined and this is not a welcome email
    if ($data['newsletter']->type !== Newsletter::TYPE_WELCOME) {
      $data['queue'] = (!empty($data['queue_id']))
        ? SendingQueue::findOne($data['queue_id'])
        : SendingQueue::where('newsletter_id', $data['newsletter']->id)->findOne();
    } else {
      $data['queue'] = false;
    }

    // reset queue when automatic email is being previewed
    if ($data['newsletter']->type === Newsletter::TYPE_AUTOMATIC && !empty($data['preview'])) {
      $data['queue'] = false;
    }

    // allow users with permission to manage emails to preview any newsletter
    if (!empty($data['preview']) && $this->accessControl->validatePermission(AccessControl::PERMISSION_MANAGE_EMAILS)) {
      return $data;
    }

    // allow others to preview newsletters only when newsletter hash is defined
    if (!empty($data['preview']) && empty($data['newsletter_hash'])) {
      return false;
    }

    // if queue and subscriber exist, subscriber must have received the newsletter
    if ($data['queue'] instanceof SendingQueue && $data['subscriber'] && !$data['queue']->isSubscriberProcessed($data['subscriber']->id)) {
      return false;
    }

    return $data;
  }

  public function _displayNewsletter($result) {
    header('Content-Type: text/html; charset=utf-8');
    echo $result;
    exit;
  }

  public function _abort() {
    WPFunctions::get()->statusHeader(404);
    exit;
  }
}