/** @return list<string> */
function phone_inventory_status_options(): array
{
    return ['available', 'reserved', 'sold'];
}

function phone_normalize_inventory_status(string $raw): string
{
    $raw = strtolower(trim($raw));

    return in_array($raw, phone_inventory_status_options(), true) ? $raw : 'available';
}

function phone_inventory_status(array $phone): string
{
    $status = strtolower(trim((string)($phone['inventory_status'] ?? ''));
    if (in_array($status, phone_inventory_status_options(), true)) {
        return $status;
    }

    return 'available';
}

function phone_inventory_status_label(string $status): string
{
    return match (phone_normalize_inventory_status($status)) {
        'available' => 'Available',
        'reserved'  => 'Reserved',
        'sold'      => 'Sold',
        default     => 'Available',
    };
}

function phone_is_sold(array $phone): bool
{
    return phone_inventory_status($phone) === 'sold';
}

/** Listed on the public shop (not manually marked sold). Legacy stock-0/hidden still excluded. */
function phone_listed_on_shop(array $phone): bool
{
    if (phone_is_sold($phone)) {
        return false;
    }

    return ($phone['status'] ?? '') === 'active' && (int)($phone['stock'] ?? 0) > 0;
}

function phone_normalize_new_battery(string $raw): string
{
    $raw = strtolower(trim($raw));

    return in_array($raw, ['yes', 'no'], true) ? $raw : '';
}

function phone_new_battery_label(array $phone): string
{
    return match (phone_normalize_new_battery((string)($phone['new_battery'] ?? ''))) {
        'yes' => 'Yes',
        'no'  => 'No',
        default => '',
    };
}

function hold_active_for_phone(string $phoneId): ?array
{
    $phoneId = trim($phoneId);
    if ($phoneId === '') {
        return null;
    }

    foreach (json_db_read('holds.json')['holds'] ?? [] as $hold) {
        if ((string)($hold['phone_id'] ?? '') !== $phoneId) {
            continue;
        }
        $status = (string)($hold['status'] ?? '');
        if ($status === 'pending' || $status === 'confirmed') {
            return $hold;
        }
    }

    return null;
}

function phone_reservation_blocks_reserve(array $phone): bool
{
    return hold_active_for_phone((string)($phone['id'] ?? '')) !== null;
}

function phone_update_by_id(string $phoneId, callable $mutator): bool
{
    $phoneId = trim($phoneId);
    if ($phoneId === '') {
        return false;
    }

    $ok = false;
    json_db_transaction('phones.json', static function (array $data) use ($phoneId, $mutator, &$ok): array {
        foreach ($data['phones'] as &$phone) {
            if ((string)($phone['id'] ?? '') !== $phoneId) {
                continue;
            }
            $phone = $mutator($phone);
            $phone['updated_at'] = date('c');
            $ok = true;
            break;
        }
        unset($phone);

        return $data;
    });

    return $ok;
}

function phone_sync_reserved_on_confirm(string $phoneId, string $holdId): void
{
    if ($phoneId === '' || $holdId === '') {
        return;
    }

    phone_update_by_id($phoneId, static function (array $phone): array {
        $phone['inventory_status'] = 'reserved';
        $phone['reserved_hold_id'] = $holdId;

        return $phone;
    });
}

function phone_sync_available_on_hold_end(string $phoneId, string $holdId): void
{
    if ($phoneId === '') {
        return;
    }

    phone_update_by_id($phoneId, static function (array $phone) use ($holdId): array {
        if (phone_inventory_status($phone) === 'sold') {
            return $phone;
        }

        $linked = (string)($phone['reserved_hold_id'] ?? '');
        if ($linked !== '' && $linked !== $holdId) {
            return $phone;
        }

        $phone['inventory_status'] = 'available';
        $phone['reserved_hold_id'] = '';

        return $phone;
    });
}

function phone_mark_sold(string $phoneId): bool
{
    return phone_update_by_id($phoneId, static function (array $phone): array {
        $phone['inventory_status'] = 'sold';
        $phone['reserved_hold_id'] = '';
        $phone['sold_at'] = date('Y-m-d H:i:s');
        $phone['stock'] = 0;
        $phone['stock_held'] = 0;
        $phone['status'] = phone_status_from_stock(0);

        return $phone;
    });
}

function phone_mark_available(string $phoneId): bool
{
    return phone_update_by_id($phoneId, static function (array $phone): array {
        $phone['inventory_status'] = 'available';
        $phone['reserved_hold_id'] = '';
        $phone['sold_at'] = '';
        if ((int)($phone['stock'] ?? 0) <= 0) {
            $phone['stock'] = 1;
        }
        $phone['status'] = phone_status_from_stock((int)$phone['stock']);

        return $phone;
    });
}

function phone_admin_hold_summary(string $phoneId): ?array
{
    $hold = hold_active_for_phone($phoneId);
    if (!$hold) {
        return null;
    }

    $status = (string)($hold['status'] ?? '');
    $customer = $hold['customer'] ?? [];

    return [
        'id'        => (string)($hold['id'] ?? ''),
        'memo'      => (string)($hold['memo'] ?? ''),
        'status'    => $status,
        'status_label' => hold_status_label($status),
        'customer'  => (string)($customer['name'] ?? ''),
        'admin_url' => url('/admin/holds?status=' . rawurlencode($status === 'confirmed' ? 'confirmed' : 'pending')),
    ];
}