// A console conway's game of life program by Bruce Hill
// Released under the MIT license, see LICENSE for details.
// This file contains the main code for the table viewer.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <termbox.h>
#include <unistd.h>

#ifndef bool
typedef char bool;
#endif

static bool survive[9] = {0,0,1,1,0,0,0,0,0};
static bool birth[9] =   {0,0,0,1,0,0,0,0,0};

static void update(const bool *cells, bool *future_cells)
{
    int W = tb_width()/2, H = tb_height();
    for (int y = 0; y < H; y++) {
        for (int x = 0; x < W; x++) {
            int neighbors = (
                cells[(y-1 % H)*W + (x-1 % W)] +
                cells[(y-1 % H)*W + (x % W)] +
                cells[(y-1 % H)*W + (x+1 % W)] +
                cells[y*W + (x-1 % W)] +
                cells[y*W + (x+1 % W)] +
                cells[(y+1 % H)*W + (x-1 % W)] +
                cells[(y+1 % H)*W + (x % W)] +
                cells[(y+1 % H)*W + (x+1 % W)]
            );
            future_cells[y*W + x] = cells[y*W + x] ? survive[neighbors] : birth[neighbors];
            if (future_cells[y*W + x] != cells[y*W + x]) {
                tb_change_cell(2*x, y, ' ', 0, future_cells[y*W + x] ? 8 : 0);
                tb_change_cell(2*x+1, y, ' ', 0, future_cells[y*W + x] ? 8 : 0);
            }
        }
    }
}

int main(int argc, char **argv) {
    for (int i = 1; i < argc; i++) {
        if (strcmp(argv[i], "--help") == 0) {
            printf("Conway's Game of Life Viewer\nUsage: conway [-S012345678] [-B012345678]\n");
            return 0;
        } else if (strncmp(argv[i], "-B", 2) == 0) {
            memset(birth, 0, sizeof(birth));
            for (char *p = &argv[i][2]; *p; p++) {
                if ('0' <= *p && *p <= '8')
                    birth[*p - '0'] = 1;
            }
        } else if (strncmp(argv[i], "-S", 2) == 0) {
            memset(survive, 0, sizeof(survive));
            for (char *p = &argv[i][2]; *p; p++) {
                if ('0' <= *p && *p <= '8')
                    survive[*p - '0'] = 1;
            }
        }
    }

    int ret = tb_init();
    if (ret) {
        fprintf(stderr, "tb_init() failed with error code %d\n", ret);
        return 1;
    }
    tb_select_input_mode(TB_INPUT_MOUSE);

    int flipflop = 0;
    int W = tb_width()/2, H = tb_height();
    bool *buffers[2];
  resize:
    buffers[0] = calloc(W*H, sizeof(bool));
    buffers[1] = calloc(W*H, sizeof(bool));
    for (int x = 0; x < W; x++) {
        for (int y = 0; y < H; y++) {
            buffers[flipflop][y*W+x] = random() % 2;
        }
    }

    tb_clear();
    while (1) {
        update(buffers[flipflop], buffers[!flipflop]);
        flipflop = !flipflop;
        tb_present();
        usleep(60000);
        struct tb_event ev;
        while (tb_peek_event(&ev, 0)) {
            switch (ev.type) {
                case TB_EVENT_RESIZE:
                    W = tb_width()/2, H = tb_height();
                    goto resize;

                case TB_EVENT_KEY:
                    switch (ev.key) {
                        case TB_KEY_ESC:
                            if (tb_peek_event(&ev, 50) == 0)
                                goto done;
                            else break;
                    }
                    switch (ev.ch) {
                        case 'q':
                            goto done;
                    }
                    break;

                case TB_EVENT_MOUSE:
                    buffers[flipflop][ev.y*W + ev.x/2] = !buffers[flipflop][ev.y*W + ev.x/2];
                    tb_change_cell(2*(ev.x/2), ev.y, ' ', 0, buffers[flipflop][ev.y*W + ev.x/2] ? 8 : 0);
                    tb_change_cell(2*(ev.x/2)+1, ev.y, ' ', 0, buffers[flipflop][ev.y*W + ev.x/2] ? 8 : 0);
                    tb_present();
                    usleep(10000);
                    break;
            }
        }
    }
  done:
    tb_shutdown();
    return 0;
}