<?php

namespace Admin_Ajax;

class No_Thank_You
{
    protected static $settings;

    public function __construct()
    {
        self::load_settings();
        
        add_filter( 'admin_url', [$this, 'rewrite_ajax_admin_url'], 10, 3 );
        add_action( 'rest_api_init', [$this, 'rest_api_init'] );
        add_filter( 'pre_get_posts', [$this, 'rewrite_ajax_pre_get_posts'], 1, 1 );
        add_filter( 'query_vars', [$this, 'rewrite_ajax_query_vars'], 10, 1 );
        add_filter( 'root_rewrite_rules', [$this, 'rewrite_ajax_root_rewrite_rules'], 10, 1 );

        // testing
        add_action( 'wp_ajax_admin-ajax-test', [$this, 'wp_ajax_test'] );
        //add_action( 'wp_ajax_nopriv_admin-ajax-test', [$this, 'wp_ajax_test'] );
    }

    /**
    *
    *   @return array
    */
    public static function get_settings()
    {
        return self::$settings;
    }

    /**
    *
    *   @return string
    */
    public static function get_endpoint_rest($blog_id = null)
    {
        $url = get_rest_url( $blog_id, self::$settings['endpoint']['rest-api'] );
        $url = add_query_arg( [
            '_wpnonce' => wp_create_nonce( 'wp_rest' )
        ], $url );

        return $url;
    }

    /**
    *
    *   @return string
    */
    public static function get_endpoint_rewrite($blog_id = null)
    {
        $rewrite = trim( self::$settings['endpoint']['rewrite'] );
        return get_home_url( $blog_id, sprintf('/%s/', $rewrite) );
    }

    /**
    *
    */
    public static function load_settings()
    {
        $defaults = [
            'default' => '',
            'enabled' => [],
            'endpoint' => [
                'rewrite' => 'ajax',
                'rest-api' => 'wp/v2/admin-ajax'
            ]
        ];

        $settings = get_option( 'admin_ajax_no_thank_you', [] );
        
        self::$settings = array_merge( $defaults, $settings );
    }

    /**
    *   requires the wp core file and dies
    */
    public function require_admin_ajax()
    {
        require_once ABSPATH . 'wp-admin/includes/class-wp-screen.php';
        $GLOBALS['current_screen'] = \WP_Screen::get('no-thank-you');

        require ABSPATH.'/wp-admin/admin-ajax.php';
        exit();
    }

    /**
    *   attached to `admin_url` filter
    *   replace /wp-admin/admin-ajax.php with rewrite
    *   @param string
    *   @param string
    *   @param int
    *   @return string
    */
    public function rewrite_ajax_admin_url($url, $path, $blog_id)
    {
        if (\stripos( $path, 'admin-ajax.php') !== 0) {
            return $url;
        }
        
        $parsed = \parse_url( $url );
        
        if ((self::$settings['default'] == 'rest-api') && in_array('rest-api', self::$settings['enabled'])) {
            $url = self::get_endpoint_rest( $blog_id );
        } elseif ((self::$settings['default'] == 'rewrite') && in_array('rewrite', self::$settings['enabled'])) {
            $url = self::get_endpoint_rewrite( $blog_id );
        }
        
        if (!empty($parsed['query'])) {
            parse_str( $parsed['query'], $query_vars );
            $url = add_query_arg( $query_vars, $url );
        }
        
        return $url;
    }

    /**
    *   attached to `pre_get_posts` for request to /ajax/ to be intercepted and include admin-ajax.php
    *   @param WP_Query
    *   @return WP_Query
    */
    public function rewrite_ajax_pre_get_posts($wp_query)
    {
        if ($wp_query->is_main_query() && $wp_query->get('admin_ajax_no_thank_you')) {
            $this->require_admin_ajax();
        }

        return $wp_query;
    }

    /**
    *   attatched to `root_rewrite_rules` to register rewrite rule for /ajax/ or custom
    *   @param array
    *   @return array
    */
    public function rewrite_ajax_root_rewrite_rules($rules)
    {
        $rewrite = trim( self::$settings['endpoint']['rewrite'], '/' );
        
        if ($rewrite && in_array('rewrite', self::$settings['enabled'])) {
            $rules[$rewrite.'/?$'] = 'index.php?&admin_ajax_no_thank_you=1';
        }

        return $rules;
    }

    /**
    *   attached to `query_vars` filter to register `admin_ajax_no_thank_you`
    *   @param array
    *   @return array
    */
    public function rewrite_ajax_query_vars($qv)
    {
        array_push( $qv, 'admin_ajax_no_thank_you' );

        return $qv;
    }

    /**
    *   @todo check class WP_REST_Server constants for permissions in `methods` argument
    *   https://github.com/WP-API/WP-API/blob/ab446e34462bfb0bbfb593505962a843ded21d29/lib/infrastructure/class-wp-rest-server.php#L17-L34
    */
    public function rest_api_init()
    {
        $endpoint = array_filter( explode('/', self::$settings['endpoint']['rest-api']) );
        if (count($endpoint) < 3) {
            return;
        }

        $namespace = implode( '/', array_slice($endpoint, 0, 2) );
        $route = implode( '/', array_slice($endpoint, 2) );
        
        register_rest_route( $namespace, $route, [
            'methods' => 'GET, POST',
            'callback' => [$this, 'require_admin_ajax'],
        ] );
    }

    /**
    *   returns post data in json
    *   used for testing wp-admin/options-general.php?page=admin-ajax.php-no-thank-you
    */
    function wp_ajax_test()
    {
        $response = [
            'post' => $_POST
        ];

        wp_send_json( $response );
    }
}