#include "aoc.h"
#include "iccmp.h"
#include "allocator.h"
#include "dvec_s.h"
#include "util.h"

#include <assert.h>
#include <stdbool.h>
#include <stdlib.h>

bool
deploy(struct icc *icc, size_t x, size_t y)
{
	int input;

	input = 0;
	while (icc->state != ICC_HALT) {
		icc_step_inst(icc);
		switch (icc->state) {
		case ICC_INPUT:
			switch (input) {
			case 0:
				mi_setv(&icc->in, x, MI_POS);
				input++;
				break;
			case 1:
				mi_setv(&icc->in, y, MI_POS);
				input++;
				break;
			}
			break;
		case ICC_OUTPUT:
			return mi_cast_ul(&icc->out);
		}
	}

	assert(false);
}

void
part1(void)
{
	struct icc icc, save;
	size_t x, y;
	size_t answer;
	bool inbeam;
	bool inbeam_p;
	size_t beam_start;

	icc_init(&icc);
	icc_parse_inst(&icc, aoc.input, aoc.input_size);

	while (icc.state == ICC_RUN)
		icc_step_inst(&icc);
	assert(icc.state == ICC_INPUT);

	icc_init(&save);
	icc_copy(&save, &icc);

	answer = 0;
	beam_start = 0;
	for (y = 0; y < 50; y++) {
		inbeam_p = false;
		for (x = beam_start; x < 50; x++) {
			icc_copy(&icc, &save);
			inbeam = deploy(&icc, x, y);
			aoc_debug("%lu %lu %i\n", y, x, inbeam);
			if (inbeam && !inbeam_p)
				beam_start = x;
			if (!inbeam && inbeam_p)
				break;
			inbeam_p = inbeam;

			answer += inbeam;
		}
	}

	aoc.answer = aprintf("%lu", answer);
	aoc.solution = "141";

	icc_deinit(&save);
	icc_deinit(&icc);
}

void
part2(void)
{
	const size_t sqw = 100, sqh = 100;
	struct icc icc, save;
	struct dvec ends;
	size_t x, y;
	size_t answer;
	size_t beam_start;
	size_t beam_end;
	size_t *end;
	bool inbeam;

	icc_init(&icc);
	icc_parse_inst(&icc, aoc.input, aoc.input_size);

	while (icc.state == ICC_RUN)
		icc_step_inst(&icc);
	assert(icc.state == ICC_INPUT);

	icc_init(&save);
	icc_copy(&save, &icc);

	dvec_init(&ends, sizeof(size_t), 10, &stdlib_strict_heap_allocator);

	answer = 0;

	beam_start = beam_end = 0;
	for (y = 0; ; y++) {
		inbeam = false;
		for (x = beam_start; !inbeam; x++) {
			if (x > beam_start + 10) {
				aoc_debug("SKIP %lu\n", y);
				end = dvec_add_slot(&ends);
				*end = 0;
				goto skip;
			}
			icc_copy(&icc, &save);
			inbeam = deploy(&icc, x, y);
		}
		beam_start = x - 1;

		inbeam = true;
		if (beam_end < beam_start) beam_end = beam_start + 1;
		for (x = beam_end; inbeam; x++) {
			icc_copy(&icc, &save);
			inbeam = deploy(&icc, x, y);
		}
		beam_end = x - 1;

		end = dvec_add_slot(&ends);
		*end = beam_end;

		if (y >= sqh - 1) {
			end = dvec_at(&ends, y - (sqh - 1));
			if (*end >= beam_start + sqw) {
				answer = beam_start * 10000 + (y - (sqh - 1));
				goto exit;
			}
		}

skip:
		aoc_debug("%lu %lu %lu\n", y, beam_start, beam_end);
	}

exit:
	aoc.answer = aprintf("%lu", answer);
	aoc.solution = "15641348";

	dvec_deinit(&ends);
	icc_deinit(&save);
	icc_deinit(&icc);
}