/********************************************************************************
 *                                                                              *
 * Copyright 2015 IfcOpenShell and ROOT B.V.                                    *
 *                                                                              *
 * This file is part of IfcOpenShell.                                           *
 *                                                                              *
 * IfcOpenShell is free software: you can redistribute it and/or modify         *
 * it under the terms of the Lesser GNU General Public License as published by  *
 * the Free Software Foundation, either version 3.0 of the License, or          *
 * (at your option) any later version.                                          *
 *                                                                              *
 * IfcOpenShell is distributed in the hope that it will be useful,              *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of               *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                 *
 * Lesser GNU General Public License for more details.                          *
 *                                                                              *
 * You should have received a copy of the Lesser GNU General Public License     *
 * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
 *                                                                              *
 ********************************************************************************/

#include <string>
#include <fstream>
#include <cstdio>
#include <limits>
#include <algorithm>

#include <gp_Pln.hxx>
#include <TopoDS.hxx>
#include <TopoDS_Edge.hxx>
#include <BRepBuilderAPI_GTransform.hxx>
#include <BRepBuilderAPI_Transform.hxx>
#include <TopExp_Explorer.hxx>
#include <BRep_Tool.hxx>
#include <BRepAlgo_Section.hxx>
#include <BRepTools.hxx>
#include <BRepAlgoAPI_Section.hxx>
#include <ShapeAnalysis_FreeBounds.hxx>
#include <TopTools_HSequenceOfShape.hxx>

#include <Geom_Curve.hxx>
#include <Geom_Line.hxx>
#include <Geom_Circle.hxx>
#include <Geom_Ellipse.hxx>
#include <gp_Ax22d.hxx>
#include <Standard_Version.hxx>
#include "../ifcparse/IfcGlobalId.h"

#include "SvgSerializer.h"

const double PI2 = M_PI * 2.;

bool SvgSerializer::ready() {
	return true;
}

void SvgSerializer::write(path_object& p, const TopoDS_Wire& wire) {
	/* ShapeFix_Wire fix;
	Handle(ShapeExtend_WireData) data = new ShapeExtend_WireData;
	for (TopExp_Explorer edges(result, TopAbs_EDGE); edges.More(); edges.Next()) {
		data->Add(edges.Current());
	}
	fix.Load(data);
	fix.FixReorder();
	fix.FixConnected();
	const TopoDS_Wire fixed_wire = fix.Wire(); */

	bool first = true;
	util::string_buffer path;
	path.add("            <path style=\"stroke:black; fill:none;\" d=\"");
	for (TopExp_Explorer edges(wire, TopAbs_EDGE); edges.More(); edges.Next()) {
		const TopoDS_Edge& edge = TopoDS::Edge(edges.Current());

		double u1, u2;
		Handle(Geom_Curve) curve = BRep_Tool::Curve(edge, u1, u2);

		const bool reversed = edge.Orientation() == TopAbs_REVERSED;

		gp_Pnt p1, p2;
		curve->D0(u1, p1);
		curve->D0(u2, p2);

		if (reversed) {
			std::swap(p1, p2);
		}
				
		if (first) {
			path.add("M");
			addXCoordinate(path.add(p1.X()));
			path.add(",");
			addYCoordinate(path.add(p1.Y()));

			growBoundingBox(p1.X(), p1.Y());
		}

		growBoundingBox(p2.X(), p2.Y());

		Handle(Standard_Type) ty = curve->DynamicType();

		if (ty == STANDARD_TYPE(Geom_Circle) || ty == STANDARD_TYPE(Geom_Ellipse)) {
			Handle(Geom_Conic) conic = Handle(Geom_Conic)::DownCast(curve);
			const bool mirrored = conic->Position().Axis().Direction().Z() < 0;
					
			double r1, r2;
			bool larger_arc_segment = (fmod(u2 - u1 + PI2, PI2) > M_PI);
			bool positive_direction = (u2 > u1);

			if (mirrored != reversed) {
				// In case the local coordinate system is mirrored
				// the direction is reversed.
				positive_direction = !positive_direction;
			}
					
			if (ty == STANDARD_TYPE(Geom_Circle)) {
				Handle(Geom_Circle) circle = Handle(Geom_Circle)::DownCast(curve);
				r1 = r2 = circle->Radius();
			} else {
				Handle(Geom_Ellipse) ellipse = Handle(Geom_Ellipse)::DownCast(curve);
				r1 = ellipse->MajorRadius();
				r2 = ellipse->MinorRadius();
			}
					
			// Calculate the angle between 2d vecs to have signed result
			const gp_Dir& d = conic->Position().XDirection();
			const gp_Dir2d d2(d.X(), d.Y());
			const double ang = d2.Angle(gp::DX2d());

			// Write radii
			path.add(" A");
			addSizeComponent(path.add(r1));
			path.add(",");
			addSizeComponent(path.add(r2));
					
			// Write X-axis rotation
			{ std::stringstream ss; ss << " " << ang << " ";
			path.add(ss.str()); }
					
			// Write large-arc-flag and sweep-flag
			path.add(std::string(1, '0'+static_cast<int>(larger_arc_segment)));
			path.add(",");
			path.add(std::string(1, '0'+static_cast<int>(positive_direction)));
					
			path.add(" ");

			// Write arc end point
			xcoords.push_back(path.add(p2.X()));
			path.add(",");
			ycoords.push_back(path.add(p2.Y()));
		} else {
			// Either a Geom_Line or something unimplemented,
			// drawn as a straight line segment.
			path.add(" L");
			xcoords.push_back(path.add(p2.X()));
			path.add(",");
			ycoords.push_back(path.add(p2.Y()));
		}

		first = false;
	}

	path.add("\"/>\n");
	p.second.push_back(path);
}

SvgSerializer::path_object& SvgSerializer::start_path(IfcSchema::IfcBuildingStorey* storey, const std::string& id) {
	SvgSerializer::path_object& p = paths.insert(std::make_pair(storey, path_object()))->second;
	p.first = id;
	return p;
}

void SvgSerializer::write(const IfcGeom::BRepElement<double>* o) {
	IfcSchema::IfcBuildingStorey* storey = 0;
	IfcSchema::IfcObjectDefinition* obdef = static_cast<IfcSchema::IfcObjectDefinition*>(file->entityById(o->id()));

#ifndef USE_IFC4
	typedef IfcSchema::IfcRelDecomposes decomposition_element;
#else
	typedef IfcSchema::IfcRelAggregates decomposition_element;
#endif

	for (;;) {
		// Iterate over the decomposing element to find the parent IfcBuildingStorey
		decomposition_element::list::ptr decomposes = obdef->Decomposes();
		if (!decomposes->size()) {
			if (obdef->declaration().is(IfcSchema::Type::IfcElement)) {
				IfcSchema::IfcRelContainedInSpatialStructure::list::ptr containment = ((IfcSchema::IfcElement*)obdef)->ContainedInStructure();
				if (!containment->size()) {
					break;
				}
				for (IfcSchema::IfcRelContainedInSpatialStructure::list::it it = containment->begin(); it != containment->end(); ++it) {
					IfcSchema::IfcRelContainedInSpatialStructure* container = *it;
					if (container->RelatingStructure() != obdef) {
						obdef = container->RelatingStructure();
					}
				}
			} else {
				break;
			}
		} else {
			for (decomposition_element::list::it it = decomposes->begin(); it != decomposes->end(); ++it) {
				decomposition_element* decompose = *it;
				if (decompose->RelatingObject() != obdef) {
					obdef = decompose->RelatingObject();
				}
			}
		}
		if (obdef->declaration().is(IfcSchema::Type::IfcBuildingStorey)) {
			storey = static_cast<IfcSchema::IfcBuildingStorey*>(obdef);
			break;
		}
	}

	if (!storey) return;

	path_object& p = start_path(storey, nameElement(o));

	for (IfcGeom::IfcRepresentationShapeItems::const_iterator it = o->geometry().begin(); it != o->geometry().end(); ++ it) {
		gp_GTrsf gtrsf = it->Placement();
		
		const gp_Trsf& o_trsf = o->transformation().data();
		gtrsf.PreMultiply(o_trsf);

		const TopoDS_Shape& s = it->Shape();			
			
		bool trsf_valid = false;
		gp_Trsf trsf;
		try {
			trsf = gtrsf.Trsf();
			trsf_valid = true;
		} catch (...) {}
			
		const TopoDS_Shape moved_shape = trsf_valid
			? BRepBuilderAPI_Transform(s, trsf, true).Shape()
			: BRepBuilderAPI_GTransform(s, gtrsf, true).Shape();
			
		const double inf = std::numeric_limits<double>::infinity();
		double zmin = inf;
		double zmax = -inf;
		{TopExp_Explorer exp(moved_shape, TopAbs_VERTEX);
		for (; exp.More(); exp.Next()) {
			const TopoDS_Vertex& vertex = TopoDS::Vertex(exp.Current());
			gp_Pnt pnt = BRep_Tool::Pnt(vertex);
			if (pnt.Z() < zmin) { zmin = pnt.Z(); }
			if (pnt.Z() > zmax) { zmax = pnt.Z(); }
		}}

		if (section_height) {
			if (zmin > section_height || zmax < section_height) continue;
		} else {
			if (zmin == inf || (zmax - zmin) < 1.) continue;
		}

		const double cut_z = section_height.get_value_or(zmin + 1.);

		// Create a horizontal cross section 1 meter above the bottom point of the shape		
		TopoDS_Shape result = BRepAlgoAPI_Section(moved_shape, gp_Pln(gp_Pnt(0, 0, cut_z), gp::DZ()));

		Handle(TopTools_HSequenceOfShape) edges = new TopTools_HSequenceOfShape();
		Handle(TopTools_HSequenceOfShape) wires = new TopTools_HSequenceOfShape();
		{TopExp_Explorer exp(result, TopAbs_EDGE);
		for (; exp.More(); exp.Next()) {
			 edges->Append(exp.Current());
		}}
		ShapeAnalysis_FreeBounds::ConnectEdgesToWires(edges, 1e-5, false, wires);

		gp_Pnt prev;

		for (int i = 1; i <= wires->Length(); ++i) {
			const TopoDS_Wire& wire = TopoDS::Wire(wires->Value(i));
			write(p, wire);
		}
	}	
}

void SvgSerializer::setBoundingRectangle(double width, double height) {
	this->width = width;
	this->height = height;
	this->rescale = true;
}

void SvgSerializer::finalize() {

	if (rescale) {
		// Scale the resulting image to a bounding rectangle specified by command line arguments
		const double dx = xmax - xmin;
		const double dy = ymax - ymin;

		double sc = 1.;

		if (dx / width > dy / height) {
			sc = width / dx;
		} else {
			sc = height / dy;
		}

		const double cx = xmin * sc;
		const double cy = ymin * sc;

		{std::vector< boost::shared_ptr<util::string_buffer::float_item> >::const_iterator it;
		for (it = xcoords.begin(); it != xcoords.end(); ++it) {
			double& v = (*it)->value();
			v = v * sc - cx;
		}
		for (it = ycoords.begin(); it != ycoords.end(); ++it) {
			double& v = (*it)->value();
			v = v * sc - cy;
		}
		for (it = radii.begin(); it != radii.end(); ++it) {
			(*it)->value() *= sc;
		}}
	}

	std::multimap<IfcSchema::IfcBuildingStorey*, path_object>::const_iterator it;

	IfcSchema::IfcBuildingStorey* previous = 0;
	bool first = true;
	for (it = paths.begin(); it != paths.end(); ++it) {
		if (it->first != previous || first) {
			if (!first) {
				svg_file << "    </g>\n";
			}
			std::ostringstream oss;
			svg_file << "    <g " << nameElement(it->first) << ">\n";
		}
		svg_file << "        <g " << it->second.first << ">\n";
		std::vector<util::string_buffer>::const_iterator jt;
		for (jt = it->second.second.begin(); jt != it->second.second.end(); ++jt) {
			svg_file << jt->str();
		}
		svg_file << "        </g>\n";
		previous = it->first;
		first = false;
	}
	
	svg_file << "    </g>\n";
	svg_file << "</svg>" << std::endl;
}

void SvgSerializer::writeHeader() {
	svg_file << "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">\n";
}

std::string SvgSerializer::nameElement(const IfcGeom::Element<double>* elem) {
	std::ostringstream oss;
	const std::string type = "product";
	oss << "id=\"" << type << "-" << elem->unique_id() << "\"";
	return oss.str();
}

std::string SvgSerializer::nameElement(const IfcSchema::IfcProduct* elem) {
	std::ostringstream oss;
	const std::string type = elem->declaration().is(IfcSchema::Type::IfcBuildingStorey) ? "storey" : "product";
	oss << "id=\"product-" << IfcParse::IfcGlobalId(elem->GlobalId()).formatted() << "\"";
	return oss.str();
}
