#include <iostream>
#include <cstdlib>

using namespace std;

enum RPSChoice
{
    ROCK = 1,
    PAPER = 2,
    SCISSORS = 3
};

// Convert an user input character to a choice ID
int characterToChoice(char c)
{
    c = tolower(c);
    if (c == 'r')
        return ROCK;
    else if (c == 's')
        return SCISSORS;
    else if (c == 'p')
        return PAPER;
    else
        return 0; // Not a proper choice!
}

// Decide who is the winner
int winner(int user1, int user2) {
    if (user1 == user2) {
        return 0; // tie
    }
    else if ((user1 == ROCK && user2 == PAPER) ||
             (user1 == PAPER && user2 == SCISSORS) ||
             (user1 == SCISSORS && user2 == ROCK)) {
        return 2; // user2 is the winner
    }
    else {
        return 1; // user1 is the winner
    }
}

// Print someone's decision at the game
void printDecision(string who, int choice) {
    cout << who; // no matter what, we will tell who took a decision
    if (choice == ROCK)
        cout << " chose ROCK!" << endl;
    else if (choice == PAPER)
        cout << " chose PAPER!" << endl;
    else if (choice == SCISSORS)
        cout << " chose SCISSORS!" << endl;
}

void playRPS (char x) {
    int user1 = characterToChoice(x);
    int user2 = rand() % 3 + 1;

    printDecision("You", user1);
    printDecision("The computer", user2);

    int result = winner(user1, user2);
    if (result == 0)
        cout << "It's a TIE!" << endl;
    else if (result == 1)
        cout << "You WON!" << endl;
    else
        cout << "You LOSE!" << endl;
}

int main() {
    char letter;

    cout << "Welcome to COP3014 ROCK PAPER SCISSORS!\n\n";

    cout << "Please select: " << endl
         << "Rock(r), Paper(p), or Scissors(s)? " << endl
         << "Or enter q to quit --> ";

    bool correctInput = false;

    do {
        cin >> letter;

        if (characterToChoice(letter) != 0) {
            playRPS(letter);
            correctInput = true;
        }
        else {
            cout << "Please enter r, p, or s" << endl;
        }
    } while (!correctInput);

    return 0;
}