Design an object-oriented parking lot system

Design an object-oriented model for a parking lot management system.

Requirements:

• The parking lot has multiple levels; each level has multiple parking spots.
• Each spot has a size: small, medium, or large.
• Vehicles can be of different types: motorcycle, car, or bus/truck.
• A vehicle can only be parked in a spot of a compatible size. A bus or truck may require multiple adjacent large spots.
• The system must support:
  • Vehicle entry: find and reserve an appropriate spot (or group of spots) for an incoming vehicle.
  • Vehicle exit: free the spot(s) and calculate the parking fee based on time parked.
  • Query operations: report the number of available spots per size and per level, and whether the lot is full.

Assumptions:

• Ignore distributed systems concerns; you are designing an in-process object-oriented model, not a networked service.
• You may assume time and payment processing are handled by simple helper components.

Describe:

• The main classes, their responsibilities, and key attributes.
• The relationships between classes (inheritance, composition, etc.).
• The main methods needed to support the above operations.
• Any design patterns or principles (for example, SOLID) you apply.