PMPro Group Account Upgrade/Downgrade Seats Proration

pmpro-group-accounts-upgrade-seat-count.php

<?php
/**
 * For existing group parents, show current seat count and pre-fill the seats field.
 * Runs before the group-accounts plugin's own pmpro_checkout_boxes hook (priority 10).
 */
function my_pmpro_group_parent_existing_seats_notice() {
	if ( ! function_exists( 'pmprogroupacct_get_settings_for_level' ) || ! class_exists( 'PMProGroupAcct_Group' ) ) {
		return;
	}

	$user_id = get_current_user_id();
	if ( ! $user_id ) {
		return;
	}

	$level = pmpro_getLevelAtCheckout();
	if ( empty( $level->id ) ) {
		return;
	}

	$settings = pmprogroupacct_get_settings_for_level( $level->id );
	if ( empty( $settings ) ) {
		return;
	}

	$existing_group = PMProGroupAcct_Group::get_group_by_parent_user_id_and_parent_level_id( $user_id, $level->id );
	if ( empty( $existing_group ) ) {
		return;
	}

	$existing_seats = intval( $existing_group->group_total_seats );
	$ajax_url       = admin_url( 'admin-ajax.php' );
	$ajax_nonce     = wp_create_nonce( 'my_pmpro_seats_cost_text' );
	?>
	<script>
	document.addEventListener( 'DOMContentLoaded', function () {
		var field = document.getElementById( 'pmprogroupacct_seats' );
		if ( ! field ) {
			return;
		}
		// Pre-fill with existing seat count.
		// (We do not bump field.min — the server still allows downgrades down to the plugin's min_seats.)
		field.value = <?php echo (int) $existing_seats; ?>;

		// Live-update the level cost text whenever the seat count changes.
		var levelId    = <?php echo (int) $level->id; ?>;
		var ajaxUrl    = <?php echo wp_json_encode( $ajax_url ); ?>;
		var ajaxNonce  = <?php echo wp_json_encode( $ajax_nonce ); ?>;
		var debounceId = null;

		function refreshLevelCostText() {
			var target = document.querySelector( '.pmpro_level_cost_text' );
			if ( ! target ) {
				return;
			}
			var seats = parseInt( field.value, 10 );
			if ( isNaN( seats ) ) {
				return;
			}
			var body = new URLSearchParams();
			body.append( 'action', 'my_pmpro_seats_cost_text' );
			body.append( '_ajax_nonce', ajaxNonce );
			body.append( 'level_id', levelId );
			body.append( 'pmprogroupacct_seats', seats );

			fetch( ajaxUrl, {
				method: 'POST',
				credentials: 'same-origin',
				headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
				body: body.toString()
			} )
			.then( function ( r ) { return r.json(); } )
			.then( function ( data ) {
				if ( data && data.success && data.data && typeof data.data.cost_text === 'string' ) {
					target.innerHTML = data.data.cost_text;
				}
			} )
			.catch( function () { /* ignore */ } );
		}

		field.addEventListener( 'input', function () {
			clearTimeout( debounceId );
			debounceId = setTimeout( refreshLevelCostText, 250 );
		} );
	} );
	</script>
	<p class="<?php echo esc_attr( pmpro_get_element_class( 'pmpro_message' ) ); ?>">
		<?php
		printf(
			/* translators: %s: current seat count */
			esc_html( _n( 'You currently have %s seat. Enter the new total number of seats you want.', 'You currently have %s seats. Enter the new total number of seats you want.', $existing_seats, 'pmpro-group-accounts' ) ),
			'<strong>' . esc_html( number_format_i18n( $existing_seats ) ) . '</strong>'
		);
		?>
		<br />
		<?php
		if ( pmpro_isLevelRecurring( $level ) ) {
			// Show the customer's next billing date so they know it stays the same.
			$next_payment_date_str = '';
			if ( class_exists( 'PMPro_Subscription' ) ) {
				$subscriptions = PMPro_Subscription::get_subscriptions_for_user( $user_id, $level->id );
				if ( ! empty( $subscriptions ) ) {
					$next_payment_ts = $subscriptions[0]->get_next_payment_date( 'timestamp' );
					if ( ! empty( $next_payment_ts ) ) {
						$next_payment_date_str = date_i18n( get_option( 'date_format' ), $next_payment_ts );
					}
				}
			}

			if ( ! empty( $next_payment_date_str ) ) {
				printf(
					/* translators: %s: next billing date */
					esc_html__( 'If you add seats, you will only be charged a prorated amount today for the remaining days in your current billing cycle. If you remove seats, you will not be charged today. Either way, your next billing date stays %s and the new seat total takes effect then.', 'pmpro-group-accounts' ),
					'<strong>' . esc_html( $next_payment_date_str ) . '</strong>'
				);
			} else {
				esc_html_e( 'If you add seats, you will only be charged a prorated amount today for the remaining days in your current billing cycle. If you remove seats, you will not be charged today. Your billing date stays the same.', 'pmpro-group-accounts' );
			}
		} else {
			esc_html_e( 'Today you will only be charged for the additional seats added to your group.', 'pmpro-group-accounts' );
		}
		?>
	</p>
	<?php
}
add_action( 'pmpro_checkout_boxes', 'my_pmpro_group_parent_existing_seats_notice', 5 );

/**
 * Ajax handler: return the formatted level cost text for the given level + seat count.
 *
 * `pmpro_getLevelAtCheckout()` runs the `pmpro_checkout_level` filter chain (including
 * our prorate filter), and reads `$_REQUEST['pmprogroupacct_seats']` — which the JS
 * sends. `pmpro_getLevelCost()` then renders the standard "X now and then Y per Z" string.
 */
function my_pmpro_seats_cost_text_ajax() {
	check_ajax_referer( 'my_pmpro_seats_cost_text' );

	$level_id = isset( $_POST['level_id'] ) ? intval( $_POST['level_id'] ) : 0;
	if ( ! $level_id || ! function_exists( 'pmpro_getLevelAtCheckout' ) ) {
		wp_send_json_error();
	}

	$level = pmpro_getLevelAtCheckout( $level_id );
	if ( empty( $level ) ) {
		wp_send_json_error();
	}

	wp_send_json_success( array(
		'cost_text' => pmpro_getLevelCost( $level ),
	) );
}
add_action( 'wp_ajax_my_pmpro_seats_cost_text', 'my_pmpro_seats_cost_text_ajax' );
add_action( 'wp_ajax_nopriv_my_pmpro_seats_cost_text', 'my_pmpro_seats_cost_text_ajax' );

/**
 * Prorate a group account parent level checkout when an existing parent adds seats.
 *
 * Runs after pmprogroupacct_pmpro_checkout_level_parent (priority 10) which already
 * added new_total_seats × price_per_seat to initial_payment and/or billing_amount.
 *
 * What this does:
 *   - Initial payment → price of ADDITIONAL seats only (new_total − existing_total).
 *   - Recurring billing → price of ALL seats (new_total) — already correct, left alone.
 *   - profile_start_date → member's current enddate (next billing date) so the
 *     subscription cycle continues rather than restarting from today.
 */
function my_pmpro_prorate_parent_seat_upgrade( $level ) {
	// Require the group-accounts plugin to be active.
	if ( ! function_exists( 'pmprogroupacct_get_settings_for_level' ) || ! class_exists( 'PMProGroupAcct_Group' ) ) {
		return $level;
	}

	$user_id = get_current_user_id();
	if ( ! $user_id ) {
		return $level;
	}

	// Only act on group parent levels with per-seat (fixed) pricing.
	$settings = pmprogroupacct_get_settings_for_level( $level->id );
	if ( empty( $settings ) || $settings['pricing_model'] !== 'fixed' ) {
		return $level;
	}

	// Only prorate recurring levels. Non-recurring (one-time) levels with an
	// expiration date should charge the full amount and let PMPro extend the
	// enddate by their remaining days as it normally would.
	if ( ! pmpro_isLevelRecurring( $level ) ) {
		return $level;
	}

	// Only act when an existing group is being upgraded.
	$existing_group = PMProGroupAcct_Group::get_group_by_parent_user_id_and_parent_level_id( $user_id, $level->id );
	if ( empty( $existing_group ) ) {
		return $level;
	}

	$price_per_seat  = (float) $settings['pricing_model_settings'];
	$new_total_seats = intval( isset( $_REQUEST['pmprogroupacct_seats'] ) ? $_REQUEST['pmprogroupacct_seats'] : $settings['min_seats'] );
	$existing_seats  = intval( $existing_group->group_total_seats );

	$is_downgrade     = $new_total_seats < $existing_seats;
	$additional_seats = $is_downgrade ? 0 : ( $new_total_seats - $existing_seats );

	// Fetch the existing subscription's next payment date — needed for both proration
	// math (upgrade) and preserving the billing anchor (downgrade).
	$existing_next_payment_ts = 0;
	if ( class_exists( 'PMPro_Subscription' ) ) {
		$subscriptions = PMPro_Subscription::get_subscriptions_for_user( $user_id, $level->id );
		if ( ! empty( $subscriptions ) ) {
			$existing_next_payment_ts = (int) $subscriptions[0]->get_next_payment_date( 'timestamp' );
		}
	}

	// True mid-cycle proration: charge only for the days remaining in the current
	// billing cycle. e.g. 5 added seats at $10/mo with 3 days left = 5 × $10 × (3/30) = $5.
	$proration_ratio = 1.0;
	if ( ! empty( $existing_next_payment_ts ) && ! empty( $level->cycle_number ) && ! empty( $level->cycle_period ) ) {
		$now            = current_time( 'timestamp' );
		$cycle_seconds  = strtotime( '+' . (int) $level->cycle_number . ' ' . $level->cycle_period, $now ) - $now;
		$remaining_secs = max( 0, $existing_next_payment_ts - $now );
		if ( $cycle_seconds > 0 ) {
			$proration_ratio = min( 1.0, $remaining_secs / $cycle_seconds );
		}
	}

	switch ( $settings['price_application'] ) {
		case 'both':
		case 'initial':
			// Upgrade: charge a prorated amount for the additional seats only.
			// Downgrade: $0 today; the lower recurring amount takes effect next cycle.
			$level->initial_payment = $additional_seats * $price_per_seat * $proration_ratio;
			if ( $level->initial_payment > 0 && $level->initial_payment < 0.5 ) {
				$level->initial_payment = 1;
			}
			break;
	}

	// Always preserve the existing subscription's next_payment_date — billing rhythm
	// stays exactly where it was for both upgrades and downgrades.
	if ( ! empty( $existing_next_payment_ts ) ) {
		$level->profile_start_date = date( 'Y-m-d H:i:s', $existing_next_payment_ts );
	}

	return $level;
}
add_filter( 'pmpro_checkout_level', 'my_pmpro_prorate_parent_seat_upgrade', 20 );