#include "outlinearea.h"

namespace {

	struct DrawBezier {

	private:

		const Context &context;

		const Bezier &bezier;

		const Real width;

		const Real precision_sqr;

		const int max_level = 16;

		int level;

		Vector p0;

		Real l0;

		Vector func(const Real &l)

			{ return bezier(l) + bezier.t(l).perp().norm()*width; }

		void step(const Real &l1) {

			Vector p1 = bezier(l1) + bezier.t(l1).perp().norm()*width;

			if (++level < max_level)

				while (greater((p1 - p0).lensqr(), precision_sqr))

					step(l0 + 0.5*(l1 - l0));

			--level;

			context.line_to(p1);

			p0 = p1; l0 = l1;

		}

	public:

		DrawBezier(const Context &context, const Bezier &bezier, const Real &width = 0, bool jump = false):

			context(context), bezier(bezier), width(width), precision_sqr(context.pixelsize_sqr()), level(), l0()

		{

			p0 = func(0);

			if (jump) context.move_to(p0); else context.line_to(p0);

			step(1);

		}

	};

}

OutlineArea::OutlineArea():

	w(new ActivePoint(Vector(), Color::red()))

{

	set_size_request(500, 500);

	Vector center(250, 250);

	const Real radius = 100;

	const Real tangent_len = 50;

	const int count = 5;

	for(int i = 0; i < count; ++i) {

		Real a = 2*pi*i/count;

		Vector v = Vector::from_angle(a);

		curve.push_back(ActiveCurvePoint(center + v*radius, v*tangent_len));

		curve.back().add_to(*this);

	}

	//curve.loop = true;

	curve.set_tail_tangents_visible();

	add_point(w);

	set_width(50);

}

Real OutlineArea::get_width() const

	{ return fabs(dot(curve.front().get_t1().perp().norm(), w->position - curve.front().get_p())); }

void OutlineArea::set_width(const Real &width)

	{ w->position = curve.front().get_p() + curve.front().get_t1().perp().norm()*width; }

void OutlineArea::on_point_move(const ActivePoint::Handle &point, const Vector &oldposition, const Vector &newposition) {

	Real width = -1;

	if (point == w)

		width = get_width();

	if (!curve.empty())

		if (curve.front().p == point || curve.front().t1 == point)

			width = get_width();

	curve.on_point_move(point, oldposition, newposition);

	if (width >= 0)

		set_width(width);

}

void OutlineArea::put_bezier(const Context &context, const Bezier &bezier, const Real &width, bool jump) {

	if (equal(width, 0))

		context.bezier(bezier, jump);

	else

		DrawBezier(context, bezier, width, jump);

}

void OutlineArea::put_curve(const Context &context, const ActiveCurve &curve, const Real &width) {

	for(ActiveCurve::SegIter i(curve); i; i.next())

		put_bezier(context, i.bezier(), width);

	if (curve.loop) context->close_path();

	for(ActiveCurve::SegRIter i(curve); i; i.next())

		put_bezier(context, i.bezier(), width);

	context->close_path();

}

void OutlineArea::draw_curve(const Context &context, const ActiveCurve &curve, const Real &width) {

	context->save();

	curve.draw(context);

	context.set_line_width_px(1);

	context.set_source_rgba(Color::blue());

	put_curve(context, curve, width);

	context->stroke();

	context->restore();

}

void OutlineArea::on_draw_content(const Context &context) {

	draw_curve(context, curve, get_width());

}