Implement serialization/deserialization and persistent storage across services

- Add serialize/deserialize support for core models
- Add file-based load/save functions in management services
- Introduce FileManager, Config, Utility and helper utilities
- Persist observer IDs for notification services
- Resolve object relationships during load (services, bookings, invoices, job cards)
- Add controller-level loadSystemData/saveSystemData
- Load data at app startup and save on shutdown

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.cpp

@@ -1,4 +1,9 @@
+#include <sstream>
+#include <stdexcept>
 #include "ComboPackage.h"
+#include "Service.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ComboPackage::m_uid = 0;
 
@@ -12,7 +17,29 @@ ComboPackage::ComboPackage(const std::string& packageName, double discountPercen
     m_packageName(packageName),
     m_discountPercentage(discountPercentage),
     m_status(util::State::ACTIVE),
-    m_services(services) {}
+    m_services(services)
+{
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
+}
+
+ComboPackage::ComboPackage(const std::string& id, const std::string& packageName, double discountPercentage, const util::Vector<std::string>& serviceIDs, util::State status)
+    : m_id(id),
+    m_packageName(packageName),
+    m_discountPercentage(discountPercentage),
+    m_serviceIDs(serviceIDs),
+    m_status(status)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
 
 const std::string& ComboPackage::getId() const
 {
@@ -34,6 +61,11 @@ util::State ComboPackage::getState() const
     return m_status;
 }
 
+const util::Vector<std::string>& ComboPackage::getServiceIDs() const
+{
+    return m_serviceIDs;
+}
+
 const util::Map<std::string, Service*>& ComboPackage::getServices() const
 {
     return m_services;
@@ -57,9 +89,89 @@ void ComboPackage::setDiscountPercentage(double discountPercentage)
 void ComboPackage::setServices(const util::Map<std::string, Service*>& services)
 {
     m_services = services;
+    m_serviceIDs.clear();
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
 }
 
 void ComboPackage::setState(util::State status)
 {
     m_status = status;
 }
+
+static std::string getServiceIDsAsString(const util::Vector<std::string>& serviceIDs)
+{
+    int numberOfServices = serviceIDs.getSize();
+    std::string serviceIDsString;
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        serviceIDsString += serviceIDs[index];
+        if (index < numberOfServices - 1)
+        {
+            serviceIDsString += '|';
+        }
+    }
+    return serviceIDsString;
+}
+
+static util::Vector<std::string> getServiceIDsAsVector(const std::string& serviceIDsString)
+{
+    util::Vector<std::string> serviceIDs;
+    std::string serviceID;
+    std::istringstream serializedServiceIDs(serviceIDsString);
+    while (getline(serializedServiceIDs, serviceID, '|'))
+    {
+        serviceIDs.push_back(serviceID);
+    }
+    return serviceIDs;
+}
+
+std::string ComboPackage::serialize() const
+{
+    std::ostringstream serializedComboPackage;
+    serializedComboPackage << m_id << ','
+        << m_packageName << ','
+        << m_discountPercentage << ','
+        << getServiceIDsAsString(m_serviceIDs) << ','
+        << util::getStateString(m_status);
+    return serializedComboPackage.str();
+}
+
+ComboPackage* ComboPackage::deserialize(const std::string& record)
+{
+    std::string id, packageName;
+    std::string discountPercentageString, serviceIDsString, statusString;
+    double discountPercentage;
+    std::istringstream serializedComboPackage(record);
+    getline(serializedComboPackage, id, ',');
+    getline(serializedComboPackage, packageName, ',');
+    getline(serializedComboPackage, discountPercentageString, ',');
+    getline(serializedComboPackage, serviceIDsString, ',');
+    getline(serializedComboPackage, statusString, ',');
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid combo package data");
+    }
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    util::State status = util::getState(statusString);
+    return Factory::getObject<ComboPackage>(
+        id,
+        packageName,
+        discountPercentage,
+        serviceIDs,
+        status
+    );
+}
+
+std::string ComboPackage::getHeaders()
+{
+    return "ID,PackageName,DiscountPercentage,ServiceIDs,Status";
+}