//game_of_life.c - generates a random initial state of the grid, then cycles through the # of generations specified.
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <math.h>
#include <string.h>

#define KBLU  "\x1B[34m"

const int NUM_ROWS = 65; // note: one-cell border is included in this size
const int NUM_COLS = 129; // ^
const int GENERATIONS = 128;

void generate(int grid[NUM_ROWS][NUM_COLS]);

int main(void)
{
    int grid[NUM_ROWS][NUM_COLS];
    srand(time(NULL));
    // initialise one-cell border around grid
    for(int i = 0; i < NUM_ROWS; i++)
    {
        grid[i][0] = 0;
        grid[i][NUM_COLS - 1] = 0;
    }
    for(int i = 1; i < NUM_COLS; i++)
    {
        grid[0][i] = 0;
        grid[NUM_ROWS - 1][i] = 0;
    }
    for(int i = 1; i < NUM_ROWS - 1; i++)
    {
        for(int j = 1; j < NUM_COLS - 1; j++)
        {
            grid[i][j] = rint((float) (rand() % 10) - 5);
        }
    }
    // cycle through generations
    generate(grid);
}

void generate(int grid[NUM_ROWS][NUM_COLS])
{
    for(int i = 0; i < GENERATIONS; i++)
    {
        int new_grid[NUM_ROWS][NUM_COLS];
        printf("\e[1;1H\e[2J");
        sleep(1);
        // print current state to screen
        for (int i = 0; i < NUM_ROWS; i++)
        {
            for(int j = 0; j < NUM_COLS; j++)
            {
                printf(KBLU "%c", grid[i][j] == 1 ? 'o' : ' ');
            }
            printf("\n");
        }
        // initialise one-cell border around grid
        for(int i = 0; i < NUM_ROWS; i++)
        {
            new_grid[i][0] = 0;
            new_grid[i][NUM_COLS - 1] = 0;
        }
        for(int i = 1; i < NUM_COLS; i++)
        {
            new_grid[0][i] = 0;
            new_grid[NUM_ROWS - 1][i] = 0;
        }
        // apply rules
        for(int i = 1; i < NUM_ROWS - 1; i++)
        {
            for(int j = 1; j < NUM_COLS - 1; j++)
            {
                int count = 0;
                count = grid[i-1][j-1] + grid[i-1][j] + grid[i-1][j+1] + grid[i][j-1] + grid[i][j+1]
                        + grid[i+1][j-1] + grid[i+1][j] + grid[i+1][j+1];
                if(grid[i][j] && (count < 2 || count > 3))
                    new_grid[i][j] = 0;
                else if (grid[i][j])
                    new_grid[i][j] = 1;
                else if (!grid[i][j] && count == 3)
                    new_grid[i][j] = 1;
                else
                    new_grid[i][j] = 0;
            }

        }
        memcpy(grid, new_grid, NUM_ROWS * NUM_COLS * sizeof(int));

    }
}