#include <assert.h>
#include <user/stdio.h>
#include <user/syscall.h>

#define PID_SNAKE 0
#define PAGE_SIZE 4096
#define DATA_SEG_SIZE (4 * PAGE_SIZE)

typedef struct Food {
    char hint[16];
    int x;
    int y;
    int score;
} Food;

char __attribute__((aligned(0x1000))) snake_seg_data[DATA_SEG_SIZE];
// this attribute is necessary to make the pointer 4K aligned
int main()
{
	Food* food = NULL;
	lml_mmap(PID_SNAKE, (void*)0x0804d000, (void*)snake_seg_data, DATA_SEG_SIZE);
	// data segment: 
	// Type Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
	// LOAD 0x004000 0x0804d000 0x0804d000 0x0163c 0x12500 RW  0x1000
	// 'This is a food' starts @ file offset 0x542c, while .data starts @ 0x4000
	// so, offset is 0x142c
	food = (Food*)(snake_seg_data + 0x142c);
	// printf("%s\n", food->hint);
	while (1) {
		// printf("%d %d", food->x, food->y);
		if (food->x <= 0) food->x = 1;
		if (food->y <= 0) food->y = 1;
		if (food->x >= 70) food->x = 69;
		if (food->y >= 25) food->y = 24;
		// according to some trial, XMAX(right veritcal line border)=69, YMAX(low edge of screen)=24
	}
	return 0;
}