public interface Player {

    public String getUserInput(Board Connect4) throws IOException;
    public boolean hasWon(Board Connect4);
}

public class HumanPlayer implements Player {
    private int boardColumn = 0;

    @Override
    public String getUserInput(Board Connect4) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            //Player One Logic ----------------------------------------------------------------

            while (true) {
                System.out.println();
                System.out.println("Player 1, please select your column:");
                boardColumn = Integer.parseInt(br.readLine());

                if (Connect4.canMakeMove(boardColumn)) {

                    break;
                } else
                    System.out.println("Column " + boardColumn + " is already full!!");
            }
        return null;
    }

    @Override
    public boolean hasWon(Board Connect4) {
        if(Connect4.placeCounter(boardColumn, 1)){
            Connect4.printBoard();
            System.out.println("");
            System.out.println("Congratulations! Player 1 has won the game");
            return true;
        }
        return false;
    }
}

public class ComputerPlayer implements Player{
    private int boardColumn = 0;

    @Override
    public String getUserInput(Board Connect4) throws IOException {

        outer:
        while(true){
            System.out.println("");
            System.out.println("The Computer has selected a column and played a counter");
            System.out.println("");

            Random r = new Random();
            int num = r.nextInt(7);

            boardColumn = num;

            if(Connect4.canMakeMove(boardColumn)){

                break;
            }
            else
                System.out.println("Column "+boardColumn+" is already full!!");
        }

        return null;
    }

    @Override
    public boolean hasWon(Board Connect4) {
        if(Connect4.placeCounter(boardColumn, 2)){
            Connect4.printBoard();
            System.out.println("");
            System.out.println("Unlucky! The Computer has won this game");
            return true;
        }
        return false;
    }
}

public class Main {

    public static void main(String args[])throws IOException{
        Board Connect4 = new Board();


        HumanPlayer human = new HumanPlayer();
        ComputerPlayer computer = new ComputerPlayer();

        while(!human.hasWon(Connect4) && !computer.hasWon(Connect4)) {
            Connect4.printBoard();
            human.getUserInput(Connect4);
            computer.getUserInput(Connect4);
        }
    }


    public static void welcomeMessage() {
        System.out.println("Welcome to Connect 4");
        System.out.println("There are 2 players red and yellow");
        System.out.println("Player 1 is Red, Player 2 is Yellow");
        System.out.println("To play the game type in the number of the boardColumn you want to drop you counter in");
        System.out.println("A player wins by connecting 4 counters in a row - vertically, horizontally or diagonally");
        System.out.println("");
    }

}