// SPDX-FileCopyrightText: 2024 Lizzy Fleckenstein <lizzy@vlhl.dev>
//
// SPDX-License-Identifier: AGPL-3.0-or-later

#include <stdlib.h>
#include <string.h>
#include "chunk.h"

node *chunk_col(chunk c, uint32_t x)
{
	return &c.data[c.pitch*x];
}

node *chunk_index(chunk c, uvec2 v)
{
	return &chunk_col(c, v.x)[v.y];
}

node *chunk_index_abs(chunk c, vec2 v)
{
	if (box2_contains(c.bounds, v))
		return chunk_index(c, CUVEC2(vec2_sub(v, c.bounds.pos)));
	else
		return NULL;
}

chunk chunk_sub(chunk c, box2 area)
{
	return (chunk) {
		.pitch = c.pitch,
		.bounds = area,
		.data = chunk_index(c, CUVEC2(vec2_sub(area.pos, c.bounds.pos))),
	};
}

chunk chunk_alloc(box2 b)
{
	return (chunk) {
		.pitch = b.size.y,
		.bounds = b,
		.data = calloc(b.size.x * b.size.y, sizeof(node)),
	};
}

void chunk_copy(chunk dst, chunk src)
{
	box2 area = box2_overlap(dst.bounds, src.bounds);
	if (box2_empty(area))
		return;

	chunk d = chunk_sub(dst, area);
	chunk s = chunk_sub(src, area);

	if (d.pitch == area.size.y && s.pitch == area.size.y)
		memcpy(d.data, s.data, area.size.x * area.size.y * sizeof(node));
	else for (uint32_t x = 0; x < area.size.x; x++)
		memcpy(chunk_col(d, x), chunk_col(s, x), area.size.y * sizeof(node));
}

void chunk_clear(chunk c)
{
	if (c.bounds.size.y == c.pitch)
		memset(c.data, 0, c.bounds.size.x * c.bounds.size.y * sizeof(node));
	else for (uint32_t x = 0; x < c.bounds.size.x; x++)
		memset(chunk_col(c, x), 0, c.bounds.size.y * sizeof(node));
}