import java.util.Scanner;

public class RockPaperScissors {
    public static void main(String[] args) {
        
        Scanner scan = new Scanner(System.in);

        System.out.println("Let's play Rock Paper Scissors.");
        System.out.println("When I say 'shoot', Choose: rock, paper, or scissors.\n");
        System.out.println("Are you ready? Write 'yes' if you are.");
        String ready = scan.nextLine();
       //Task 1: See if the user wants to play. 

       //Task 2: Set up the game

        if (ready.equals("yes")) {
            System.out.println("\nGreat!");
            System.out.println("rock - paper - scissors, shoot!");            
            String yourChoice = scan.next();
            String computerChoice = computerChoice();
            String result = result(yourChoice, computerChoice);
            printResult(yourChoice, computerChoice, result);
        } else {
            System.out.println("Darn, some other time...");
        }
        scan.close();
    }



    //Task 3  – Write a function where the computer picks a random choice.

    /**
     * Function name: computerChoice - picks a randomly between rock paper and scissors
     * @return a choice (String).
     * 
     * Inside the function:
     *   1. Picks a random number between 0 and 2.
     *   2. if 0: returns the choice 'rock'
     *      if 1: returns the choice 'paper'
     *      if 2: returns the choice 'scissors'
     */

     

    public static String computerChoice() {
        double randomNumber = Math.random() * 3;
        int integer = (int) randomNumber;


        switch (integer) {
            case 0: return "rock";
            case 1: return "paper";
            case 2: return "scissors";
            default: return "";  //default case not possible.

        }


        
        //You can also use if statements:

        // if (integer == 0) {
        //     return "rock";
        // } else if (integer == 1) {
        //     return "paper";
        // } else if (integer == 2) {
        //     return "scissors";
        // }
        

    } 

    //Task 4  – Write a function that compares the choices and returns the result.

    /**
     * Function name: result - It returns the result of the game.
     *  @param yourChoice (String)
     *  @param computerChoice (String) 
     *  @return result (String) 
     * 
     * Inside the function:
     *   1. result is "You win" if:
     * 
     *       You: "rock"      Computer: "scissors"
     *       You: "paper"     Computer: "rock"
     *       You: "scissors"  Computer: "paper"
     * 
     *   2. result is "You lose" if:
     * 
     *       Computer: "rock"      You: "scissors"
     *       Computer: "paper"     You: "rock"
     *       Computer: "scissors"  You: "paper"
     * 
     *   3. result is "It's a tie" if:
     * 
     *       your choice equals computer choice.
     *   
     *   4. Otherwise, print "ERROR" and exit the program.
     */

    public static String result(String yourChoice, String computerChoice) {
        String result = "";
        
        if (yourChoice.equals("rock") && computerChoice.equals("scissors")) {
            result = "You win!";
        } else if (yourChoice.equals("rock") && computerChoice.equals("paper")) {
            result = "You lose!";
        } else if (yourChoice.equals("paper") && computerChoice.equals("rock")) {
            result = "You win!";
        } else if (yourChoice.equals("paper") && computerChoice.equals("scissors")) {
            result = "You lose!";
        } else if (yourChoice.equals("scissors") && computerChoice.equals("paper")) {
            result = "You win!";
        } else if (yourChoice.equals("scissors") && computerChoice.equals("rock")) {
            result = "You lose!";
        } else if (yourChoice.equals(computerChoice)) {
            result = "It's a tie!";
        } else {
            System.out.println("INVALID CHOICE");
            System.exit(0);
        }
        return result;
      }


    //Task 5  – Write a function that prints your choice, the computer's, and the result.


    /**
     * Name: printResult - It prints everything (your choice, computer choice, result)
     * @param yourChoice (String)
     * @param computerChoice (String)
     * @param result (String)
     * 
     * Inside the function:
     *  1. prints everything:
     *      – prints: You chose: (tab of space) <your choice>
     *      – prints: The computer chose: (tab of space) <computer choice>
     *      – prints: <result>
     */


      public static void printResult(String yourChoice, String computerChoice, String result) {
        System.out.println("\nYou chose:\t" + yourChoice);
        System.out.println("The computer chose:\t" + computerChoice);
        System.out.println(result);
    }

}