<?php
/**
 * AMP WP Utility Functions
 *
 * @category    Utility
 * @package     Amp_WP/Functions
 * @author      Pixelative <mohsin@pixelative.co>
 * @copyright   Copyright (c) 2018, Pixelative
 */

if( !function_exists( 'amp_wp_remove_query_string' ) ) :
    /**
     * Remove anything after question mark
     *
     * Example: pixelative.co/?publisher=great
     * becomes: pixelative.co/
     *
     * @param string $string
     *
     * @since 1.0.0
     *
     * @return string
     */
    function amp_wp_remove_query_string( $string ) {
        if ( preg_match( '/([^\?]+)\?/', $string, $matches ) ) {
            return $matches[1];
        }
        return $string;
    }
endif;

if( !function_exists( 'amp_wp_filter_attributes' ) ) :
    /**
     * Filter AMP element attributes
     *
     * @param   array   $attributes         key-value paired attributes list
     * @param   array   $valid_attributes   valid attributes key
     * @param   string  $tag_name           optional. amp tag-name
     *
     * @since   1.0.0
     *
     * @return  array   filtered attributes
     */
    function amp_wp_filter_attributes( $attributes, $valid_attributes, $tag_name = '' ) {
        $attributes = wp_array_slice_assoc( $attributes, $valid_attributes );
        return apply_filters( 'amp-wp-htmldom-filter-attributes', $attributes, $tag_name, $valid_attributes );
    }
endif;

if( !function_exists( 'amp_wp_remove_class_filter' ) ) :
    /**
     * Remove Class Filter Without Access to Class Object
     *
     * In order to use the core WordPress remove_filter() on a filter added with the callback
     * to a class, you either have to have access to that class object, or it has to be a call
     * to a static method.  This method allows you to remove filters with a callback to a class
     * you don't have access to.
     *
     * Works with WordPress 1.2+ (4.7+ support added 9-19-2016)
     * Updated 2-27-2017 to use internal WordPress removal for 4.7+ (to prevent PHP warnings output)
     *
     * @param string $tag         Filter to remove
     * @param string $class_name  Class name for the filter's callback
     * @param string $method_name Method name for the filter's callback
     * @param int    $priority    Priority of the filter (default 10)
     *
     *
     * Copyright: https://gist.github.com/tripflex/c6518efc1753cf2392559866b4bd1a53
     *
     * @return bool Whether the function is removed.
     */
    function amp_wp_remove_class_filter( $tag, $class_name = '', $method_name = '', $priority = 10 ) {
        global $wp_filter;

        // Check that filter actually exists first
        if( ! isset( $wp_filter[ $tag ] ) ) { return FALSE; }

        /**
         * If filter config is an object, means we're using WordPress 4.7+ and the config is no longer
         * a simple array, rather it is an object that implements the ArrayAccess interface.
         *
         * To be backwards compatible, we set $callbacks equal to the correct array as a reference (so $wp_filter is updated)
         *
         * @see https://make.wordpress.org/core/2016/09/08/wp_hook-next-generation-actions-and-filters/
         */
        if( is_object( $wp_filter[ $tag ] ) && isset( $wp_filter[ $tag ]->callbacks ) ) {
            // Create $fob object from filter tag, to use below
            $fob = $wp_filter[ $tag ];
            $callbacks = &$wp_filter[ $tag ]->callbacks;
        } else {
            $callbacks = &$wp_filter[ $tag ];
        }

        // Exit if there aren't any callbacks for specified priority
        if( !isset( $callbacks[ $priority ] ) || empty( $callbacks[ $priority ] ) ) {
            return FALSE;
        }

        // Loop through each filter for the specified priority, looking for our class & method
        foreach( (array) $callbacks[ $priority ] as $filter_id => $filter ) {
            // Filter should always be an array - array( $this, 'method' ), if not goto next
            if( !isset( $filter['function'] ) || ! is_array( $filter['function'] ) ) {
                continue;
            }
            // If first value in array is not an object, it can't be a class
            if( !is_object( $filter['function'][0] ) ) {
                continue;
            }
            // Method doesn't match the one we're looking for, goto next
            if( $filter['function'][1] !== $method_name ) {
                continue;
            }
            // Method matched, now let's check the Class
            if( get_class( $filter['function'][0] ) === $class_name ) {
                // WordPress 4.7+ use core remove_filter() since we found the class object
                if( isset( $fob ) ) {
                    // Handles removing filter, reseting callback priority keys mid-iteration, etc.
                    $fob->remove_filter( $tag, $filter['function'], $priority );
                } else {
                    // Use legacy removal process (pre 4.7)
                    unset( $callbacks[ $priority ][ $filter_id ] );
                    // and if it was the only filter in that priority, unset that priority
                    if( empty( $callbacks[ $priority ] ) ) {
                        unset( $callbacks[ $priority ] );
                    }
                    // and if the only filter for that tag, set the tag to an empty array
                    if( empty( $callbacks ) ) {
                        $callbacks = array();
                    }
                    // Remove this filter from merged_filters, which specifies if filters have been sorted
                    unset( $GLOBALS['merged_filters'][ $tag ] );
                }
                return TRUE;
            }
        }
        return FALSE;
    }
endif;

if( !function_exists( 'amp_wp_remove_class_action' ) ) :
    /**
     * In order to use the core WordPress remove_action() on an action added with the callback
     * to a class, you either have to have access to that class object, or it has to be a call
     * to a static method.  This method allows you to remove actions with a callback to a class
     * you don't have access to.
     *
     * Works with WordPress 1.2+ (4.7+ support added 9-19-2016)
     *
     * @param   string  $tag            Action to remove
     * @param   string  $class_name     Class name for the action's callback
     * @param   string  $method_name    Method name for the action's callback
     * @param   int $priority           Priority of the action (default 10)
     *
     * Copyright: https://gist.github.com/tripflex/c6518efc1753cf2392559866b4bd1a53
     *
     * @return  bool    Whether the function is removed.
     */
    function amp_wp_remove_class_action( $tag, $class_name = '', $method_name = '', $priority = 10 ) {
        amp_wp_remove_class_filter( $tag, $class_name, $method_name, $priority );
    }
endif;

if( !function_exists( 'amp_wp_trans_allowed_html' ) ) :
    /**
     *
     * Handy function for translation wp_kses when we need it for descriptions and help HTMLs
     */
    function amp_wp_trans_allowed_html() {
        return array(
            'a' => array(
                'href'   => array(),
                'target' => array(),
                'id'     => array(),
                'class'  => array(),
                'rel'    => array(),
                'style'  => array(),
            ),
            'span' => array(
                'class' => array(),
                'id'    => array(),
                'style' => array(),
            ),
            'p' => array(
                'class' => array(),
                'id'    => array(),
                'style' => array(),
            ),
            'strong' => array(
                'class' => array(),
                'style' => array(),
            ),
            'hr' => array(
                'class' => array(),
            ),
            'br' => '',
            'b' => '',
            'h6' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'h5' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'h4' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'h3' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'h2' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'h1' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'code' => array(
                'class' => array(),
                'id'    => array(),
            ),
            'em' => array(
                'class' => array(),
            ),
            'i' => array(
                'class' => array(),
            ),
            'img' => array(
                'class' => array(),
                'style' => array(),
            ),
            'label' => array(
                'for'   => array(),
                'style' => array(),
            ),
            'ol' => array(
                'class' => array(),
            ),
            'ul' => array(
                'class' => array(),
            ),
            'li' => array(
                'class' => array(),
            ),
        );
    }
endif;

if( !function_exists( 'amp_wp_is' ) ) {
    /**
     * Handy function for checking current AMP WP state
     *
     * @param   string $id
     * 
     * @version 1.0.0
     * @since   1.0.0
     *
     * @return  bool
     */
    function amp_wp_is( $id = '' ) {
        switch ( $id ) {
            /**
             * Doing Ajax
             */
            case 'doing_ajax':
            case 'doing-ajax':
            case 'ajax':
                return defined( 'DOING_AJAX' ) && DOING_AJAX;
            break;

            /**
             * Development Mode
             */
            case 'dev':
                return defined( 'AMPWP_DEV_MODE' ) && AMPWP_DEV_MODE;
            break;

            /*
             *
             * Demo development mode,
             * Define This If You Want to Load All Demo Importing Functionality From Your Local Not Remote Server
             *
             */
            case 'demo-dev':
                return defined( 'AMPWP_DEMO_DEV_MODE' ) && AMPWP_DEMO_DEV_MODE;
            break;
            default:
                return FALSE;
        }
    }
}

/**
 * Retrieves the full AMP-specific permalink for the given post ID.
 *
 * @since 1.0.0
 *
 * @param int $post_id Post ID.
 *
 * @return string AMP permalink.
 */
function amp_wp_get_permalink( $post_id ) {

    /**
     * Filters the AMP permalink to short-circuit normal generation.
     *
     * Returning a non-false value in this filter will cause the `get_permalink()` to get called and the `amp_wp_get_permalink` filter to not apply.
     *
     * @since 0.4
     *
     * @param false $url     Short-circuited URL.
     * @param int   $post_id Post ID.
     */
    $pre_url = apply_filters( 'amp_wp_pre_get_permalink', FALSE, $post_id );

    if( FALSE !== $pre_url ) {
        return $pre_url;
    }

    if( amp_wp_is_canonical() ) {
        $amp_url = get_permalink( $post_id );
    } else {
        $parsed_url = wp_parse_url( get_permalink( $post_id ) );
        $structure = get_option( 'permalink_structure' );
        if( empty( $structure ) || !empty( $parsed_url['query'] ) || is_post_type_hierarchical( get_post_type( $post_id ) ) ) {
            $amp_url = add_query_arg( Amp_WP_Public::AMP_WP_STARTPOINT, '', get_permalink( $post_id ) );
        } else {
            $amp_url = trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( Amp_WP_Public::AMP_WP_STARTPOINT, 'single_amp' );
        }
    }

    /**
     * Filters AMP Permalink.
     *
     * @since 1.0.0
     *
     * @param   FALSE   $amp_url    AMP URL.
     * @param   int     $post_id    Post ID.
     */
    return apply_filters( 'amp_wp_get_permalink', $amp_url, $post_id );
}


/**
 * Whether this is in 'canonical mode.'
 *
 * Themes can register support for this with `add_theme_support( 'amp' )`.
 * Then, this will change the plugin from 'paired mode,' and it won't use its own templates.
 * Nor output frontend markup like the 'rel' link. If the theme registers support for AMP with:
 * `add_theme_support( 'amp', array( 'template_dir' => 'amp-wp' ) )`
 * it will retain 'paired mode.
 *
 * @return boolean Whether this is in AMP 'canonical mode'.
 */
function amp_wp_is_canonical() {
    $support = get_theme_support( 'amp' );
    if( TRUE === $support ) {
        return TRUE;
    }
    if( is_array( $support ) ) {
        $args = array_shift( $support );
        if( empty( $args['template_dir'] ) ) {
            return TRUE;
        }
    }
    return FALSE;
}