WordPress/Woocommerce: Multiple PHP errors

Hi everyone, This site of mine was running all this while suddenly this morning, it had reverted to the twentyfifteen theme. So looking through the admin, I noticed the old theme was broken. I re-uploaded the theme, and now I get the following errors:

PHP Warning: in_array() expects parameter 2 to be array, string given

PHP Warning: in_array() expects parameter 2 to be array, string given

PHP Fatal error: Call to undefined function WC()

The first error code:

if ( in_array( 'woocommerce/woocommerce.php', apply_filters( 'active_plugins', get_option( 'active_plugins' ) ) ) ) {
function trizzy_woocommerce_recent_products( $atts, $content ) {
    extract(shortcode_atts(array(
        'orderby'=> 'date',
        'order'=> 'DESC',
        'per_page'  => '12',
        'category'  => '',
        'ids' => '',
        ), $atts));

global $woocommerce, $product;

The third error code:

<div class="cart-btn">
    <a href="#" class="button adc"><?php echo WC()->cart->get_cart_subtotal(); ?></a>
</div>

The second error is pretty similar to the first. So that should not be an issue to resolve.

Thanks and Regards