#include <sys/mman.h>
#include <unistd.h>
#include <math.h>
#include <stdlib.h>

#include "drw.h"
#include "util.h"

/* static function declarations */
static Color to_color(uint32_t color);
static uint32_t to_uint32_t(Color color);


Canvas*
create_drw(struct wl_shm *shm, unsigned width, unsigned height)
{
	struct wl_shm_pool *pool;
	Canvas *canvas;
	int stride;
	int fd;

	canvas = malloc(sizeof(Canvas));
	canvas->width = width;
	canvas->height = height;

	stride = width * sizeof(uint32_t);
	canvas->size = stride * height;

	fd = allocate_shm_file(canvas->size);
	if (fd == -1) {
		return NULL;
	}

	canvas->data = mmap(
			NULL,
			canvas->size,
			PROT_READ | PROT_WRITE,
			MAP_SHARED,
			fd,
			0
		);

	if (canvas->data == MAP_FAILED) {
		close(fd);
		return NULL;
	}

	pool = wl_shm_create_pool(
			shm,
			fd,
			canvas->size
	);

	canvas->buffer = wl_shm_pool_create_buffer(
			pool,
			0,
			width,
			height,
			stride,
			WL_SHM_FORMAT_XRGB8888
		);

	wl_shm_pool_destroy(pool);
	close(fd);

	return canvas;
}


void
free_drw(Canvas *canvas)
{
	munmap(canvas->data, canvas->size);
	free(canvas);
}


void
draw_point(Canvas *canvas, unsigned x, unsigned y, uint32_t color)
{
	if (!(x < canvas->width && y < canvas->height))
		return;

	canvas->data[x + canvas->width * y] = color;
}


void
draw_rect(Canvas *canvas, unsigned x, unsigned y, unsigned width, unsigned height, uint32_t color) {
	int py;
	int px;

	for (py = y; py < y + height; ++py) {
		for (px = x; px < x + width; ++px) {
			draw_point(canvas, px, py, color);
		}
	}
}