/* SPDX-License-Identifier: GPL-3.0-or-later */
/* Copyright (C) 2021 KikooDX */

#include "conf.h"
#include "level.h"
#include "player.h"
#include "tiles.h"

extern struct Level level;

static Tile collide_single(int x, int y);
static int collide_sub_single(int x, int y, Tile sub, Tile rep);

void player_collide(Tile collisions[COLLIDE_POINTS], int x, int y)
{
	const int rx = x + PLAYER_WIDTH - 1;
	const int dy = y + PLAYER_HEIGHT - 1;
	collisions[UP_LEFT] = collide_single(x, y);
	collisions[UP_RIGHT] = collide_single(rx, y);
	collisions[DOWN_LEFT] = collide_single(x, dy);
	collisions[DOWN_RIGHT] = collide_single(rx, dy);
}

int player_collide_tile(Tile collisions[COLLIDE_POINTS], int x, int y,
                        Tile tile, int update)
{
	int i;
	if (update)
		player_collide(collisions, x, y);
	for (i = 0; i < COLLIDE_POINTS; i += 1)
		if (collisions[i] == tile)
			return 1;
	return 0;
}

/* collide and replace tiles, return the number of tiles affecter */
int player_collide_sub(int x, int y, Tile sub, Tile rep)
{
	const int rx = x + PLAYER_WIDTH - 1;
	const int dy = y + PLAYER_HEIGHT - 1;
	return collide_sub_single(x, y, sub, rep) +
	       collide_sub_single(rx, y, sub, rep) +
	       collide_sub_single(x, dy, sub, rep) +
	       collide_sub_single(rx, dy, sub, rep);
}

int player_collide_solid(int x, int y)
{
	Tile collisions[COLLIDE_POINTS];
	return player_collide_tile(collisions, x, y, TILE_SOLID, 1);
}

static Tile collide_single(int x, int y)
{
	const int tx = x / TILE_WIDTH;
	const int ty = y / TILE_WIDTH;
	/* out of bounds handling */
	if (x < 0 || y < 0 || tx >= level.width || ty >= level.height)
		return TILE_OOB;
	return level.data[tx + ty * level.width];
}

/* try collide and replace tile at pixel position, return 1 if tile
 * replaced */
static int collide_sub_single(int x, int y, Tile sub, Tile rep)
{
	if (collide_single(x, y) == sub) {
		const int tile_index =
		    (int)(x / TILE_WIDTH) +
		    (int)(y / TILE_WIDTH) * level.width;
		level.data[tile_index] = rep;
		return 1;
	}
	return 0;
}