footnotes-made-easy.php

<?php
/*
Plugin Name: Footnotes Made Easy
Plugin URI: https://github.com/wpcorner/footnotes-made-easy/
Description: Allows post authors to easily add and manage footnotes in posts.
Version: 3.0.4.1
Author: Patrick Lumumba
Author URI: https://wpcorner.co/author/patrick-l/
Text Domain: footnotes-made-easy
*/

/**
* Footnotes Made Easy
*
* Easily add footnotes to a post
*
* @package    footnotes-made-easy
* @since    1.0
*/

// Exit if accessed directly

if (!defined('ABSPATH')) {
    exit; 
}

/**
 * Enqueue plugin styles
 */
function fme_enqueue_styles() {
    wp_enqueue_style('gbad-styles', plugin_dir_url(__FILE__) . 'css/gbad.css', array(), filemtime(plugin_dir_path(__FILE__) . 'css/gbad.css'));
}
add_action('admin_enqueue_scripts', 'fme_enqueue_styles');

// Instantiate the class

$swas_wp_footnotes = new swas_wp_footnotes();

// Encapsulate in a class

class swas_wp_footnotes {

    private $current_options;
    private $default_options;
    private $styles;

    const OPTIONS_VERSION = "5"; // Incremented when the options array changes

    // Constructor

    function __construct() {

        // Define the implemented option styles

        $this->styles = array(
            'decimal' => '1,2...10',
            'decimal-leading-zero' => '01, 02...10',
            'lower-alpha' => 'a,b...j',
            'upper-alpha' => 'A,B...J',
            'lower-roman' => 'i,ii...x',
            'upper-roman' => 'I,II...X',
            'symbol' => 'Symbol'
        );

        // Define default options

        $this->default_options = array(
            'superscript' => true,
            'pre_backlink' => ' [',
            'backlink' => '&#8617;',
            'post_backlink' => ']',
            'pre_identifier' => '',
            'inner_pre_identifier' => '',
            'list_style_type' => 'decimal',
            'list_style_symbol' => '&dagger;',
            'inner_post_identifier' => '',
            'post_identifier' => '',
            'pre_footnotes' => '',
            'post_footnotes' => '',
            'no_display_home' => false,
            'no_display_preview' => false,
            'no_display_archive' => false,
            'no_display_date' => false,
            'no_display_category' => false,
            'no_display_search' => false,
            'no_display_feed' => false,
            'combine_identical_notes' => true,
            'priority' => 11,
            'footnotes_open' => ' ((',
            'footnotes_close' => '))',
            'pretty_tooltips' => false,
            'version' => self::OPTIONS_VERSION
        );

        // Get the current settings or setup some defaults if needed
     
        $this->current_options = get_option('swas_footnote_options');
        if (!$this->current_options) {        
            $this->current_options = $this->default_options;
            update_option('swas_footnote_options', $this->current_options);
        } else {
            // Set any unset options
            if (!isset($this->current_options['version']) || $this->current_options['version'] !== self::OPTIONS_VERSION) {
                foreach ($this->default_options as $key => $value) {
                    if (!isset($this->current_options[$key])) {
                        $this->current_options[$key] = $value;
                    }
                }
                $this->current_options['version'] = self::OPTIONS_VERSION;
                update_option('swas_footnote_options', $this->current_options);
            }
        }

        $footnotes_options = array();
            
        $post_array = $_POST;

        if (!empty($post_array['save_options']) && !empty($post_array['save_footnotes_made_easy_options'])) {
            $footnotes_options['superscript'] = (array_key_exists('superscript', $post_array)) ? true : false;
            $footnotes_options['pre_backlink'] = sanitize_text_field($post_array['pre_backlink']);
            $footnotes_options['backlink'] = sanitize_text_field($post_array['backlink']);
            $footnotes_options['post_backlink'] = sanitize_text_field($post_array['post_backlink']);
            $footnotes_options['pre_identifier'] = sanitize_text_field($post_array['pre_identifier']);
            $footnotes_options['inner_pre_identifier'] = sanitize_text_field($post_array['inner_pre_identifier']);
            $footnotes_options['list_style_type'] = sanitize_text_field($post_array['list_style_type']);
            $footnotes_options['inner_post_identifier'] = sanitize_text_field($post_array['inner_post_identifier']);
            $footnotes_options['post_identifier'] = sanitize_text_field($post_array['post_identifier']);
            $footnotes_options['list_style_symbol'] = sanitize_text_field($post_array['list_style_symbol']);
            $footnotes_options['pre_footnotes'] = $post_array['pre_footnotes'];
            $footnotes_options['post_footnotes'] = $post_array['post_footnotes'];
            $footnotes_options['no_display_home'] = (array_key_exists('no_display_home', $post_array)) ? true : false;
            $footnotes_options['no_display_preview'] = (array_key_exists('no_display_preview', $post_array)) ? true : false;
            $footnotes_options['no_display_archive'] = (array_key_exists('no_display_archive', $post_array)) ? true : false;
            $footnotes_options['no_display_date'] = (array_key_exists('no_display_date', $post_array)) ? true : false;
            $footnotes_options['no_display_category'] = (array_key_exists('no_display_category', $post_array)) ? true : false;
            $footnotes_options['no_display_search'] = (array_key_exists('no_display_search', $post_array)) ? true : false;
            $footnotes_options['no_display_feed'] = (array_key_exists('no_display_feed', $post_array)) ? true : false;
            $footnotes_options['combine_identical_notes'] = (array_key_exists('combine_identical_notes', $post_array)) ? true : false;
            $footnotes_options['priority'] = sanitize_text_field($post_array['priority']);
            $footnotes_options['footnotes_open'] = sanitize_text_field($post_array['footnotes_open']);
            $footnotes_options['footnotes_close'] = sanitize_text_field($post_array['footnotes_close']);
            $footnotes_options['pretty_tooltips'] = (array_key_exists('pretty_tooltips', $post_array)) ? true : false;

            update_option('swas_footnote_options', $footnotes_options);
            $this->current_options = $footnotes_options;
        }

        // Hook me up
        
        // Adding a filter to modify the fields processed by the plugin
        $fields_to_process = apply_filters('footnotes_made_easy_fields', array('the_content')); 
        // Hooking the process function to each field
        foreach ($fields_to_process as $field) {
            add_action($field, array($this, 'process'), $this->current_options['priority']);
        }
        add_action('admin_menu', array($this, 'add_options_page'));         // Insert the Admin panel.
        add_action('wp_head', array($this, 'insert_styles'));
        if ($this->current_options['pretty_tooltips']) add_action('wp_enqueue_scripts', array($this, 'tooltip_scripts'));

        add_filter('plugin_action_links', array($this, 'add_settings_link'), 10, 2);
        add_filter('plugin_row_meta', array($this, 'plugin_meta'), 10, 2);    
    }

    /**
    * Searches the text and extracts footnotes
    *
    * Adds the identifier links and creats footnotes list
    *
    * @since    1.0
    *
    * @param    $data    string    The content of the post
    * @return            string     The new content with footnotes generated
    */

    function process($data) {

        global $post;
        
        // check against post existing before processing
        if (!$post) {
            return $data;
        }

        // Check for and setup the starting number

        $start_number = (1 === preg_match("|<!\-\-startnum=(\d+)\-\->|", $data, $start_number_array)) ? $start_number_array[1] : 1;

        // Regex extraction of all footnotes (or return if there are none)

        if (!preg_match_all("/(" . preg_quote($this->current_options['footnotes_open'], "/") . ")(.*)(" . preg_quote($this->current_options['footnotes_close'], "/") . ")/Us", $data, $identifiers, PREG_SET_ORDER)) {
            return $data;
        }

        // Check whether we are displaying them or not

        $display = true;
        if ($this->current_options['no_display_home'] && is_home()) $display = false;
        if ($this->current_options['no_display_archive'] && is_archive()) $display = false;
        if ($this->current_options['no_display_date'] && is_date()) $display = false;
        if ($this->current_options['no_display_category'] && is_category()) $display = false;
        if ($this->current_options['no_display_search'] && is_search()) $display = false;
        if ($this->current_options['no_display_feed'] && is_feed()) $display = false;
        if ($this->current_options['no_display_preview'] && is_preview()) $display = false;

        $footnotes = array();

        // Check if this post is using a different list style to the settings

        if (get_post_meta($post->ID, 'footnote_style', true) && array_key_exists(get_post_meta($post->ID, 'footnote_style', true), $this->styles)) {
            $style = get_post_meta($post->ID, 'footnote_style', true);
        } else {
            $style = $this->current_options['list_style_type'];
        }

        // Create 'em

        for ($i = 0; $i < count($identifiers); $i++) {

            // Look for ref: and replace in identifiers array

            if ('ref:' === substr($identifiers[$i][2], 0, 4)) {
                $ref = (int)substr($identifiers[$i][2], 4);
                $identifiers[$i]['text'] = $identifiers[$ref-1][2];
            } else {
                $identifiers[$i]['text'] = $identifiers[$i][2];
            }

            // if we're combining identical notes check if we've already got one like this & record keys

            if ($this->current_options['combine_identical_notes']) {
                for ($j = 0; $j < count($footnotes); $j++) {
                    if ($footnotes[$j]['text'] === $identifiers[$i]['text']) {
                        $identifiers[$i]['use_footnote'] = $j;
                        $footnotes[$j]['identifiers'][] = $i;
                        break;
                    }
                }
            }

            if (!isset($identifiers[$i]['use_footnote'])) {

                // Add footnote and record the key

                $identifiers[$i]['use_footnote'] = count($footnotes);
                $footnotes[$identifiers[$i]['use_footnote']]['text'] = $identifiers[$i]['text'];
                $footnotes[$identifiers[$i]['use_footnote']]['symbol'] = isset($identifiers[$i]['symbol']) ? $identifiers[$i]['symbol'] : '';
                $footnotes[$identifiers[$i]['use_footnote']]['identifiers'][] = $i;
            }
        }

        // Footnotes and identifiers are stored in the array

        $use_full_link = false;
        if (is_feed()) $use_full_link = true;

        if (is_preview()) $use_full_link = false;

        // Display identifiers

        foreach ($identifiers as $key => $value) {

            $id_id = "identifier_" . $key . "_" . $post->ID;
            $id_num = ($style === 'decimal') ? $value['use_footnote'] + $start_number : $this->convert_num($value['use_footnote'] + $start_number, $style, count($footnotes));
            $id_href = (($use_full_link) ? get_permalink($post->ID) : '') . "#footnote_" . $value['use_footnote'] . "_" . $post->ID;
            $id_title = str_replace('"', "&quot;", htmlentities(html_entity_decode(wp_strip_all_tags($value['text']), ENT_QUOTES, 'UTF-8'), ENT_QUOTES, 'UTF-8'));
            $id_replace = $this->current_options['pre_identifier'] . '<a href="' . $id_href . '" id="' . $id_id . '" class="footnote-link footnote-identifier-link" title="' . $id_title . '">' . $this->current_options['inner_pre_identifier'] . $id_num . $this->current_options['inner_post_identifier'] . '</a>' . $this->current_options['post_identifier'];
            if ($this->current_options['superscript']) $id_replace = '<sup>' . $id_replace . '</sup>';
            if ($display) $data = substr_replace($data, $id_replace, strpos($data, $value[0]), strlen($value[0]));
            else $data = substr_replace($data, '', strpos($data, $value[0]), strlen($value[0]));
        }

        // Display footnotes

        if ($display) {

            $footnotes_markup = '';
            $start = ($start_number !== 1) ? 'start="' . $start_number . '" ' : '';
            $footnotes_markup = $footnotes_markup . $this->current_options['pre_footnotes'];

            $footnotes_markup = $footnotes_markup . '<ol ' . $start . 'class="footnotes">';
            foreach ($footnotes as $key => $value) {
                $footnotes_markup = $footnotes_markup . '<li id="footnote_' . $key . '_' . $post->ID . '" class="footnote"';
                if ('symbol' === $style) {
                    $footnotes_markup = $footnotes_markup . ' style="list-style-type:none;"';
                } elseif ($style !== $this->current_options['list_style_type']) {
                    $footnotes_markup = $footnotes_markup . ' style="list-style-type:' . $style . ';"';
                }
                $footnotes_markup = $footnotes_markup . '>';
                if ('symbol' === $style) {
                    $footnotes_markup = $footnotes_markup . '<span class="symbol">' . $this->convert_num($key + $start_number, $style, count($footnotes)) . '</span> ';
                }
                $footnotes_markup = $footnotes_markup . $value['text'];
                if (!is_feed()) {
                    $footnotes_markup .= '<span class="footnote-back-link-wrapper">';
                    foreach ($value['identifiers'] as $identifier) {
                        $footnotes_markup = $footnotes_markup . $this->current_options['pre_backlink'] . '<a href="' . (($use_full_link) ? get_permalink($post->ID) : '') . '#identifier_' . $identifier . '_' . $post->ID . '" class="footnote-link footnote-back-link">' . $this->current_options['backlink'] . '</a>' . $this->current_options['post_backlink'];
                    }
                    $footnotes_markup .= '</span>';
                }
                $footnotes_markup = $footnotes_markup . '</li>';
            }
            $footnotes_markup = $footnotes_markup . '</ol>' . $this->current_options['post_footnotes'];
            
            $data = $data . $footnotes_markup;
        }

        return $data;
    }

    /**
    * Add Settings link to plugin list
    *
    * Add a Settings link to the options listed against this plugin
    *
    * @since    1.0.2
    *
    * @param    string  $links    Current links
    * @param    string  $file    File in use
    * @return   string            Links, now with settings added
    */

    function add_settings_link($links, $file) {

        static $this_plugin;

        if (!$this_plugin) { $this_plugin = plugin_basename(__FILE__); }

        if (strpos($file, 'footnotes-made-easy.php') !== false) {
            $settings_link = '<a href="options-general.php?page=footnotes-options-page">' . __('Settings', 'footnotes-made-easy') . '</a>';
            array_unshift($links, $settings_link);
        }

        return $links;
    }

    /**
    * Add meta to plugin details
    *
    * Add options to plugin meta line
    *
    * @since    1.0.2
    *
    * @param    string  $links  Current links
    * @param    string  $file   File in use
    * @return   string          Links, now with settings added
    */

    function plugin_meta($links, $file) {

        if (false !== strpos($file, 'footnotes-made-easy.php')) {

            $links = array_merge($links, array('<a href="https://github.com/wpcorner/footnotes-made-easy/">' . __('Github', 'footnotes-made-easy') . '</a>'));

            $links = array_merge($links, array('<a href="https://wordpress.org/support/plugin/footnotes-made-easy">' . __('Support', 'footnotes-made-easy') . '</a>'));

            $links = array_merge($links, array('<a href="https://wpcorner.co/support/footnotes-made-easy/">' . __('Documentation', 'footnotes-made-easy') . '</a>'));
            
        }

        return $links;
    }

    /**
    * Options Page
    *
    * Get the options and display the page
    *
    * @since    1.0
    */

    function footnotes_options_page() {

        $this->current_options = get_option('swas_footnote_options');
        $new_setting = array();
        foreach ($this->current_options as $key => $setting) {
            $new_setting[$key] = htmlentities($setting);
        }
        $this->current_options = $new_setting;
        unset($new_setting);
        include(dirname(__FILE__) . '/options.php');
    }

    /**
    * Add Options Help
    *
    * Add help tab to options screen
    *
    * @since    1.0
    *
    */

    function footnotes_help() {

        global $footnotes_hook;
        $screen = get_current_screen();

        if ($screen->id !== $footnotes_hook) { return; }

        $screen->add_help_tab(array('id' => 'footnotes-help-tab', 'title' => __('Help', 'footnotes-made-easy'), 'content' => $this->add_help_content()));

        $screen->set_help_sidebar($this->add_sidebar_content());

    }

    /**
    * Options Help
    *
    * Return help text for options screen
    *
    * @since    1.0
    *
    * @return    string    Help Text
    */

    function add_help_content() {

        $help_text = '<p>' . __('This screen allows you to specify the default options for the Footnotes Made Easy plugin.', 'footnotes-made-easy') . '</p>';
        $help_text .= '<p>' . __("The identifier is what appears when a footnote is inserted into your page contents. The back-link appear after each footnote, linking back to the identifier.", 'footnotes-made-easy') . '</p>';
        $help_text .= '<p>' . __('Remember to click the Save Changes button at the bottom of the screen for new settings to take effect.', 'footnotes-made-easy') . '</p></h4>';

        return $help_text;
    }

    /**
    * Options Help Sidebar
    *
    * Add a links sidebar to the options help
    *
    * @since    1.0
    *
    * @return    string    Help Text
    */

    function add_sidebar_content() {

        $help_text = '<p><strong>' . __('For more information:', 'footnotes-made-easy') . '</strong></p>';
        $help_text .= '<p><a href="https://wordpress.org/plugins/footnotes-made-easy/">' . __('Instructions', 'footnotes-made-easy') . '</a></p>';
        $help_text .= '<p><a href="https://wordpress.org/support/plugin/footnotes-made-easy">' . __('Support Forum', 'footnotes-made-easy') . '</a></p></h4>';

        return $help_text;
    }

    /**
    * Add to Admin
    *
    * Add the options page to the admin menu
    *
    * @since    1.0
    */

    function add_options_page() {

        global $footnotes_hook;

        $footnotes_hook = add_options_page(__('Footnotes Made Easy', 'footnotes-made-easy'), __('Footnotes', 'footnotes-made-easy'), 'manage_options', 'footnotes-options-page', array($this, 'footnotes_options_page'));

        add_action('load-' . $footnotes_hook, array($this, 'footnotes_help'));

    }

    /**
    * Insert additional CSS
    *
    * Add additional CSS to the page for the footnotes styling
    *
    * @since    1.0
    */

    function insert_styles() {
        ?>
        <style type="text/css">
            <?php if ('symbol' !== $this->current_options['list_style_type']): ?>
            ol.footnotes>li {list-style-type:<?php echo $this->current_options['list_style_type']; ?>;}
            <?php endif; ?>
            <?php echo "ol.footnotes { color:#666666; }\nol.footnotes li { font-size:80%; }\n"; ?>
        </style>
        <?php
    }

    /**
    * Convert number
    *
    * Convert number to a specific style
    *
    * @since    1.0
    *
    * @param    $num    string    The number to be converted
    * @param    $style    string    The style of output required
    * @param    $total    string    The total length
    * @return            string     The converted number
    */

    function convert_num($num, $style, $total) {

        switch ($style) {
            case 'decimal-leading-zero':
                $width = max(2, strlen($total));
                return sprintf("%0{$width}d", $num);
            case 'lower-roman':
                return $this->roman($num, 'lower');
            case 'upper-roman':
                return $this->roman($num);
            case 'lower-alpha':
                return $this->alpha($num, 'lower');
            case 'upper-alpha':
                return $this->alpha($num);
            case 'symbol':
                $sym = '';
                for ($i = 0; $i < $num; $i++) {
                    $sym .= $this->current_options['list_style_symbol'];
                }
                return $sym;
        }
    }

    /**
    * Convert to a roman numeral
    *
    * Convert a provided number into a roman numeral
    *
    * @since    1.0
    *
    * @param    int        $num    The number to convert.
    * @param    string    $case    Upper or lower case.
    * @return    string            The roman numeral
    */

    function roman($num, $case = 'upper') {

        $num = (int) $num;
        $conversion = array(
            'M' => 1000,
            'CM' => 900,
            'D' => 500,
            'CD' => 400,
            'C' => 100,
            'XC' => 90,
            'L' => 50,
            'XL' => 40,
            'X' => 10,
            'IX' => 9,
            'V' => 5,
            'IV' => 4,
            'I' => 1
        );
        $roman = '';

        foreach ($conversion as $r => $d) {
            $roman .= str_repeat($r, (int)($num / $d));
            $num %= $d;
        }

        return ($case === 'lower') ? strtolower($roman) : $roman;
    }

    function alpha($num, $case = 'upper') {
        $j = 1;
        for ($i = 'A'; $i <= 'ZZ'; $i++) {
            if ($j === $num) {
                if ('lower' === $case)
                    return strtolower($i);
                else
                    return $i;
            }
            $j++;
        }
    }

    /**
    * Tooltip Scripts
    *
    * Add scripts and CSS for pretty tooltips
    *
    * @since    1.0
    */

    function tooltip_scripts() {

        wp_enqueue_script(
            'wp-footnotes-tooltips',
            plugins_url('js/tooltips.min.js', __FILE__),
            array(
                'jquery',
                'jquery-ui-widget',
                'jquery-ui-tooltip',
                'jquery-ui-core',
                'jquery-ui-position'
            )
        );

        wp_enqueue_style('wp-footnotes-tt-style', plugins_url('css/tooltips.min.css', __FILE__), array(), null);
    }
}