#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include "util.h"

s32 reduce(s32 (*f)(s32 x, s32 y), s32 arr[], s32 len)
{
	s32 ret = arr[0];

	for (s32 i = 1; i < len; ++i) {
		ret = f(ret, arr[i]);
	}

	return ret;
}

s32 mul(s32 x, s32 y)
{
	return x * y;
}

s32 max(s32 x, s32 y)
{
	return x > y ? x : y;
}

s32 count_char_in_string(char c, char *s)
{
	s32 count = 0;
	do
		if (c == *s)
			count++;
	while (*s++);
	return count;
}

char *goto_char_in_string(char c, char *s)
{
	do
		if (c == *s)
			return s;
	while (*s++);
	return NULL;
}

#define PP(arr, y,x) *(*(arr+y)+x)

// char filename[] = "in/day08.ref";
char filename[] = "in/day08.pzl";

#define BUF_LEN 10000
char file_buf[BUF_LEN];

int main()
{
	int fd = open(filename, O_RDONLY);
	s32 data_len = read(fd, file_buf, LEN(file_buf));

	if (data_len == -1) {
		printf("error opening file\n");
		exit(1);
	} else if (data_len == LEN(file_buf)) {
		printf("buffer probably not big enough\n");
		exit(1);
	}
	file_buf[data_len] = '\0';

	s32 y_len = count_char_in_string('\n', file_buf);
	s32 x_len;
	// printf("y_len: %d\n", y_len);

	s32 **arr = malloc(y_len * sizeof(s32*));
	s32 **flag = malloc(y_len * sizeof(s32*));
	char *start  = file_buf;
	for (s32 i = 0; i < y_len; ++i) {
		char *end = goto_char_in_string('\n', start);
		x_len = end - start;
		// printf("x_len: %d\n", x_len);

		*(arr+i) = malloc(x_len * sizeof(s32*));
		*(flag+i) = malloc(x_len * sizeof(s32*));

		for (s32 j = 0; j < x_len; ++j) {
			*(*(arr+i) + j) = *(start + j) - '0';
			*(*(flag+i) + j) = 0;
		}
		start = end+1;
	}


	s32 res1 = 0;
	s32 maxval;

#define RES1_CHECK() \
			if (PP(arr, y, x) > maxval) {       \
				maxval = PP(arr, y, x);     \
				if (PP(flag, y, x) == 0) {  \
					PP(flag, y, x) = 1; \
					res1 += 1;          \
				}                           \
			}

	for (s32 y = 0; y < y_len; ++y) {
		maxval = -1;
		for (s32 x = 0; x < x_len; ++x)
			RES1_CHECK();
		maxval = -1;
		for (s32 x = x_len-1; x >= 0 ; --x)
			RES1_CHECK();
	}
	for (s32 x = 0; x < x_len; ++x) {
		maxval = -1;
		for (s32 y = 0; y < y_len; ++y)
			RES1_CHECK();
		maxval = -1;
		for (s32 y = y_len-1; y >= 0 ; --y)
			RES1_CHECK();
	}


	s32 res2 = 0;
	for (s32 y = 0; y < y_len; ++y) {
		for (s32 x = 0; x < x_len; ++x) {

			s32 rldu[4] = {0};
			for (s32 r = x+1; r < x_len; ++r)
				if ((PP(arr,y,r) >= PP(arr,y,x)) || (r==(x_len-1))) {
					rldu[0] += r-x;
					break;
				}
			for (s32 l = x-1; l >= 0; --l)
				if ((PP(arr,y,l) >= PP(arr,y,x)) || (l==0)) {
					rldu[1] += x-l;
					break;
				}
			for (s32 d = y+1; d < y_len; ++d)
				if ((PP(arr,d,x) >= PP(arr,y,x)) || (d==(y_len-1))) {
					rldu[2] += d-y;
					break;
				}
			for (s32 u = y-1; u >= 0; --u)
				if ((PP(arr,u,x) >= PP(arr,y,x)) || (u==0)) {
					rldu[3] += y-u;
					break;
				}
			res2 = max(res2, reduce(mul, rldu, LEN(rldu)));
		}
	}

	printf("res1: %d\n", res1);
	printf("res2: %d\n", res2);
	// asm("int3");
}