Vehicle Rental Service

Let's build a Vehicle Rental Service system that manages a fleet of vehicles, tracks customer rentals, and calculates pricing based on vehicle type. This comprehensive challenge brings together inheritance, interfaces, encapsulation, and the State pattern to create a realistic rental business application.

You'll organize your code across seven files:

• VehicleState.php — Define a VehicleState interface that represents the different states a vehicle can be in. Include two methods: getStatus(): string and canRent(): bool. Then create three classes implementing this interface:
  • AvailableState — returns "Available" and true
  • RentedState — returns "Rented" and false
  • MaintenanceState — returns "Maintenance" and false
• Vehicle.php — Include the VehicleState file. Create an abstract Vehicle class with constructor promotion for licensePlate (string, public readonly), brand (string, public readonly), and dailyRate (float, protected). Store the current state in a private property, defaulting to AvailableState. Implement:
  • getState(): VehicleState — returns current state
  • setState(VehicleState $state): void — changes the state
  • getStatus(): string — delegates to state's getStatus()
  • canRent(): bool — delegates to state's canRent()
  • abstract calculateCost(int $days): float — each vehicle type calculates differently
  • getType(): string — returns the class name using static::class
• Vehicles.php — Include the Vehicle file. Create three concrete vehicle classes:
  • Car — extends Vehicle; calculateCost() returns dailyRate * days
  • Motorcycle — extends Vehicle; calculateCost() returns dailyRate * days * 0.8 (20% discount)
  • Van — extends Vehicle with an additional $mileageRate (float) parameter; calculateCost(int $days, int $miles = 0) returns (dailyRate * days) + (mileageRate * miles)
• Customer.php — Create a Customer class with constructor promotion for id (int, public readonly) and name (string, public readonly). Track rental history in a private array. Implement:
  • addRental(string $vehiclePlate, float $cost): void — adds to history
  • getRentalCount(): int — returns number of rentals
  • getTotalSpent(): float — returns sum of all rental costs
• Rental.php — Include the Vehicle and Customer files. Create a Rental class that links a customer to a vehicle. Use constructor promotion for customer (Customer, public readonly), vehicle (Vehicle, public readonly), days (int, private), and optionally miles (int, private, default 0). Implement:
  • calculateTotal(): float — if vehicle is a Van, pass miles to calculateCost(); otherwise just pass days
  • complete(): string — calculates total, adds to customer's history, sets vehicle to AvailableState, returns "Rental completed: $[total]" (2 decimal places)
• RentalService.php — Include the Rental and Vehicles files. Create a RentalService class that manages the fleet. Store vehicles in a private array indexed by license plate. Implement:
  • addVehicle(Vehicle $vehicle): void — adds to fleet
  • findVehicle(string $plate): ?Vehicle — returns vehicle or null
  • getAvailableVehicles(): array — returns vehicles where canRent() is true
  • rentVehicle(Customer $customer, string $plate, int $days, int $miles = 0): string|Rental — if vehicle not found, return "Vehicle not found"; if not available, return "Vehicle is not available"; otherwise set vehicle to RentedState and return a new Rental object
  • setMaintenance(string $plate): string — sets vehicle to MaintenanceState; return "[plate] set to maintenance" or "Vehicle not found"
• main.php — Include the RentalService and Customer files. You'll receive three inputs: fleet data (JSON), customer data (JSON), and operations (JSON).

  Fleet JSON format:

  [{"type": "car", "plate": "CAR-001", "brand": "Toyota", "rate": 50}, {"type": "van", "plate": "VAN-001", "brand": "Ford", "rate": 80, "mileage_rate": 0.25}]

  Customer JSON format:

  {"id": 1, "name": "Alice"}

  Operations JSON format:

  [{"op": "available"}, {"op": "rent", "plate": "CAR-001", "days": 3}, {"op": "complete", "plate": "CAR-001"}, {"op": "maintenance", "plate": "VAN-001"}, {"op": "customer_stats"}]

  Create the rental service, add all vehicles to the fleet, and create the customer. Keep track of active rentals by plate. Process each operation:

  • "available" — Print "Available vehicles: [count]"
  • "rent" — Rent the vehicle; if successful, store the Rental and print "Rented [plate] for [days] days"; if Van, include miles from the operation; otherwise print the error message
  • "complete" — Complete the stored rental for that plate; print the result
  • "maintenance" — Print the result of setMaintenance()
  • "status" — Print "[plate]: [status]" for the given plate
  • "customer_stats" — Print "[name]: [count] rentals, $[total] spent" (2 decimal places)

  Print each result on a new line.

This system showcases how the State pattern elegantly handles vehicle availability without complex conditionals, how inheritance creates a clean vehicle hierarchy with polymorphic pricing, and how encapsulation protects rental data integrity throughout the workflow.