implement todos for GasCar.java

src/main/java/org/model/GasCar.java

@@ -27,12 +27,37 @@ public class GasCar extends Car implements Refuelable {
         this.fuelType = fuelType;
     }
 
+    public boolean needsService(Vehicle v) {
+        return v.getMileage() > 8000;
+    }
+    public void performService() {
+        System.out.println("Engine oil changed");
+        this.fuelLevel = 100;
+    }
+
+    @Override
+    public String getEnergyType() {
+        return this.fuelType + " (Gas)";
+    }
     // TODO: Override getEnergyType() → return fuelType + " (Gas)"
 
+
+    public void refuel(double amount) {
+        if (amount > 0 && this.fuelLevel + amount <= 100) {
+            this.fuelLevel += amount;
+        } else if (amount > 0 && this.fuelLevel + amount > 100) {
+            this.fuelLevel = 100; //if input amount causes the fuel to fill pass 100%, we set it to 100%.
+        }
+    }
     // TODO: Implement refuel(double amount)
     // Validate amount
     // Cap at 100
 
+    @Override
+    public void showDetails() {
+        super.showDetails();
+        System.out.println("Feul level: " + this.fuelLevel + ", Feul type: " + this.fuelType);
+    }
     // TODO: Override showDetails()
     // Call super.showDetails()
     // Print fuel level and fuel type