type FlyCategory = 'economy' | 'business' | 'first';

type CategoryPrices = Record<FlyCategory, number>;

const MIN_PASSENGERS = 1;
const MIN_DISTANCE = 100;
const BASE_PRICE = 0.10;
const BUSINESS_PRICE = 0.25;
const FIRST_CLASS_PRICE = 0.45;
const PRICE_PER_LUGGAGE = 30;
const MIN_PASSENGERS_DISCOUNT = 5;
const DISCOUNT = 0.10;
const INVALID_OPERATION = -1;
const FOR_ROUNDING = 100;

const PRICES_PER_CATEGORY: CategoryPrices = {
  economy: BASE_PRICE,
  business: BUSINESS_PRICE,
  first: FIRST_CLASS_PRICE,
};

function isVerified(passengers: number, distance: number): number | undefined {
  if (passengers < MIN_PASSENGERS || distance < MIN_DISTANCE) return INVALID_OPERATION;
  return;
};

function subtotalPerCategory(
  passengers: number,
  category: FlyCategory,
  distance: number,
) {
  const SUBTOTAL = distance * passengers * PRICES_PER_CATEGORY[category];
  return SUBTOTAL;
};

function getPriceBeforeDiscount(
  passengers: number,
  category: FlyCategory,
  distance: number,
  luggage: boolean,
) {
  let subTotal = subtotalPerCategory(passengers, category, distance);

  if (category === 'economy' && luggage) {
    subTotal = subTotal + PRICE_PER_LUGGAGE * passengers;
  }
  return (subTotal = Math.round(subTotal * FOR_ROUNDING) / FOR_ROUNDING);
};

function getDiscount( total: number ): number {
    const FINAL_PRIZE = total - (total * DISCOUNT);
    return FINAL_PRIZE;
};

export function calculateFlightTicketPrice(  passengers: number,  category: FlyCategory,  distance: number,  luggage: boolean,): number {

  if(isVerified(passengers, distance) === INVALID_OPERATION) return INVALID_OPERATION;

  const TICKET_PRIZE = getPriceBeforeDiscount( passengers, category, distance, luggage );

  if (passengers >= MIN_PASSENGERS_DISCOUNT) {
      return getDiscount(TICKET_PRIZE);

  } else {
  return TICKET_PRIZE;
  }   
}