<?php
    session_start();
    require '../../../assets/utils/db_auth.php';
    require '../../../assets/utils/classes/PurchaseOrderManager.php';

    $po = new PurchaseOrderManager($pdo2, $company_id);

    $id = (int)($data['id'] ?? 0);

    if ($id > 0) {
        $result = $po->getPoById($id);
        if (!$result) {
            http_response_code(404);
            $answer['message'] = 'Purchase order not found.';
            exit(json_encode($answer));
        }
        $answer['output'] = $result;

        // Calculate receivable items — PO items minus already received qty
        $po_items   = $result['items'] ?? [];
        $receivable = [];
        foreach ($po_items as $i => $item) {
            $ordered  = (float)($item['quantity']     ?? 0);
            $received = (float)($item['received_qty'] ?? 0);
            $remaining = $ordered - $received;
            if ($remaining > 0) {
                $receivable[] = array_merge($item, [
                    'item_id'       => (int)($item['item_id'] ?? $i),
                    'ordered_qty'   => $ordered,
                    'received_qty'  => $received,
                    'remaining_qty' => $remaining,
                ]);
            }
        }
        $answer['receivable_items'] = $receivable;

    } else {
        $answer['output'] = $po->getPoList();
    }

    $answer['success'] = 1;
    exit(json_encode($answer));
?>