#include <genesis.h>
#include "creep.h"
#include "map.h"

creep creeps[MAX_CREEPS];
u16 cur_creeps;

const s16 speeds[NUM_SPECIES] = { 2 };

u16 spawn_creep(u8 species, s16 x, s16 y)
{
	u16 index;
	for (index = 0; index < MAX_SPRITE; index++)
	{
		if (spriteDefCache[index].posx == -0x80) {
			break;
		}
	}
	if (index > 0) {
		VDP_setSprite(index, x, y, SPRITE_SIZE(1, 1), TILE_ATTR_FULL(2, 0, 0, 0, 'C' + TILE_FONTINDEX), spriteDefCache[0].link);
		spriteDefCache[0].link = index;
	} else {
		VDP_setSprite(index, x, y, SPRITE_SIZE(1, 1), TILE_ATTR_FULL(2, 0, 0, 0, 'C' + TILE_FONTINDEX), 0);
	}
	creeps[cur_creeps].index = index;
	creeps[cur_creeps].health = 1000;
	creeps[cur_creeps].species = species;
	creeps[cur_creeps].direction = 0;
	creeps[cur_creeps].targetx = x;
	creeps[cur_creeps].targety = y;
	return cur_creeps++;
}

void update_creeps(void)
{
	s16 i, disty, distx, mdist;
	for (i = cur_creeps-1; i >= 0; --i)
	{
		creep *cur = creeps + i;
		SpriteDef * sprite = spriteDefCache + cur->index;
		distx = sprite->posx - cur->targetx;
		if (distx < 0)
			distx = -distx;
		disty = sprite->posy - cur->targety;
		if (disty < 0)
			disty = -disty;
		mdist = distx > disty ? distx : disty;
		if (mdist < speeds[cur->species])
		{
			s16 dindex = sprite->posx / 16 + (sprite->posy / 16) * 20;
			if (distances[dindex])
			{
				u16 bestdist = 0xFFFF;
				s16 bestindex = 0xFFFF,diff,next;
				if (sprite->posx > 8 && distances[dindex-1] < bestdist)
				{
					bestindex = dindex-1;
					bestdist = distances[bestindex];
				}
				if (sprite->posx < (320-16) && distances[dindex+1] < bestdist)
				{
					bestindex = dindex+1;
					bestdist = distances[bestindex];
				}
				if (sprite->posy > 8 && distances[dindex-20] < bestdist)
				{
					bestindex = dindex-20;
					bestdist = distances[bestindex];
				}
				if (sprite->posy < (224-16) && distances[dindex+20] < bestdist)
				{
					bestindex = dindex+20;
					bestdist = distances[bestindex];
				}
				diff = bestindex-dindex;
				next = bestindex + diff;
				while (next >= 0 && next < 20*14 && distances[next] < bestdist)
				{
					bestindex = next;
					bestdist = distances[bestindex];
				}
				cur->targetx = (bestindex % 20) * 16 + 4;
				cur->targety = (bestindex / 20) * 16 + 4;
			} else {
				//creep is at the goal
				VDP_setSpritePosition(cur->index, -0x80, -0x80);
				cur_creeps--;
				if (i != cur_creeps)
				{
					memcpy(cur, creeps+cur_creeps, sizeof(creep));
				}
			}
		} else {
			if (distx > disty) {
				VDP_setSpritePosition(cur->index,
					sprite->posx + (sprite->posx > cur->targetx ? -speeds[cur->species] : speeds[cur->species]),
					sprite->posy);
			} else {
				VDP_setSpritePosition(cur->index,
					sprite->posx,
					sprite->posy + (sprite->posy > cur->targety ? -speeds[cur->species] : speeds[cur->species]));
			}
		}
	}
}