Automattic\WooCommerce\Internal\RestApi\Routes\V4\Refunds
DataUtils{} │ WC 1.0
Helper methods for the REST API.
Class DataUtils
No Hooks.
Usage
$DataUtils = new DataUtils(); // use class methods
Methods
- public build_refund_preview( WC_Order $order, array $line_items )
- public calculate_refund_amount( array $line_items )
- public compute_line_item_refund_total( $item, int $quantity )
- public compute_refund_preview_or_error( WC_Order $order, array $line_items, string $log_source )
- public compute_refunded_quantities_and_totals( WC_Order $order )
- public convert_line_items_to_internal_format( $line_items, WC_Order $order )
- public fill_missing_refund_totals( array $line_items, WC_Order $order )
- public get_preview_line_items_arg_schema()
- public normalize_refund_totals( array $line_items )
- public prepare_refund_creation_or_error( WC_Order $order, array $line_items, bool $has_amount_override, $amount_override, string $log_source )
- public validate_line_items( $line_items, WC_Order $order )
- public validate_preview_line_items( array $line_items, WC_Order $order )
- private compute_quantity_refund_total( $item, int $quantity, array $refund_data )
- protected convert_line_item_taxes_to_internal_format( $line_item_taxes )
- protected convert_proportional_taxes_to_schema_format( array $calculated_taxes )
- private line_refund_history_matches_quantities( WC_Order_Item_Product $item, array $line_refunds )
- protected split_inclusive_by_stored_ratio( float $amount, $item, int $dp )
Notes
| Package: Automattic\WooCommerce\Internal\RestApi\Routes\V4\Refunds |
DataUtils{} DataUtils{} code WC 11.1.1
class DataUtils {
/**
* Order statuses that allow refunds.
*/
public const REFUNDABLE_STATUSES = array(
OrderStatus::COMPLETED,
OrderStatus::PROCESSING,
OrderStatus::ON_HOLD,
);
/**
* Convert line items (schema format) to internal format. This keys arrays by item ID and has some different naming
* conventions.
*
* 111 => [
* "qty" => 1,
* "refund_total" => 123,
* "refund_tax" => [
* 1 => 123,
* 2 => 456,
* ],
* ]
*
* @param array $line_items The line items to convert.
* @param WC_Order $order The order being refunded.
* @return array The converted line items.
*/
public function convert_line_items_to_internal_format( $line_items, WC_Order $order ) {
$prepared_line_items = array();
foreach ( $line_items as $line_item ) {
// A line item is processable when it has an ID and at least one of
// quantity or refund_total. The legacy v3-style form may omit
// quantity entirely; in that case qty=0 is recorded on the refund,
// matching v3 semantics ("refunded $X of this line without consuming
// specific units"). Dollar accounting via get_remaining_refund_amount
// still bounds subsequent refunds, so per-unit looseness here does
// not enable over-refunding.
if ( ! isset( $line_item['line_item_id'] ) ) {
continue;
}
if ( ! isset( $line_item['quantity'] ) && ! isset( $line_item['refund_total'] ) ) {
continue;
}
// refund_tax presence is the discriminator for how refund_total is interpreted:
// when refund_tax is absent, refund_total is tax-inclusive and the tax portion is
// split out below; when refund_tax is present, refund_total is the tax-exclusive
// subtotal and is stored as-is, with the supplied taxes added on top.
//
// If no explicit refund_tax provided, extract tax from the tax-inclusive
// refund_total. Skip when refund_total is also missing — there's nothing
// to extract tax from. The split is by the line's own stored total/tax
// ratio via split_inclusive_by_stored_ratio(), the same method the preview
// uses, so the stored refund matches what build_refund_preview() showed.
if ( ! isset( $line_item['refund_tax'] ) && isset( $line_item['refund_total'] ) ) {
$original_item = $order->get_item( $line_item['line_item_id'] );
if ( $original_item instanceof WC_Order_Item_Product || $original_item instanceof WC_Order_Item_Shipping || $original_item instanceof WC_Order_Item_Fee ) {
$split = $this->split_inclusive_by_stored_ratio( (float) $line_item['refund_total'], $original_item, wc_get_price_decimals() );
// Leave a tax-free line untouched: refund_total stays the full
// (tax-exclusive == tax-inclusive) amount and no refund_tax is set.
if ( ! empty( $split['taxes'] ) ) {
$line_item['refund_tax'] = $this->convert_proportional_taxes_to_schema_format( $split['taxes'] );
$line_item['refund_total'] = $split['subtotal'];
}
}
}
// Default qty=0 when quantity was omitted (legacy v3-style explicit
// refund_total path). Default refund_total=0 defensively; in practice
// validate_line_items ensures one of them is set by this point.
$prepared_line_items[ $line_item['line_item_id'] ] = array(
'qty' => $line_item['quantity'] ?? 0,
'refund_total' => $line_item['refund_total'] ?? 0,
'refund_tax' => $this->convert_line_item_taxes_to_internal_format( $line_item['refund_tax'] ?? array() ),
);
}
return $prepared_line_items;
}
/**
* Convert line item taxes (schema format) to internal format. This keys arrays by tax ID and has some different naming.
*
* @param array $line_item_taxes The taxes to convert.
* @return array The converted taxes.
*
* @since 10.9.0
*/
protected function convert_line_item_taxes_to_internal_format( $line_item_taxes ) {
$prepared_taxes = array();
foreach ( $line_item_taxes as $line_item_tax ) {
if ( ! isset( $line_item_tax['id'], $line_item_tax['refund_total'] ) ) {
continue;
}
$prepared_taxes[ $line_item_tax['id'] ] = $line_item_tax['refund_total'];
}
return $prepared_taxes;
}
/**
* Calculate the gross refund amount from line items (schema format).
*
* Sums refund_total plus any explicit refund_tax. This yields the tax-inclusive gross
* for both forms: when refund_tax is omitted, refund_total is already tax-inclusive (and
* there is no refund_tax to add); when refund_tax is supplied, refund_total is the
* tax-exclusive subtotal and the taxes are added on top.
*
* @param array $line_items The line items to calculate the refund amount from.
* @return float|null The refund amount, or null if it can't be calculated.
*/
public function calculate_refund_amount( array $line_items ): ?float {
if ( empty( $line_items ) ) {
return null;
}
$amount = 0;
foreach ( $line_items as $line_item ) {
// is_numeric() (not !empty) — an explicit refund_total of 0 can be part
// of a valid tax-only refund and must be included in the gross sum.
if ( isset( $line_item['refund_total'] ) && is_numeric( $line_item['refund_total'] ) ) {
$amount += $line_item['refund_total'];
}
if ( ! empty( $line_item['refund_tax'] ) && is_array( $line_item['refund_tax'] ) ) {
foreach ( $line_item['refund_tax'] as $tax ) {
if ( isset( $tax['refund_total'] ) && is_numeric( $tax['refund_total'] ) ) {
$amount += $tax['refund_total'];
}
}
}
}
return (float) NumberUtil::round( $amount, wc_get_price_decimals() );
}
/**
* Validate line items (schema format) before conversion to internal format.
*
* @param array $line_items The line items to validate.
* @param WC_Order $order The order object.
* @return boolean|WP_Error
*/
public function validate_line_items( $line_items, WC_Order $order ) {
// Reject non-refundable order statuses up front, mirroring the preview path
// so create and preview agree on which orders accept refunds.
if ( ! in_array( $order->get_status(), self::REFUNDABLE_STATUSES, true ) ) {
return new WP_Error(
'order_not_refundable',
__( 'This order cannot be refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
// Reject a fully-refunded order up front with the same code/status the
// preview path returns, so a fully-refunded order is rejected identically
// by both endpoints rather than via the controller's later
// refund_exceeds_remaining guard.
if ( (float) $order->get_remaining_refund_amount() <= 0 ) {
return new WP_Error(
'order_not_refundable',
__( 'This order has already been fully refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
// Precompute refunded quantities/totals once so the over-refund check
// below caps against remaining refundable quantity, not the original.
// Loaded here rather than passed in: the controller dispatches through this
// method so subclass overrides keep working, and WC_Order::get_refunds()
// serves repeat loads within the request from the object cache.
$refund_data = $this->compute_refunded_quantities_and_totals( $order );
$seen_ids = array();
foreach ( $line_items as $line_item ) {
$line_item_id = $line_item['line_item_id'] ?? null;
if ( ! $line_item_id ) {
return new WP_Error(
'missing_line_item_id',
__( 'Line item ID is required.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Reject duplicate line items: each is validated against the same remaining
// snapshot, so repeating an ID would let the per-line cap pass twice for the
// same line. Callers must combine a line into a single entry.
if ( isset( $seen_ids[ $line_item_id ] ) ) {
return new WP_Error(
'duplicate_line_item',
__( 'Each line item may appear only once per request.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$seen_ids[ $line_item_id ] = true;
$item = $order->get_item( $line_item_id );
// Validate item exists and belongs to the order.
if ( ! $item || $item->get_order_id() !== $order->get_id() ) {
return new WP_Error(
'line_item_not_found',
__( 'Line item not found.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
if ( ! $item instanceof \WC_Order_Item_Product && ! $item instanceof \WC_Order_Item_Fee && ! $item instanceof \WC_Order_Item_Shipping ) {
return new WP_Error(
'unsupported_item_type',
__( 'Line item is not a product, fee, or shipping line.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Quantity is required only when the client omits refund_total — the
// auto-compute path needs a real quantity to derive the unit price.
// When refund_total is provided explicitly (legacy v3-style path),
// quantity is informational and can be missing/zero, matching the
// original v4 schema's `default: 0` behavior.
$refund_total_missing = ! array_key_exists( 'refund_total', $line_item ) || null === $line_item['refund_total'];
// Reject the ambiguous "auto-computed refund_total + explicit refund_tax"
// combination. Auto-compute writes a tax-inclusive value; the
// converter then skips tax extraction because refund_tax is set,
// and calculate_refund_amount double-counts the tax. The client
// must either supply refund_total explicitly (and may then supply
// refund_tax to override the auto-extracted split) or let the
// server handle taxes (omit both).
if ( $refund_total_missing && isset( $line_item['refund_tax'] ) ) {
return new WP_Error(
'invalid_line_item',
__( 'refund_tax cannot be combined with an auto-computed refund_total. Provide refund_total explicitly when supplying refund_tax.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
if ( $refund_total_missing && ( ! isset( $line_item['quantity'] ) || ! is_int( $line_item['quantity'] ) || $line_item['quantity'] < 1 ) ) {
return new WP_Error(
'missing_quantity_or_refund_total',
__( 'Line item quantity must be a positive integer when refund_total is omitted.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// When refund_total is provided, a supplied quantity is informational, but it must
// still be a non-negative integer so it round-trips cleanly onto the refund line —
// a negative or fractional value would be stored verbatim as the line qty. 0 (or an
// omitted quantity) means "dollars only". This mirrors the integer/range checks the
// preview path applies before branching on item type.
if ( ! $refund_total_missing && isset( $line_item['quantity'] ) && ( ! is_int( $line_item['quantity'] ) || $line_item['quantity'] < 0 ) ) {
return new WP_Error(
'invalid_quantity',
__( 'Line item quantity must be a non-negative integer.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Auto-compute requires a non-zero source quantity to derive the unit
// price from. If the client omitted refund_total (or sent null) and the
// source product has zero quantity, surface a clear error rather than
// letting the request slip into the misleading "must be greater than
// zero" branch downstream.
if ( $refund_total_missing && $item instanceof \WC_Order_Item_Product && 0 === $item->get_quantity() ) {
return new WP_Error(
'invalid_line_item',
sprintf(
/* translators: %d: line item id */
__( 'Cannot auto-compute refund for line item %d: source quantity is zero. Provide an explicit refund_total.', 'woocommerce' ),
(int) $line_item_id
),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Validate refund quantity does not exceed remaining refundable
// quantity for this line. compute_refunded_quantities_and_totals
// returns negative values for already-refunded units (matches the
// convention used by validate_preview_line_items), so adding to
// $item->get_quantity() yields the remaining count.
// Only fires when a quantity was provided — the legacy
// explicit-refund_total path may omit it.
if ( isset( $line_item['quantity'] ) && $item instanceof \WC_Order_Item_Product ) {
$remaining_qty = $item->get_quantity() + ( $refund_data['qtys'][ $line_item_id ] ?? 0 );
if ( $line_item['quantity'] > $remaining_qty ) {
return new WP_Error(
'quantity_exceeds_refundable',
sprintf(
/* translators: %d: remaining refundable quantity */
__( 'Line item quantity cannot be greater than the remaining refundable quantity (%d).', 'woocommerce' ),
$remaining_qty
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
} elseif ( isset( $line_item['quantity'] ) && $line_item['quantity'] > 1 ) {
return new WP_Error(
'invalid_quantity',
__( 'Shipping and fee line items must be refunded with quantity of 1.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Validate refund total against the remaining refundable amount for this
// line (including tax), subtracting any prior partial refunds. Rounds both
// sides to currency precision and uses abs() so the cap matches
// validate_preview_line_items() exactly — a previewed amount that is
// accepted (or rejected) there behaves the same way here.
if ( isset( $line_item['refund_total'] ) ) {
$price_decimals = wc_get_price_decimals();
$signed_line_total = (float) $item->get_total() + (float) $item->get_total_tax();
// Reject a refund_total whose sign is opposite the line: you cannot refund
// a positive amount from a discount line, or a negative amount from a normal
// line. Without this, abs() in the cap below would let a wrong-sign value
// pass and be stored (e.g. a negative refund_total on a positive line in a
// mixed-line request whose total stays positive). A gross line refund that
// rounds to 0 is rejected below, so create and preview stay aligned for the
// tax-inclusive form while explicit tax-only create requests remain valid.
if ( (float) $line_item['refund_total'] * $signed_line_total < 0 ) {
return new WP_Error(
'invalid_refund_total',
__( 'Refund total has the wrong sign for this line item.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Cap and zero-check the GROSS line refund against the line's tax-inclusive
// total. When an explicit refund_tax breakdown is supplied, refund_total is
// the tax-exclusive (net) subtotal and the tax is added on top (core Woo
// semantics — see RefundSchema); without it, refund_total is already
// tax-inclusive, so the gross equals refund_total. Capping the net alone
// would let a client push the overage into refund_tax and over-refund the
// line. Preview has no refund_tax field, so its (refund_total-only) cap stays
// equivalent for the inclusive form.
$line_refund_gross = (float) $line_item['refund_total'];
if ( ! empty( $line_item['refund_tax'] ) && is_array( $line_item['refund_tax'] ) ) {
$seen_tax_ids = array();
foreach ( $line_item['refund_tax'] as $tax ) {
// Reject duplicate tax IDs within a line: the gross sum here and
// calculate_refund_amount() count every entry, but the internal
// conversion keys taxes by ID, so a duplicate would silently
// overwrite its sibling and store less than the refund amount.
$tax_id = $tax['id'] ?? null;
if ( null !== $tax_id && isset( $seen_tax_ids[ $tax_id ] ) ) {
return new WP_Error(
'duplicate_tax_id',
__( 'Each tax can appear at most once per line item in refund_tax.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
if ( null !== $tax_id ) {
$seen_tax_ids[ $tax_id ] = true;
}
$line_refund_gross += (float) ( $tax['refund_total'] ?? 0 );
}
}
// Reject a gross line refund that rounds to zero. A zero line refund is a
// no-op that would otherwise be stored as an empty qty:0 refund line.
if ( 0.0 === (float) NumberUtil::round( $line_refund_gross, $price_decimals ) ) {
return new WP_Error(
'invalid_refund_total',
__( 'refund_total must be a number greater than zero.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$item_total_with_tax = abs( $signed_line_total );
$abs_refund_total = abs( $line_refund_gross );
// Mirror the preview path's three distinct over-refund errors (same
// codes, messages, and 422 status) so create and preview reject the
// same input identically. An over-refund is a well-formed but
// unprocessable request, so 422 — not 400 — is the correct status,
// matching the order-level cap the controller already returns.
if ( $abs_refund_total > NumberUtil::round( $item_total_with_tax, $price_decimals ) ) {
return new WP_Error(
'refund_total_exceeds_line',
sprintf(
/* translators: %s: line item total including tax */
__( 'refund_total cannot exceed the line item total including tax (%s).', 'woocommerce' ),
wc_format_decimal( $item_total_with_tax, $price_decimals )
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
// Remaining is rounded to currency precision before both checks, so a
// sub-cent residue left by rounding drift counts as fully refunded
// rather than producing a "cannot exceed 0.00" rejection.
$refunded_total = abs( (float) ( $refund_data['totals'][ $line_item_id ] ?? 0.0 ) );
$remaining_total = NumberUtil::round( $item_total_with_tax - $refunded_total, $price_decimals );
if ( $remaining_total <= 0 ) {
return new WP_Error(
'line_item_already_refunded',
__( 'This line item has already been fully refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
if ( $abs_refund_total > $remaining_total ) {
return new WP_Error(
'refund_total_exceeds_remaining',
sprintf(
/* translators: %s: remaining refundable amount */
__( 'refund_total cannot exceed the remaining refundable amount for this line item (%s).', 'woocommerce' ),
wc_format_decimal( $remaining_total, $price_decimals )
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
}
if ( isset( $line_item['refund_tax'] ) ) {
$item_taxes = $item->get_taxes();
if ( $item_taxes ) {
$allowed_tax_ids = array_keys( $item_taxes['total'] ?? array() );
foreach ( $line_item['refund_tax'] as $refund_tax ) {
if ( ! isset( $refund_tax['id'], $refund_tax['refund_total'] ) ) {
return new WP_Error( 'invalid_line_item', __( 'Tax id and refund_total are required.', 'woocommerce' ), array( 'status' => WP_Http::BAD_REQUEST ) );
}
$tax_id = $refund_tax['id'];
$tax_refund_total = $refund_tax['refund_total'];
if ( ! in_array( $tax_id, $allowed_tax_ids, true ) ) {
return new WP_Error(
'invalid_line_item',
sprintf(
/* translators: %s: tax IDs */
__( 'Line item tax not found. Must be: %s.', 'woocommerce' ),
implode( ', ', $allowed_tax_ids )
),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$price_decimals = wc_get_price_decimals();
$stored_tax = (float) $item_taxes['total'][ $tax_id ];
$requested_tax = (float) $tax_refund_total;
// Reject a refund_tax whose sign is opposite the stored tax bucket: you
// cannot refund a positive tax from a negative (discount) bucket or vice
// versa. Mirrors the refund_total wrong-sign guard. Compare on absolute
// magnitudes below so a negative bucket is capped the same way a positive
// one is — a signed `<` admits an over-refund of a negative bucket and
// rejects a valid partial one. An explicit 0 is allowed (a no-op).
if ( $requested_tax * $stored_tax < 0 ) {
return new WP_Error(
'invalid_refund_amount',
__( 'Refund tax total has the wrong sign for this line item.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Cap against the remaining tax for this bucket, subtracting any tax
// already refunded for this tax id on prior refunds — not the original
// line tax — so sequential refunds cannot over-refund a single bucket.
// $already_refunded_tax is accumulated as a positive magnitude
// (compute_refunded_quantities_and_totals() uses abs()), so compare it
// against the stored bucket's magnitude. Round both sides to currency
// precision: the accumulator is built from repeated float additions, so
// an unrounded compare could reject or admit an exactly-correct amount by
// a sub-cent residue.
$already_refunded_tax = (float) ( $refund_data['tax_totals'][ $line_item_id ][ $tax_id ] ?? 0.0 );
$remaining_tax = abs( $stored_tax ) - $already_refunded_tax;
if ( abs( $requested_tax ) > NumberUtil::round( $remaining_tax, $price_decimals ) ) {
// 400, not the 422 the over-refund caps above use: this is the
// status the released wc/v4 envelope already backfills for this
// error, so anything else would change a shipped response. It
// also keeps the code-to-status mapping one-to-one across this
// file — invalid_refund_amount is 400 at every site, sharing the
// code with the wrong-sign guard above, which is malformed
// input, while each 422 carries its own over-refund code.
return new WP_Error(
'invalid_refund_amount',
sprintf(
/* translators: %s: remaining refundable tax total */
__( 'Refund tax total cannot be greater than the remaining refundable tax for this line item (%s).', 'woocommerce' ),
wc_format_decimal( $remaining_tax, $price_decimals )
),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
}
}
}
}
return true;
}
/**
* Convert calculated taxes (internal format) to schema format.
*
* @param array $calculated_taxes Taxes keyed by tax ID with amounts.
* @return array Schema format with id and refund_total keys.
*
* @since 10.9.0
*/
protected function convert_proportional_taxes_to_schema_format( array $calculated_taxes ): array {
$result = array();
foreach ( $calculated_taxes as $tax_id => $amount ) {
$result[] = array(
'id' => (int) $tax_id,
'refund_total' => $amount,
);
}
return $result;
}
/**
* Split a tax-inclusive amount into net subtotal and per-tax-ID tax amounts using
* the line item's own stored total/tax ratio.
*
* Splitting by the line's actual stored proportion — rather than re-deriving tax
* from the order tax item's rate percent — returns exactly what was charged. It
* stays correct when the stored tax is not an exact rate% of net (manually edited
* tax, or a rate that changed after the order) and when a taxed line's rate
* resolves to zero. Preview ({@see build_refund_preview()}) and create
* ({@see convert_line_items_to_internal_format()}) share this method so a previewed
* split always matches the split stored on the created refund.
*
* Per-ID amounts are rounded and the subtotal is derived as amount - sum(tax), so
* the invariant subtotal + total_tax == amount holds exactly at $dp precision.
*
* @param float $amount Tax-inclusive amount to split. Rounded to $dp before splitting.
* @param WC_Order_Item_Product|WC_Order_Item_Shipping|WC_Order_Item_Fee $item Order item supplying the stored total/tax ratio.
* @param int $dp Price decimal places.
* @return array{subtotal: float, total_tax: float, taxes: array<int, float>} Net subtotal, summed tax, and per-tax-ID amounts.
*
* @since 10.9.0
*/
protected function split_inclusive_by_stored_ratio( float $amount, $item, int $dp ): array {
$amount = NumberUtil::round( $amount, $dp );
$stored_total = (float) $item->get_total();
// Keep only non-zero numeric stored taxes (positive or negative). A negative-tax
// discount fee must retain its breakdown; a zero entry contributes nothing.
$stored_taxes = array_filter(
$item->get_taxes()['total'] ?? array(),
function ( $t ) {
return is_numeric( $t ) && 0.0 !== (float) $t;
}
);
$stored_tax_total = array_sum( array_map( 'floatval', $stored_taxes ) );
$stored_with_tax = $stored_total + $stored_tax_total;
// Fallback used whenever the stored data can't yield a sane proportional split:
// treat the whole amount as net (no tax) and log for observability.
$unsplittable = function ( string $reason ) use ( $amount, $item ) {
wc_get_logger()->warning(
sprintf(
'Refund tax split: cannot split tax for item %d on order %d (%s).',
(int) $item->get_id(),
(int) $item->get_order_id(),
$reason
),
array( 'source' => 'wc-v4-refunds' )
);
return array(
'subtotal' => $amount,
'total_tax' => 0.0,
'taxes' => array(),
);
};
// No tax on the line: the whole amount is net (not an error, no log).
if ( empty( $stored_taxes ) ) {
return array(
'subtotal' => $amount,
'total_tax' => 0.0,
'taxes' => array(),
);
}
// A zero-value line (stored total nets to zero while a tax was charged) can't be
// split proportionally — avoid division by zero.
if ( 0.0 === (float) $stored_with_tax ) {
return $unsplittable( 'stored total incl. tax is zero' );
}
// Scale each stored tax by the share of the line being refunded.
$taxes = array();
foreach ( $stored_taxes as $tax_id => $stored_tax ) {
$taxes[ (int) $tax_id ] = NumberUtil::round( $amount * ( (float) $stored_tax / $stored_with_tax ), $dp );
}
$total_tax = NumberUtil::round( array_sum( $taxes ), $dp );
// Sanity clamp: the tax portion of a tax-inclusive amount can never exceed the
// amount itself. A larger value means the stored total/tax nearly cancel (e.g. a
// near-zero inclusive total from manually edited data), which would explode the
// ratio. Fall back rather than emit a nonsensical negative subtotal.
if ( abs( $total_tax ) > abs( $amount ) ) {
return $unsplittable( 'stored total and tax nearly cancel' );
}
$subtotal = NumberUtil::round( $amount - $total_tax, $dp );
return array(
'subtotal' => $subtotal,
'total_tax' => $total_tax,
'taxes' => $taxes,
);
}
/**
* Compute the tax-inclusive refund total for a line item at a given quantity.
*
* Precondition: $item must be one of WC_Order_Item_Product, WC_Order_Item_Shipping,
* WC_Order_Item_Fee, and $quantity must be a positive integer (>= 1). For
* shipping and fee items the quantity is informational only — the full item
* total is returned regardless. Callers using untrusted input should validate
* via {@see validate_preview_line_items()} first.
*
* @param WC_Order_Item_Product|WC_Order_Item_Shipping|WC_Order_Item_Fee $item The order item.
* @param int $quantity The quantity to refund (>= 1).
* @return float The tax-inclusive refund total. May be negative for items with negative totals (e.g. discount fees).
* @throws \InvalidArgumentException When $quantity is less than 1.
*
* @since 10.9.0
*/
public function compute_line_item_refund_total( $item, int $quantity ): float {
if ( $quantity < 1 ) {
// Exception message is developer-facing only; the value is a typed int and the format is a literal string.
// phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
throw new \InvalidArgumentException( sprintf( 'Quantity must be >= 1, got %d.', (int) $quantity ) );
}
$price_decimals = wc_get_price_decimals();
if ( $item instanceof WC_Order_Item_Product ) {
$original_qty = $item->get_quantity();
if ( 0 === $original_qty ) {
wc_get_logger()->warning(
sprintf( 'Refund preview: product item %d has zero original quantity on order %d.', $item->get_id(), $item->get_order_id() ),
array( 'source' => 'wc-v4-refunds' )
);
return 0.0;
}
$unit_price_with_tax = ( (float) $item->get_total() + (float) $item->get_total_tax() ) / $original_qty;
return NumberUtil::round( $unit_price_with_tax * $quantity, $price_decimals );
}
return NumberUtil::round( (float) $item->get_total() + (float) $item->get_total_tax(), $price_decimals );
}
/**
* Compute the tax-inclusive refund total for a quantity-form line item, capped to
* the line's remaining refundable amount.
*
* {@see compute_line_item_refund_total()} rounds each request independently, so a
* sequence of partial quantity refunds can drift from the stored line gross by up
* to a cent per request — round(unit × 2) + round(unit × 4) may exceed the line
* total that round(unit × 6) would produce. The quantity form is "server, compute
* the amount for me", so rather than rejecting its own arithmetic the server caps
* the result:
*
* - The unit-derived amount is always clamped down to the remaining amount, so
* rounding drift can never push it over the remaining-amount cap the validators
* enforce. Shipping and fee lines carry a single unit whose derived amount is the
* full line total, so partially-refunded ones always resolve to their remainder
* through this clamp.
* - A product quantity that consumes the line's remaining refundable units is
* topped up to the exact remaining amount — closing the line at currency
* precision with no stranded cents — but only when every prior refund on the
* line matches its own quantity-derived amount, i.e. the shortfall is provably
* accumulated rounding drift. An off-schedule prior refund (an explicit partial
* amount, or a dollar-only refund with no units) means the residue was
* deliberately withheld, and the quantity form must never silently pay it back
* out; the residue stays refundable through an explicit refund_total.
*
* When no refundable amount remains, the unclamped amount is returned as-is:
* clamping to zero would trip the zero-refund guard with a misleading error, while
* the validators reject the line with line_item_already_refunded. Explicit
* client-supplied refund_total values are never capped — those stay strictly
* validated.
*
* @param WC_Order_Item_Product|WC_Order_Item_Shipping|WC_Order_Item_Fee $item The order item.
* @param int $quantity The quantity to refund (>= 1).
* @param array $refund_data Refund-history snapshot from {@see compute_refunded_quantities_and_totals()} (see its return shape).
* @return float The tax-inclusive refund total, carrying the line's sign.
*
* @since 11.1.0
*/
private function compute_quantity_refund_total( $item, int $quantity, array $refund_data ): float {
$computed = $this->compute_line_item_refund_total( $item, $quantity );
$price_decimals = wc_get_price_decimals();
$signed_line_total = (float) $item->get_total() + (float) $item->get_total_tax();
$refunded_total = abs( (float) ( $refund_data['totals'][ $item->get_id() ] ?? 0.0 ) );
$remaining_total = NumberUtil::round( abs( $signed_line_total ) - $refunded_total, $price_decimals );
if ( $remaining_total <= 0 ) {
return $computed;
}
$sign = $signed_line_total < 0 ? -1.0 : 1.0;
$abs_computed = abs( $computed );
if ( $abs_computed > $remaining_total ) {
return $sign * $remaining_total;
}
if ( $item instanceof WC_Order_Item_Product && $abs_computed < $remaining_total ) {
$remaining_qty = $item->get_quantity() + ( $refund_data['qtys'][ $item->get_id() ] ?? 0 );
if (
$quantity >= $remaining_qty &&
$this->line_refund_history_matches_quantities( $item, $refund_data['line_refunds'][ $item->get_id() ] ?? array() )
) {
return $sign * $remaining_total;
}
}
return $computed;
}
/**
* Whether every prior refund line for a product matches its quantity-derived amount.
*
* True means the difference between the line's refunded total and the sum of
* unit-price amounts is pure rounding drift, so the final-chunk top-up in
* {@see compute_quantity_refund_total()} can safely reconcile it. Gross values are
* compared as formatted decimals at currency precision — never raw float
* equality. A refund line with no units (qty 0, the dollar-only form) is
* off-schedule by definition.
*
* @param WC_Order_Item_Product $item The original order line.
* @param array $line_refunds Prior refund lines as list<array{qty: int, gross: float}> (positive magnitudes).
* @return bool
*/
private function line_refund_history_matches_quantities( WC_Order_Item_Product $item, array $line_refunds ): bool {
$price_decimals = wc_get_price_decimals();
foreach ( $line_refunds as $refund_line ) {
if ( $refund_line['qty'] <= 0 ) {
return false;
}
$expected = abs( $this->compute_line_item_refund_total( $item, $refund_line['qty'] ) );
if ( wc_format_decimal( $refund_line['gross'], $price_decimals ) !== wc_format_decimal( $expected, $price_decimals ) ) {
return false;
}
}
return true;
}
/**
* Round every caller-supplied refund_total to currency precision.
*
* Applied at the entry of both the preview and create flows so a value the client
* sends is validated, summed, split, and stored at the same precision. A previewed
* amount therefore always matches the created refund to the cent. A missing or null
* refund_total (the auto-compute form) is left untouched — those are computed later
* and already rounded by {@see compute_line_item_refund_total()}.
*
* @param array $line_items Line items in schema format.
* @return array Line items with numeric refund_total values rounded to wc_get_price_decimals().
*
* @since 10.9.0
*/
public function normalize_refund_totals( array $line_items ): array {
$price_decimals = wc_get_price_decimals();
foreach ( $line_items as $key => $line_item ) {
if ( isset( $line_item['refund_total'] ) && is_numeric( $line_item['refund_total'] ) ) {
$line_items[ $key ]['refund_total'] = NumberUtil::round( (float) $line_item['refund_total'], $price_decimals );
}
}
return $line_items;
}
/**
* Fill in refund_total for any line item that omits it, computing the value from
* the order item's unit price × quantity via compute_quantity_refund_total(),
* which caps the result to the line's remaining refundable amount.
*
* Items that already have refund_total (including an explicit 0) are left
* untouched so validation can decide whether the explicit amount is valid.
* Items where refund_total is omitted OR is explicitly null are treated as
* "compute it for me". Items that can't be resolved (missing line_item_id,
* item not on order, invalid quantity, unsupported item type, product with
* zero source quantity) are also left untouched — validate_line_items surfaces
* the right error for those cases.
*
* Auto-computed values are tax-inclusive, matching the convention enforced by
* the existing converter (convert_line_items_to_internal_format extracts tax
* from a tax-inclusive refund_total).
*
* @param array $line_items Line items from the request (schema format).
* Each item: array{line_item_id?: int, quantity?: int,
* refund_total?: float|int|null, refund_tax?: array<int, mixed>}.
* @param WC_Order $order The order being refunded.
* @return array The line items with refund_total populated where possible (same shape as input).
*
* @since 10.9.0
*/
public function fill_missing_refund_totals( array $line_items, WC_Order $order ): array {
// Round caller-supplied amounts up front so explicit values are stored at the
// same precision the preview validated and showed. Computed values below are
// already rounded by compute_quantity_refund_total().
$line_items = $this->normalize_refund_totals( $line_items );
// Loaded lazily: only requests with at least one auto-computed line pay for
// the refund-history scan the remaining-amount cap needs.
$refund_data = null;
foreach ( $line_items as $key => $line_item ) {
// Treat a missing key and an explicit `null` value the same — both mean
// "compute it for me". An explicit `0` is caller-supplied input, so leave
// it untouched and let validation decide whether the gross line refund is valid.
if ( array_key_exists( 'refund_total', $line_item ) && null !== $line_item['refund_total'] ) {
continue;
}
// Skip auto-compute when the client also supplied an explicit
// refund_tax. Auto-compute writes a tax-inclusive refund_total, but
// the converter then skips tax extraction whenever refund_tax is
// already present — and calculate_refund_amount would add both,
// inflating the total by the tax amount. Leave refund_total unset;
// validate_line_items rejects this ambiguous combination with a
// clear error.
if ( isset( $line_item['refund_tax'] ) ) {
continue;
}
$line_item_id = $line_item['line_item_id'] ?? null;
$quantity = $line_item['quantity'] ?? null;
if ( ! $line_item_id || ! is_int( $quantity ) || $quantity < 1 ) {
continue;
}
$item = $order->get_item( $line_item_id );
if ( ! $item || ! ( $item instanceof WC_Order_Item_Product || $item instanceof WC_Order_Item_Shipping || $item instanceof WC_Order_Item_Fee ) ) {
continue;
}
// A product whose source line has zero quantity has no unit price to
// derive a refund from. Skip so validate_line_items surfaces a clear
// 'invalid_line_item' error to the API consumer instead of letting a
// silent 0.0 propagate into the misleading "must be greater than zero"
// branch downstream.
if ( $item instanceof WC_Order_Item_Product && 0 === $item->get_quantity() ) {
continue;
}
if ( null === $refund_data ) {
$refund_data = $this->compute_refunded_quantities_and_totals( $order );
}
$line_items[ $key ]['refund_total'] = $this->compute_quantity_refund_total( $item, $quantity, $refund_data );
}
return $line_items;
}
/**
* Build a refund preview showing authoritative totals and breakdowns.
*
* Callers must invoke {@see validate_preview_line_items()} first — this
* method assumes inputs have been validated and throws on missing items.
*
* Each line item must have 'line_item_id' and at least one of 'quantity'
* (positive int) or 'refund_total' (positive tax-inclusive float). When
* 'refund_total' is present and positive it is used directly; otherwise the
* total is computed from quantity via {@see compute_quantity_refund_total()},
* capped to the line's remaining refundable amount — the same computation the
* create flow stores, so the previewed amounts always match the created refund.
*
* @param WC_Order $order The order being previewed for refund.
* @param array $line_items Line items. Each: array{line_item_id: int, quantity?: int, refund_total?: float}.
* @return array The structured preview response.
* @throws \InvalidArgumentException When a line_item_id does not resolve to an item on the order.
*
* @since 10.9.0
*/
public function build_refund_preview( WC_Order $order, array $line_items ): array {
$price_decimals = wc_get_price_decimals();
$refund_data = $this->compute_refunded_quantities_and_totals( $order );
$sections = array(
'products' => array(
'items' => array(),
'subtotal' => 0.0,
'tax' => 0.0,
'total' => 0.0,
),
'shipping' => array(
'items' => array(),
'subtotal' => 0.0,
'tax' => 0.0,
'total' => 0.0,
),
'fees' => array(
'items' => array(),
'subtotal' => 0.0,
'tax' => 0.0,
'total' => 0.0,
),
);
foreach ( $line_items as $line_item ) {
$item = $order->get_item( $line_item['line_item_id'] );
if ( ! $item ) {
// Exception message is developer-facing only; both values are typed ints and the format is a literal string.
// phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
throw new \InvalidArgumentException( sprintf( 'Line item %d not found on order %d.', (int) $line_item['line_item_id'], (int) $order->get_id() ) );
}
/**
* Validated by validate_preview_line_items() upstream.
*
* @var WC_Order_Item_Product|WC_Order_Item_Shipping|WC_Order_Item_Fee $item
*/
// When the caller provides an explicit refund_total (partial-amount form) use it
// directly. The quantity-based form computes the tax-inclusive total from unit price,
// capped to the line's remaining refundable amount — the same computation
// fill_missing_refund_totals() feeds the create flow.
// A non-zero check (not > 0) mirrors validate_preview_line_items(), which accepts a
// negative refund_total for a negative discount line and rejects a present-but-zero
// one before this method runs — so a signed value is honoured rather than falling
// through to the (possibly absent) quantity.
$refund_total_with_tax = isset( $line_item['refund_total'] ) && is_numeric( $line_item['refund_total'] ) && 0.0 !== (float) $line_item['refund_total']
? NumberUtil::round( (float) $line_item['refund_total'], $price_decimals )
: $this->compute_quantity_refund_total( $item, (int) $line_item['quantity'], $refund_data );
// Split by the line's own stored total/tax ratio so the preview reflects what
// was actually charged and matches the split create stores (both call this).
$split = $this->split_inclusive_by_stored_ratio( $refund_total_with_tax, $item, $price_decimals );
$subtotal = $split['subtotal'];
$tax = $split['total_tax'];
$item_data = array(
'id' => $line_item['line_item_id'],
'quantity' => $line_item['quantity'] ?? null,
'subtotal' => wc_format_decimal( $subtotal, $price_decimals ),
'tax' => wc_format_decimal( $tax, $price_decimals ),
'total' => wc_format_decimal( $refund_total_with_tax, $price_decimals ),
);
$item_data['name'] = $item->get_name();
if ( $item instanceof WC_Order_Item_Product ) {
$variation_id = $item->get_variation_id();
$item_data['product_id'] = $variation_id > 0 ? $variation_id : $item->get_product_id();
$section_key = 'products';
} elseif ( $item instanceof WC_Order_Item_Shipping ) {
$section_key = 'shipping';
} else {
$section_key = 'fees';
}
$sections[ $section_key ]['items'][] = $item_data;
$sections[ $section_key ]['subtotal'] += $subtotal;
$sections[ $section_key ]['tax'] += $tax;
$sections[ $section_key ]['total'] += $refund_total_with_tax;
}
$format_section = function ( array $section ) use ( $price_decimals ): array {
return array(
'items' => $section['items'],
'subtotal' => wc_format_decimal( $section['subtotal'], $price_decimals ),
'tax' => wc_format_decimal( $section['tax'], $price_decimals ),
'total' => wc_format_decimal( $section['total'], $price_decimals ),
);
};
$grand_subtotal = $sections['products']['subtotal'] + $sections['shipping']['subtotal'] + $sections['fees']['subtotal'];
$grand_tax = $sections['products']['tax'] + $sections['shipping']['tax'] + $sections['fees']['tax'];
$grand_total = $sections['products']['total'] + $sections['shipping']['total'] + $sections['fees']['total'];
return array(
'breakdown' => array(
'products' => $format_section( $sections['products'] ),
'shipping' => $format_section( $sections['shipping'] ),
'fees' => $format_section( $sections['fees'] ),
),
'subtotal' => wc_format_decimal( $grand_subtotal, $price_decimals ),
'tax' => wc_format_decimal( $grand_tax, $price_decimals ),
'total' => wc_format_decimal( $grand_total, $price_decimals ),
'max_refundable' => wc_format_decimal( $order->get_remaining_refund_amount(), $price_decimals ),
);
}
/**
* Validate line items for a preview request.
*
* @param array $line_items The line items to validate.
* @param WC_Order $order The order object.
* @return true|WP_Error True on success, WP_Error on failure.
*
* @since 10.9.0
*/
public function validate_preview_line_items( array $line_items, WC_Order $order ) {
if ( empty( $line_items ) ) {
return new WP_Error(
'missing_line_items',
__( 'At least one line item is required.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
if ( ! in_array( $order->get_status(), self::REFUNDABLE_STATUSES, true ) ) {
return new WP_Error(
'order_not_refundable',
__( 'This order cannot be refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
if ( (float) $order->get_remaining_refund_amount() <= 0 ) {
return new WP_Error(
'order_not_refundable',
__( 'This order has already been fully refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
$refund_data = $this->compute_refunded_quantities_and_totals( $order );
$seen_ids = array();
foreach ( $line_items as $line_item ) {
$line_item_id = $line_item['line_item_id'] ?? null;
if ( ! $line_item_id ) {
return new WP_Error(
'missing_line_item_id',
__( 'Line item ID is required.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Reject duplicate line items: each is validated against the same remaining
// snapshot, so repeating an ID would let the per-line cap pass twice for the
// same line and double-count it in the preview breakdown.
if ( isset( $seen_ids[ $line_item_id ] ) ) {
return new WP_Error(
'duplicate_line_item',
__( 'Each line item may appear only once per request.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$seen_ids[ $line_item_id ] = true;
// A bad line_item_id reference (not on the order, or an unsupported type) is a
// malformed request, returned as 400 to match the create endpoint's handling
// of the same conditions.
$item = $order->get_item( $line_item_id );
if ( ! $item || $item->get_order_id() !== $order->get_id() ) {
return new WP_Error(
'line_item_not_found',
__( 'Line item not found.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
if ( ! $item instanceof WC_Order_Item_Product && ! $item instanceof WC_Order_Item_Fee && ! $item instanceof WC_Order_Item_Shipping ) {
return new WP_Error(
'unsupported_item_type',
__( 'Line item is not a product, fee, or shipping line.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// A present refund_total may be negative (a discount/credit line) but must be a
// non-zero number with the same sign as the line — validated below, mirroring
// validate_line_items() so create and preview accept and reject the same input.
// A null refund_total means "use the quantity form" (isset() is false for null).
$has_refund_total = isset( $line_item['refund_total'] );
if ( $has_refund_total && ! is_numeric( $line_item['refund_total'] ) ) {
return new WP_Error(
'invalid_refund_total',
__( 'refund_total must be a number greater than zero.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$has_quantity = isset( $line_item['quantity'] ) && is_int( $line_item['quantity'] ) && $line_item['quantity'] >= 1;
if ( ! $has_quantity && ! $has_refund_total ) {
return new WP_Error(
'missing_quantity_or_refund_total',
__( 'Either a positive integer quantity or a numeric refund_total is required.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$price_decimals = wc_get_price_decimals();
$signed_line_total = (float) $item->get_total() + (float) $item->get_total_tax();
// Validate an explicit refund_total. Mirrors validate_line_items() exactly (sign,
// zero, and the three over-refund caps) so a previewed amount that is accepted or
// rejected here behaves identically at create.
if ( $has_refund_total ) {
$refund_total = (float) $line_item['refund_total'];
// Reject a refund_total whose sign is opposite the line: you cannot refund a
// positive amount from a discount line, or a negative amount from a normal line.
if ( $refund_total * $signed_line_total < 0 ) {
return new WP_Error(
'invalid_refund_total',
__( 'Refund total has the wrong sign for this line item.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Reject a refund_total that rounds to zero — a no-op the create path also rejects.
if ( 0.0 === (float) NumberUtil::round( $refund_total, $price_decimals ) ) {
return new WP_Error(
'invalid_refund_total',
__( 'refund_total must be a number greater than zero.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
$item_total_with_tax = abs( $signed_line_total );
$abs_refund_total = abs( $refund_total );
if ( $abs_refund_total > NumberUtil::round( $item_total_with_tax, $price_decimals ) ) {
return new WP_Error(
'refund_total_exceeds_line',
sprintf(
/* translators: %s: line item total including tax */
__( 'refund_total cannot exceed the line item total including tax (%s).', 'woocommerce' ),
wc_format_decimal( $item_total_with_tax, $price_decimals )
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
// Cap against the remaining refundable amount for this line.
// compute_refunded_quantities_and_totals() tracks tax-inclusive totals
// for all item types so the comparison is consistent. Remaining is
// rounded to currency precision before both checks, matching
// validate_line_items(), so a sub-cent residue counts as fully refunded.
$refunded_total = abs( (float) ( $refund_data['totals'][ $line_item_id ] ?? 0.0 ) );
$remaining_total = NumberUtil::round( $item_total_with_tax - $refunded_total, $price_decimals );
if ( $remaining_total <= 0 ) {
return new WP_Error(
'line_item_already_refunded',
__( 'This line item has already been fully refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
if ( $abs_refund_total > $remaining_total ) {
return new WP_Error(
'refund_total_exceeds_remaining',
sprintf(
/* translators: %s: remaining refundable amount */
__( 'refund_total cannot exceed the remaining refundable amount for this line item (%s).', 'woocommerce' ),
wc_format_decimal( $remaining_total, $price_decimals )
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
}
// Validate a supplied quantity whenever present — even alongside refund_total —
// matching validate_line_items(). Skipping this when refund_total was given let a
// preview accept a quantity the create path then rejects.
if ( $has_quantity ) {
$quantity = $line_item['quantity'];
if ( $item instanceof WC_Order_Item_Product ) {
$remaining_qty = $item->get_quantity() + ( $refund_data['qtys'][ $line_item_id ] ?? 0 );
if ( $quantity > $remaining_qty ) {
return new WP_Error(
'quantity_exceeds_refundable',
sprintf(
/* translators: %d: remaining refundable quantity */
__( 'Requested quantity exceeds remaining refundable quantity (%d).', 'woocommerce' ),
$remaining_qty
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
} elseif ( 1 !== $quantity ) {
// Shipping and fee lines carry a single refundable unit.
return new WP_Error(
'invalid_quantity',
__( 'Shipping and fee line items must be refunded with quantity of 1.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
}
// Amount-from-quantity: the server derives the amount itself via
// compute_quantity_refund_total(), which caps it to the remaining line amount,
// so the only invalid state left to reject is a line with nothing refundable
// remaining. Rounded to currency precision so a sub-cent residue left by
// rounding drift counts as fully refunded. Create fills refund_total through
// the same capped computation, so preview and create accept identical input.
if ( $has_quantity && ! $has_refund_total ) {
$refunded_total = abs( (float) ( $refund_data['totals'][ $line_item_id ] ?? 0.0 ) );
$remaining_total = NumberUtil::round( abs( $signed_line_total ) - $refunded_total, $price_decimals );
if ( $remaining_total <= 0 ) {
return new WP_Error(
'line_item_already_refunded',
__( 'This line item has already been fully refunded.', 'woocommerce' ),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
}
}
return true;
}
/**
* Run the full refund preview pipeline for one request.
*
* Normalizes the caller-supplied refund_total values, validates the line
* items, builds the preview, and applies the two aggregate guards (a
* non-positive total, and a total exceeding the order's remaining
* refundable amount). Shared by the wc/v3 and wc/v4 preview endpoints so
* a fix lands once; error codes are emitted unprefixed and each caller
* applies its own surface convention (wc/v3 prefixes with
* `woocommerce_rest_`, wc/v4 wraps in its error envelope).
*
* @param WC_Order $order The order the preview is computed for.
* @param array $line_items Line items in schema format (line_item_id keyed).
* @param string $log_source Log source for invariant violations, per caller.
* @return array|WP_Error Preview data, or WP_Error carrying its HTTP status in the error data.
*
* @since 11.1.0
*/
public function compute_refund_preview_or_error( WC_Order $order, array $line_items, string $log_source ) {
// Round caller-supplied refund_total values once, up front, so validation and
// the computed preview use the same precision the create flow stores. Reused
// for both validate and build below.
$line_items = $this->normalize_refund_totals( $line_items );
$validation_error = $this->validate_preview_line_items( $line_items, $order );
if ( is_wp_error( $validation_error ) ) {
return $validation_error;
}
try {
$preview = $this->build_refund_preview( $order, $line_items );
} catch ( \InvalidArgumentException $e ) {
// validate_preview_line_items above should have caught any bad input.
// If build_refund_preview still throws InvalidArgumentException, treat
// it as a server-side invariant violation, log for observability, and
// return a generic message (do not leak internal IDs to clients).
wc_get_logger()->error(
sprintf( 'Refund preview invariant violation on order %d: %s', $order->get_id(), $e->getMessage() ),
array( 'source' => $log_source )
);
return new WP_Error(
'invalid_preview_request',
__( 'The refund preview could not be generated due to an unexpected error.', 'woocommerce' ),
array( 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
} catch ( \Throwable $e ) {
wc_get_logger()->error(
sprintf( 'Refund preview unexpected error on order %d: %s', $order->get_id(), $e->getMessage() ),
array( 'source' => $log_source )
);
return new WP_Error(
'unexpected_preview_error',
__( 'An unexpected error occurred while generating the refund preview.', 'woocommerce' ),
array( 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
}
// Reject a non-positive aggregate total up front. A refund of only a negative
// discount line, or a product plus discount that nets to zero, would otherwise
// preview successfully and then fail at create time.
if ( (float) $preview['total'] <= 0 ) {
return new WP_Error(
'invalid_refund_amount',
__( 'Refund total must be greater than zero.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Final guard: even when per-line validation passes, the aggregate
// preview total can still exceed the order's remaining refundable
// amount (e.g. an amount-only partial refund applied previously).
// `total` is already tax-inclusive; compare directly against max_refundable.
$preview_total_with_tax = abs( (float) $preview['total'] );
if ( $preview_total_with_tax > (float) $preview['max_refundable'] ) {
return new WP_Error(
'preview_exceeds_max_refundable',
sprintf(
/* translators: 1: requested preview total including tax, 2: remaining refundable */
__( 'Requested refund preview (%1$s) exceeds the remaining refundable amount (%2$s).', 'woocommerce' ),
wc_format_decimal( $preview_total_with_tax, wc_get_price_decimals() ),
$preview['max_refundable']
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
return $preview;
}
/**
* Run the shared refund creation preparation pipeline for one request.
*
* Fills missing refund_total values from quantities, validates the line
* items against the order's refund history, converts them to the internal
* wc_create_refund() format, resolves the refund amount, and applies the
* three aggregate guards (non-positive amount, an override below the line
* items total, and an amount exceeding the order's remaining refundable
* amount). Shared by the wc/v3 compute_totals path and the wc/v4 creation
* endpoint so a fix lands once; error codes are emitted unprefixed with
* their HTTP status in the error data, and each caller applies its own
* surface convention. Request mutation, hooks, metadata, and the
* wc_create_refund() call itself stay with the callers.
*
* The amount override is passed as a flag plus raw value because an
* explicitly supplied zero or null must be rejected, never silently
* replaced with the calculated total: a request meaning "refund nothing"
* must not refund the full computed amount.
*
* @param WC_Order $order The order the refund is prepared for.
* @param array $line_items Line items in schema format (line_item_id keyed).
* @param bool $has_amount_override Whether the client explicitly supplied an amount.
* @param mixed $amount_override The raw client-supplied amount, when $has_amount_override.
* @param string $log_source Log source for invariant violations, per caller.
* @return array|WP_Error Array with internal-format `line_items`, filled schema-format
* `schema_line_items`, and the resolved raw `amount`, or WP_Error
* carrying its HTTP status in the error data.
*
* @since 11.1.0
*/
public function prepare_refund_creation_or_error( WC_Order $order, array $line_items, bool $has_amount_override, $amount_override, string $log_source ) {
// Fill in refund_total for any line items that omit it. The simplified
// request form sends only {line_item_id, quantity}; the backend derives
// the tax-inclusive total from the order's unit price × quantity. Scoped
// try: compute_line_item_refund_total throws InvalidArgumentException on
// quantity < 1, but fill_missing_refund_totals pre-checks that condition,
// so this branch is defensive against a future invariant break only.
try {
$line_items = $this->fill_missing_refund_totals( $line_items, $order );
} catch ( \InvalidArgumentException $e ) {
wc_get_logger()->error(
sprintf( 'Refund creation invariant violation on order %d (%s): %s', $order->get_id(), get_class( $e ), $e->getMessage() ),
array( 'source' => $log_source )
);
return new WP_Error(
'invalid_refund_request',
__( 'The refund could not be created due to an unexpected error.', 'woocommerce' ),
array( 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
}
// The WP_Error already carries its HTTP status (400/422) in the error
// data, so create and preview return the same code for the same invalid
// input.
$validation_error = $this->validate_line_items( $line_items, $order );
if ( is_wp_error( $validation_error ) ) {
return $validation_error;
}
// Convert line items to internal format. refund_total is tax-inclusive when no
// explicit refund_tax is supplied (auto-computed values, or client values) — the
// converter splits the tax portion out via the line's stored total/tax ratio
// (split_inclusive_by_stored_ratio(), the same method the preview uses). When
// the client supplies an explicit refund_tax breakdown, refund_total is the
// tax-exclusive subtotal and the tax is added on top (core Woo semantics).
// Either way calculate_refund_amount sums refund_total + refund_tax to the
// gross line amount, so mixing the two forms across line items is well-defined.
$internal_line_items = $this->convert_line_items_to_internal_format( $line_items, $order );
$calculated_total = ! empty( $line_items ) ? $this->calculate_refund_amount( $line_items ) : 0;
$amount = $has_amount_override ? $amount_override : $calculated_total;
if ( (float) $amount <= 0 ) {
return new WP_Error(
'invalid_refund_amount',
__( 'Refund total must be greater than zero.', 'woocommerce' ),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Prevent under-refunding: the amount cannot be less than the calculated line
// items total. Over-refunding is allowed for goodwill/compensation scenarios.
if ( $has_amount_override && $calculated_total > 0 && NumberUtil::round( (float) $amount, wc_get_price_decimals() ) < NumberUtil::round( $calculated_total, wc_get_price_decimals() ) ) {
return new WP_Error(
'invalid_refund_amount',
sprintf(
/* translators: %1$s: refund amount, %2$s: calculated total from line items */
__( 'Refund amount (%1$s) cannot be less than the total of line items (%2$s).', 'woocommerce' ),
wc_format_decimal( $amount, wc_get_price_decimals() ),
wc_format_decimal( $calculated_total, wc_get_price_decimals() )
),
array( 'status' => WP_Http::BAD_REQUEST )
);
}
// Over-refunding line items is allowed (goodwill), but the amount can never
// exceed the order's remaining refundable amount. Reject up-front with a clear
// 422 rather than relying on wc_create_refund's generic failure, mirroring the
// preview pipeline's preview_exceeds_max_refundable guard.
$remaining_refundable = (float) $order->get_remaining_refund_amount();
if ( NumberUtil::round( (float) $amount, wc_get_price_decimals() ) > NumberUtil::round( $remaining_refundable, wc_get_price_decimals() ) ) {
return new WP_Error(
'refund_exceeds_remaining',
sprintf(
/* translators: %1$s: requested refund amount, %2$s: remaining refundable amount */
__( 'Refund amount (%1$s) exceeds the remaining refundable amount (%2$s).', 'woocommerce' ),
wc_format_decimal( $amount, wc_get_price_decimals() ),
wc_format_decimal( $remaining_refundable, wc_get_price_decimals() )
),
array( 'status' => WP_Http::UNPROCESSABLE_ENTITY )
);
}
return array(
'line_items' => $internal_line_items,
'schema_line_items' => $line_items,
'amount' => $amount,
);
}
/**
* Get the REST argument schema for a preview request's line_items parameter.
*
* Shared by the wc/v3 and wc/v4 preview endpoints so the accepted payload
* cannot drift between versions.
*
* @return array
*
* @since 11.1.0
*/
public function get_preview_line_items_arg_schema(): array {
return array(
'description' => __( 'Line items to include in the refund preview.', 'woocommerce' ),
'type' => 'array',
'required' => true,
'minItems' => 1,
'validate_callback' => 'rest_validate_request_arg',
// Hand-registered args get no default sanitizer; this coerces validated
// values to their schema types (numeric strings become numbers) like the
// args generated from an item schema.
'sanitize_callback' => 'rest_sanitize_request_arg',
'items' => array(
'type' => 'object',
'required' => array( 'line_item_id' ),
'additionalProperties' => false,
'properties' => array(
'line_item_id' => array(
'description' => __( 'ID of the original order line item.', 'woocommerce' ),
'type' => 'integer',
'minimum' => 1,
),
'quantity' => array(
'description' => __( 'Quantity to refund. Required when refund_total is omitted.', 'woocommerce' ),
'type' => 'integer',
'minimum' => 1,
),
'refund_total' => array(
// No `minimum` here on purpose: validate_preview_line_items() owns
// the sign rule and returns the actionable `invalid_refund_total`
// code. A refund_total must be non-zero and match the line's sign —
// negative is valid for a discount/credit line, positive for a normal
// line; zero and wrong-sign values are rejected. A schema `minimum`
// would wrongly forbid the negative form, and a generic
// `rest_invalid_param` is less useful to clients.
'description' => __( 'Tax-inclusive amount to refund for this line item. Must be non-zero and match the line\'s sign (negative for discount or credit lines, positive otherwise). Required when quantity is omitted.', 'woocommerce' ),
'type' => array( 'number', 'null' ),
),
),
),
);
}
/**
* Pre-compute refund data for all line items in an order.
*
* Loads refunds once and builds lookup maps for refunded quantities and totals per item ID,
* avoiding repeated get_refunds() calls during serialization. Fee and shipping totals are
* tax-inclusive so they can be compared directly against {@see compute_line_item_refund_total()}.
*
* line_refunds records each product refund line individually — quantity and tax-inclusive
* gross, both as positive magnitudes — so the quantity-form top-up can verify that prior
* refunds match their quantity-derived amounts before reconciling rounding drift.
*
* @param WC_Order $order Order instance.
* @return array{qtys: array<int, int>, totals: array<int, float>, tax_totals: array<int, array<int, float>>, line_refunds: array<int, list<array{qty: int, gross: float}>>}
*/
public function compute_refunded_quantities_and_totals( WC_Order $order ): array {
$qtys = array();
$totals = array();
$tax_totals = array();
$line_refunds = array();
// Accumulate the already-refunded tax per original item, keyed by tax rate
// id, as a positive amount. Refund line items store taxes as negatives, so
// flip the sign. Lets the per-tax-id cap subtract prior refunds.
$add_refunded_taxes = function ( $refunded_item, int $original_id ) use ( &$tax_totals ) {
$taxes = $refunded_item->get_taxes();
foreach ( (array) ( $taxes['total'] ?? array() ) as $tax_id => $amount ) {
$tax_totals[ $original_id ][ $tax_id ] = ( $tax_totals[ $original_id ][ $tax_id ] ?? 0.0 ) + abs( (float) $amount );
}
};
foreach ( $order->get_refunds() as $refund ) {
/**
* Refunded product line items.
*
* @var \WC_Order_Item_Product[] $refunded_line_items
*/
$refunded_line_items = $refund->get_items( 'line_item' );
foreach ( $refunded_line_items as $refunded_item ) {
$original_id = absint( $refunded_item->get_meta( '_refunded_item_id' ) );
$qtys[ $original_id ] = ( $qtys[ $original_id ] ?? 0 ) + $refunded_item->get_quantity();
$totals[ $original_id ] = ( $totals[ $original_id ] ?? 0.0 ) + ( (float) $refunded_item->get_total() + (float) $refunded_item->get_total_tax() ) * -1;
$line_refunds[ $original_id ][] = array(
'qty' => absint( $refunded_item->get_quantity() ),
'gross' => abs( (float) $refunded_item->get_total() + (float) $refunded_item->get_total_tax() ),
);
$add_refunded_taxes( $refunded_item, $original_id );
}
/**
* Refunded fee items.
*
* @var \WC_Order_Item_Fee[] $refunded_fees
*/
$refunded_fees = $refund->get_items( 'fee' );
foreach ( $refunded_fees as $refunded_item ) {
$original_id = absint( $refunded_item->get_meta( '_refunded_item_id' ) );
$totals[ $original_id ] = ( $totals[ $original_id ] ?? 0.0 ) + ( (float) $refunded_item->get_total() + (float) $refunded_item->get_total_tax() ) * -1;
$add_refunded_taxes( $refunded_item, $original_id );
}
/**
* Refunded shipping items.
*
* @var \WC_Order_Item_Shipping[] $refunded_shipping
*/
$refunded_shipping = $refund->get_items( 'shipping' );
foreach ( $refunded_shipping as $refunded_item ) {
$original_id = absint( $refunded_item->get_meta( '_refunded_item_id' ) );
$totals[ $original_id ] = ( $totals[ $original_id ] ?? 0.0 ) + ( (float) $refunded_item->get_total() + (float) $refunded_item->get_total_tax() ) * -1;
$add_refunded_taxes( $refunded_item, $original_id );
}
}
return array(
'qtys' => $qtys,
'totals' => $totals,
'tax_totals' => $tax_totals,
'line_refunds' => $line_refunds,
);
}
}