Gist UK Taxes on Checkout / Invoice / Etc.

pmpro-uk-taxes.php

<?php
/**
 * 1. Adds 20% tax text to the level cost text.
 * 2. Adds 20% tax to invoice if checking out as UK customer.
 * 3. Adds 20% tax if UK to checkout and invoice.
 * 
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function band_my_pmpro_uk_tax( $tax, $values, $order ) {
	if ( isset( $_SESSION['user_in_uk_taxregion'] ) ) {
		$tax = round( (float) $values['price'] * 0.20, 2);
	}
	return $tax;
}

/**
 * Edit level cost text to make users aware of tax for UK residents.
 */
function band_my_pmpro_uk_tax_level_cost_text( $cost, $level ) {
	$uk_tax = pmpro_formatPrice( round( (float) $level->initial_payment * 0.20, 2) );
	$cost .= '<br /><br />';
	$cost .= sprintf( 'UK customers will be charged <strong>%s</strong> tax.', esc_html( $uk_tax ) );
	return $cost;
}
 add_filter( 'pmpro_level_cost_text', 'band_my_pmpro_uk_tax_level_cost_text', 10, 2 );

/**
 * Set the default country for billing to Canada.
 */
function band_my_pmpro_uk_tax_default_country( $country ) {
	return 'GB';
}
 add_filter( 'pmpro_default_country', 'band_my_pmpro_uk_tax_default_country' );

/**
 * Add checkbox and dropdown for users to declare themselves as UK
 * residents and choose their state.
 */
function band_my_pmpro_uk_tax_checkout_boxes() {
	?>
<table id="pmpro_pricing_fields" class="pmpro_checkout" width="100%" cellpadding="0" cellspacing="0" border="0">
<thead>
	<tr>
		<th>
			<?php esc_html_e( 'UK Residents', 'pmpro-uk-tax' ); ?>
		</th>						
	</tr>
</thead>
<tbody>                
	<tr>	
		<td>
			<div>				
				<input id="user_in_uk_taxregion" name="user_in_uk_taxregion" type="checkbox" value="1" onchange="band_my_pmpro_uk_taxes_checkbox_changed()" 
				<?php
				if ( ! empty( $_REQUEST['user_in_uk_taxregion'] ) || ! empty( $_SESSION['user_in_uk_taxregion'] ) ) {
					?>
					checked="checked"<?php } ?> /> <label for="user_in_uk_taxregion" class="pmpro_normal pmpro_clickable"><?php _e( 'Check this box if your billing address is in the UK.', 'pmpro-uk-tax' ); ?></label>
			</div>				
		</td>
	</tr>
</tbody>
</table>
	<?php
}
 add_action( 'pmpro_checkout_boxes', 'band_my_pmpro_uk_tax_checkout_boxes' );

/**
 * Check whether user declared themself as UK resident.
 */
function band_my_pmpro_uk_tax_check() {

	if ( isset( $_SESSION['user_in_uk_taxregion'] ) && ! empty( $_SESSION['user_in_uk_taxregion'] ) || ( isset( $_REQUEST['user_in_uk_taxregion'] ) && ! empty( $_REQUEST['user_in_uk_taxregion'] ) ) ) {
		add_filter( 'pmpro_tax', 'band_my_pmpro_uk_tax', 10, 3 );
	}
}
add_action( 'init', 'band_my_pmpro_uk_tax_check', 22 );

/**
 * Save UK residence info into $_SESSION for off-site checkouts
 */
function band_my_pmpro_uk_tax_session_vars() {
	if ( isset( $_REQUEST['user_in_uk_taxregion'] ) ) {
		$_SESSION['user_in_uk_taxregion'] = $_REQUEST['user_in_uk_taxregion'];
	}
}
add_action( 'pmpro_paypalexpress_session_vars', 'band_my_pmpro_uk_tax_session_vars' );
add_action( 'pmpro_before_send_to_twocheckout', 'band_my_pmpro_uk_tax_session_vars', 10, 0 );

/**
 * Remove the session variables after checkout is complete.
 */
function band_my_pmpro_uk_tax_after_checkout() {
	if ( isset( $_SESSION['user_in_uk_taxregion'] ) ) {
		unset( $_SESSION['user_in_uk_taxregion'] );
	}
}
/**
 * Read in session vars and add in tax.
 */
function band_my_pmpro_add_uk_tax() {
	if ( isset( $_REQUEST['user_in_uk_taxregion'] ) ) {
		$_SESSION['user_in_uk_taxregion'] = $_REQUEST['user_in_uk_taxregion'];
	}
}
add_action( 'pmpro_checkout_before_processing', 'band_my_pmpro_add_uk_tax' );
add_action( 'pmpro_after_checkout', 'band_my_pmpro_uk_tax_after_checkout' );