#include <iostream>
#include <cstdlib>
#include <string.h>

/*
 * nearest neighbor computation.
 *    2 or 3 cells remain alive
 *    3 cells generate new life
 *    Other die.
 *
 *    Perodic boundry conditions.
 * */

using namespace std;

const int MAX_ROWS = 20;
const int MAX_COLS = 40;
const float LIFE_CHANCE = .3;
bool DEBUG = false;

void InitBoard(int board[][MAX_COLS], int rows, int cols);
void InitBoard1(int board[][MAX_COLS], int rows, int cols);
void PrintBoard(int board[][MAX_COLS], int rows, int cols);
void UpdateBoard(int board1[][MAX_COLS],int board2[][MAX_COLS], 
                 int rows, int cols);
void CopyBoard(int board1[][MAX_COLS],int board2[][MAX_COLS],
               int rows, int cols);
int NeighborCount(int board[][MAX_COLS], int rows, int cols, int r, int c);

int main (int argc, char * argv[]) {

    int board1[MAX_ROWS][MAX_COLS];
    int board2[MAX_ROWS][MAX_COLS];
    int rows = MAX_ROWS, columns = MAX_COLS;
    int turn=0;
    bool randInit = true;
    int i;
 
    i = 1;
    while(i < argc) {
       cout << "Looking at argv[i] = " << argv[i] << endl;
       if (!strcmp(argv[i],"-x")){
          if (i+1 < argc) {
	      i++;
	      columns = atoi(argv[i]);
	      cout << "Changing columns to be " << columns << endl;
	  }
	  i++;
       } else if (!strcmp(argv[i],"-y")){
          if (i+1 < argc) {
	      i++;
	      rows = atoi(argv[i]);
	      cout << "Changing rows to be " << rows << endl;
	  }
	  i++;
       } else if (!strcmp(argv[i],"-v")){
          cout << "Settnig debug to true " << endl;
          DEBUG = true;
	  i++;
       } else if (!strcmp(argv[i],"-r")){
          cout << "setting andom init false" << endl;
          randInit = false;
	  i++;
       } else {
          cout << "Unknown Argument " << argv[i] << endl;
	  i++;
       }
    }

    cout << "Playing LIFE" << endl;
    cout << "with rows = " << rows << " cols = " << columns << endl;
    srand(time(NULL));

    if (randInit) {
        InitBoard(board1, rows, columns);
    } else {
        InitBoard1(board1, rows, columns);
    }
    PrintBoard(board1, rows, columns);

    for(turn=0;;turn++) {
        UpdateBoard(board1, board2, rows, columns);
	cout << "Turn " << turn << endl;
        PrintBoard(board2, rows, columns);
	CopyBoard(board2, board1, rows, columns);
    }
}

void InitBoard(int board[][MAX_COLS], int rows, int cols){
   int i,j;

   for(i=0;i<rows;i++) {
       for(j=0;j<cols;j++) {
           if (rand()/float(RAND_MAX) < LIFE_CHANCE) {
	       board[i][j] = 1;
	   } else {
	       board[i][j] = 0;
	   }
       }
   }

   return;
}

void InitBoard1(int board[][MAX_COLS], int rows, int cols){
   int i,j;

   for(i=0;i<rows;i++) {
       for(j=0;j<cols;j++) {
           board[i][j] = 0;
       }
   }

   //  a block
   if (rows >1 && cols > 1) {
       board[0][0] = 1;
       board[0][1] = 1;
       board[1][0] = 1;
       board[1][1] = 1;
   }

   // a blinker
   if (rows > 5 && cols > 7) {
       board[5][5] = 1;
       board[5][6] = 1;
       board[5][7] = 1;
   }

   // a glider
   if(rows > 10 && cols > 3) {
       board [10][1] = 1;
       board [10][2] = 1;
       board [10][3] = 1;
       board [9][3] = 1;
       board [8][2] = 1;
   }


   return ;
}

void BlankLine(int cols) {
   int j;

   cout << "+";
   for(j=0;j<cols;j++) {
     cout << "-";
   } 
   cout << "+";
   cout << endl;
}

void PrintBoard(int board[][MAX_COLS], int rows, int cols){
   int i,j;

   BlankLine(cols);

   for(i=0;i<rows;i++) {
       cout << "|";
       for(j=0;j<cols;j++) {
          if(board[i][j] > 0){
	      cout << "#";
	  } else {
	      cout << " ";
	  }
       }
       cout << "|";
       cout << endl;
   }

   BlankLine(cols);

   return;
}

int FixCoord(int value, int max) {
    if (value < 0) {
       value = max-1;
    } else if (value >= max) {
       value = 0;
    }

    return value;
}

int GetCell(int board[][MAX_COLS], int rows, int cols, int r, int c) {
    r = FixCoord(r, rows);
    c = FixCoord(c, cols);
    return board[r][c];
}


int NeighborCount(int board[][MAX_COLS], int rows, int cols, int r, int c){
    int count = 0;
    int i,j;

    for(i=-1;i<2;i++) {
       for(j=-1;j<2;j++) {
          if (GetCell(board, rows,cols,r+i,c+j) > 0) {
	      count ++;
	  }
       }
    }

    if (board[r][c] > 0) {
       count --;
    }

    return count;
}


void UpdateBoard(int board1[][MAX_COLS], int board2[][MAX_COLS], 
                 int rows,int cols){
   int neighbors;
   int i,j;

   for(i=0;i<rows;i++) {
       for(j=0;j<cols;j++) {
          neighbors = NeighborCount(board1, rows,cols,i,j);
	  if (neighbors > 0 && DEBUG) {
	      cout << "cell " << i << ", " << j << " has "
	           << neighbors << " neighbors " << endl;
	  }
	  if (neighbors < 2) {
	     board2[i][j] = 0;
	  } else if (neighbors == 2 && board1[i][j] != 0) {
	     board2[i][j] = board1[i][j] + 1;
	  } else if (neighbors == 3) {
	     board2[i][j] = board1[i][j] + 1;
	  } else {
	     board2[i][j] = 0;
	  }
       }
   }
    
   return;
}

void CopyBoard(int board1[][MAX_COLS], int board2[][MAX_COLS], 
               int rows, int cols){
   int i,j;

   for(i=0;i<rows;i++) {
       for(j=0;j<cols;j++) {
          board2[i][j] = board1[i][j] ;
       }
   }

   return;
}