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

    function stockTableNameFromWarehouseId(int $warehouse_id): string {
        return 'td_stock_' . $warehouse_id;
    }

    function findProduct(PDO $pdo, int $company_id, string $sku): array|false {
        $sth = $pdo->prepare(
            "SELECT sku, product_name, uom
             FROM md_product
             WHERE company_id = :company_id
                AND sku = :sku
                AND status > 0
             LIMIT 1"
        );
        $sth->execute([':company_id' => $company_id, ':sku' => $sku]);
        return $sth->fetch(PDO::FETCH_ASSOC);
    }

    function activeStockLotExists(PDO $pdo, int $company_id, string $sku, string $lot): bool {
        $warehouses = $pdo->prepare(
            "SELECT id FROM md_warehouse
             WHERE company_id = :company_id AND status = 1"
        );
        $warehouses->execute([':company_id' => $company_id]);

        foreach ($warehouses->fetchAll(PDO::FETCH_COLUMN) as $warehouse_id) {
            $table = stockTableNameFromWarehouseId((int)$warehouse_id);
            $sth = $pdo->prepare(
                "SELECT ROUND(SUM(COALESCE(`in`, 0)) - SUM(COALESCE(`out`, 0)), 2) AS balance
                 FROM `{$table}`
                 WHERE company_id = :company_id
                    AND product_sku = :product_sku
                    AND lot_number = :lot_number
                    AND status = 1"
            );
            $sth->execute([
                ':company_id'  => $company_id,
                ':product_sku' => $sku,
                ':lot_number'  => $lot,
            ]);
            if ((float)$sth->fetchColumn() > 0) return true;
        }

        return false;
    }

    function findLot(PDO $pdo, int $company_id, string $sku, string $lot): array|false {
        $sth = $pdo->prepare(
            "SELECT
                l.product_sku,
                l.lot_number,
                l.expiry_date,
                p.product_name,
                p.uom
             FROM md_lot l
             INNER JOIN md_product p
                ON p.company_id = l.company_id
                AND p.sku = l.product_sku
             WHERE l.company_id = :company_id
                AND l.product_sku = :product_sku
                AND l.lot_number = :lot_number
                AND p.status > 0
             LIMIT 1"
        );
        $sth->execute([
            ':company_id'  => $company_id,
            ':product_sku' => $sku,
            ':lot_number'  => $lot,
        ]);
        $row = $sth->fetch(PDO::FETCH_ASSOC);
        if ($row) return $row;

        $product = findProduct($pdo, $company_id, $sku);
        if (!$product || !activeStockLotExists($pdo, $company_id, $sku, $lot)) return false;

        return [
            'product_sku'  => $product['sku'],
            'lot_number'   => $lot,
            'expiry_date'  => null,
            'product_name' => $product['product_name'],
            'uom'          => $product['uom'],
        ];
    }

    function listLabels(PDO $pdo, int $company_id, string $sku, string $lot): array {
        $params = [':company_id' => $company_id];
        $where = "WHERE b.company_id = :company_id";

        if ($sku !== '') {
            $where .= " AND b.product_sku = :product_sku";
            $params[':product_sku'] = $sku;
        }

        if ($lot !== '') {
            $where .= " AND b.lot_number = :lot_number";
            $params[':lot_number'] = $lot;
        }

        $sth = $pdo->prepare(
            "SELECT
                b.id,
                b.product_sku,
                b.lot_number,
                b.serial_number,
                b.barcode,
                b.status,
                b.print_count,
                b.last_printed_dt,
                b.created_dt,
                p.product_name
             FROM md_barcode b
             LEFT JOIN md_product p
                ON p.company_id = b.company_id
                AND p.sku = b.product_sku
             {$where}
                AND b.barcode_type = 'sku'
             ORDER BY b.created_dt DESC, b.id DESC"
        );
        $sth->execute($params);
        return $sth->fetchAll(PDO::FETCH_ASSOC);
    }

    $label_action = $data['label_action'] ?? 'read';
    $product_sku  = trim($data['product_sku'] ?? '');
    $lot_number   = trim($data['lot_number'] ?? '');

    if (in_array($label_action, ['create', 'print', 'disable', 'enable'], true)) {
        require_role($user_role, ['owner', 'admin', 'staff']);
    }

    if ($label_action === 'print') {
        $barcode = trim($data['barcode'] ?? '');
        if ($barcode === '') {
            $answer['message'] = 'No barcode provided.';
            http_response_code(400);
            exit(json_encode($answer));
        }

        $sth = $pdo2->prepare(
            "UPDATE md_barcode
             SET print_count = print_count + 1,
                 last_printed_dt = NOW()
             WHERE company_id = :company_id
                AND barcode = :barcode
                AND barcode_type = 'sku'
                AND status = 1"
        );
        $sth->execute([':company_id' => $company_id, ':barcode' => $barcode]);

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

    if ($label_action === 'disable') {
        $barcode = trim($data['barcode'] ?? '');
        if ($barcode === '') {
            $answer['message'] = 'No barcode provided.';
            http_response_code(400);
            exit(json_encode($answer));
        }

        $sth = $pdo2->prepare(
            "UPDATE md_barcode
             SET status = 0
             WHERE company_id = :company_id
                AND barcode = :barcode
                AND barcode_type = 'sku'
                AND status = 1"
        );
        $sth->execute([':company_id' => $company_id, ':barcode' => $barcode]);

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

    if ($label_action === 'create') {
        $serial_number = trim($data['serial_number'] ?? '');
        $allow_unlisted = !empty($data['allow_unlisted']);

        if ($product_sku === '' || $lot_number === '' || $serial_number === '') {
            $answer['message'] = 'SKU, lot no, and serial no are required.';
            http_response_code(400);
            exit(json_encode($answer));
        }

        $lot = findLot($pdo2, $company_id, $product_sku, $lot_number);
        if (!$lot) {
            if (!$allow_unlisted) {
                $answer['message'] = 'Lot not found.';
                http_response_code(404);
                exit(json_encode($answer));
            }

            $product = findProduct($pdo2, $company_id, $product_sku);
            if (!$product) {
                $answer['message'] = 'SKU not found.';
                http_response_code(404);
                exit(json_encode($answer));
            }

            $lot = [
                'product_sku'  => $product['sku'],
                'lot_number'   => $lot_number,
                'expiry_date'  => null,
                'product_name' => $product['product_name'],
                'uom'          => $product['uom'],
            ];
        }

        $barcode = "SKU|{$product_sku}|{$lot_number}|{$serial_number}";

        $sth = $pdo2->prepare(
            "INSERT INTO md_barcode
                (company_id, barcode_type, barcode, product_sku, lot_number, serial_number)
             VALUES
                (:company_id, 'sku', :barcode, :product_sku, :lot_number, :serial_number)
             ON DUPLICATE KEY UPDATE
                barcode_type = VALUES(barcode_type),
                product_sku = VALUES(product_sku),
                lot_number = VALUES(lot_number),
                serial_number = VALUES(serial_number),
                status = 1"
        );
        $sth->execute([
            ':company_id'    => $company_id,
            ':product_sku'   => $product_sku,
            ':lot_number'    => $lot_number,
            ':serial_number' => $serial_number,
            ':barcode'       => $barcode,
        ]);

        $answer['success'] = 1;
        $answer['output'] = [
            'product_sku'   => $product_sku,
            'product_name'  => $lot['product_name'],
            'lot_number'    => $lot_number,
            'serial_number' => $serial_number,
            'barcode'       => $barcode,
        ];
        exit(json_encode($answer));
    }

    $answer['success'] = 1;
    $answer['output']  = listLabels($pdo2, $company_id, $product_sku, $lot_number);
    exit(json_encode($answer));
?>