How to set a minimum order price within this code - php

Question

Looking at a piece of code at the moment and trying to work out how to set a minimum order price of £10 within this code. I want the 'Confirm your order' CTA to be inactive unless the order is £10 - Or maybe upon selecting the CTA, no action, just a message to display saying the order should be £10 or over when the CTA is selected.
Any help would be great, I have a huge headache from this. I've been trying to learn to code but I am in way over my head with this one.
<?php
use mp_restaurant_menu\classes\models;
use mp_restaurant_menu\classes\View;
/**
* #return mixed
*/
function mprm_is_checkout() {
return models\Checkout::get_instance()->is_checkout();
}
/**
* #return mixed
*/
function mprm_get_checkout_uri() {
return models\Checkout::get_instance()->get_checkout_uri();
}
function mprm_get_checkout_cart_template() {
$data = array();
$data[ 'is_ajax_disabled' ] = models\Settings::get_instance()->is_ajax_disabled();
$data[ 'cart_items' ] = models\Cart::get_instance()->get_cart_contents();
mprm_get_template('shop/checkout-cart', $data);
}
/**
* #return mixed
*/
function mprm_checkout_button_next() {
$color = mprm_get_option('checkout_color', 'mprm-btn blue');
$color = ($color == 'inherit') ? '' : $color;
$padding = mprm_get_option('checkout_padding', 'mprm-inherit');
$style = mprm_get_option('button_style', 'button');
$purchase_page = mprm_get_option('purchase_page', '0');
ob_start();
?>
<input type="hidden" name="mprm_action" value="gateway_select"/>
<input type="hidden" name="page_id" value="<?php echo absint($purchase_page); ?>"/>
<input type="submit" name="gateway_submit" id="mprm_next_button" class="mprm-submit <?php echo $color; ?> <?php echo $padding; ?> <?php echo $style; ?>" value="<?php _e('Next', 'mp-restaurant-menu'); ?>"/>
<?php
return apply_filters('mprm_checkout_button_next', ob_get_clean());
}
/**
* Checkout purchase button
* #return mixed
*/
function mprm_checkout_button_purchase() {
$color = mprm_get_option('checkout_color', 'mprm-btn blue');
$color = ($color == 'inherit') ? '' : $color;
$style = mprm_get_option('button_style', 'button');
$label = mprm_get_option('checkout_label', '');
$padding = mprm_get_option('checkout_padding', 'mprm-inherit');
if (mprm_get_cart_total()) {
$complete_purchase = !empty($label) ? $label : __('Purchase', 'mp-restaurant-menu');
} else {
$complete_purchase = !empty($label) ? $label : __('Free Menu item', 'mp-restaurant-menu');
}
ob_start();
?>
<input type="submit" class="mprm-submit <?php echo $color; ?> <?php echo $padding; ?> <?php echo $style; ?>" id="mprm-purchase-button" name="mprm-purchase" value="<?php echo $complete_purchase; ?>"/>
<?php
return apply_filters('mprm_checkout_button_purchase', ob_get_clean());
}
/**
* #return bool
*/
function mprm_is_no_guest_checkout() {
return models\Misc::get_instance()->no_guest_checkout();
}
function mprm_checkout_tax_fields() {
if (models\Taxes::get_instance()->cart_needs_tax_address_fields() && mprm_get_cart_total()) {
mprm_default_cc_address_fields();
}
}
function mprm_checkout_submit() { ?>
<fieldset id="mprm_purchase_submit">
<?php do_action('mprm_purchase_form_before_submit'); ?>
<?php mprm_checkout_hidden_fields(); ?>
<?php echo mprm_checkout_button_purchase(); ?>
<?php do_action('mprm_purchase_form_after_submit'); ?>
</fieldset>
<?php
}
function mprm_checkout_additional_information() {
View::get_instance()->get_template('/shop/checkout-additional-information');
}
function mprm_checkout_final_total() {
?>
<p id="mprm_final_total_wrap">
<strong><?php _e('Total:', 'mp-restaurant-menu'); ?></strong>
<span class="mprm_cart_amount" data-subtotal="<?php echo mprm_get_cart_subtotal(); ?>" data-total="<?php echo mprm_get_cart_subtotal(); ?>"><?php echo mprm_currency_filter(mprm_format_amount(mprm_get_cart_total())); ?></span>
</p>
<?php
}
function mprm_checkout_hidden_fields() {
?>
<?php if (is_user_logged_in()) { ?>
<input type="hidden" name="mprm-user-id" value="<?php echo get_current_user_id(); ?>"/>
<?php } ?>
<input type="hidden" name="mprm_action" value="purchase"/>
<input type="hidden" name="controller" value="cart"/>
<input type="hidden" name="mprm-gateway" value="<?php echo models\Gateways::get_instance()->get_chosen_gateway(); ?>"/>
<?php
}
/**
* Delivery address default
*/
function mprm_checkout_delivery_address() {
if (mprm_get_option('shipping_address')): ?>
<p id="mprm-address-wrap">
<label for="shipping_address" class="mprm-label">
<?php _e('Shipping address:', 'mp-restaurant-menu'); ?>
</label>
<input type="text" name="shipping_address" value="" class="medium-text" placeholder="<?php _e('Enter your address.', 'mp-restaurant-menu'); ?>"/>
</p>
<?php endif;
}
/**
* Checkout order notes
*/
function mprm_checkout_order_note() {
?>
<p id="mprm-phone-number-wrap">
<label for="customer_note" class="mprm-label">
<?php _e('Order notes:', 'mp-restaurant-menu'); ?>
</label>
<textarea type="text" name="customer_note" id="customer_note" class="phone-number mprm-input"></textarea>
</p>
<?php }
/**
* Summary table
*/
function mprm_checkout_summary_table() { ?>
<span class="mprm-payment-details-label"><legend><?php _e('Order totals', 'mp-restaurant-menu'); ?></legend></span>
<table class="mprm-table">
<?php do_action('mprm_checkout_table_subtotal_before'); ?>
<tr>
<td class=""><span><?php _e('Subtotal', 'mp-restaurant-menu'); ?> </span></td>
<td><span class="mprm_cart_subtotal_amount"><?php echo mprm_currency_filter(mprm_format_amount(mprm_get_cart_subtotal())) ?></span></td>
</tr>
<?php do_action('mprm_checkout_table_subtotal_after'); ?>
<?php do_action('mprm_checkout_table_tax_before'); ?>
<?php if (mprm_use_taxes()) : ?>
<tr <?php if (!mprm_is_cart_taxed()) echo ' style="display:none;"'; ?>>
<td><span><?php _e('Tax', 'mp-restaurant-menu'); ?></span></td>
<td><span class="mprm_cart_tax_amount" data-tax="<?php echo mprm_get_cart_tax(); ?>"><?php echo mprm_currency_filter(mprm_format_amount(mprm_get_cart_tax())) ?></span></td>
</tr>
<?php endif; ?>
<?php do_action('mprm_checkout_table_tax_after'); ?>
<?php do_action('mprm_checkout_table_total_before'); ?>
<tr class="mprm-checkout-total">
<td>
<span><b><?php _e('Total', 'mp-restaurant-menu'); ?></b></span>
</td>
<td><span class="mprm_cart_amount"><b><?php echo mprm_currency_filter(mprm_format_amount(mprm_get_cart_total())) ?></b></span></td>
</tr>
<?php do_action('mprm_checkout_table_total_after'); ?>
</table>
<?php }
/**
* Send to success page
*
* #param string $query_string
*/
function mprm_send_to_success_page($query_string) {
return models\Checkout::get_instance()->send_to_success_page($query_string);
}
/**
* Send back to checkout
*
* #param $args
*/
function mprm_send_back_to_checkout($args) {
return models\Checkout::get_instance()->send_back_to_checkout($args);
}