<?php

namespace ABT;

if (!defined('ABSPATH')) {
    exit(1);
}

require_once __DIR__ . '/i18n.php';

if (is_admin()) {
    add_action('load-post.php', array('ABT\Backend', 'init'));
    add_action('load-post-new.php', array('ABT\Backend', 'init'));
}

/**
 * Main Backend Class.
 */
class Backend {
    /**
     * Sets up all actions and filters for the backend class.
     */
    public function __construct() {
        $post_type = get_current_screen()->post_type;
        $disabled_post_types = apply_filters('abt_disabled_post_types', array('acf', 'um_form'));
        $is_invalid_post_type = in_array(
            $post_type,
            array_merge(
                array('attachment'),
                is_array($disabled_post_types) ? $disabled_post_types : array()
            )
        );

        if ($is_invalid_post_type) {
            return;
        }
        add_action('add_meta_boxes', array($this, 'add_metaboxes'));
        add_action('admin_enqueue_scripts', array($this, 'enqueue_admin_scripts'));
        add_action('admin_head', array($this, 'init_tinymce'));
        add_action('admin_notices', array($this, 'user_alert'));
        add_action('save_post', array($this, 'save_meta'));
        add_filter('mce_css', array($this, 'load_tinymce_css'));
    }

    public static function init() {
        $class = __CLASS__;
        new $class;
    }

    /**
     * Alerts the user that the plugin will not work if he/she doesn't have 'Rich Editing' enabled.
     */
    public function user_alert() {
        if ('true' === get_user_option('rich_editing')) {
            return;
        }
        $class = 'notice notice-warning is-dismissible';
        $message = __("<strong>Notice:</strong> Rich editing must be enabled to use the Academic Blogger's Toolkit plugin", 'academic-bloggers-toolkit');
        printf('<div class="%1$s"><p>%2$s</p></div>', $class, $message);
    }

    /**
     * Instantiates the TinyMCE plugin.
     */
    public function init_tinymce() {
        if ('true' === get_user_option('rich_editing')) {
            add_filter('mce_external_plugins', array($this, 'register_tinymce_plugins'));
            echo '<link href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700&subset=cyrillic,cyrillic-ext,greek,greek-ext,latin-ext,vietnamese" rel="stylesheet">';
        }
    }

    /**
     * Registers the TinyMCE plugins + loads fonts.
     *
     * @param string[] $plugin_array Array of TinyMCE plugins
     *
     * @return string[] Array of TinyMCE plugins with plugins added
     */
    public function register_tinymce_plugins($plugin_array) {
        $plugin_array['noneditable'] = plugins_url('academic-bloggers-toolkit/vendor/noneditable.js');
        return $plugin_array;
    }

    /**
     * Loads the required stylesheet into TinyMCE (required for proper citation parsing).
     *
     * @param string $mce_css CSS string
     *
     * @return string CSS string + custom CSS appended
     */
    public function load_tinymce_css($mce_css) {
        if (!empty($mce_css)) {
            $mce_css .= ',';
        }
        $mce_css .= plugins_url('academic-bloggers-toolkit/css/editors/tinymce.css');
        return $mce_css;
    }

    /**
     * Adds metaboxes to posts and pages.
     *
     * @param string $post_type The post type
     */
    public function add_metaboxes($post_type) {
        $disabled_post_types = apply_filters('abt_disabled_post_types', array('acf', 'um_form'));
        $all_types = get_post_types();
        add_meta_box(
            'abt-reflist',
            __('Reference List', 'academic-bloggers-toolkit'),
            array($this, 'render_reference_list'),
            $all_types,
            'side',
            'high'
        );
    }

    /**
     * Renders the HTML for React to mount into.
     *
     * @param mixed $post
     */
    public function render_reference_list($post) {
        wp_nonce_field(basename(__FILE__), 'abt_nonce');
        include __DIR__ . '/views/reference-list.php';
    }

    /**
     * Saves the Peer Review meta fields to the database.
     *
     * @param string $post_id The post ID
     */
    public function save_meta($post_id) {
        $is_autosave = wp_is_post_autosave($post_id);
        $is_revision = wp_is_post_revision($post_id);
        $is_valid_nonce = (isset($_POST['abt_nonce']) && wp_verify_nonce($_POST['abt_nonce'], basename(__FILE__))) ? true : false;

        if ($is_autosave || $is_revision || !$is_valid_nonce) {
            return;
        }

        $reflist_state = $_POST['abt-reflist-state'];
        update_post_meta($post_id, '_abt-reflist-state', $reflist_state);
    }

    /**
     * Registers and enqueues all required scripts.
     */
    public function enqueue_admin_scripts() {
        global $post;

        $ABT_i18n = i18n\generate_translations();
        $state = json_decode(get_post_meta($post->ID, '_abt-reflist-state', true), true);
        $opts = get_option('abt_options');

        $custom_preferred = $opts['citation_style']['prefer_custom'] === true;
        $custom_valid = file_exists($opts['citation_style']['custom_url']);

        $style = $custom_preferred && $custom_valid ? 'abt-user-defined' : $opts['citation_style']['style'];

        if (empty($state)) {
            $state = array(
                'cache' => array(
                    'style' => $style,
                    'locale' => get_locale(),
                ),
                'citationByIndex' => array(),
                'CSL' => (object)array(),
            );
        }

        $state['bibOptions'] = array(
            'heading' => $opts['display_options']['bib_heading'],
            'headingLevel' => $opts['display_options']['bib_heading_level'],
            'links' => $opts['display_options']['links'],
            'style' => $opts['display_options']['bibliography'],
        );

        // Fix legacy post meta
        if (array_key_exists('processorState', $state)) {
            $state['CSL'] = $state['processorState'];
            unset($state['processorState']);
        }

        if (array_key_exists('citations', $state)) {
            $state['citationByIndex'] = $state['citations']['citationByIndex'];
            unset($state['citations']);
        }

        wp_register_script('abt-reflist', plugins_url('academic-bloggers-toolkit/js/reference-list/index.js'), array(), ABT_VERSION);
        wp_localize_script('abt-reflist', 'ABT', array(
            'state' => $state,
            'i18n' => $ABT_i18n,
            'styles' => $this->get_citation_styles(),
            'wp' => $this->localize_wordpress_constants(),
            'custom_csl' => $this->get_user_defined_csl($opts['citation_style']['custom_url']),
        ));

        wp_dequeue_script('autosave');
        wp_enqueue_style('dashicons');
        wp_enqueue_script('abt-reflist');
    }

    /**
     * Returns an array of citation styles from citationstyles.php.
     */
    private function get_citation_styles() {
        $json = json_decode(file_get_contents(ABT_ROOT_PATH . '/vendor/citation-styles.json'), true);
        return $json;
    }

    /**
     * Returns an array of a few select wordpress constants (for use in JS).
     */
    private function localize_wordpress_constants() {
        return array(
            'abt_url' => plugins_url() . '/academic-bloggers-toolkit',
            'home_url' => home_url(),
            'plugins_url' => plugins_url(),
            'wp_upload_dir' => wp_get_upload_dir(),
            'info' => array(
                'site' => array(
                    'language' => get_bloginfo('language'),
                    'name' => get_bloginfo('name'),
                    'plugins' => get_option('active_plugins'),
                    'theme' => get_template(),
                    'url' => get_bloginfo('url'),
                ),
                'versions' => array(
                    'abt' => ABT_VERSION,
                    'php' => PHP_VERSION,
                    'wordpress' => get_bloginfo('version'),
                ),
            ),
        );
    }

    /**
     * Checks to see if custom CSL XML is saved and available. If so, returns an
     * array containing the XML, label, and value. If not, returns an array
     * containing only the key 'value' with the value of null.
     *
     * @param string $path path to CSL XML file
     *
     * @return mixed[] array as described above
     */
    private function get_user_defined_csl($path) {
        if (!file_exists($path)) {
            return array('value' => null);
        }

        $contents = file_get_contents($path);
        $xml = new SimpleXMLElement($contents);
        $label = $xml->info->title->__toString() !== ''
            ? $xml->info->title->__toString()
            : 'ABT Custom Style';

        return array(
            'label' => $label,
            'value' => 'abt-user-defined',
            'CSL' => $contents,
        );
    }
}