#ifndef PATH_H
#define PATH_H

#include <Indoor/floorplan/v2/Floorplan.h>
#include <Indoor/nav/dijkstra/DijkstraPath.h>


#include "../gl/GLHelper.h"
#include "../gl/GLTriangles.h"
#include "../Renderable.h"


class Path : public Renderable {

private:

	GLTriangles<VertNormTex> lines;

public:

	/** ctor */
	Path() {
		;
	}


	void initGL() override {

		loadShader(":/res/gl/vertex1.glsl", ":/res/gl/fragmentLine.glsl");
		program.setUniformValue("color", QVector4D(0.0, 0.4, 1.0, 0.6));

		//loadShader(":/res/gl/vertex1.glsl", ":/res/gl/fragmentTexSimple.glsl");

		lines.setDiffuse(":/res/gl/tex/arrows.png");
		program.setUniformValue("texNormalMap", 0);

	}

	/** render the floor */
	void _render() override {
		lines.rebuild();
		glLineWidth(30);
		glEnable(GL_BLEND);
		glDisable(GL_CULL_FACE);
		glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		lines.render(&program);
		glDisable(GL_BLEND);
		glEnable(GL_CULL_FACE);

	}


	template <typename Node> void set(const DijkstraPath<Node>& path) {

		std::vector<Point3> out;
		for (const DijkstraNode<Node>* node : path.getVector()) {
			if (!node) {break;}
			const Node* elem = node->element;
			out.push_back(Point3(elem->x_cm/100.0f, elem->y_cm/100.0f, elem->z_cm/100.0f));
		}

		out = simplify(out);
		set(out);

	}

	/*
	void setSimple(const std::vector<Point3>& path) {


		lines.clear();
		const float s = 0.5;

		Point3 lastDir(0,0,0);
		std::vector<Floorplan::Quad3> quads;

		for (int i = 1; i < (int) path.size(); ++i) {

			Point3 pa = path[i-1];
			Point3 pb = path[i-0];
			const Point3 pc(0, 0, 1);

			Point3 dir = pb - pa; dir /= dir.length();
			Point3 perb = cross(pa-pb, pc);	perb /= perb.length();

			const Point3 p1 = pa - perb*s;
			const Point3 p2 = pa + perb*s;
			const Point3 p3 = pb + perb*s;
			const Point3 p4 = pb - perb*s;

			if (dir == lastDir) {
				quads.back().p3 = p3;
				quads.back().p4 = p4;
			} else {
				quads.push_back(Floorplan::Quad3(p1,p2,p3,p4));
			}

			lastDir = dir;

//			// produce a small gap between path-lines [will be filled with another quad!]
//			pa += dir * 0.6;
//			pb -= dir * 0.6;

//
		}

		for (int i = 0; i < (int) quads.size(); ++i) {

			// add the line-segment
			const Floorplan::Quad3 q1 = quads[i];
			addQuad(q1);

//				// construct the quad between adjacent segments
//				if (i < (int) quads.size() - 1) {
//					const Floorplan::Quad3 q2 = quads[i+1];
//					const Floorplan::Quad3 q3(q1.p3, q2.p2, q2.p1, q1.p4);
//					addQuad(q3);
//				}


		}

	}
	*/

	/** combine nodes while the direction stays the same (many small quads -> one large quad) */
	std::vector<Point3> simplify(const std::vector<Point3>& path) {

		std::vector<Point3> out;

		Point3 lastDir(0,0,0);
		if (!path.empty()) {
			out.push_back(path.back());
		}

		for (int i = path.size() - 1; i >= 1; --i) {

			const Point3 pa = path[i-0];
			const Point3 pb = path[i-1];
			const Point3 dir = (pb - pa).normalized();

			if (dir == lastDir) {
				out[out.size()-1] = pb;
			} else {
				out.push_back(pb);
			}

			lastDir = dir;

		}

		// remove unneccesary nodes
		for (int i = 1; i < (int) out.size() - 1; ++i) {

			const Point3 pa = out[i-1];
			const Point3 pb = out[i-0];
			const Point3 pc = out[i+1];

			const float min = 0.6;
			const float d1 = pb.getDistance(pa);
			const float d2 = pb.getDistance(pc);

			if (d1 < min || d2 < min) {
				out.erase(out.begin() + i);
			}

		}

		return out;

	}

//	void set(const std::vector<Point3>& path) {

//		lines.clear();

//		const float s = 0.4;
//		std::vector<Point3> pts;

//		for (int i = 0; i < (int) path.size(); ++i) {

//			const Point3 pa = path[i-1];
//			const Point3 pb = path[i-0];
//			const Point3 pc(0, 0, 1);

//			const Point3 perb = cross(pa-pb, pc).normalized();

//			// quad's edges
//			const Point3 p1 = pa - perb*s;
//			const Point3 p2 = pa + perb*s;
//			const Point3 p3 = pb + perb*s;
//			const Point3 p4 = pb - perb*s;

//			pts.push_back(p1);
//			pts.push_back(p2);

//		}

//		std::vector<Floorplan::Quad3> quads;
//		for (int i = 0; i < (int) pts.size(); i+=2) {
//			quads.push_back(Floorplan::Quad3(pts[i+0], pts[i+1], pts[i+3], pts[i+2]));
//		}

//		float l1 = 0;
//		float l2 = 0;

//		for (int i = 0; i < (int) quads.size(); ++i) {

//			// add the line-segment
//			const Floorplan::Quad3 q1 = quads[i];
//			l2 += ((q1.p1 + q1.p2) / 2).getDistance( (q1.p3 + q1.p4) / 2 );
//			addQuad(q1, l1, l2);
//			l1 = l2;

//		}

//	}



	void set(const std::vector<Point3>& path) {


		lines.clear();

		// half the width of the path
		const float s = 0.4;
		std::vector<Floorplan::Quad3> quads;

		for (int i = 1; i < (int) path.size(); ++i) {

			Point3 pa = path[i-1];
			Point3 pb = path[i-0];
			const Point3 pc(0, 0, 1);
			Point3 dir = (pb - pa).normalized();

			// produce a small gap between path-segments
			// those segments will be smoothly connected using another quad
			pa += dir * 0.35;
			pb -= dir * 0.35;

			const Point3 perb = cross(pa-pb, pc).normalized();

			// quad's edges
			const Point3 p1 = pa - perb*s;
			const Point3 p2 = pa + perb*s;
			const Point3 p3 = pb + perb*s;
			const Point3 p4 = pb - perb*s;

			// add
			quads.push_back(Floorplan::Quad3(p1,p2,p3,p4));

		}

		float l1 = 0;
		float l2 = 0;

		for (int i = 0; i < (int) quads.size(); ++i) {

			// add the line-segment
			const Floorplan::Quad3 q1 = quads[i];
			l2 += ((q1.p1 + q1.p2) / 2).getDistance( (q1.p3 + q1.p4) / 2 );
			addQuad(q1, l1, l2);
			l1 = l2;

			// done?
			if (i == (int) quads.size() - 1) {break;}

			// construct the quad between adjacent segments
			const Floorplan::Quad3 q2 = quads[i+1];
			const Floorplan::Quad3 q3(q1.p4, q1.p3, q2.p2, q2.p1);
			l2 += ((q3.p1 + q3.p2) / 2).getDistance( (q3.p3 + q3.p4) / 2 );
			addQuad(q3, l1, l2);
			l1 = l2;

		}

	}

private:

	void addQuad(const Floorplan::Quad3& q, const float l1, const float l2) {

		// move the path upwards (slightly above the ground)
		const float h = 0.40;

		const QVector3D v1(q.p1.x, q.p1.z+h, q.p1.y);
		const QVector3D v2(q.p2.x, q.p2.z+h, q.p2.y);
		const QVector3D v3(q.p3.x, q.p3.z+h, q.p3.y);
		const QVector3D v4(q.p4.x, q.p4.z+h, q.p4.y);

		const QVector3D n(0,1,0);

		const QVector2D tex1(0, l1);
		const QVector2D tex2(1, l1);
		const QVector2D tex3(1, l2);
		const QVector2D tex4(0, l2);

//		const QVector2D tex1(q.p1.x, q.p1.y);
//		const QVector2D tex2(q.p2.x, q.p2.y);
//		const QVector2D tex3(q.p3.x, q.p3.y);
//		const QVector2D tex4(q.p4.x, q.p4.y);

		const VertNormTex vnt1(v1, n, tex1);
		const VertNormTex vnt2(v2, n, tex2);
		const VertNormTex vnt3(v3, n, tex3);
		const VertNormTex vnt4(v4, n, tex4);


		lines.addQuadCCW(vnt1, vnt2, vnt3, vnt4);

	}


};

#endif // PATH_H