//-------------------------------------------------
//
// A small predator/prey example.
//
// We have a(nother) grid world on which there lives
// a rabbit.
//
// The user plays the fox which tries to catch the rabbit.
// Since the moves are, effectively, simultaneous, and the
// rabbit moves randomly, the game can go on for a surprisingly
// long time.
//
// Simon Parsons
// March 14th 2007
//
//-------------------------------------------------

// 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

// A method that prints a grid with the fox and
// the rabbit

void displayPosition(int xFox, int yFox, int xRabbit, int yRabbit)
{
    int dx;
    int dy;

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

        for (dx=0; dx<=11; dx++)
        {
            if((xFox == dx) && (yFox == dy))
            {
                cout << "|F";
            }
            else
            if((xRabbit ==dx) && (yRabbit == dy))
            {
                cout << "|R";
            }
            else
            {
                cout << "| ";
            }
        }
    }

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

}

// Methods to move the animals around. Each method
// moves the animal one square in the given direction.
// The world "wraps around", so that if the animal
// moves off the "top" of the grid it reappears at
// the bottom, and so on.

int moveNorth(int y)
{
  cout << "moving North...\n";
  if (y <= 9)
    {
        y = y + 1;
    }
  else
    {
      y = 0;
    }
  return y;
}

int moveSouth(int y)
{
  cout << "moving South...\n";
  if (y >= 1)
    {
        y = y - 1;
    }
  else
    {
        y = 10;
    }
  return y;
}

int moveWest(int x)
{
  cout << "moving West...\n";
  if (x >= 1)
    {
        x = x - 1;
    }
  else
    {
        x = 10;
    }
  return x;
}

int moveEast(int x)
{
  cout << "moving East...\n";
  if (x <= 9)
    {
        x = x + 1;
    }
  else
    {
        x = 0;
    }
  return x;
}

//------------------------------------------------
//
// 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
    int moveRabbit;    // How we move the rabbit
    char c;            // User's input
    bool quit = false; // Do we want to quit?

  // Initialisation

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

  xFox    = rand() % 11;
  yFox    = rand() % 11;
  xRabbit = rand() % 11;
  yRabbit = rand() % 11;

  //distance = 0;

  displayPosition(xFox, yFox, xRabbit, yRabbit);

  while(!quit)
  {
   // Get input from user

   cout << "Which way should the fox move (enter N,S,E,W or Q)? ";
   cin  >> c;

   // Depending on what the user entered, move the fox the right way

   if ( c=='N' )
   {
     yFox = moveNorth(yFox);
   }

   if ( c=='S' )
   {
     yFox = moveSouth(yFox);
   }

   if ( c=='E' )
   {
     xFox = moveEast(xFox);
   }

   if ( c=='W' )
   {
     xFox = moveWest(xFox);
   }

   // At the same time, the rabbit moves
   //
   // Move the rabbit randomly. Generate a random number
   // and use that to choose a direction to move in.
   // One time in 5 the rabbit doesn't move.

   moveRabbit = rand() % 5;

   if(moveRabbit == 0)
     {
       yRabbit = moveNorth(yRabbit);
     }
   
   if(moveRabbit == 1)
     {
       yRabbit = moveSouth(yRabbit);
     }

   if(moveRabbit == 2)
     {
       xRabbit = moveEast(xRabbit);
     }

   if(moveRabbit == 3)
     {
       xRabbit = moveWest(xRabbit);
     }

   // See where we ended up.

   displayPosition(xFox, yFox, xRabbit, yRabbit);

   // Did the fox catch the rabbit?

   if ((xFox == xRabbit) && (yFox == yRabbit))
     {
       cout << "Yay! The fox caught the rabbit\n";
       quit = true;
     }

   // If we entered Q, then we want to quit.
   
   if (c=='Q')
     {
       quit = true;
     }

  }

  cout << "Bye" << endl;

  return 0;
}