function xk_ai_activate()
{
    $folders = array(
        XK_AI_KNOWLEDGE,
        XK_AI_KNOWLEDGE . 'livros',
        XK_AI_KNOWLEDGE . 'artigos',
        XK_AI_KNOWLEDGE . 'faq',
        XK_AI_KNOWLEDGE . 'panorama',
        XK_AI_PATH . 'templates',
        XK_AI_PATH . 'assets',
        XK_AI_PATH . 'assets/css',
        XK_AI_PATH . 'assets/js',
        XK_AI_LOGS
    );

    foreach ($folders as $folder) {

        if (!file_exists($folder)) {
            wp_mkdir_p($folder);
        }

    }

    global $wpdb;

    $table = $wpdb->prefix . 'xk_documents';

    $charset = $wpdb->get_charset_collate();

    $sql = "CREATE TABLE {$table} (

        id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,

        titulo VARCHAR(255) NOT NULL,

        categoria VARCHAR(30) NOT NULL,

        arquivo VARCHAR(255) NOT NULL,

        extensao VARCHAR(20) NOT NULL,

        tamanho BIGINT NOT NULL DEFAULT 0,

        hash VARCHAR(64),

        status VARCHAR(20) DEFAULT 'ativo',

        criado_em DATETIME DEFAULT CURRENT_TIMESTAMP,

        PRIMARY KEY (id),

        KEY categoria (categoria),

        KEY status (status)

    ) {$charset};";

    require_once ABSPATH . 'wp-admin/includes/upgrade.php';

    dbDelta($sql);
}