#include <gint/keyboard.h>
#include "draw.h"
#include "collide.h"
#include "levels.h"

void jump_test(char *jump_pressed, char *jump_buffer); //test if jump pressed
char sgn(int number); //return the sign of input double

int main(void)
{
	char level[14*25];
	unsigned char level_id = 0;
	char jump_pressed = 0; //avoid holding jump
	char jump_buffer = 0; //jump buffer, last 3 frames
	double vspd = 0; //player vertical speed
	char hspd = 0; //player horizontal speed
	char on_ground = 6; //remember if player is on solid
	int player_x = 0;
	int player_y = 0;
	int old_x, old_y;
	const double jump_spd = -4; //default jump speed
	const double grav = 0.2;
	const double min_vspd = -8;
	dclear(0); //0 -> black
	set_level(level_id, level);
	draw_level(level, &player_x, &player_y);
	old_x = player_x + 1; //offset to draw it on first cycle
	old_y = player_y;
	while (1) {
		draw_player(old_x, old_y, player_x, player_y);
		dupdate();
		old_x = player_x;
		old_y = player_y;
		pollevent();
		//horizontal movement
		hspd = 0;
		if (keydown(KEY_LEFT)) hspd--;
		if (keydown(KEY_RIGHT)) hspd++;
		if (!collide(player_x + hspd, player_y, level, '0'))
		{
			player_x += hspd;
		}
		//ground detection
		if (collide(player_x, player_y + 1, level, '0')) on_ground = 6;
		else
		{
			if (vspd > min_vspd) vspd += grav;
			if (on_ground) on_ground--;
		}
		//vertical movement
		jump_test(&jump_pressed, &jump_buffer);
		//if jump is pressed and on ground
		if (jump_buffer && on_ground) {
			vspd = jump_spd;
			on_ground = 0;
		}
		//vertical collision
		{
			int trunc_vspd = vspd; //truncate vspd
			if (!collide(player_x, player_y + trunc_vspd, level, '0'))
			{
				player_y += trunc_vspd;
			}
			else
			{
				char sign_vspd = sgn(trunc_vspd);
				while (!collide(player_x, player_y + sign_vspd, level, '0'))
				{
					player_y += sign_vspd;
				}
				vspd = 0;
			}
		}
		//exit
		if (keydown(KEY_EXIT)) return 0;
	}
}

void jump_test(char *jump_pressed, char *jump_buffer)
{
	if (keydown(KEY_SHIFT))
	{
		if (!*jump_pressed)
		{
			*jump_pressed = 1;
			*jump_buffer = 3;
		}
	}
	else {
		*jump_pressed = 0;
	}
	if (*jump_buffer) *jump_buffer -= 1;
}

char sgn(int number)
{
	if (number < 0) return -1;
	else return 1;
}