examples.php

<?php
// Only search for WooCommerce Products and Posts
add_action( 'pre_get_posts', 'f4d_search_woocommerce_only' );
function f4d_search_woocommerce_only( $query ) {
    if( !is_admin() && is_search() && $query->is_main_query() ) {
        $query->set('post_type', array( 'product', 'post' ) );
    }
}

// Alter Avia (ENFOLD theme) search query
add_filter('avf_ajax_search_query', 'f4d_alter_avia_search_query', 10, 1);
function f4d_alter_avia_search_query($search_parameters){
    parse_str($search_parameters, $output);
    $output['post_type'] = array( 'product', 'post' );
    return http_build_query($output);
    //$defaults = array('numberposts' => 5, 'post_type' => 'any', 'post_status' => 'publish', 'post_password' => '', 'suppress_filters' => false, 'results_hide_fields' => '');
}


// Hide other shipping methods if free shipping is available.
// Also keep "local pickup" as an option to choose from
add_filter( 'woocommerce_package_rates', 'f4d_hide_shipping_when_free_available', 10, 2 ); 
function f4d_hide_shipping_when_free_available($rates, $package){
    $new_rates = array();
    foreach($rates as $rate_id => $rate){
        if('free_shipping'===$rate->method_id){
            $new_rates[ $rate_id ] = $rate;
            break;
        }
    }
    if(!empty($new_rates)){
        foreach ($rates as $rate_id => $rate){
            if('local_pickup'===$rate->method_id){
                $new_rates[ $rate_id ] = $rate;
                break;
            }
        }
        return $new_rates;
    }
    return $rates;
}

// Block none logged in users from visiting WC pages such as shop/categories/products etc. except My Account page
// For a full list of conditional tags that you can use with WooCommerce visit:
// https://docs.woocommerce.com/document/conditional-tags/
function f4d_redirect_none_logged_in_users() {
	if( ( (!is_user_logged_in()) && (is_woocommerce()) ) && (!is_account_page()) ) {
		wp_redirect( get_permalink( get_option('woocommerce_myaccount_page_id') ) );
		exit;
	}
}
add_action( 'template_redirect', 'f4d_redirect_none_logged_in_users' );


// Filter to disable need for woocommerce payment
add_filter( 'woocommerce_cart_needs_payment', '__return_false' );


// Filter to alter payment gateways
add_filter( 'woocommerce_available_payment_gateways', 'f4d_unset_specific_payment_gateways' );


// Function to either disable all payment gateways for woocommerce or to unset a specific one
add_action('wp', 'f4d_alter_woocommerce_payment_gateways');
function f4d_alter_woocommerce_payment_gateways(){
	$post_id = get_the_ID();
	if($post_id==2441){ // replace with current page ID, or do different if statement
		// Enable need for payment
		add_filter( 'woocommerce_cart_needs_payment', '__return_true' );
		// Remove all methods except "Phone manual on hold" method
		add_filter( 'woocommerce_available_payment_gateways', 'f4d_unset_gateway_by_category' );
	}else{
		if( f4d_is_request('ajax') ) {

			// Because woocommerce does a ajax request to generates prices and payment methods
			// on the fly when items and address is changed, the $post_id is always 1 or 0.
			// So in order to still know on what page the request was made, we can retrieve the _wp_http_referer
			// parameter from the post_data parameter in the 'update_order_review' Ajax request made by WC
			
			// Note that you could also save the $post_id in a session each time the page was loaded
			// This way you can retrieve this session value during the Ajax request to still
			// determine on what page the Ajax request was made 
			parse_str($_POST['post_data'], $output);
			if( basename( $output['_wp_http_referer'] ) == 'orderbevestiging' ){
				// Enable need for payment
				add_filter( 'woocommerce_cart_needs_payment', '__return_true' );
				// Remove all methods except "Phone manual on hold" method
				add_filter( 'woocommerce_available_payment_gateways', 'f4d_unset_gateway_by_category' );
			}else{
				// Disable need for payment
				add_filter( 'woocommerce_cart_needs_payment', '__return_false' );
			}
		}else{
			// Disable need for payment
			add_filter( 'woocommerce_cart_needs_payment', '__return_false' );
		}
	}
}
function f4d_unset_gateway_by_category( $available_gateways ) {
	foreach($available_gateways as $k => $v){
		if($k!='phone_manual_on_hold'){
			unset($available_gateways[$k]);
		}
	}
	return $available_gateways;
}

// Function to check what the current request type was
// admin, ajax, cron or frontend
function f4d_is_request($type){
	switch ($type){
		case 'admin' :
			return is_admin();
		case 'ajax' :
			return defined( 'DOING_AJAX' );
		case 'cron' :
			return defined( 'DOING_CRON' );
		case 'frontend' :
			return (!is_admin() || defined('DOING_AJAX')) && ! defined('DOING_CRON');
	}
}

// Trigger specific emails after an order was processed
add_action( 'woocommerce_checkout_order_processed', 'f4d_order_processed', 10, 2);
function f4d_order_processed( $order_id, $posted_data ) {

	$order = new WC_Order($order_id);

	// Send email
	$mailer = WC()->mailer();
	$mails = $mailer->get_emails();
	if ( ! empty( $mails ) ) {
	    foreach ( $mails as $mail ) {
	    	//new_order
	    	//cancelled_order
	    	//customer_processing_order
	    	//customer_completed_order
	    	//customer_invoice
	    	//customer_refunded_order
	    	if( ($mail->id=='new_order') || ($mail->id=='customer_invoice') ) {
	        	$mail->trigger( $order->id );
	        }
	     }
	}

	// Get redirect URL
	// This will generates a URL for the thanks page (order received)
	$return_url = $order->get_checkout_order_received_url();

	// Redirect to success/confirmation/payment page
	if ( is_ajax() ) {
		wp_send_json( array(
			'result' 	=> 'success',
			'redirect'  => apply_filters( 'woocommerce_checkout_no_payment_needed_redirect', $return_url, $order )
		) );
	} else {
		wp_safe_redirect(
			apply_filters( 'woocommerce_checkout_no_payment_needed_redirect', $return_url, $order )
		);
		exit;
	}
}