<?php
/*
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC. All rights reserved.                        |
 |                                                                    |
 | This work is published under the GNU AGPLv3 license with some      |
 | permitted exceptions and without any warranty. For full license    |
 | and copyright information, see https://civicrm.org/licensing       |
 +--------------------------------------------------------------------+
*/

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC https://civicrm.org/licensing
 *
 */


// This file must not accessed directly
if ( ! defined( 'ABSPATH' ) ) exit;


/**
 * Define CiviCRM_For_WordPress_Basepage Class.
 *
 * @since 4.6
 */
class CiviCRM_For_WordPress_Basepage {

  /**
   * Plugin object reference.
   *
   * @since 4.6
   * @access public
   * @var object $civi The plugin object reference.
   */
  public $civi;


  /**
   * Instance constructor.
   *
   * @since 4.6
   */
  function __construct() {

    // Store reference to CiviCRM plugin object
    $this->civi = civi_wp();

    // Always listen for activation action
    add_action( 'civicrm_activation', array( $this, 'activate' ) );

    // Always listen for deactivation action
    add_action( 'civicrm_deactivation', array( $this, 'deactivate' ) );

    // Always check if the basepage needs to be created
    add_action( 'civicrm_instance_loaded', array( $this, 'maybe_create_basepage' ) );

  }


  /**
   * Register hooks to handle CiviCRM in a WordPress wpBasePage context.
   *
   * @since 4.6
   */
  public function register_hooks() {

    // Kick out if not CiviCRM
    if (!$this->civi->initialize()) {
      return;
    }

    // In WP 4.6.0+, tell it URL params are part of canonical URL
    add_filter( 'get_canonical_url', array( $this, 'basepage_canonical_url' ), 999 );

    // Yoast SEO has separate way of establishing canonical URL
    add_filter( 'wpseo_canonical', array( $this, 'basepage_canonical_url' ), 999 );

    // And also for All in One SEO to handle canonical URL
    add_filter( 'aioseop_canonical_url', array( $this, 'basepage_canonical_url' ), 999 );

    // Regardless of URL, load page template
    add_filter( 'template_include', array( $this, 'basepage_template' ), 999 );

    // Check permission
    $argdata = $this->civi->get_request_args();
    if ( ! $this->civi->users->check_permission( $argdata['args'] ) ) {
      add_filter( 'the_content', array( $this->civi->users, 'get_permission_denied' ) );
      return;
    }

    // Cache CiviCRM base page markup
    add_action( 'wp', array( $this, 'basepage_handler' ), 10, 1 );

  }


  /**
   * Trigger the process whereby the WordPress basepage is created.
   *
   * Sets a one-time-only option to flag that we need to create a basepage -
   * it will not update the option once it has been set to another value nor
   * create a new option with the same name.
   *
   * As a result of doing this, we know that a basepage needs to be created, but
   * the moment to do so is once CiviCRM has been successfully installed.
   *
   * @see do_basepage_creation()
   *
   * @since 5.6
   */
  public function activate() {

    // Save option
    add_option( 'civicrm_activation_create_basepage', 'true' );

  }


  /**
   * Plugin deactivation.
   *
   * @since 5.6
   */
  public function deactivate() {

    // Delete option
    delete_option( 'civicrm_activation_create_basepage' );

  }


  /**
   * Register the hook to create the WordPress basepage, if necessary.
   *
   * Changes the one-time-only option so that the basepage can only be created
   * once. Thereafter, we're on our own until there's a 'delete_post' callback
   * to prevent the basepage from being deleted.
   *
   * @since 5.6
   */
  public function maybe_create_basepage() {

    // Bail if CiviCRM not installed
    if ( ! CIVICRM_INSTALLED ) {
      return;
    }

    // Bail if not installing
    if ( get_option( 'civicrm_activation_create_basepage' ) !== 'true' ) {
      return;
    }

    // Bail if not WordPress admin
    if ( ! is_admin() ) {
      return;
    }

    // Create basepage
    add_action( 'wp_loaded', array( $this, 'create_wp_basepage' ) );

    // Change option so the callback above never runs again
    update_option( 'civicrm_activation_create_basepage', 'done' );

  }


  /**
   * Create WordPress basepage and save setting.
   *
   * @since 4.6
   * @since 5.6 Relocated from CiviCRM_For_WordPress to here.
   */
  public function create_wp_basepage() {

    if (!$this->civi->initialize()) {
      return;
    }

    $config = CRM_Core_Config::singleton();

    // Bail if we already have a basepage setting
    if ( !empty( $config->wpBasePage ) ) {
      return;
    }

    /**
     * Filter the default page slug.
     *
     * @since 4.6
     *
     * @param str The default basepage slug.
     * @return str The modified basepage slug.
     */
    $slug = apply_filters( 'civicrm_basepage_slug', 'civicrm' );

    // Get existing page with that slug
    $page = get_page_by_path( $slug );

    // Does it exist?
    if ( $page ) {

      // We already have a basepage
      $result = $page->ID;

    } else {

      // Create the basepage
      $result = $this->create_basepage( $slug );

    }

    // Were we successful?
    if ( $result !== 0 AND !is_wp_error($result) ) {

      // Get the post object
      $post = get_post( $result );

      $params = array(
        'version' => 3,
        'wpBasePage' => $post->post_name,
      );

      // Save the setting
      civicrm_api3('setting', 'create', $params);

    }

  }


  /**
   * Create a WordPress page to act as the CiviCRM base page.
   *
   * @since 4.6
   * @since 5.6 Relocated from CiviCRM_For_WordPress to here.
   *
   * @param string $slug The unique slug for the page - same as wpBasePage setting.
   * @return int|WP_Error The page ID on success. The value 0 or WP_Error on failure.
   */
  private function create_basepage( $slug ) {

    // If multisite, switch to main site
    if ( is_multisite() && !is_main_site() ) {

      // Store this site
      $original_site = get_current_blog_id();

      // Switch
      global $current_site;
      switch_to_blog( $current_site->blog_id );

    }

    // Define basepage
    $page = array(
      'post_status' => 'publish',
      'post_type' => 'page',
      'post_parent' => 0,
      'comment_status' => 'closed',
      'ping_status' => 'closed',
      'to_ping' => '', // Quick fix for Windows
      'pinged' => '', // Quick fix for Windows
      'post_content_filtered' => '', // Quick fix for Windows
      'post_excerpt' => '', // Quick fix for Windows
      'menu_order' => 0,
      'post_name' => $slug,
    );

    /**
     * Filter the default page title.
     *
     * @since 4.6
     *
     * @param str The default base page title.
     * @return str The modified base page title.
     */
    $page['post_title'] = apply_filters( 'civicrm_basepage_title', __( 'CiviCRM', 'civicrm' ) );

    // Default content
    $content = __( 'Do not delete this page. Page content is generated by CiviCRM.', 'civicrm' );

    /**
     * Filter the default page content.
     *
     * @since 4.6
     *
     * @param str $content The default base page content.
     * @return str $content The modified base page content.
     */
    $page['post_content'] = apply_filters( 'civicrm_basepage_content', $content );

    // Insert the post into the database
    $page_id = wp_insert_post( $page );

    // Switch back if we've switched
    if ( isset( $original_site ) ) {
      restore_current_blog();
    }

    return $page_id;

  }


  /**
   * Build CiviCRM base page content.
   *
   * Callback method for 'wp' hook, always called from WP front-end.
   *
   * @since 4.6
   *
   * @param object $wp The WP object, present but not used.
   */
  public function basepage_handler( $wp ) {

    /*
     * At this point, all conditional tags are available
     * @see http://codex.wordpress.org/Conditional_Tags
     */

    // Bail if this is a 404
    if ( is_404() ) return;

    // Kick out if not CiviCRM
    if (!$this->civi->initialize()) {
      return '';
    }

    // Add core resources for front end
    add_action( 'wp', array( $this->civi, 'front_end_page_load' ), 100 );

    // CMW: why do we need this? Nothing that follows uses it...
    require_once ABSPATH . WPINC . '/pluggable.php';

    /*
     * Let's do the_loop.
     * This has the effect of bypassing the logic in
     * https://github.com/civicrm/civicrm-wordpress/pull/36
     */
    if ( have_posts() ) {
      while ( have_posts() ) : the_post();

        global $post;

        ob_start(); // Start buffering
        $this->civi->invoke(); // Now, instead of echoing, base page output ends up in buffer
        $this->basepage_markup = ob_get_clean(); // Save the output and flush the buffer

        /*
         * The following logic is in response to some of the complexities of how
         * titles are handled in WordPress, particularly when there are SEO
         * plugins present that modify the title for Open Graph purposes. There
         * have also been issues with the default WordPress themes, which modify
         * the title using the 'wp_title' filter.
         *
         * First, we try and set the title of the page object, which will work
         * if the loop is not run subsequently and if there are no additional
         * filters on the title.
         *
         * Second, we store the CiviCRM title so that we can construct the base
         * page title if other plugins modify it.
         */

        // Override post title
        global $civicrm_wp_title;
        $post->post_title = $civicrm_wp_title;

        // Because the above seems unreliable, store title for later use
        $this->basepage_title = $civicrm_wp_title;

        // Disallow commenting
        $post->comment_status = 'closed';

      endwhile;
    }

    // Reset loop
    rewind_posts();

    // Override page title with high priority
    add_filter( 'wp_title', array( $this, 'wp_page_title' ), 100, 3 );
    add_filter( 'document_title_parts', array( $this, 'wp_page_title_parts' ), 100, 1 );

    // Add compatibility with Yoast SEO plugin's Open Graph title
    add_filter( 'wpseo_opengraph_title', array( $this, 'wpseo_page_title' ), 100, 1 );

    // Don't let the Yoast SEO plugin parse the basepage title
    if ( class_exists( 'WPSEO_Frontend' ) ) {
      $frontend = WPSEO_Frontend::get_instance();
      remove_filter( 'pre_get_document_title', array( $frontend, 'title' ), 15 );
    }

    // Include this content when base page is rendered
    add_filter( 'the_content', array( $this, 'basepage_render' ) );

    // Hide the edit link
    add_action( 'edit_post_link', array( $this->civi, 'clear_edit_post_link' ) );

    // Tweak admin bar
    add_action( 'wp_before_admin_bar_render', array( $this->civi, 'clear_edit_post_menu_item' ) );

    // Add body classes for easier styling
    add_filter( 'body_class', array( $this, 'add_body_classes' ) );

    // Flag that we have parsed the base page
    $this->basepage_parsed = TRUE;

    /**
     * Broadcast that the base page is parsed.
     *
     * @since 4.4
     */
    do_action( 'civicrm_basepage_parsed' );

  }


  /**
   * Get CiviCRM basepage title for <title> element.
   *
   * Callback method for 'wp_title' hook, called at the end of function wp_title.
   *
   * @since 4.6
   *
   * @param string $title Title that might have already been set.
   * @param string $separator Separator determined in theme (but defaults to WordPress default).
   * @param string $separator_location Whether the separator should be left or right.
   */
  public function wp_page_title( $title, $separator = '&raquo;', $separator_location = '' ) {

    // If feed, return just the title
    if ( is_feed() ) return $this->basepage_title;

    // Set default separator location, if it isn't defined
    if ( '' === trim( $separator_location ) ) {
      $separator_location = ( is_rtl() ) ? 'left' : 'right';
    }

    // If we have WP SEO present, use its separator
    if ( class_exists( 'WPSEO_Options' ) ) {
      $separator_code = WPSEO_Options::get_default( 'wpseo_titles', 'separator' );
      $separator_array = WPSEO_Option_Titles::get_instance()->get_separator_options();
      if ( array_key_exists( $separator_code, $separator_array ) ) {
        $separator = $separator_array[$separator_code];
      }
    }

    // Construct title depending on separator location
    if ( $separator_location == 'right' ) {
      $title = $this->basepage_title . " $separator " . get_bloginfo( 'name', 'display' );
    } else {
      $title = get_bloginfo( 'name', 'display' ) . " $separator " . $this->basepage_title;
    }

    // Return modified title
    return $title;

  }


  /**
   * Get CiviCRM basepage title for <title> element.
   *
   * Callback method for 'document_title_parts' hook. This filter was introduced
   * in WordPress 3.8 but it depends on whether the theme has implemented that
   * method for generating the title or not.
   *
   * @since 5.14
   *
   * @param array $parts The existing title parts.
   * @return array $parts The modified title parts.
   */
  public function wp_page_title_parts( $parts ) {

    // Override with CiviCRM's title
    if ( isset( $parts['title'] ) ) {
      $parts['title'] = $this->basepage_title;
    }

    // Return modified title parts
    return $parts;

  }


  /**
   * Get CiviCRM base page title for Open Graph elements.
   *
   * Callback method for 'wpseo_opengraph_title' hook, to provide compatibility
   * with the WordPress SEO plugin.
   *
   * @since 4.6.4
   *
   * @param string $post_title The title of the WordPress page or post.
   * @return string $basepage_title The title of the CiviCRM entity.
   */
  public function wpseo_page_title( $post_title ) {

    // Hand back our base page title
    return $this->basepage_title;

  }


  /**
   * Get CiviCRM base page content.
   *
   * Callback method for 'the_content' hook, always called from WP front-end.
   *
   * @since 4.6
   *
   * @return str $basepage_markup The base page markup.
   */
  public function basepage_render() {

    // Hand back our base page markup
    return $this->basepage_markup;

  }


  /**
   * Provide the canonical URL for a page accessed through a basepage.
   *
   * WordPress will default to saying the canonical URL is the URL of the base
   * page itself, but we need to indicate that in this case, the whole thing
   * matters.
   *
   * Note: this function is used for three different but similar hooks:
   *  - `get_canonical_url` (WP 4.6.0+)
   *  - `aioseop_canonical_url` (All in One SEO)
   *  - `wpseo_canonical` (Yoast WordPress SEO)
   *
   * The native WordPress one passes the page object, while the other two do
   * not.  We don't actually need the page object, so the argument is omitted
   * here.
   *
   * @since 4.6
   *
   * @param string $canonical The canonical URL.
   * @return string The complete URL to the page as it should be accessed.
   */
  public function basepage_canonical_url( $canonical ) {

    // Access Civi config object
    $config = CRM_Core_Config::singleton();

    // Retain old logic when not using clean URLs
    if (!$config->cleanURL) {

      /*
       * It would be better to specify which params are okay to accept as the
       * canonical URLs, but this will work for the time being.
       */
      if ( empty( $_GET['page'] )
        || empty( $_GET['q'] )
        || 'CiviCRM' !== $_GET['page'] ) {
        return $canonical;
      }
      $path = $_GET['q'];
      unset( $_GET['q'] );
      unset( $_GET['page'] );
      $query = http_build_query( $_GET );

    }
    else {

      $argdata = $this->civi->get_request_args();
      $path = $argdata['argString'];
      $query = http_build_query( $_GET );

    }

    // We should, however, build the URL the way that CiviCRM expects it to be
    // (rather than through some other funny base page).
    return CRM_Utils_System::url( $path, $query );

  }


  /**
   * Get CiviCRM base page template.
   *
   * Callback method for 'template_include' hook, always called from WP front-end.
   *
   * @since 4.6
   *
   * @param string $template The path to the existing template.
   * @return string $template The modified path to the desired template.
   */
  public function basepage_template( $template ) {

    // Get template filename
    $template_name = basename( $template );

    // Use the provided page template, but allow overrides.
    $page_template = locate_template( array(

      /**
       * Allow base page template to be overridden.
       *
       * In most cases, the logic will not progress beyond here. Shortcodes in
       * posts and pages will have a template set, so we leave them alone unless
       * specifically overridden by the filter.
       *
       * @since 4.6
       *
       * @param string $template_name The provided template name.
       * @return string The overridden template name.
       */
      apply_filters( 'civicrm_basepage_template', $template_name )

    ) );

    // If not homepage and template is found
    if ( '' != $page_template && !is_front_page() ) {
      return $page_template;
    }

    // Find homepage the template
    $home_template = locate_template( array(

      /**
       * Override the template, but allow plugins to amend.
       *
       * This filter handles the scenario where no basepage has been set, in
       * which case CiviCRM will try to load its content in the site's homepage.
       * Many themes, however, do not have a call to "the_content()" on the
       * homepage - it is often used as a gateway page to display widgets,
       * archives and so forth.
       *
       * Be aware that if the homepage is set to show latest posts, then this
       * template override will not have the desired effect. A basepage *must*
       * be set if this is the case.
       *
       * @since 4.6
       *
       * @param string The template name (set to the default page template).
       * @return string The overridden template name.
       */
      apply_filters( 'civicrm_basepage_home_template', 'page.php' )

    ) );

    // Use it if found
    if ( '' != $home_template ) {
      return $home_template;
    }

    // Fall back to provided template
    return $template;

  }


  /**
   * Add classes to body element when on basepage.
   *
   * This allows selectors to be written for particular CiviCRM "pages" despite
   * them all being rendered on the one WordPress basepage.
   *
   * @since 4.7.18
   *
   * @param array $classes The existing body classes.
   * @return array $classes The modified body classes.
   */
  public function add_body_classes( $classes ) {

     $args = $this->civi->get_request_args();

     // Bail if we don't have any
     if ( is_null( $args['argString'] ) ) {
       return $classes;
     }

     // Check for top level - it can be assumed this always 'civicrm'
     if ( isset( $args['args'][0] ) AND ! empty( $args['args'][0] ) ) {
       $classes[] = $args['args'][0];
     }

     // Check for second level - the component
     if ( isset( $args['args'][1] ) AND ! empty( $args['args'][1] ) ) {
       $classes[] = $args['args'][0] . '-' . $args['args'][1];
     }

     // Check for third level - the component's configuration
     if ( isset( $args['args'][2] ) AND ! empty( $args['args'][2] ) ) {
       $classes[] = $args['args'][0] . '-' . $args['args'][1] . '-' . $args['args'][2];
     }

     // Check for fourth level - because well, why not?
     if ( isset( $args['args'][3] ) AND ! empty( $args['args'][3] ) ) {
       $classes[] = $args['args'][0] . '-' . $args['args'][1] . '-' . $args['args'][2] . '-' . $args['args'][3];
     }

     return $classes;

  }


} // Class CiviCRM_For_WordPress_Basepage ends
