Ticket #12891: lazy.php

<?php

class WP_Tax_Group extends WP_Tax_Query {

        function __construct($operator, $args) {
                $this->operator = $operator;
                $this->args = $args;
        }

        function get_sql() {
                $args = $this->traverse($this->args);

                return "(" . implode(" $this->operator ", $args) . ")";
        }

        function traverse($arg) {
                if ( is_array($arg) )
                        return array_map(array($this, 'traverse'), $this->args);

                if ( is_a($arg, 'WP_Tax_Query') )
                        return $arg->get_sql();

                return $arg;
        }
}

class WP_Tax_Item extends WP_Tax_Query {
        function __construct($taxonomy, $term_ids, $not = false) {
                $this->taxonomy = $taxonomy;
                $this->term_ids = $term_ids;
                $this->not = $not;
        }

        function get_sql() {
                return _wp_tax($this->taxonomy, $this->term_ids, $this->not);
        }
}

class WP_Tax_Query {
        function get_sql() {
                return '';
        }
}


function wp_tax_and() {
        $args = func_get_args();

        return new WP_Tax_Group('AND', $args);
}

function wp_tax_or() {
        $args = func_get_args();

        return new WP_Tax_Group('OR', $args);
}


function wp_tax($taxonomy, $term_ids) {
        return new WP_Tax_Item($taxonomy, $term_ids);
}

function wp_tax_not($taxonomy, $term_ids) {
        return new WP_Tax_Item($taxonomy, $term_ids, true);
}

function _wp_tax($taxonomy, $term_ids, $not = false) {
        global $wpdb;

        $term_ids = implode(',', array_map('intval', (array) $term_ids));

        $operator = $not ? 'NOT IN' : 'IN';

        return $wpdb->prepare("(
                SELECT object_id
                FROM $wpdb->term_relationships
                WHERE term_taxonomy_id $operator (
                        SELECT term_taxonomy_id
                        FROM $wpdb->term_taxonomy
                        WHERE taxonomy = %s
                        AND term_id IN ($term_ids)
                )
        )", $taxonomy);
}

// Example
$query = wp_tax_and(
        wp_tax_or(
                wp_tax( 'post_category', 59 ),
                wp_tax( 'post_tag', 'web' )
        ),
        wp_tax_not( 'post_category', 24 ),
        wp_tax_not( 'post_tag', 'wordpress' )
);

var_dump($query->get_sql());