import java.util.Scanner;
/*
You could also use "import drinks.*" instead of the 4 lines below
 */
import drinks.Beer;
import drinks.Coke;
import drinks.Drink;
import drinks.GreenTea;

public class VendingMachine {
    private static final Drink[] availableDrinks = new Drink[3];
    int drinkSelection = 0;

    public VendingMachine() {
        availableDrinks[0] = new Beer();
        availableDrinks[1] = new Coke();
        availableDrinks[2] = new GreenTea();
    }

    public double selectDrink() {
        drinkSelection = presentDrinkMenu() - 1; // This " - 1 " is to keep "drinkSelection" within the "availableDrinks" array range
        return availableDrinks[drinkSelection].getPrice();
    }

    public double insertCoins() {
        double amount = 0.0;

        Scanner sc = new Scanner(System.in);
        printCoinOptions();

        do {
            char coin = sc.next().charAt(0);
            amount += processCoinAmount(coin);
            System.out.printf("Coins inserted: %.2f \n", amount);
        } while (amount < availableDrinks[drinkSelection].getPrice());
        return amount;
    }

    public void checkChange(double amount)
    {
        double change = 0.0;
        if (amount > availableDrinks[drinkSelection].getPrice())
        {
            change = amount - availableDrinks[drinkSelection].getPrice();
            System.out.printf("Change $ %.2f \n", change);
        }
    }

    public void printReceipt()
    {
        System.out.println("Please collect your drink");
        System.out.println("Thank you!!");
    }

    private Integer presentDrinkMenu() {
        Scanner sc = new Scanner(System.in);
        int drinkSelection;

        System.out.print("====== Vending Machine ====== \n");
        /*
         Note. The for loop below is just an enhanced way of writing the following:

            for (int i = 0; i < availableDrinks.length; i++) {
               System.out.printf("|%d. Buy %s ($%.2f)   \n", i + 1, availableDrinks[i].getName(), availableDrinks[i].getPrice());
            }
         */
        int i = 1;
        for (Drink drink : availableDrinks) {
            System.out.printf("|%d. Buy %s ($%.2f)   \n", i++, drink.getName(), drink.getPrice());
        }
        System.out.print("|============================ \n");

        do {
            System.out.println("Please enter selection: ");
            drinkSelection = sc.nextInt();
        } while (drinkSelection < 1 || drinkSelection > (availableDrinks.length + 1));

        return drinkSelection;
    }

    private void printCoinOptions() {
        System.out.println("Please insert coins: ");
        System.out.println("========== Coins Input ===========");
        System.out.println("|Enter 'Q' for ten cents input   |");
        System.out.println("|Enter 'T' for twenty cents input|");
        System.out.println("|Enter 'F' for fifty cents input |");
        System.out.println("|Enter 'N' for a dollar input    |");
        System.out.println("==================================");
    }

    private double processCoinAmount(char coin) {
        /*
        Note. The code below is just an enhanced way of writing the following:

        switch (coin)
        {
            case 'Q': case 'q': return 0.10;
            case 'T': case 't': return 0.20;
            case 'F': case 'f': return 0.50;
            case 'N': case 'n': return 1.00;
        }
        return 0.0;

        This enhanced way or writing switch-cases was introduced in Java 12 and Java 13 (we are currently at Java LTS 22, with Java 23 and Java 24 under early-access);
        The "->" was introduced in Java 8. It denotes a Lambda expression: https://www.w3schools.com/java/java_lambda.asp

        The Switch with a lambda-like syntax expression was introduced in Java 14: https://www.javacodegeeks.com/2020/05/switch-as-an-expression-in-java-with-lambda-like-syntax.html
         */
        return switch (coin) {
            case 'Q', 'q' -> 0.10;
            case 'T', 't' -> 0.20;
            case 'F', 'f' -> 0.50;
            case 'N', 'n' -> 1.00;
            default -> 0.0;
        };
    }
}