starting the codebase cleanup for final delivery- single process prototype removal

testing

main/src/main/java/sd/Entry.java

@@ -1,94 +0,0 @@
-package sd;
-
-import java.io.IOException;
-
-import sd.config.SimulationConfig;
-import sd.engine.SimulationEngine;
-
-/**
- * Main entry point for the traffic simulation.
- * * This class is responsible for loading the simulation configuration,
- * initializing the {@link SimulationEngine}, and starting the simulation run.
- * It also prints initial configuration details and final execution time.
- */
-public class Entry {
-    
-    /**
-     * The default path to the simulation configuration file.
-     * This is used if no command-line arguments are provided.
-     */
-    private static final String DEFAULT_CONFIG_FILE = "src/main/resources/simulation.properties";
-    
-    /**
-     * The main method to start the simulation.
-     * * @param args Command-line arguments. If provided, args[0] is expected
-     * to be the path to a custom configuration file.
-     */
-    public static void main(String[] args) {
-        System.out.println("=".repeat(60));
-        System.out.println("TRAFFIC SIMULATION - DISCRETE EVENT SIMULATOR");
-        System.out.println("=".repeat(60));
-        
-        try {
-            // 1. Load configuration
-            String configFile = args.length > 0 ? args[0] : DEFAULT_CONFIG_FILE;
-            System.out.println("Loading configuration from: " + configFile);
-            
-            SimulationConfig config = new SimulationConfig(configFile);
-            
-            // 2. Display configuration
-            displayConfiguration(config);
-            
-            // 3. Create and initialize simulation engine
-            SimulationEngine engine = new SimulationEngine(config);
-            engine.initialize();
-            
-            System.out.println("\n" + "=".repeat(60));
-            
-            // 4. Run simulation
-            long startTime = System.currentTimeMillis();
-            engine.run();
-            long endTime = System.currentTimeMillis();
-            
-            // 5. Display execution time
-            double executionTime = (endTime - startTime) / 1000.0;
-            System.out.println("\nExecution time: " + String.format("%.2f", executionTime) + " seconds");
-            System.out.println("=".repeat(60));
-            
-        } catch (IOException e) {
-            System.err.println("Error loading configuration: " + e.getMessage());
-            e.printStackTrace();
-        } catch (Exception e) {
-            System.err.println("Error during simulation: " + e.getMessage());
-            e.printStackTrace();
-        }
-    }
-    
-    /**
-     * Displays the main configuration parameters to the console.
-     * This provides a summary of the simulation settings before it starts.
-     *
-     * @param config The {@link SimulationConfig} object containing the loaded settings.
-     */
-    private static void displayConfiguration(SimulationConfig config) {
-        System.out.println("\nSIMULATION CONFIGURATION:");
-        System.out.println("  Duration: " + config.getSimulationDuration() + " seconds");
-        System.out.println("  Arrival Model: " + config.getArrivalModel());
-        
-        if ("POISSON".equalsIgnoreCase(config.getArrivalModel())) {
-            System.out.println("  Arrival Rate (λ): " + config.getArrivalRate() + " vehicles/second");
-        } else {
-            System.out.println("  Fixed Interval: " + config.getFixedArrivalInterval() + " seconds");
-        }
-        
-        System.out.println("  Statistics Update Interval: " + config.getStatisticsUpdateInterval() + " seconds");
-        
-        System.out.println("\nVEHICLE TYPES:");
-        System.out.println("  Bike: " + (config.getBikeVehicleProbability() * 100) + "% " +
-                         "(crossing time: " + config.getBikeVehicleCrossingTime() + "s)");
-        System.out.println("  Light: " + (config.getLightVehicleProbability() * 100) + "% " +
-                         "(crossing time: " + config.getLightVehicleCrossingTime() + "s)");
-        System.out.println("  Heavy: " + (config.getHeavyVehicleProbability() * 100) + "% " +
-                         "(crossing time: " + config.getHeavyVehicleCrossingTime() + "s)");
-    }
-}

main/src/main/java/sd/ExitNodeProcess.java

@@ -18,12 +18,13 @@ import sd.model.Vehicle;
 import sd.model.VehicleType;
 import sd.protocol.MessageProtocol;
 import sd.protocol.SocketConnection;
-import sd.serialization.SerializationException;
 
 /**
- * Processo responsável pelo nó de saída do sistema de simulação de tráfego distribuído.
+ * Processo responsável pelo nó de saída do sistema de simulação de tráfego
+ * distribuído.
  * 
- * Este processo representa o ponto final ("S") onde os veículos completam as suas rotas.
+ * Este processo representa o ponto final ("S") onde os veículos completam as
+ * suas rotas.
  * As suas principais responsabilidades são:
  * - Receber veículos que terminam a sua rota vindos das interseções
  * - Calcular e agregar estatísticas finais dos veículos
@@ -36,7 +37,10 @@ public class ExitNodeProcess {
     private ServerSocket serverSocket;
     private final ExecutorService connectionHandlerPool;
 
-    /** Flag para controlar a execução do processo (volatile para visibilidade entre threads) */
+    /**
+     * Flag para controlar a execução do processo (volatile para visibilidade entre
+     * threads)
+     */
     private volatile boolean running;
 
     /** Simulation start time (milliseconds) to calculate relative times */
@@ -99,10 +103,12 @@ public class ExitNodeProcess {
     /**
      * Constrói um novo processo de nó de saída.
      * 
-     * Inicializa todas as estruturas de dados necessárias para recolher estatísticas
+     * Inicializa todas as estruturas de dados necessárias para recolher
+     * estatísticas
      * e configura o pool de threads para processar as ligações concorrentes.
      * 
-     * @param config Configuração da simulação contendo portas e endereços dos serviços
+     * @param config Configuração da simulação contendo portas e endereços dos
+     *               serviços
      */
     public ExitNodeProcess(SimulationConfig config) {
         this.config = config;
@@ -159,7 +165,8 @@ public class ExitNodeProcess {
      * 2. Aguarda pelas ligações das interseções
      * 3. Delega cada ligação a uma thread da pool para processamento assíncrono
      * 
-     * @throws IOException Se o socket não puder ser criado ou houver erro na aceitação
+     * @throws IOException Se o socket não puder ser criado ou houver erro na
+     *                     aceitação
      */
     public void start() throws IOException {
         int port = config.getExitPort();
@@ -186,7 +193,8 @@ public class ExitNodeProcess {
      * Processa uma ligação recebida de uma interseção.
      * 
      * Mantém a ligação aberta e processa continuamente mensagens do tipo
-     * VEHICLE_TRANSFER. Cada mensagem representa um veículo que chegou ao nó de saída.
+     * VEHICLE_TRANSFER. Cada mensagem representa um veículo que chegou ao nó de
+     * saída.
      * 
      * @param clientSocket Socket da ligação estabelecida com a interseção
      */
@@ -280,18 +288,6 @@ public class ExitNodeProcess {
         sendStatsToDashboard();
     }
 
-    /**
-     * Obtém o tempo atual da simulação em segundos.
-     * 
-     * @return Tempo atual em segundos desde "epoch"
-     * 
-     * "Epoch" é um ponto de referência temporal Unix (1 de janeiro de 1970).
-     * Este método retorna os segundos decorridos desde esse momento.
-     */
-    private double getCurrentTime() {
-        return System.currentTimeMillis() / 1000.0;
-    }
-    
     /**
      * Envia as estatísticas para o dashboard.
      * 
@@ -315,6 +311,11 @@ public class ExitNodeProcess {
             payload.setTotalSystemTime((long) (totalSystemTime * 1000.0)); // s -> ms
             payload.setTotalWaitingTime((long) (totalWaitingTime * 1000.0)); // s -> ms
 
+            // Set intersection-like stats so it shows up correctly in the dashboard table
+            payload.setIntersectionArrivals(totalVehiclesReceived);
+            payload.setIntersectionDepartures(totalVehiclesReceived);
+            payload.setIntersectionQueueSize(0);
+
             // Set vehicle type stats
             Map<VehicleType, Integer> typeCounts = new HashMap<>();
             Map<VehicleType, Long> typeWaitTimes = new HashMap<>();
@@ -332,8 +333,7 @@ public class ExitNodeProcess {
                     MessageType.STATS_UPDATE,
                     "ExitNode",
                     "Dashboard",
-                payload
+                    payload);
-            );
 
             dashboardClient.send(message);
 

main/src/main/java/sd/IntersectionProcess.java

@@ -4,6 +4,7 @@ import java.io.IOException;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -64,7 +65,6 @@ public class IntersectionProcess {
     private volatile String currentGreenDirection;
 
     private SocketClient dashboardClient;
-    private long simulationStartMillis;
     private volatile int totalArrivals = 0;
     private volatile int totalDepartures = 0;
     private long lastStatsUpdateTime;
@@ -167,23 +167,12 @@ public class IntersectionProcess {
     private void createTrafficLights() {
         System.out.println("\n[" + intersectionId + "] Creating traffic lights...");
 
-        String[] directions = new String[0];
+        SimulationConfig.IntersectionConfig intersectionConfig = getIntersectionConfig();
-        switch (intersectionId) {
+        List<String> directions = intersectionConfig.getLights();
-            case "Cr1":
+
-                directions = new String[] { "East", "South" };
+        if (directions == null || directions.isEmpty()) {
-                break;
+            System.err.println("  Warning: No traffic lights configured for " + intersectionId);
-            case "Cr2":
+            return;
-                directions = new String[] { "West", "East", "South" };
-                break;
-            case "Cr3":
-                directions = new String[] { "West", "South" };
-                break;
-            case "Cr4":
-                directions = new String[] { "East" };
-                break;
-            case "Cr5":
-                directions = new String[] { "East" };
-                break;
         }
 
         for (String direction : directions) {
@@ -202,36 +191,31 @@ public class IntersectionProcess {
         }
     }
 
+    private SimulationConfig.IntersectionConfig getIntersectionConfig() {
+        if (config.getNetworkConfig() == null || config.getNetworkConfig().getIntersections() == null) {
+            throw new RuntimeException("Network configuration not loaded or empty.");
+        }
+        return config.getNetworkConfig().getIntersections().stream()
+                .filter(i -> i.getId().equals(intersectionId))
+                .findFirst()
+                .orElseThrow(() -> new RuntimeException("Intersection config not found for " + intersectionId));
+    }
+
     private void configureRouting() {
         System.out.println("\n[" + intersectionId + "] Configuring routing...");
 
-        switch (intersectionId) {
+        SimulationConfig.IntersectionConfig intersectionConfig = getIntersectionConfig();
-            case "Cr1":
+        Map<String, String> routes = intersectionConfig.getRoutes();
-                intersection.configureRoute("Cr2", "East");
-                intersection.configureRoute("Cr4", "South");
-                break;
 
-            case "Cr2":
+        if (routes != null) {
-                intersection.configureRoute("Cr1", "West");
+            for (Map.Entry<String, String> entry : routes.entrySet()) {
-                intersection.configureRoute("Cr3", "East");
+                String destination = entry.getKey();
-                intersection.configureRoute("Cr5", "South");
+                String direction = entry.getValue();
-                break;
+                intersection.configureRoute(destination, direction);
-
+                System.out.println("  Route configured: To " + destination + " -> Use " + direction);
-            case "Cr3":
+            }
-                intersection.configureRoute("Cr2", "West");
+        } else {
-                intersection.configureRoute("S", "South");
+            System.out.println("  No routes configured.");
-                break;
-
-            case "Cr4":
-                intersection.configureRoute("Cr5", "East");
-                break;
-
-            case "Cr5":
-                intersection.configureRoute("S", "East");
-                break;
-
-            default:
-                System.err.println("  Error: unknown intersection ID: " + intersectionId);
         }
 
         System.out.println("  Routing configured.");
@@ -447,7 +431,6 @@ public class IntersectionProcess {
 
                     // Handle simulation start time synchronization
                     if (message.getType() == MessageType.SIMULATION_START) {
-                        simulationStartMillis = ((Number) message.getPayload()).longValue();
                         System.out.println("[" + intersectionId + "] Simulation start time synchronized");
                         continue;
                     }
@@ -601,7 +584,8 @@ public class IntersectionProcess {
     }
 
     /**
-     * Checks if it's time to send statistics to the dashboard and sends them if needed.
+     * Checks if it's time to send statistics to the dashboard and sends them if
+     * needed.
      */
     private void checkAndSendStats() {
         long now = System.currentTimeMillis();
@@ -638,8 +622,7 @@ public class IntersectionProcess {
                     MessageType.STATS_UPDATE,
                     intersectionId,
                     "Dashboard",
-                payload
+                    payload);
-            );
 
             dashboardClient.send(message);
 
@@ -650,43 +633,4 @@ public class IntersectionProcess {
             System.err.println("[" + intersectionId + "] Failed to send stats to dashboard: " + e.getMessage());
         }
     }
-
-    // --- Inner class for Vehicle Transfer Messages ---
-
-    /**
-     * Implementation of MessageProtocol for vehicle transfers between processes.
-     */
-    private static class VehicleTransferMessage implements MessageProtocol {
-        private static final long serialVersionUID = 1L;
-
-        private final String sourceNode;
-        private final String destinationNode;
-        private final Vehicle payload;
-
-        public VehicleTransferMessage(String sourceNode, String destinationNode, Vehicle vehicle) {
-            this.sourceNode = sourceNode;
-            this.destinationNode = destinationNode;
-            this.payload = vehicle;
-        }
-
-        @Override
-        public MessageType getType() {
-            return MessageType.VEHICLE_TRANSFER;
-        }
-
-        @Override
-        public Object getPayload() {
-            return payload;
-        }
-
-        @Override
-        public String getSourceNode() {
-            return sourceNode;
-        }
-
-        @Override
-        public String getDestinationNode() {
-            return destinationNode;
-        }
-    }
 }

main/src/main/java/sd/config/SimulationConfig.java

@@ -3,8 +3,16 @@ package sd.config;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
+import com.google.gson.Gson;
+
 /**
  * Class to load and manage simulation configurations.
  * Configurations are read from a .properties file. This class provides
@@ -17,59 +25,144 @@ public class SimulationConfig {
      * Holds all properties loaded from the file.
      */
     private final Properties properties;
+    private NetworkConfig networkConfig;
+
+    public static class NetworkConfig {
+        private List<IntersectionConfig> intersections;
+
+        public List<IntersectionConfig> getIntersections() {
+            return intersections;
+        }
+    }
+
+    public static class IntersectionConfig {
+        private String id;
+        private List<String> lights;
+        private Map<String, String> routes;
+
+        public String getId() {
+            return id;
+        }
+
+        public List<String> getLights() {
+            return lights;
+        }
+
+        public Map<String, String> getRoutes() {
+            return routes;
+        }
+    }
 
     /**
      * Constructs a new SimulationConfig object by loading properties
      * from the specified file path.
      * 
-     * @param filePath The path to the .properties file (e.g., "src/main/resources/simulation.properties").
+     * This constructor attempts to load the configuration file using multiple
-     * @throws IOException If the file cannot be found or read.
+     * strategies:
+     * 1. Direct file system path
+     * 2. Classpath resource (with automatic path normalization)
+     * 3. Classpath resource with leading slash
+     *
+     * @param filePath The path to the .properties file (e.g.,
+     *                 "src/main/resources/simulation.properties").
+     * @throws IOException If the file cannot be found or read from any location.
      */
     public SimulationConfig(String filePath) throws IOException {
         properties = new Properties();
-        /**Tenta carregar diretamente a partir do sistema de ficheiros, se o ficheiro não existir
-         * (por exemplo quando executado a partir do classpath/jar),
-         * faz fallback para carregar a partir do classpath usando o ClassLoader.
-        */
-        IOException lastException = null; //FIXME: melhorar esta parte para reportar erros de forma mais clara
 
-        try {
+        // List to track all attempted paths for better error reporting
+        List<String> attemptedPaths = new ArrayList<>();
+        IOException fileSystemException = null;
+
+        // Strategy 1: Try to load directly from file system
         try (InputStream input = new FileInputStream(filePath)) {
             properties.load(input);
-                return; // carregado com sucesso a partir do caminho fornecido
+            loadNetworkConfig();
-            }
+            return; // Successfully loaded from file system
         } catch (IOException e) {
-            lastException = e;
+            fileSystemException = e;
-            //tenta carregar a partir do classpath sem prefixos comuns
+            attemptedPaths.add("File system: " + filePath);
-            String resourcePath = filePath;
-            //Remove prefixos que apontam para src/main/resources quando presentes
-            resourcePath = resourcePath.replace("src/main/resources/", "").replace("src\\main\\resources\\", "");
-            //Remove prefixo classpath: se fornecido
-            if (resourcePath.startsWith("classpath:")) {
-                resourcePath = resourcePath.substring("classpath:".length());
-                if (resourcePath.startsWith("/")) resourcePath = resourcePath.substring(1);
         }
 
+        // Strategy 2: Try to load from classpath with path normalization
+        String resourcePath = filePath;
+
+        // Remove common src/main/resources prefixes
+        resourcePath = resourcePath.replace("src/main/resources/", "").replace("src\\main\\resources\\", "");
+
+        // Remove classpath: prefix if provided
+        if (resourcePath.startsWith("classpath:")) {
+            resourcePath = resourcePath.substring("classpath:".length());
+            if (resourcePath.startsWith("/")) {
+                resourcePath = resourcePath.substring(1);
+            }
+        }
+
+        // Try loading from classpath using thread context class loader
         InputStream resourceStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(resourcePath);
+        attemptedPaths.add("Classpath (context): " + resourcePath);
+
         if (resourceStream == null) {
-                //como último recurso, tentar com um leading slash
+            // Strategy 3: Try with leading slash
-                resourceStream = SimulationConfig.class.getResourceAsStream('/' + resourcePath);
+            String slashPath = "/" + resourcePath;
+            resourceStream = SimulationConfig.class.getResourceAsStream(slashPath);
+            attemptedPaths.add("Classpath (class): " + slashPath);
         }
 
         if (resourceStream != null) {
             try (InputStream input = resourceStream) {
                 properties.load(input);
+                loadNetworkConfig();
+                return; // Successfully loaded from classpath
+            } catch (IOException e) {
+                // Failed to read from classpath resource
+                throw new IOException(
+                        String.format("Failed to read properties from classpath resource '%s': %s",
+                                resourcePath, e.getMessage()),
+                        e);
+            }
+        }
+
+        // All strategies failed - provide comprehensive error message
+        StringBuilder errorMsg = new StringBuilder();
+        errorMsg.append("Configuration file '").append(filePath).append("' could not be found.\n");
+        errorMsg.append("Attempted locations:\n");
+        for (String path : attemptedPaths) {
+            errorMsg.append("  - ").append(path).append("\n");
+        }
+
+        if (fileSystemException != null) {
+            errorMsg.append("\nOriginal error: ").append(fileSystemException.getMessage());
+        }
+
+        throw new IOException(errorMsg.toString(), fileSystemException);
+    }
+
+    private void loadNetworkConfig() {
+        try (InputStream is = getClass().getClassLoader().getResourceAsStream("network_config.json")) {
+            if (is == null) {
+                System.err.println("Warning: network_config.json not found in classpath. Using defaults/empty.");
                 return;
             }
+            try (Reader reader = new InputStreamReader(is, StandardCharsets.UTF_8)) {
+                Gson gson = new Gson();
+                this.networkConfig = gson.fromJson(reader, NetworkConfig.class);
+            }
+        } catch (IOException e) {
+            System.err.println("Failed to load network_config.json: " + e.getMessage());
+            e.printStackTrace();
         }
     }
-        if (lastException != null) throw lastException;
+
+    public NetworkConfig getNetworkConfig() {
+        return networkConfig;
     }
 
     // --- Network configurations ---
 
     /**
      * Gets the host address for a specific intersection.
+     * 
      * @param intersectionId The ID of the intersection (e.g., "Cr1").
      * @return The host (e.g., "localhost").
      */
@@ -79,6 +172,7 @@ public class SimulationConfig {
 
     /**
      * Gets the port number for a specific intersection.
+     * 
      * @param intersectionId The ID of the intersection (e.g., "Cr1").
      * @return The port number.
      */
@@ -88,6 +182,7 @@ public class SimulationConfig {
 
     /**
      * Gets the host address for the dashboard server.
+     * 
      * @return The dashboard host.
      */
     public String getDashboardHost() {
@@ -96,6 +191,7 @@ public class SimulationConfig {
 
     /**
      * Gets the port number for the dashboard server.
+     * 
      * @return The dashboard port.
      */
     public int getDashboardPort() {
@@ -104,6 +200,7 @@ public class SimulationConfig {
 
     /**
      * Gets the host address for the exit node.
+     * 
      * @return The exit node host.
      */
     public String getExitHost() {
@@ -112,6 +209,7 @@ public class SimulationConfig {
 
     /**
      * Gets the port number for the exit node.
+     * 
      * @return The exit node port.
      */
     public int getExitPort() {
@@ -122,6 +220,7 @@ public class SimulationConfig {
 
     /**
      * Gets the total duration of the simulation in virtual seconds.
+     * 
      * @return The simulation duration.
      */
     public double getSimulationDuration() {
@@ -130,6 +229,7 @@ public class SimulationConfig {
 
     /**
      * Gets the vehicle arrival model ("POISSON" or "FIXED").
+     * 
      * @return The arrival model as a string.
      */
     public String getArrivalModel() {
@@ -139,6 +239,7 @@ public class SimulationConfig {
     /**
      * Gets the average arrival rate (lambda) for the POISSON model.
      * This represents the average number of vehicles arriving per second.
+     * 
      * @return The arrival rate.
      */
     public double getArrivalRate() {
@@ -147,6 +248,7 @@ public class SimulationConfig {
 
     /**
      * Gets the fixed time interval between vehicle arrivals for the FIXED model.
+     * 
      * @return The fixed interval in seconds.
      */
     public double getFixedArrivalInterval() {
@@ -157,6 +259,7 @@ public class SimulationConfig {
 
     /**
      * Gets the duration of the GREEN light state for a specific traffic light.
+     * 
      * @param intersectionId The ID of the intersection (e.g., "Cr1").
      * @param direction      The direction of the light (e.g., "North").
      * @return The green light time in seconds.
@@ -168,6 +271,7 @@ public class SimulationConfig {
 
     /**
      * Gets the duration of the RED light state for a specific traffic light.
+     * 
      * @param intersectionId The ID of the intersection (e.g., "Cr1").
      * @param direction      The direction of the light (e.g., "North").
      * @return The red light time in seconds.
@@ -181,6 +285,7 @@ public class SimulationConfig {
 
     /**
      * Gets the probability (0.0 to 1.0) that a generated vehicle is of type LIGHT.
+     * 
      * @return The probability for LIGHT vehicles.
      */
     public double getLightVehicleProbability() {
@@ -189,6 +294,7 @@ public class SimulationConfig {
 
     /**
      * Gets the average time it takes a LIGHT vehicle to cross an intersection.
+     * 
      * @return The crossing time in seconds.
      */
     public double getLightVehicleCrossingTime() {
@@ -197,6 +303,7 @@ public class SimulationConfig {
 
     /**
      * Gets the probability (0.0 to 1.0) that a generated vehicle is of type BIKE.
+     * 
      * @return The probability for BIKE vehicles.
      */
     public double getBikeVehicleProbability() {
@@ -205,6 +312,7 @@ public class SimulationConfig {
 
     /**
      * Gets the average time it takes a BIKE vehicle to cross an intersection.
+     * 
      * @return The crossing time in seconds.
      */
     public double getBikeVehicleCrossingTime() {
@@ -213,6 +321,7 @@ public class SimulationConfig {
 
     /**
      * Gets the probability (0.0 to 1.0) that a generated vehicle is of type HEAVY.
+     * 
      * @return The probability for HEAVY vehicles.
      */
     public double getHeavyVehicleProbability() {
@@ -221,26 +330,58 @@ public class SimulationConfig {
 
     /**
      * Gets the average time it takes a HEAVY vehicle to cross an intersection.
+     * 
      * @return The crossing time in seconds.
      */
     public double getHeavyVehicleCrossingTime() {
         return Double.parseDouble(properties.getProperty("vehicle.crossing.time.heavy", "4.0"));
     }
 
+    /**
+     * Gets the base travel time between intersections for light vehicles.
+     * 
+     * @return The base travel time in seconds.
+     */
+    public double getBaseTravelTime() {
+        return Double.parseDouble(properties.getProperty("vehicle.travel.time.base", "8.0"));
+    }
+
+    /**
+     * Gets the travel time multiplier for bike vehicles.
+     * Bike travel time = base time × this multiplier.
+     * 
+     * @return The multiplier for bike travel time.
+     */
+    public double getBikeTravelTimeMultiplier() {
+        return Double.parseDouble(properties.getProperty("vehicle.travel.time.bike.multiplier", "0.5"));
+    }
+
+    /**
+     * Gets the travel time multiplier for heavy vehicles.
+     * Heavy vehicle travel time = base time × this multiplier.
+     * 
+     * @return The multiplier for heavy vehicle travel time.
+     */
+    public double getHeavyTravelTimeMultiplier() {
+        return Double.parseDouble(properties.getProperty("vehicle.travel.time.heavy.multiplier", "2.0"));
+    }
+
     // --- Statistics ---
 
     /**
      * Gets the interval (in virtual seconds) between periodic statistics updates.
+     * 
      * @return The statistics update interval.
      */
     public double getStatisticsUpdateInterval() {
-        return Double.parseDouble(properties.getProperty("statistics.update.interval", "10.0"));
+        return Double.parseDouble(properties.getProperty("statistics.update.interval", "1.0"));
     }
 
     // --- Generic getters ---
 
     /**
      * Generic method to get any property as a string, with a default value.
+     * 
      * @param key          The property key.
      * @param defaultValue The value to return if the key is not found.
      * @return The property value or the default.
@@ -251,6 +392,7 @@ public class SimulationConfig {
 
     /**
      * Generic method to get any property as a string.
+     * 
      * @param key The property key.
      * @return The property value, or null if not found.
      */

main/src/main/java/sd/engine/SimulationEngine.java

@@ -1,628 +0,0 @@
-package sd.engine;
-
-import java.util.HashMap;
-import java.util.Map;
-import java.util.PriorityQueue;
-
-import sd.config.SimulationConfig;
-import sd.model.Event;
-import sd.model.EventType;
-import sd.model.Intersection;
-import sd.model.TrafficLight;
-import sd.model.TrafficLightState;
-import sd.model.Vehicle;
-import sd.model.VehicleType;
-import sd.util.StatisticsCollector;
-import sd.util.VehicleGenerator;
-
-/**
- * Core simulation engine using discrete event simulation (DES).
- * * This class orchestrates the entire simulation. It maintains a
- * {@link PriorityQueue} of {@link Event} objects, representing all
- * scheduled future actions. The engine processes events in strict
- * chronological order (based on their timestamp).
- * * It manages the simulation's state, including:
- * - The current simulation time ({@code currentTime}).
- * - The collection of all {@link Intersection} objects.
- * - The {@link VehicleGenerator} for creating new vehicles.
- * - The {@link StatisticsCollector} for tracking metrics.
- */
-public class SimulationEngine {
-    
-    /**
-     * Holds all simulation parameters loaded from the properties file.
-     */
-    private final SimulationConfig config;
-    
-    /**
-     * The core of the discrete event simulation. Events are pulled from this
-     * queue in order of their timestamp.
-     */
-    private final PriorityQueue<Event> eventQueue;
-    
-    /**
-     * A map storing all intersections in the simulation, keyed by their ID (e.g., "Cr1").
-     */
-    private final Map<String, Intersection> intersections;
-    
-    /**
-     * Responsible for creating new vehicles according to the configured arrival model.
-     */
-    private final VehicleGenerator vehicleGenerator;
-    
-    /**
-     * Collects and calculates statistics throughout the simulation.
-     */
-    private final StatisticsCollector statisticsCollector;
-    
-    /**
-     * The current time in the simulation (in virtual seconds).
-     * This time advances based on the timestamp of the event being processed.
-     */
-    private double currentTime;
-    
-    /**
-     * A simple counter to generate unique IDs for vehicles.
-     */
-    private int vehicleCounter;
-    
-    /**
-     * Constructs a new SimulationEngine.
-     *
-     * @param config The {@link SimulationConfig} object containing all
-     * simulation parameters.
-     */
-    public SimulationEngine(SimulationConfig config) {
-        this.config = config;
-        this.eventQueue = new PriorityQueue<>();
-        this.intersections = new HashMap<>();
-        this.vehicleGenerator = new VehicleGenerator(config);
-        this.statisticsCollector = new StatisticsCollector(config);
-        this.currentTime = 0.0;
-        this.vehicleCounter = 0;
-    }
-    
-    /**
-     * Initializes the simulation. This involves:
-     * 1. Creating all {@link Intersection} and {@link TrafficLight} objects.
-     * 2. Configuring the routing logic between intersections.
-     * 3. Scheduling the initial events (first traffic light changes,
-     * first vehicle generation, and periodic statistics updates).
-     */
-    public void initialize() {
-        System.out.println("Initializing simulation...");
-        
-        setupIntersections();
-        setupRouting();
-        
-        // Schedule initial events to "bootstrap" the simulation
-        scheduleTrafficLightEvents();
-        scheduleNextVehicleGeneration(0.0);
-        scheduleStatisticsUpdates();
-        
-        System.out.println("Simulation initialized with " + intersections.size() + " intersections");
-    }
-    
-    /**
-     * Creates all intersections defined in the configuration
-     * and adds their corresponding traffic lights.
-     */
-    private void setupIntersections() {
-        String[] intersectionIds = {"Cr1", "Cr2", "Cr3", "Cr4", "Cr5"};
-        // Note: "North" is commented out, so it won't be created.
-        String[] directions = {/*"North",*/ "South", "East", "West"};
-        
-        for (String id : intersectionIds) {
-            Intersection intersection = new Intersection(id);
-            
-            // Add traffic lights for each configured direction
-            for (String direction : directions) {
-                double greenTime = config.getTrafficLightGreenTime(id, direction);
-                double redTime = config.getTrafficLightRedTime(id, direction);
-                
-                TrafficLight light = new TrafficLight(
-                    id + "-" + direction,
-                    direction,
-                    greenTime,
-                    redTime
-                );
-                
-                intersection.addTrafficLight(light);
-            }
-            
-            intersections.put(id, intersection);
-        }
-    }
-    
-    /**
-     * Configures how vehicles should be routed between intersections.
-     * This hardcoded logic defines the "map" of the city.
-     * * For example, `intersections.get("Cr1").configureRoute("Cr2", "East");` means
-     * "at intersection Cr1, any vehicle whose *next* destination is Cr2
-     * should be sent to the 'East' traffic light queue."
-     */
-    private void setupRouting() {
-        // Cr1 routing
-        intersections.get("Cr1").configureRoute("Cr2", "East");
-        intersections.get("Cr1").configureRoute("Cr4", "South");
-        
-        // Cr2 routing
-        intersections.get("Cr2").configureRoute("Cr1", "West");
-        intersections.get("Cr2").configureRoute("Cr3", "East");
-        intersections.get("Cr2").configureRoute("Cr5", "South");
-        
-        // Cr3 routing
-        intersections.get("Cr3").configureRoute("Cr2", "West");
-        intersections.get("Cr3").configureRoute("S", "South"); // "S" is the exit
-        
-        // Cr4 routing
-        //intersections.get("Cr4").configureRoute("Cr1", "North");
-        intersections.get("Cr4").configureRoute("Cr5", "East");
-        
-        // Cr5 routing
-        //intersections.get("Cr5").configureRoute("Cr2", "North");
-        //intersections.get("Cr5").configureRoute("Cr4", "West");
-        intersections.get("Cr5").configureRoute("S", "East"); // "S" is the exit
-    }
-    
-    /**
-     * Schedules the initial {@link EventType#TRAFFIC_LIGHT_CHANGE} event
-     * for every traffic light in the simulation.
-     * A small random delay is added to "stagger" the lights, preventing
-     * all of them from changing at the exact same time at t=0.
-     */
-    private void scheduleTrafficLightEvents() {
-        for (Intersection intersection : intersections.values()) {
-            for (TrafficLight light : intersection.getTrafficLights()) {
-                // Start with lights in RED state, schedule first GREEN change
-                // Stagger the start times slightly to avoid all lights changing at once
-                double staggerDelay = Math.random() * 1.5;
-                scheduleTrafficLightChange(light, intersection.getId(), staggerDelay);
-            }
-        }
-    }
-    
-    /**
-     * Creates and schedules a new {@link EventType#TRAFFIC_LIGHT_CHANGE} event.
-     * The event is scheduled to occur at {@code currentTime + delay}.
-     *
-     * @param light The {@link TrafficLight} that will change state.
-     * @param intersectionId The ID of the intersection where the light is located.
-     * @param delay The time (in seconds) from {@code currentTime} when the change should occur.
-     */
-    private void scheduleTrafficLightChange(TrafficLight light, String intersectionId, double delay) {
-        double changeTime = currentTime + delay;
-        Event event = new Event(changeTime, EventType.TRAFFIC_LIGHT_CHANGE, light, intersectionId);
-        eventQueue.offer(event);
-    }
-    
-    /**
-     * Schedules the next {@link EventType#VEHICLE_GENERATION} event.
-     * The time of the next arrival is determined by the {@link VehicleGenerator}.
-     *
-     * @param baseTime The time from which to calculate the next arrival (usually {@code currentTime}).
-     */
-    private void scheduleNextVehicleGeneration(double baseTime) {
-        // Get the absolute time for the next arrival.
-        double nextArrivalTime = vehicleGenerator.getNextArrivalTime(baseTime);
-        
-        // Only schedule the event if it's within the simulation's total duration.
-        if (nextArrivalTime < config.getSimulationDuration()) {
-            Event event = new Event(nextArrivalTime, EventType.VEHICLE_GENERATION, null, null);
-            eventQueue.offer(event);
-        }
-    }
-    
-    /**
-     * Schedules all periodic {@link EventType#STATISTICS_UPDATE} events
-     * for the entire duration of the simulation.
-     */
-    private void scheduleStatisticsUpdates() {
-        double interval = config.getStatisticsUpdateInterval();
-        double duration = config.getSimulationDuration();
-        
-        for (double time = interval; time < duration; time += interval) {
-            Event event = new Event(time, EventType.STATISTICS_UPDATE, null, null);
-            eventQueue.offer(event);
-        }
-    }
-    
-    /**
-     * Runs the main simulation loop.
-     * The loop continues as long as there are events in the queue and
-     * the {@code currentTime} is less than the total simulation duration.
-     * * In each iteration, it:
-     * 1. Polls the next event from the {@link #eventQueue}.
-     * 2. Advances {@link #currentTime} to the event's timestamp.
-     * 3. Calls {@link #processEvent(Event)} to handle the event.
-     * * After the loop, it prints the final statistics.
-     */
-    public void run() {
-        System.out.println("Starting simulation...");
-        double duration = config.getSimulationDuration();
-        
-        while (!eventQueue.isEmpty() && currentTime < duration) {
-            // Get the next event in chronological order
-            Event event = eventQueue.poll();
-            
-            // Advance simulation time to this event's time
-            currentTime = event.getTimestamp();
-            
-            // Process the event
-            processEvent(event);
-        }
-        
-        System.out.println("\nSimulation completed at t=" + String.format("%.2f", currentTime) + "s");
-        printFinalStatistics();
-    }
-    
-    /**
-     * Main event processing logic.
-     * Delegates the event to the appropriate handler method based on its {@link EventType}.
-     *
-     * @param event The {@link Event} to be processed.
-     */
-    private void processEvent(Event event) {
-        switch (event.getType()) {
-            case VEHICLE_GENERATION -> handleVehicleGeneration();
-                
-            case VEHICLE_ARRIVAL -> handleVehicleArrival(event);
-                
-            case TRAFFIC_LIGHT_CHANGE -> handleTrafficLightChange(event);
-                
-            case CROSSING_START -> handleCrossingStart(event);
-                
-            case CROSSING_END -> handleCrossingEnd(event);
-                
-            case STATISTICS_UPDATE -> handleStatisticsUpdate();
-                
-            default -> System.err.println("Unknown event type: " + event.getType());
-        }
-    }
-    
-    /**
-     * Handles {@link EventType#VEHICLE_GENERATION}.
-     * 1. Creates a new {@link Vehicle} using the {@link #vehicleGenerator}.
-     * 2. Records the generation event with the {@link #statisticsCollector}.
-     * 3. Schedules a {@link EventType#VEHICLE_ARRIVAL} event for the vehicle
-     * at its first destination intersection.
-     * 4. Schedules the *next* {@link EventType#VEHICLE_GENERATION} event.
-     * (Note: This line is commented out in the original, which might be a bug,
-     * as it implies only one vehicle is ever generated. It should likely be active.)
-     */
-    private void handleVehicleGeneration() {
-        Vehicle vehicle = vehicleGenerator.generateVehicle("V" + (++vehicleCounter), currentTime);
-        
-        System.out.printf("[t=%.2f] Vehicle %s generated (type=%s, route=%s)%n",
-            currentTime, vehicle.getId(), vehicle.getType(), vehicle.getRoute());
-        
-        // Register with statistics collector
-        statisticsCollector.recordVehicleGeneration(vehicle, currentTime);
-        
-        // Schedule arrival at first intersection
-        String firstIntersection = vehicle.getCurrentDestination();
-        if (firstIntersection != null && !firstIntersection.equals("S")) {
-            // Assume minimal travel time to first intersection (e.g., 1-3 seconds)
-            double arrivalTime = currentTime + 1.0 + Math.random() * 2.0;
-            Event arrivalEvent = new Event(arrivalTime, EventType.VEHICLE_ARRIVAL, vehicle, firstIntersection);
-            eventQueue.offer(arrivalEvent);
-        }
-        
-        // Schedule next vehicle generation
-        // This was commented out in the original file.
-        // For a continuous simulation, it should be enabled:
-        scheduleNextVehicleGeneration(currentTime);
-    }
-    
-    /**
-     * Handles {@link EventType#VEHICLE_ARRIVAL} at an intersection.
-     * 1. Records the arrival for statistics.
-     * 2. Advances the vehicle's internal route planner to its *next* destination.
-     * 3. If the next destination is the exit ("S") or null,
-     * the vehicle exits the system via {@link #handleVehicleExit(Vehicle)}.
-     * 4. Otherwise, the vehicle is placed in the correct queue at the
-     * current intersection using {@link Intersection#receiveVehicle(Vehicle)}.
-     * 5. Attempts to process the vehicle immediately if its light is green.
-     *
-     * @param event The arrival event, containing the {@link Vehicle} and intersection ID.
-     */
-    private void handleVehicleArrival(Event event) {
-        Vehicle vehicle = (Vehicle) event.getData();
-        String intersectionId = event.getLocation();
-        
-        Intersection intersection = intersections.get(intersectionId);
-        if (intersection == null) {
-            System.err.println("Unknown intersection: " + intersectionId);
-            return;
-        }
-        
-        System.out.printf("[t=%.2f] Vehicle %s arrived at %s%n",
-            currentTime, vehicle.getId(), intersectionId);
-        
-        // Record arrival time (used to calculate waiting time later)
-        statisticsCollector.recordVehicleArrival(vehicle, intersectionId, currentTime);
-        
-        // Advance the vehicle's route to the *next* stop
-        // (it has now arrived at its *current* destination)
-        boolean hasNext = vehicle.advanceRoute();
-        
-        if (!hasNext) {
-            // This was the last stop
-            handleVehicleExit(vehicle);
-            return;
-        }
-        
-        String nextDestination = vehicle.getCurrentDestination();
-        if (nextDestination == null || "S".equals(nextDestination)) {
-            // Next stop is the exit
-            handleVehicleExit(vehicle);
-            return;
-        }
-        
-        // Add vehicle to the appropriate traffic light queue based on its next destination
-        intersection.receiveVehicle(vehicle);
-        
-        // Try to process the vehicle immediately if its light is already green
-        tryProcessVehicle(vehicle, intersection);
-    }
-    
-    /**
-     * Checks if a newly arrived vehicle (or a vehicle in a queue
-     * that just turned green) can start crossing.
-     *
-     * @param vehicle The vehicle to process.
-     * @param intersection The intersection where the vehicle is.
-     */
-    private void tryProcessVehicle(Vehicle vehicle, Intersection intersection) { //FIXME
-        // Find the direction (and light) this vehicle is queued at
-        // This logic is a bit flawed: it just finds the *first* non-empty queue
-        // A better approach would be to get the light from the vehicle's route
-        String direction = intersection.getTrafficLights().stream()
-            .filter(tl -> tl.getQueueSize() > 0)
-            .map(TrafficLight::getDirection)
-            .findFirst()
-            .orElse(null);
-        
-        if (direction != null) {
-            TrafficLight light = intersection.getTrafficLight(direction);
-            // If the light is green and it's the correct one...
-            if (light != null && light.getState() == TrafficLightState.GREEN) {
-                // ...remove the vehicle from the queue (if it's at the front)
-                Vehicle v = light.removeVehicle();
-                if (v != null) {
-                    // ...and schedule its crossing.
-                    scheduleCrossing(v, intersection);
-                }
-            }
-        }
-    }
-    
-    /**
-     * Schedules the crossing for a vehicle that has just been dequeued
-     * from a green light.
-     * 1. Calculates and records the vehicle's waiting time.
-     * 2. Schedules an immediate {@link EventType#CROSSING_START} event.
-     *
-     * @param vehicle The {@link Vehicle} that is crossing.
-     * @param intersection The {@link Intersection} it is crossing.
-     */
-    private void scheduleCrossing(Vehicle vehicle, Intersection intersection) {
-        // Calculate time spent waiting at the red light
-        double waitTime = currentTime - statisticsCollector.getArrivalTime(vehicle);
-        vehicle.addWaitingTime(waitTime);
-        
-        // Schedule crossing start event *now*
-        Event crossingStart = new Event(currentTime, EventType.CROSSING_START, vehicle, intersection.getId());
-        processEvent(crossingStart); // Process immediately
-    }
-    
-    /**
-     * Handles {@link EventType#CROSSING_START}.
-     * 1. Determines the crossing time based on vehicle type.
-     * 2. Schedules a {@link EventType#CROSSING_END} event to occur
-     * at {@code currentTime + crossingTime}.
-     *
-     * @param event The crossing start event.
-     */
-    private void handleCrossingStart(Event event) {
-        Vehicle vehicle = (Vehicle) event.getData();
-        String intersectionId = event.getLocation();
-        
-        double crossingTime = getCrossingTime(vehicle.getType());
-        
-        System.out.printf("[t=%.2f] Vehicle %s started crossing at %s (duration=%.2fs)%n",
-            currentTime, vehicle.getId(), intersectionId, crossingTime);
-        
-        // Schedule the *end* of the crossing
-        double endTime = currentTime + crossingTime;
-        Event crossingEnd = new Event(endTime, EventType.CROSSING_END, vehicle, intersectionId);
-        eventQueue.offer(crossingEnd);
-    }
-    
-    /**
-     * Handles {@link EventType#CROSSING_END}.
-     * 1. Updates intersection and vehicle statistics.
-     * 2. Checks the vehicle's *next* destination.
-     * 3. If the next destination is the exit ("S"), call {@link #handleVehicleExit(Vehicle)}.
-     * 4. Otherwise, schedule a {@link EventType#VEHICLE_ARRIVAL} event at the
-     * *next* intersection, after some travel time.
-     *
-     * @param event The crossing end event.
-     */
-    private void handleCrossingEnd(Event event) {
-        Vehicle vehicle = (Vehicle) event.getData();
-        String intersectionId = event.getLocation();
-        
-        // Update stats
-        Intersection intersection = intersections.get(intersectionId);
-        if (intersection != null) {
-            intersection.incrementVehiclesSent();
-        }
-        
-        double crossingTime = getCrossingTime(vehicle.getType());
-        vehicle.addCrossingTime(crossingTime);
-        
-        System.out.printf("[t=%.2f] Vehicle %s finished crossing at %s%n",
-            currentTime, vehicle.getId(), intersectionId);
-        
-        // Decide what to do next
-        String nextDest = vehicle.getCurrentDestination();
-        if (nextDest != null && !nextDest.equals("S")) {
-            // Route to the *next* intersection
-            // Assume 5-10 seconds travel time between intersections
-            double travelTime = 5.0 + Math.random() * 5.0; 
-            double arrivalTime = currentTime + travelTime;
-            Event arrivalEvent = new Event(arrivalTime, EventType.VEHICLE_ARRIVAL, vehicle, nextDest);
-            eventQueue.offer(arrivalEvent);
-        } else {
-            // Reached the exit
-            handleVehicleExit(vehicle);
-        }
-    }
-    
-    /**
-     * Handles a vehicle exiting the simulation.
-     * Records final statistics for the vehicle.
-     *
-     * @param vehicle The {@link Vehicle} that has completed its route.
-     */
-    private void handleVehicleExit(Vehicle vehicle) {
-        System.out.printf("[t=%.2f] Vehicle %s exited the system (wait=%.2fs, travel=%.2fs)%n",
-            currentTime, vehicle.getId(), 
-            vehicle.getTotalWaitingTime(), 
-            vehicle.getTotalTravelTime(currentTime));
-        
-        // Record the exit for final statistics calculation
-        statisticsCollector.recordVehicleExit(vehicle, currentTime);
-    }
-    
-    /**
-     * Handles {@link EventType#TRAFFIC_LIGHT_CHANGE}.
-     * 1. Toggles the light's state (RED to GREEN or GREEN to RED).
-     * 2. If the light just turned GREEN, call {@link #processGreenLight(TrafficLight, Intersection)}
-     * to process any waiting vehicles.
-     * 3. Schedules the *next* state change for this light based on its
-     * green/red time duration.
-     *
-     * @param event The light change event.
-     */
-    private void handleTrafficLightChange(Event event) {
-        TrafficLight light = (TrafficLight) event.getData();
-        String intersectionId = event.getLocation();
-        
-        // Toggle state
-        TrafficLightState newState = (light.getState() == TrafficLightState.RED) 
-            ? TrafficLightState.GREEN 
-            : TrafficLightState.RED;
-        
-        light.changeState(newState);
-        
-        System.out.printf("[t=%.2f] Traffic light %s changed to %s%n",
-            currentTime, light.getId(), newState);
-        
-        // If changed to GREEN, process waiting vehicles
-        if (newState == TrafficLightState.GREEN) {
-            Intersection intersection = intersections.get(intersectionId);
-            if (intersection != null) {
-                processGreenLight(light, intersection);
-            }
-        }
-        
-        // Schedule the *next* state change for this same light
-        double nextChangeDelay = (newState == TrafficLightState.GREEN) 
-            ? light.getGreenTime() 
-            : light.getRedTime();
-        
-        scheduleTrafficLightChange(light, intersectionId, nextChangeDelay);
-    }
-    
-    /**
-     * Processes vehicles when a light turns green.
-     * It loops as long as the light is green and there are vehicles in the queue,
-     * dequeuing one vehicle at a time and scheduling its crossing.
-     * * *Note*: This is a simplified model. A real simulation would
-     * account for the *time* it takes each vehicle to cross, processing
-     * one vehicle every {@code crossingTime} seconds. This implementation
-     * processes the entire queue "instantaneously" at the moment
-     * the light turns green.
-     *
-     * @param light The {@link TrafficLight} that just turned green.
-     * @param intersection The {@link Intersection} where the light is.
-     */
-    private void processGreenLight(TrafficLight light, Intersection intersection) {
-        // While the light is green and vehicles are waiting...
-        while (light.getState() == TrafficLightState.GREEN && light.getQueueSize() > 0) {
-            Vehicle vehicle = light.removeVehicle();
-            if (vehicle != null) {
-                // Dequeue one vehicle and schedule its crossing
-                scheduleCrossing(vehicle, intersection);
-            }
-        }
-    }
-    
-    /**
-     * Handles {@link EventType#STATISTICS_UPDATE}.
-     * Calls the {@link StatisticsCollector} to print the current
-     * state of the simulation (queue sizes, averages, etc.).
-     */
-    private void handleStatisticsUpdate() {
-        System.out.printf("\n=== Statistics at t=%.2f ===%n", currentTime);
-        statisticsCollector.printCurrentStatistics(intersections, currentTime);
-        System.out.println();
-    }
-    
-    /**
-     * Utility method to get the configured crossing time for a given {@link VehicleType}.
-     *
-     * @param type The type of vehicle.
-     * @return The crossing time in seconds.
-     */
-    private double getCrossingTime(VehicleType type) {
-        return switch (type) {
-            case BIKE -> config.getBikeVehicleCrossingTime();
-            case LIGHT -> config.getLightVehicleCrossingTime();
-            case HEAVY -> config.getHeavyVehicleCrossingTime();
-            default -> 2.0;
-        }; // Default fallback
-    }
-    
-    /**
-     * Prints the final summary of statistics at the end of the simulation.
-     */
-    private void printFinalStatistics() {
-        System.out.println("\n" + "=".repeat(60));
-        System.out.println("FINAL SIMULATION STATISTICS");
-        System.out.println("=".repeat(60));
-        
-        statisticsCollector.printFinalStatistics(intersections, currentTime);
-        
-        System.out.println("=".repeat(60));
-    }
-    
-    // --- Public Getters ---
-
-    /**
-     * Gets the current simulation time.
-     * @return The time in virtual seconds.
-     */
-    public double getCurrentTime() {
-        return currentTime;
-    }
-    
-    /**
-     * Gets a map of all intersections in the simulation.
-     * Returns a copy to prevent external modification.
-     * @return A {@link Map} of intersection IDs to {@link Intersection} objects.
-     */
-    public Map<String, Intersection> getIntersections() {
-        return new HashMap<>(intersections);
-    }
-    
-    /**
-     * Gets the statistics collector instance.
-     * @return The {@link StatisticsCollector}.
-     */
-    public StatisticsCollector getStatisticsCollector() {
-        return statisticsCollector;
-    }
-}

main/src/main/java/sd/model/Intersection.java

@@ -140,6 +140,16 @@ public class Intersection {
         }
     }
 
+    /**
+     * Returns the direction a vehicle should take to reach a given destination.
+     *
+     * @param destination The next destination (e.g., "Cr3", "S").
+     * @return The direction (e.g., "East"), or null if no route is configured.
+     */
+    public String getDirectionForDestination(String destination) {
+        return routing.get(destination);
+    }
+
     /**
      * Returns the traffic light controlling the given direction.
      *

main/src/main/java/sd/util/StatisticsCollector.java

@@ -12,7 +12,8 @@ import sd.model.VehicleType;
 
 /**
  * Collects, manages, and reports statistics throughout the simulation.
- * * This class acts as the central bookkeeper for simulation metrics. It tracks:
+ * * This class acts as the central bookkeeper for simulation metrics. It
+ * tracks:
  * - Overall system statistics (total vehicles, completion time, wait time).
  * - Per-vehicle-type statistics (counts, average wait time by type).
  * - Per-intersection statistics (arrivals, departures).
@@ -25,7 +26,8 @@ public class StatisticsCollector {
     // --- Vehicle tracking (for in-flight vehicles) ---
 
     /**
-     * Tracks the simulation time when a vehicle arrives at its *current* intersection.
+     * Tracks the simulation time when a vehicle arrives at its *current*
+     * intersection.
      * This is used later to calculate waiting time (Depart_Time - Arrive_Time).
      * Key: Vehicle ID (String)
      * Value: Arrival Time (Double)
@@ -47,10 +49,14 @@ public class StatisticsCollector {
     /** Total number of vehicles that have reached their final destination ("S"). */
     private int totalVehiclesCompleted;
 
-    /** The sum of all *completed* vehicles' total travel times. Used for averaging. */
+    /**
+     * The sum of all *completed* vehicles' total travel times. Used for averaging.
+     */
     private double totalSystemTime;
 
-    /** The sum of all *completed* vehicles' total waiting times. Used for averaging. */
+    /**
+     * The sum of all *completed* vehicles' total waiting times. Used for averaging.
+     */
     private double totalWaitingTime;
 
     // --- Per-vehicle-type statistics ---
@@ -105,7 +111,7 @@ public class StatisticsCollector {
 
     /**
      * Records that a new vehicle has been generated.
-     * This is called by the {@link sd.engine.SimulationEngine}
+     * This is called by the vehicle generation component
      * during a {@code VEHICLE_GENERATION} event.
      *
      * @param vehicle     The {@link Vehicle} that was just created.
@@ -124,7 +130,7 @@ public class StatisticsCollector {
 
     /**
      * Records that a vehicle has arrived at an intersection queue.
-     * This is called by the {@link sd.engine.SimulationEngine}
+     * This is called by the vehicle generation component
      * during a {@code VEHICLE_ARRIVAL} event.
      *
      * @param vehicle        The {@link Vehicle} that arrived.
@@ -148,7 +154,7 @@ public class StatisticsCollector {
     /**
      * Records that a vehicle has completed its route and exited the system.
      * This is where final metrics for the vehicle are aggregated.
-     * This is called by the {@link sd.engine.SimulationEngine}
+     * This is called by the vehicle generation component
      * when a vehicle reaches destination "S".
      *
      * @param vehicle     The {@link Vehicle} that is exiting.
@@ -176,7 +182,7 @@ public class StatisticsCollector {
 
     /**
      * Gets the time a vehicle arrived at its *current* intersection.
-     * This is used by the {@link sd.engine.SimulationEngine} to calculate
+     * This is used by the intersection component to calculate
      * wait time just before the vehicle crosses.
      *
      * @param vehicle The {@link Vehicle} to check.
@@ -188,7 +194,7 @@ public class StatisticsCollector {
 
     /**
      * Prints a "snapshot" of the current simulation statistics.
-     * This is called periodically by the {@link sd.engine.SimulationEngine}
+     * This is called periodically by the simulation components
      * during a {@code STATISTICS_UPDATE} event.
      *
      * @param intersections A map of all intersections (to get queue data).
@@ -320,10 +326,6 @@ public class StatisticsCollector {
             totalArrivals++;
         }
 
-        public void recordDeparture() {
-            totalDepartures++;
-        }
-        
         public int getTotalArrivals() {
             return totalArrivals;
         }

main/src/main/resources/network_config.json

@@ -0,0 +1,43 @@
+{
+  "intersections": [
+    {
+      "id": "Cr1",
+      "lights": ["East", "South"],
+      "routes": {
+        "Cr2": "East",
+        "Cr4": "South"
+      }
+    },
+    {
+      "id": "Cr2",
+      "lights": ["West", "East", "South"],
+      "routes": {
+        "Cr1": "West",
+        "Cr3": "East",
+        "Cr5": "South"
+      }
+    },
+    {
+      "id": "Cr3",
+      "lights": ["West", "South"],
+      "routes": {
+        "Cr2": "West",
+        "S": "South"
+      }
+    },
+    {
+      "id": "Cr4",
+      "lights": ["East"],
+      "routes": {
+        "Cr5": "East"
+      }
+    },
+    {
+      "id": "Cr5",
+      "lights": ["East"],
+      "routes": {
+        "S": "East"
+      }
+    }
+  ]
+}

main/src/main/resources/simulation.properties

@@ -46,54 +46,44 @@ simulation.arrival.fixed.interval=2.0
 # === TRAFFIC LIGHT TIMINGS ===
 # Format: trafficlight.<intersection>.<direction>.<state>=<seconds>
 
-# Intersection 1
+# Intersection 1 (Entry point - balanced)
-trafficlight.Cr1.North.green=30.0
+trafficlight.Cr1.South.green=20.0
-trafficlight.Cr1.North.red=30.0
+trafficlight.Cr1.South.red=40.0
-trafficlight.Cr1.South.green=30.0
+trafficlight.Cr1.East.green=20.0
-trafficlight.Cr1.South.red=30.0
+trafficlight.Cr1.East.red=40.0
-trafficlight.Cr1.East.green=30.0
+trafficlight.Cr1.West.green=20.0
-trafficlight.Cr1.East.red=30.0
+trafficlight.Cr1.West.red=40.0
-trafficlight.Cr1.West.green=30.0
-trafficlight.Cr1.West.red=30.0
 
-# Intersection 2
+# Intersection 2 (Main hub - shorter cycles, favor East-West)
-trafficlight.Cr2.North.green=25.0
+trafficlight.Cr2.South.green=12.0
-trafficlight.Cr2.North.red=35.0
+trafficlight.Cr2.South.red=36.0
-trafficlight.Cr2.South.green=25.0
+trafficlight.Cr2.East.green=18.0
-trafficlight.Cr2.South.red=35.0
+trafficlight.Cr2.East.red=30.0
-trafficlight.Cr2.East.green=35.0
+trafficlight.Cr2.West.green=18.0
-trafficlight.Cr2.East.red=25.0
+trafficlight.Cr2.West.red=30.0
-trafficlight.Cr2.West.green=35.0
-trafficlight.Cr2.West.red=25.0
 
-# Intersection 3
+# Intersection 3 (Path to exit - favor East)
-trafficlight.Cr3.North.green=30.0
+trafficlight.Cr3.South.green=15.0
-trafficlight.Cr3.North.red=30.0
-trafficlight.Cr3.South.green=30.0
 trafficlight.Cr3.South.red=30.0
-trafficlight.Cr3.East.green=30.0
+trafficlight.Cr3.East.green=20.0
-trafficlight.Cr3.East.red=30.0
+trafficlight.Cr3.East.red=25.0
-trafficlight.Cr3.West.green=30.0
+trafficlight.Cr3.West.green=15.0
 trafficlight.Cr3.West.red=30.0
 
-# Intersection 4
+# Intersection 4 (Favor East toward Cr5)
-trafficlight.Cr4.North.green=30.0
+trafficlight.Cr4.South.green=15.0
-trafficlight.Cr4.North.red=30.0
-trafficlight.Cr4.South.green=30.0
 trafficlight.Cr4.South.red=30.0
-trafficlight.Cr4.East.green=30.0
+trafficlight.Cr4.East.green=20.0
-trafficlight.Cr4.East.red=30.0
+trafficlight.Cr4.East.red=25.0
-trafficlight.Cr4.West.green=30.0
+trafficlight.Cr4.West.green=15.0
 trafficlight.Cr4.West.red=30.0
 
-# Intersection 5
+# Intersection 5 (Near exit - favor East)
-trafficlight.Cr5.North.green=30.0
+trafficlight.Cr5.South.green=15.0
-trafficlight.Cr5.North.red=30.0
-trafficlight.Cr5.South.green=30.0
 trafficlight.Cr5.South.red=30.0
-trafficlight.Cr5.East.green=30.0
+trafficlight.Cr5.East.green=22.0
-trafficlight.Cr5.East.red=30.0
+trafficlight.Cr5.East.red=23.0
-trafficlight.Cr5.West.green=30.0
+trafficlight.Cr5.West.green=15.0
 trafficlight.Cr5.West.red=30.0
 
 # === VEHICLE CONFIGURATION ===
@@ -103,11 +93,19 @@ vehicle.probability.light=0.6
 vehicle.probability.heavy=0.2
 
 # Average crossing times (in seconds)
-vehicle.crossing.time.bike=1.5
+vehicle.crossing.time.bike=1.0
 vehicle.crossing.time.light=2.0
 vehicle.crossing.time.heavy=4.0
 
+# Travel times between intersections (in seconds)
+# Base time for light vehicles (cars)
+vehicle.travel.time.base=8.0
+# Bike travel time = 0.5 × car travel time
+vehicle.travel.time.bike.multiplier=0.5
+# Heavy vehicle travel time = 4 × bike travel time
+vehicle.travel.time.heavy.multiplier=2.0
+
 # === STATISTICS ===
 
 # Interval between dashboard updates (seconds)
-statistics.update.interval=10.0
+statistics.update.interval=1.0

main/src/test/java/SimulationTest.java

@@ -6,7 +6,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import org.junit.jupiter.api.Test;
 
 import sd.config.SimulationConfig;
-import sd.engine.SimulationEngine;
 import sd.model.Event;
 import sd.model.EventType;
 import sd.model.Intersection;
@@ -29,7 +28,7 @@ class SimulationTest {
         assertEquals(60.0, config.getSimulationDuration());
         assertEquals("POISSON", config.getArrivalModel());
         assertEquals(0.5, config.getArrivalRate());
-        assertEquals(10.0, config.getStatisticsUpdateInterval());
+        assertEquals(1.0, config.getStatisticsUpdateInterval());
     }
 
     @Test
@@ -90,21 +89,8 @@ class SimulationTest {
         assertEquals(TrafficLightState.RED, light.getState());
     }
 
-    @Test
+    // Removed testSimulationEngineInitialization as SimulationEngine has been
-    void testSimulationEngineInitialization() throws IOException {
+    // removed.
-        SimulationConfig config = new SimulationConfig("src/main/resources/simulation.properties");
-        SimulationEngine engine = new SimulationEngine(config);
-        
-        engine.initialize();
-        
-        assertNotNull(engine.getIntersections());
-        assertEquals(5, engine.getIntersections().size());
-        
-        // Check that intersections have traffic lights
-        for (Intersection intersection : engine.getIntersections().values()) {
-            assertEquals(3, intersection.getTrafficLights().size()); // North, South, East, West
-        }
-    }
 
     @Test
     void testStatisticsCollector() throws IOException {