09 — Machine Coding Approach

flowchart TB
    S1["1️⃣ Understand Problem<br/>5 min<br/>Ask clarifying questions"] --> S2["2️⃣ Core Requirements<br/>5 min<br/>List what needs to be built"]
    S2 --> S3["3️⃣ Class Design<br/>10 min<br/>Draw class diagram"]
    S3 --> S4["4️⃣ Choose Patterns<br/>5 min<br/>Which patterns fit?"]
    S4 --> S5["5️⃣ Implement Core<br/>30 min<br/>Write main classes"]
    S5 --> S6["6️⃣ Implement Logic<br/>15 min<br/>Write business logic"]
    S6 --> S7["7️⃣ Test & Debug<br/>10 min<br/>Run through scenarios"]
    S7 --> S8["8️⃣ Extend<br/>10 min<br/>Add the requested feature"]

    style S1 fill:#f59e0b,color:#fff
    style S3 fill:#7c3aed,color:#fff
    style S5 fill:#059669,color:#fff
    style S7 fill:#3b82f6,color:#fff

Parking Lot System:
- Multiple floors, multiple spots per floor
- Different spot types (compact, large, handicapped)
- Park vehicle, remove vehicle
- Track available spots by type
- Calculate parking fee
- Generate ticket on entry

classDiagram
    class ParkingLot {
        -floors: ParkingFloor[]
        +parkVehicle(vehicle: Vehicle): Ticket
        +removeVehicle(ticket: Ticket): double
        +isFull(): boolean
    }
    class ParkingFloor {
        -floorNumber: int
        -spots: ParkingSpot[]
        +findAvailableSpot(type: SpotType): ParkingSpot
    }
    class ParkingSpot {
        -id: string
        -type: SpotType
        -isOccupied: boolean
        +park(): void
        +removeVehicle(): void
    }
    class Vehicle {
        -licensePlate: string
        -type: VehicleType
    }
    class Ticket {
        -id: string
        -spot: ParkingSpot
        -entryTime: Date
        -exitTime: Date
        +calculateFee(): double
    }
    class SpotType {
        <<enumeration>>
        COMPACT
        LARGE
        HANDICAPPED
    }

    ParkingLot *-- ParkingFloor
    ParkingFloor *-- ParkingSpot
    ParkingSpot --> SpotType
    Ticket --> ParkingSpot
    Vehicle --> Ticket

// Core implementation structure
enum SpotType { COMPACT, LARGE, HANDICAPPED }
enum VehicleType { MOTORCYCLE, CAR, TRUCK }

class ParkingSpot {
  constructor(
    public id: string,
    public type: SpotType,
    public isOccupied: boolean = false
  ) {}

  park(): void { this.isOccupied = true; }
  removeVehicle(): void { this.isOccupied = false; }
}

class ParkingFloor {
  private spots: ParkingSpot[] = [];

  constructor(public floorNumber: number) {}

  addSpot(spot: ParkingSpot): void { this.spots.push(spot); }

  findAvailableSpot(type: SpotType): ParkingSpot | null {
    return this.spots.find(s => s.type === type && !s.isOccupied) || null;
  }
}

class ParkingLot {
  private static instance: ParkingLot;
  private floors: ParkingFloor[] = [];

  static getInstance(): ParkingLot {
    if (!this.instance) this.instance = new ParkingLot();
    return this.instance;
  }

  addFloor(floor: ParkingFloor): void { this.floors.push(floor); }

  parkVehicle(type: SpotType): Ticket | null {
    for (const floor of this.floors) {
      const spot = floor.findAvailableSpot(type);
      if (spot) {
        spot.park();
        return new Ticket(spot);
      }
    }
    return null; // No spot available
  }

  removeVehicle(ticket: Ticket): number {
    ticket.spot.removeVehicle();
    ticket.exitTime = new Date();
    return ticket.calculateFee();
  }
}

// Test scenarios
const lot = ParkingLot.getInstance();
const floor1 = new ParkingFloor(1);
floor1.addSpot(new ParkingSpot("A1", SpotType.COMPACT));
floor1.addSpot(new ParkingSpot("A2", SpotType.LARGE));
lot.addFloor(floor1);

// Park a car
const ticket = lot.parkVehicle(SpotType.COMPACT);
console.log(ticket ? `Parked at ${ticket.spot.id}` : "No spots available");

// Remove vehicle
const fee = lot.removeVehicle(ticket!);
console.log(`Fee: $${fee}`);