import java.util.Random;
import java.util.Scanner;

public class Pig1 {
    public static int rollDie() {
        Random rng = new Random();
        int num = rng.nextInt(6) + 1;
        return num;
    }

    public static int askLimit() {
        Scanner in = new Scanner(System.in);
        System.out.print("What do you want to play to? ");
        int limit = in.nextInt();
        while (limit < 10 || limit > 500) {
            System.out.print("Please enter a number between 10 and 500: ");
            limit = in.nextInt();
        }

        return limit;
    }

    // return true if user wants to roll
    public static boolean getUserDecision(int roundScore) {
        Scanner in = new Scanner(System.in);

        System.out.println("You have " + roundScore + " points so far this round.");
        System.out.print("Do you want to roll or stay? ");
        String response = in.next();
        while (!response.equals("roll") && !response.equals("stay")) {
            System.out.println("Please enter \"roll\" or \"stay\"");
            System.out.print("Do you want to roll or stay? ");
            response = in.next();
        }

        return response.equals("roll");
    }

    public static boolean getAIDecision(int userScore, int compScore, int roundScore) {
        int target;

        int difference = compScore - userScore;

        // if we're within 10 points, play normally
        if (difference > -10 && difference < 10) {
            target = 10;
        }

        // if we're more than 10 points behind, play aggressibely
        else if (difference <= -10) {
            target = 20;
        }

        // if we're more than 10 points ahead, play safely
        else {
            target = 5;
        }

        if (roundScore >= target) {
            return false;
        } else {
            return true;
        }
    }

    public static void sleep() {
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }

    // play one round for user
    public static int computerRound(int userScore, int compScore) {
        int roundScore = 0;

        System.out.println("Computer has " + compScore + " points.");
        System.out.println("You have " + userScore + " points.");
        boolean rolling = getAIDecision(userScore, compScore, roundScore);

        while (rolling) {
            int die = rollDie();
            System.out.println("The computer rolled a " + die + ".");
            sleep();

            if (die == 1) {
                System.out.println("Computer busted!");
                return 0;
            } else {
                // add die to score
                roundScore += die;
            }

            // ask if they want to roll again
            rolling = getAIDecision(userScore, compScore, roundScore);
        }

        return roundScore;
    }

    // play one round for user
    public static int userRound(int userScore, int compScore) {
        int roundScore = 0;

        System.out.println("You have " + userScore + " points.");
        System.out.println("Computer has " + compScore + " points.");
        boolean rolling = getUserDecision(roundScore);

        while (rolling) {
            int die = rollDie();
            System.out.println("You rolled a " + die + ".");

            if (die == 1) {
                System.out.println("You busted!");
                return 0;
            } else {
                // add die to score
                roundScore += die;
            }

            // ask if they want to roll again
            rolling = getUserDecision(roundScore);
        }

        return roundScore;
    }

    public static void game() {
        int userScore = 0;
        int computerScore = 0;
        int limit = askLimit();

        while (userScore < limit && computerScore < limit) {
            System.out.println("Your turn!");
            int points = userRound(userScore, computerScore);
            userScore += points;
            if (userScore >= limit) {
                break;
            }

            System.out.println("Computer turn");
            points = computerRound(userScore, computerScore);
            computerScore += points;
            System.out.println("Computer got " + points + " points on its turn");
        }

        if (userScore > computerScore) {
            System.out.println("Congratulations, you won!");
        } else {
            System.out.println("Sorry you lost!");
        }
    }

    public static void main(String[] args) {
        game();
    }

}