//-------------------------------------------------
//
// A very simple predator/prey game
//
// We have a grid world on which there lives a rabbit and
// a fox. The rabbit moves randomly, and the user moves
// the fox in an attempt to catch the rabbit.
//
// This is a more advanced version of fox.cpp, using some
// techniques that we haven't covered yet, but which you
// can look up in the textbook.
//
// Simon Parsons
// October 15th 2008
//
//-------------------------------------------------

// Include C++ library definitions

#include <iostream> // For cin cout
#include <cstdlib>  // For rand
#include <cmath>    // For sqrt
#include <ctime>    // For time

using namespace std;

//-------------------------------------------------
//
// Declare methods

// Make a random movement. Either go forwards, go backwards
// or do not move. So that the rabbit doesn't move 2 squares
// too often, make a no-move happen half the time.

int makeRandomMove(void)
{

  int movement;

  movement = rand() % 4;

  if((movement == 0) || (movement == 3))
    {
      return 0;
    }
  else
  if(movement == 1)
    {
      return 1;
    }
  else
  if(movement == 2)
    {
      return -1;
    }
  else // Won't get here but the compiler creates a warning otherwise
    {
      return 0;
    }
}

// Keep the fox and the rabbit in a 10 by 10 grid

int wrapAround(int coordinate)
{
  if(coordinate > 10)
    {
      return 0;
    }
  else
  if(coordinate < 0)
    {
      return 10;
    }
  else
    {
      return coordinate;
    }
}

// Give the position of the fox and the rabbit.

void displayPosition(int xF, int yF, int xR, int yR)
{
    int dx;
    int dy;

    for(dy=10; dy>=0; dy--)
    {
        cout << "\n-----------------------\n";

        for (dx=0; dx<=11; dx++)
        {
            if((xF == dx) && (yF == dy))
            {
                cout << "|F";
            }
            else
            if((xR ==dx) && (yR == dy))
            {
                cout << "|R";
            }
            else
            {
                cout << "| ";
            }
        }
    }

    cout << "\n-----------------------\n\n";

}

// Move the fox, using a switch statement and reference parameters

void moveFox(char move, int &xF, int &yF)
{
  switch(move) {
  case 'n':
    yF = wrapAround(yF + 1);
    break;
  case 's':
    yF = wrapAround(yF - 1);
    break;
  case 'e':
    xF = wrapAround(xF + 1);
    break;
  case 'w':
    xF = wrapAround(xF - 1);
    break;
    
  default:
    cout << "The fox is confused" << endl << endl;
  }
}

//------------------------------------------------
//
// The main body of the program

int main()

{
    // Declare variables

    int xFox;          // Fox's x position
    int yFox;          // Fox's y position
    int xRabbit;       // Rabbit's x position
    int yRabbit;       // Rabbit's y position
    char c;            // User's input
    bool quit = false; // Do we want to quit?

  // Initialisation. Pick locations of fox and rabbit randomly

  srand(time(NULL));    // Set the random seed

  xFox    = rand() % 11;
  yFox    = rand() % 11;
  xRabbit = rand() % 11;
  yRabbit = rand() % 11;
 
  cout << "Your job in this game is to have the fox catch the rabbit." << endl;
  cout << "The rabbit won't stay still!" << endl << endl;

  displayPosition(xFox, yFox, xRabbit, yRabbit);

  while(!quit)
  {

    // Get input from user

    cout << endl << "Enter q to quit, or n, s, e or w to have the fox move that way: ";
    cin  >> c;

    if (c=='q'){
        quit = true;
    }
    else{
      moveFox(c, xFox, yFox);
    }

    xRabbit = wrapAround(xRabbit + makeRandomMove());
    yRabbit = wrapAround(yRabbit + makeRandomMove());

    displayPosition(xFox, yFox, xRabbit, yRabbit);

    if((xFox == xRabbit) && (yFox == yRabbit)){
      cout << "Yay!, you caught the rabbit" << endl;
      quit = true;
    }

    // Move the rabbit randomly, using wrapAround to make
    // sure that it stays within the grid.
  }
 
  cout << "Bye" << endl;

  return 0;
}