magazine-issues.php

<?php
/*
Plugin Name: Magazine Issues
Plugin URI: http://URI_Of_Page_Describing_Plugin_and_Updates
Description: Use this plugin to manage and create Magazine Issues.
    It will create a new Issue taxonomy and a new Page for the issue,
    list Posts under that Issue on the Issue page,
    and change the "Current Issue" link to point to this new Page.
Version: 0.1.0
Author: Per Nilsson
Author URI: http://sproutlab.com
License: GPL2
*/

/*  Copyright 2013  Per Nilsson  (email : per@sproutlab.com)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2, as
    published by the Free Software Foundation.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/


/*
    TODO
    - Make options for:
      - current-issue nav menu slug;
      - issue slug & issue-cover slug
*/

    function dump($what) {
        print('<pre>');
        print_r($what);
        print('</pre>');
    }


if (!class_exists('MagazineIssues')) {
    Class MagazineIssues {

        var $pluginOptions = array(
            'adminPageTitle'    => 'Add Magazine Issue',
            'adminMenuTitle'    => 'Issues',
            'adminCapability'   => 'publish_pages',
            'adminMenuSlug'     => 'add_magazine_issue',
            'adminMenuIconUrl'  => null,
            'adminMenuPosition' => 6, // After 'Posts'

            'taxonomySlug'      => 'issue',
            'taxonomy'          => ''
        );

        /* Constructor. */
        function MagazineIssues() {
            // nothing here
        }

        /* This is run on plugin activation. */
        function activate() {
            // nothing yet
        }

        /* Registers a menu item in the WP admin interface. */
        function addAdminMenuItem() {
            add_menu_page(
                $this->pluginOptions['adminPageTitle'],
                $this->pluginOptions['adminMenuTitle'],
                $this->pluginOptions['adminCapability'],
                $this->pluginOptions['adminMenuSlug'],
                array($this, 'renderAdminPage'),
                $this->pluginOptions['adminMenuIconUrl'],
                $this->pluginOptions['adminMenuPosition']
            );
        }

        /* Validates the data POSTed from the Magazine Issue admin interface */
        function validateNewIssuePostData($postData) {
            $fields = array('magazineIssueTerm', 'magazineIssueTitle');
            $validPost = true;
            foreach($fields as $field) {
                if (!isset($postData[$field]) || strlen(trim($postData[$field])) === 0) {
                    $validPost = false;
                    break;
                }
            }
            return $validPost;
        }

        /* Registers a custom 'issue' taxonomy. */
        function registerIssueTaxonomy() {
            $taxonomyLabels = array(
                'name' => _x('Issues', 'taxonomy general name'),
                'singular_name' => _x('Issue', 'taxonomy singular name'),
                'search_items' =>  __('Search Issues'),
                'popular_items' => __('Popular Issues'),
                'all_items' => __('All Issues'),
                'parent_item' => null,
                'parent_item_colon' => null,
                'edit_item' => __('Edit Issue'),
                'update_item' => __('Update Issue'),
                'add_new_item' => __('Add New Issue'),
                'new_item_name' => __('New Issue Name'),
                'separate_items_with_commas' => __('Separate issues with commas'),
                'add_or_remove_items' => __('Add or remove issues'),
                'choose_from_most_used' => __('Choose from the most commonly used issues'),
                'menu_name' => __('Issues'),
            );
            $args = array(
                'hierarchical' => false,
                'label' => 'Issues',
                'labels' => $taxonomyLabels,
                'show_ui' => true,
                'show_admin_column' => true,    // TODO
                'update_count_callback' => '_update_post_term_count',
                'query_var' => true,            // TODO
                'rewrite' => array(
                    'slug' => 'issue',
                    'with_front' => false,
                    'hierarchical' => false
                ),
            );

            register_taxonomy('issue', array('post'), $args);
        }

        /* Registers a custom 'Issue Cover' post type */
        function registerIssueCoverPostType() {
            $issueCoverLabels = array(
                'name' => 'Issue Covers',
                'singular_name' => 'Issue Cover',
                'add_new' => 'Add New',
                'add_new_item' => 'Add New Issue Cover',
                'edit_item' => 'Edit Issue Cover',
                'new_item' => 'New Issue Cover',
                'all_items' => 'All Issue Covers',
                'view_item' => 'View Issue Cover',
                'search_items' => 'Search Issue Covers',
                'not_found' =>  'No issue covers found',
                'not_found_in_trash' => 'No issue covers found in Trash',
                'parent_item_colon' => '',
                'menu_name' => 'Issue Covers'
              );

              $args = array(
                'labels' => $issueCoverLabels,
                'public' => true,
                'publicly_queryable' => true,
                'show_ui' => true,
                'show_in_menu' => false,
                'query_var' => true,
                'rewrite' => array( 'slug' => 'issue-cover' ),
                'capability_type' => 'post',
                'has_archive' => false,
                'hierarchical' => false,
                'menu_position' => null,
                'supports' => array('title', 'editor', 'author', 'thumbnail', 'excerpt', 'comments'),
                'taxonomies' => array('issue')
              );

              register_post_type('issue_cover', $args);
        }

        /* Renders the admin page available via the admin menu item. */
        function renderAdminPage() {
            if (sizeof($_POST) > 0) {
                // The user has POSTed the form!
                $result = $this->processPostback($_POST);
                if (is_wp_error($result)) {
                    print('<span class="error">Error: ' . $error->get_error_message() . '</span>');
                } else {
                    print("<span class=\"success\">{$result}</span>");
                }
            }
            // Render the form
            include_once('php/magazine-issues-admin.html.php');
        }

        function detectAdminPostbackType($postData) {
            if (isset($postData['magazineIssueCurrent'])) {
                return 'change_current_issue';
            }
            return 'new_issue';
        }

        function handleNewIssuePostback($postData) {
            if (!$this->validateNewIssuePostData($postData)) {
                return new WP_Error('invalid_post_data', "Please enter both a title and a term name for the issue.");
            }
            $post;
            $postId;
            $postTitle = trim($postData['magazineIssueTitle']);
            $term;
            $termId;
            $termName = trim($postData['magazineIssueTerm']);

            if (term_exists($termName, 'issue')) {
                return new WP_Error('term_exists', "The issue \"{$termName}\" already exists. Please choose a unique name.");
            }
            $post = array(
                'post_title' => $postTitle,
                'post_type' => 'issue_cover'
            );
            $postId = wp_insert_post($post);
            $result = wp_set_object_terms($postId, $termName, 'issue', false);
            if (is_wp_error($result)) {
                return $result;
            }

            return "Created new Issue Cover: $postTitle";
        }

        function handleChangeCurrentIssuePostback($postData) {
            $postID = $postData['magazineIssueCurrent'];
            self::setCurrentIssuePostID($postID);
            return "Changed Current Issue.";
        }

        function processPostback($postData) {
            $type = $this->detectAdminPostbackType($postData);
            if ($type == 'new_issue') {
                return $this->handleNewIssuePostback($postData);
            } else if ($type == 'change_current_issue') {
                return $this->handleChangeCurrentIssuePostback($postData);
            }
        }

        private static function getCurrentIssueNavItemPostID() {
            $postArgs = array(
                'post_type' => 'nav_menu_item',
                'name' => 'current-issue',
                'numberposts' => 1
            );
            $posts = get_posts($postArgs);
            return $posts[0]->ID;
        }

        public static function getCurrentIssueTermID() {
            $currentIssueID = get_metadata('post',
                                           self::getCurrentIssueNavItemPostID(),
                                           '_menu_item_object_id');
            return $currentIssueID[0];
        }

        private static function setCurrentIssuePostID($postID) {
            update_metadata('post',
                            self::getCurrentIssueNavItemPostID(),
                            '_menu_item_object_id',
                            $postID,
                            self::getCurrentIssueTermID());
        }
    }
}

if (class_exists('MagazineIssues')) {
    $magazineIssuesPlugin = new MagazineIssues();
}

// Actions
if (isset($magazineIssuesPlugin)) {

    // To make rewrite rules work
    add_action('admin_init', 'flush_rewrite_rules');
    // Activation of plugin (once)
    add_action('activate_magazine-issues/magazine-issues.php', array(&$magazineIssuesPlugin, 'activate'));
    // Admin menu item
    add_action('admin_menu', array(&$magazineIssuesPlugin, 'addAdminMenuItem'));
    // On each loop
    add_action('init', array(&$magazineIssuesPlugin, 'registerIssueTaxonomy'));
    add_action('init', array(&$magazineIssuesPlugin, 'registerIssueCoverPostType'));
}