#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

struct input {
	double ltx, lty;
	double rbx, rby;
	size_t width, height;
	size_t maxiter;
};

int worker_init(int version) {
	fprintf(stderr, "mandel: init(%d)\n", version);
	return version == 1 ? 0 : 1;
}

int worker_run_job(size_t inputsize, const void *input_, size_t *outputsize, void **outputp) {
	if (inputsize != sizeof(struct input)) {
		fprintf(stderr, "mandel: Input has invalid size %zu (expected %zu)\n", inputsize, sizeof(struct input));
		return -1;
	}

	fprintf(stderr, "mandel: run_job()\n");

	const struct input *const input = input_;

	*outputsize = 4 * input->width * input->height;
	uint32_t *const output = *outputp = malloc(*outputsize);

#pragma omp parallel for
	for (size_t yi = 0; yi < input->height; yi++) {
		for (size_t xi = 0; xi < input->width; xi++) {
			const double y = (input->rby - input->lty) / (input->height - 1) * yi;
			const double x = (input->rbx - input->ltx) / (input->width - 1) * xi;

			double a = x, b = y, a2 = a * a, b2 = b * b;
			size_t n;
			for (n = 0; n < input->maxiter && a2 + b2 < 4; n++) {
				b = 2 * a * b + y;
				a = a2 - b2 + x;
				a2 = a * a; b2 = b * b;
			}

			output[input->width * yi + xi] = n;
		}
	}

	fprintf(stderr, "mandel: run_job() finished\n");

	return 0;
}

void worker_free_outdata(size_t size, void *output) {
	(void)size;
	fprintf(stderr, "mandel: free_outdata()\n");
	free(output);
}