#include "blockviewwavetrace.h"


BlockViewWavetrace::BlockViewWavetrace(int width, int height) {
	max_steps = 512;
	resize(width, height);
	setPreferredDirection(Horizontal);
}


void BlockViewWavetrace::resize(int width, int height) {
	wid = width;
	hei = height;
	if (field.size() != wid) field.resize(wid);
	for (int i = 0; i < wid; ++i) {
		if (field[i].size() != hei) {
			field[i].resize(hei);
			field[i].fill(Cell());
		}
	}
}


void BlockViewWavetrace::fill(short val) {
	for (int i = 0; i < wid; ++i) {
		if (i == 0)
			field[i].fill(val);
		else
			memcpy(field[i].data(), field[0].constData(), hei * sizeof(field[0][0]));
	}
}


void BlockViewWavetrace::fill(const QRect & rect, short val) {
	for (int i = rect.left(); i <= rect.right(); ++i)
		for (int j = rect.top(); j <= rect.bottom(); ++j)
			field[i][j].value = field[i][j].direction = val;
}


void BlockViewWavetrace::fill(int px, int py, short val) {
	short p = field[px][py].value;
	if ((val == HorizontalBus && p == VerticalBus) || (val == VerticalBus && p == HorizontalBus))
		field[px][py].value = Blocked;
	else
		field[px][py].value = val;
	field[px][py].direction = field[px][py].value;
}


bool BlockViewWavetrace::trace(const QPoint & start, const QPoint & finish) {
	st = start;
	fn = finish;
	if (dir_ == NoTrace) return true;
	// qDebug() << "trace" << start << finish;
	short cl = 0;
	QRect frect(0, 0, wid - 1, hei - 1);
	QVector<QPoint> cpnts, npnts;
	fill(st, cl);
	cpnts.push_back(st);
	if (field[fn.x()][fn.y()].value == (short)Blocked) return false;
	auto checkAndFill = [this, &npnts, &frect](int x, int y, short acc_dir, short c) {
		if (!frect.contains(x, y)) return;
		short p = field[x][y].value;
		if (p == (short)Empty || p == acc_dir) {
			npnts.push_back(QPoint(x, y));
			field[x][y].value = c;
		}
	};
	while (cpnts.size() > 0) {
		npnts.clear();
		cl++;
		if (cl >= max_steps) return false;
		for (int i = 0; i < cpnts.size(); ++i) {
			if (cpnts[i] == fn) return true;
			checkAndFill(cpnts[i].x() - 1, cpnts[i].y(), (short)VerticalBus, cl);
			checkAndFill(cpnts[i].x() + 1, cpnts[i].y(), (short)VerticalBus, cl);
			checkAndFill(cpnts[i].x(), cpnts[i].y() - 1, (short)HorizontalBus, cl);
			checkAndFill(cpnts[i].x(), cpnts[i].y() + 1, (short)HorizontalBus, cl);
		}
		cpnts = npnts;
		// qDebug() << cl << ": " << cpnts.size();
	}
	return false;
}


void BlockViewWavetrace::gatherPath() {
	path_.clear();
	path_.push_back(fn);
	if (dir_ == NoTrace) {
		path_.push_front(st);
		return;
	}
	int pa = -1, ca = -1;
	bool first = true;
	short cl   = field[fn.x()][fn.y()].value;
	QRect frect(0, 0, wid, hei);
	QPoint cpnt       = fn;
	auto checkAndStep = [this, &cpnt, &first, &frect](int dir, short c, int & ca_, int pa_) -> bool {
		int cx = cpnt.x() + dps[dir].x();
		int cy = cpnt.y() + dps[dir].y();
		if (frect.contains(cx, cy)) {
			const Cell & cell(field[cx][cy]);
			if (cell.value == c) {
				if (cell.direction == HorizontalBus || cell.direction == VerticalBus) {
					if (dps[dir].x() == 0 && cell.direction == VerticalBus) return false;
					if (dps[dir].y() == 0 && cell.direction == HorizontalBus) return false;
				}
				ca_ = QLineF(QPointF(cx, cy), cpnt).angle();
				if (ca_ != pa_ && !first) path_.push_front(cpnt);
				cpnt  = QPoint(cx, cy);
				first = false;
				return true;
			}
		}
		return false;
	};
	while (cl > 0) {
		cl--;
		pa = ca;

		if (checkAndStep(0, cl, ca, pa)) continue;
		if (checkAndStep(1, cl, ca, pa)) continue;
		if (checkAndStep(2, cl, ca, pa)) continue;
		if (checkAndStep(3, cl, ca, pa)) continue;
	}
	path_.push_front(st);
}


void BlockViewWavetrace::setPreferredDirection(BlockViewWavetrace::Direction dir) {
	dir_ = dir;
	if (dir == BlockViewWavetrace::Horizontal) {
		dps[0] = QPoint(0, -1);
		dps[1] = QPoint(0, 1);
		dps[2] = QPoint(-1, 0);
		dps[3] = QPoint(1, 0);
	}
	if (dir == BlockViewWavetrace::Vertical) {
		dps[2] = QPoint(0, -1);
		dps[3] = QPoint(0, 1);
		dps[0] = QPoint(-1, 0);
		dps[1] = QPoint(1, 0);
	}
}


const QVector<QPoint> & BlockViewWavetrace::path() const {
	return path_;
}