#include "tsegmentadjuster.h"
#include "tgl.h"

#include <QDebug>

TSegmentAdjuster::TSegmentAdjuster()
	: m_traceEnabled(false)
{
}

void TSegmentAdjuster::compute(End &pa, End &pb)
{
	m_a = m_c = pa;
	m_b = m_d = pb;
	m_links.clear();
	if (m_traceEnabled)
		m_links.push_back(std::make_pair(m_a.getPoint(), m_b.getPoint()));

	double u = m_a.m_w, v = m_b.m_w;
	// double ua=w0, va=w1;
	// TPointD c = (stroke0->getPoint(ua)+stroke1->getPoint(va))*0.5;
	int count = 0;
	for (;;) {
		if (++count > 1000)
			break;
		double du, dv;
		gradient(du, dv, u, v);
		double dd = sqrt(du * du + dv * dv);
		if (dd < 0.01)
			break;
		du *= 1.0 / dd;
		dv *= 1.0 / dd;

		double a_dsda = dsda(m_a.m_stroke, u, du);
		double b_dsda = dsda(m_b.m_stroke, v, dv);

		const double ds = 0.5;
		const double eps = 0.0001;
		double a = 0.01;
		double aa;
		if (a_dsda > eps && (aa = ds / a_dsda, aa < a))
			a = aa;
		if (b_dsda > eps && (aa = ds / b_dsda, aa < a))
			a = aa;

		u -= a * du;
		v -= a * dv;
		u = tcrop(u, m_a.m_wmin, m_a.m_wmax);
		v = tcrop(v, m_b.m_wmin, m_b.m_wmax);
		if (m_traceEnabled)
			m_links.push_back(std::make_pair(m_a.m_stroke->getPoint(u), m_b.m_stroke->getPoint(v)));
	}
	m_c.m_w = u;
	m_d.m_w = v;
	pa.m_w = u;
	pb.m_w = v;
}

void TSegmentAdjuster::draw()
{
	for (int i = 0; i < (int)m_links.size(); i++) {
		glColor3d(0.9, 0.8, 0.7);
		tglDrawSegment(m_links[i].first, m_links[i].second);
	}
}