Project 3 — Design BookMyShow

classDiagram
    class Movie {
        +id: string
        +title: string
        +duration: int
        +genre: string
    }
    class Theater {
        +id: string
        +name: string
        +city: string
        -screens: Screen[]
    }
    class Screen {
        +id: string
        -seats: Seat[][]
    }
    class Seat {
        +id: string
        +row: int
        +col: int
        +type: SeatType
        -isBooked: boolean
    }
    class Show {
        +id: string
        +movie: Movie
        +screen: Screen
        +startTime: Date
        -bookedSeats: Set~string~
    }
    class Booking {
        +id: string
        +user: User
        +show: Show
        -seats: Seat[]
        +status: BookingStatus
        +totalAmount: number
        +confirm(): void
        +cancel(): void
    }
    class Payment {
        +id: string
        +amount: number
        +status: PaymentStatus
        +process(): boolean
    }
    class SeatType {
        <<enumeration>>
        NORMAL PREMIUM RECLINER
    }
    class BookingStatus {
        <<enumeration>>
        PENDING CONFIRMED CANCELLED
    }

    Theater *-- Screen
    Screen *-- Seat
    Theater --> Movie : shows
    Show --> Movie
    Show --> Screen
    Booking --> Show
    Booking --> Payment
    Booking --> Seat

class Seat {
  constructor(id, row, col, type) {
    this.id = id;
    this.row = row;
    this.col = col;
    this.type = type; // 'NORMAL', 'PREMIUM', 'RECLINER'
    this.isBooked = false;
  }
}

class Show {
  constructor(id, movie, screen, startTime) {
    this.id = id;
    this.movie = movie;
    this.screen = screen;
    this.startTime = startTime;
    this.bookedSeats = new Set();
  }

  getAvailableSeats() {
    return this.screen.seats
      .flat()
      .filter(seat => !this.bookedSeats.has(seat.id));
  }

  bookSeats(seats) {
    for (const seat of seats) {
      if (this.bookedSeats.has(seat.id)) return false; // Already booked
      this.bookedSeats.add(seat.id);
    }
    return true;
  }
}

class Booking {
  constructor(user, show, seats) {
    this.id = Math.random().toString(36).substr(2, 9);
    this.user = user;
    this.show = show;
    this.seats = seats;
    this.status = 'PENDING';
    this.totalAmount = seats.reduce((sum, s) => {
      const prices = { NORMAL: 10, PREMIUM: 15, RECLINER: 25 };
      return sum + (prices[s.type] || 10);
    }, 0);
    this.createdAt = new Date();
  }

  confirm() {
    this.status = 'CONFIRMED';
    // Process payment
    return true;
  }

  cancel() {
    this.status = 'CANCELLED';
    // Release seats
    for (const seat of this.seats) {
      this.show.bookedSeats.delete(seat.id);
    }
    // Process refund
  }
}