/*-
 *  Copyright 2020 Beuth Hochschule für Technik Berlin, Hochschule für Technik Stuttgart
 * 
 *  This file is part of CityDoctor2.
 *
 *  CityDoctor2 is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  CityDoctor2 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
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with CityDoctor2.  If not, see <https://www.gnu.org/licenses/>.
 */
package de.hft.stuttgart.citydoctor2.checks.semantics;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;

import de.hft.stuttgart.citydoctor2.check.Check;
import de.hft.stuttgart.citydoctor2.check.CheckId;
import de.hft.stuttgart.citydoctor2.check.CheckResult;
import de.hft.stuttgart.citydoctor2.check.Requirement;
import de.hft.stuttgart.citydoctor2.check.RequirementType;
import de.hft.stuttgart.citydoctor2.check.ResultStatus;
import de.hft.stuttgart.citydoctor2.check.error.NotWallError;
import de.hft.stuttgart.citydoctor2.checks.util.CollectionUtils;
import de.hft.stuttgart.citydoctor2.datastructure.BoundarySurface;
import de.hft.stuttgart.citydoctor2.datastructure.BoundarySurfaceType;
import de.hft.stuttgart.citydoctor2.datastructure.Geometry;
import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
import de.hft.stuttgart.citydoctor2.math.Vector3d;
import de.hft.stuttgart.citydoctor2.parser.ParserConfiguration;

/**
 * checks if the normal direction of a polygon labeled as WallSurface are
 * horizontal or not.
 * 
 * @author dwagner
 * @author Matthias Betz - 12bema1bif@hft-stuttgart.de
 *
 */
public class IsWallCheck extends Check {
	
	private static final String LOWER_ANGLE_NAME = "lowerAngle";
	private static final String UPPER_ANGLE_NAME = "upperAngle";

	private static final List<CheckId> dependencies;

	static {
		ArrayList<CheckId> deps = new ArrayList<>();
		deps.add(CheckId.C_GE_R_TOO_FEW_POINTS);
		deps.add(CheckId.C_GE_R_NOT_CLOSED);
		deps.add(CheckId.C_GE_R_DUPLICATE_POINT);
		deps.add(CheckId.C_GE_R_SELF_INTERSECTION);
		deps.add(CheckId.C_GE_P_NON_PLANAR);
		dependencies = Collections.unmodifiableList(deps);
		
	}

	private static final Vector3d Z_AXIS = new Vector3d(0, 0, 1);
	
	// The SIG3d handbook proposes a +-45 degree to the horizontal plane. To
	// minimize computation the upper and lower values are calculated only once
	// and in advance. The algorithm is based on the angle calculation between
	// the normal of the polygon and the positive z direction vector.
	private double lowerAngleCos = Math.cos(45 * Math.PI / 180);
	private double upperAngleCos = Math.cos(135 * Math.PI / 180);
	
	@Override
	public void init(Map<String, String> params, ParserConfiguration config) {
		String lowerAngleString = params.get(LOWER_ANGLE_NAME);
		if (lowerAngleString != null) {
			lowerAngleCos = Double.parseDouble(lowerAngleString);
			lowerAngleCos = Math.cos(lowerAngleCos * Math.PI / 180);
		}
		String upperAngleString = params.get(UPPER_ANGLE_NAME);
		if (upperAngleString != null) {
			upperAngleCos = Double.parseDouble(upperAngleString);
			upperAngleCos = Math.cos(upperAngleCos * Math.PI / 180);
		}
	}
	

	@Override
	public void check(BoundarySurface bs) {
		// works only on wall surfaces
		if (bs.getType() != BoundarySurfaceType.WALL) {
			return;
		}
		
		for (Geometry geom : bs.getGeometries()) {
			for (Polygon p : geom.getPolygons()) {
				Vector3d normal = p.calculateNormal();
				double dot = normal.dot(Z_AXIS);

				// The angle should be between 45 and 135 degree, measured
				// against the z-direction, hence the optimal angle would be 90 degree
				// CAUTION: This might seems odd, but keep in mind, that the acos won't
				// be calculated and we won't receive measures in radian or degree.
				// The values for cosine are:
				// cos [0°, 90°) > 0
				// cos ( 90° ) = 0
				// cos ( 90°, 180°] < 0
				// Hence we need to check if the calculated angle is above the lower
				// angle cosine or below the upper angle cosine
				if (dot > lowerAngleCos || dot < upperAngleCos) {
					NotWallError err = new NotWallError(bs, p, normal);
					CheckResult cr = new CheckResult(this, ResultStatus.ERROR, err);
					bs.addCheckResult(cr);
					return;
				}
			}
		}
		CheckResult cr = new CheckResult(this, ResultStatus.OK, null);
		bs.addCheckResult(cr);
	}

	@Override
	public List<CheckId> getDependencies() {
		return dependencies;
	}
	
	@Override
	public Set<Requirement> appliesToRequirements() {
		return CollectionUtils.singletonSet(Requirement.R_SE_BS_IS_WALL);
	}
	
	@Override
	public RequirementType getType() {
		return RequirementType.SEMANTIC;
	}

	@Override
	public Check createNewInstance() {
		return new IsWallCheck();
	}

	@Override
	public CheckId getCheckId() {
		return CheckId.C_SE_BS_IS_WALL;
	}

}