/*
 * Copyright (c) 2009-2010 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.jme3.scene.plugins.ogre;

import com.jme3.scene.plugins.ogre.matext.OgreMaterialKey;
import com.jme3.material.MaterialList;
import com.jme3.asset.AssetInfo;
import com.jme3.asset.AssetLoader;
import com.jme3.asset.AssetManager;
import com.jme3.asset.AssetNotFoundException;
import com.jme3.light.DirectionalLight;
import com.jme3.light.Light;
import com.jme3.light.PointLight;
import com.jme3.light.SpotLight;
import com.jme3.math.FastMath;
import com.jme3.math.Quaternion;
import com.jme3.math.Vector3f;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
import com.jme3.util.xml.SAXUtil;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import static com.jme3.util.xml.SAXUtil.*;

public class SceneLoader extends DefaultHandler implements AssetLoader {

    private static final Logger logger = Logger.getLogger(SceneLoader.class.getName());

    private Stack<String> elementStack = new Stack<String>();
    private String sceneName;
    private String folderName;
    private AssetManager assetManager;
    private MaterialList materialList;
    private Node root;
    private Node node;
    private Node entityNode;
    private Light light;
    private int nodeIdx = 0;
    private static volatile int sceneIdx = 0;

    public SceneLoader(){
        super();
    }

    @Override
    public void startDocument() {
    }

    @Override
    public void endDocument() {
    }
    
    private void reset(){
        elementStack.clear();
        nodeIdx = 0;
        
        // NOTE: Setting some of those to null is only needed
        // if the parsed file had an error e.g. startElement was called
        // but not endElement
        root = null;
        node = null;
        entityNode = null;
        light = null;
    }

    private void checkTopNode(String topNode) throws SAXException{
        if (!elementStack.peek().equals(topNode)){
            throw new SAXException("dotScene parse error: Expected parent node to be " + topNode);
        }
    }
    
    private Quaternion parseQuat(Attributes attribs) throws SAXException{
        if (attribs.getValue("x") != null){
            // defined as quaternion
            float x = parseFloat(attribs.getValue("x"));
            float y = parseFloat(attribs.getValue("y"));
            float z = parseFloat(attribs.getValue("z"));
            float w = parseFloat(attribs.getValue("w"));
            return new Quaternion(x,y,z,w);
        }else if (attribs.getValue("qx") != null){
            // defined as quaternion with prefix "q"
            float x = parseFloat(attribs.getValue("qx"));
            float y = parseFloat(attribs.getValue("qy"));
            float z = parseFloat(attribs.getValue("qz"));
            float w = parseFloat(attribs.getValue("qw"));
            return new Quaternion(x,y,z,w);
        }else if (attribs.getValue("angle") != null){
            // defined as angle + axis
            float angle = parseFloat(attribs.getValue("angle"));
            float axisX = parseFloat(attribs.getValue("axisX"));
            float axisY = parseFloat(attribs.getValue("axisY"));
            float axisZ = parseFloat(attribs.getValue("axisZ"));
            Quaternion q = new Quaternion();
            q.fromAngleAxis(angle, new Vector3f(axisX, axisY, axisZ));
            return q;
        }else{
            // defines as 3 angles along XYZ axes
            float angleX = parseFloat(attribs.getValue("angleX"));
            float angleY = parseFloat(attribs.getValue("angleY"));
            float angleZ = parseFloat(attribs.getValue("angleZ"));
            Quaternion q = new Quaternion();
            q.fromAngles(angleX, angleY, angleZ);
            return q;
        }
    }

    private void parseLightNormal(Attributes attribs) throws SAXException {
        checkTopNode("light");
        
        // SpotLight will be supporting a direction-normal, too.
        if (light instanceof DirectionalLight)
            ((DirectionalLight) light).setDirection(parseVector3(attribs));
        else if (light instanceof SpotLight){
            ((SpotLight) light).setDirection(parseVector3(attribs));
        }
    }

    private void parseLightAttenuation(Attributes attribs) throws SAXException {
        // NOTE: Derives range based on "linear" if it is used solely
        // for the attenuation. Otherwise derives it from "range"
        checkTopNode("light");

        if (light instanceof PointLight || light instanceof SpotLight){
            float range = parseFloat(attribs.getValue("range"));
            float constant = parseFloat(attribs.getValue("constant"));
            float linear = parseFloat(attribs.getValue("linear"));

            String quadraticStr = attribs.getValue("quadratic");
            if (quadraticStr == null)
                quadraticStr = attribs.getValue("quadric");

            float quadratic = parseFloat(quadraticStr);
            
            if (constant == 1 && quadratic == 0 && linear > 0){
                range = 1f / linear;
            }
            
            if (light instanceof PointLight){
                ((PointLight) light).setRadius(range);
            }else{
                ((SpotLight)light).setSpotRange(range);
            }
        }
    }

    private void parseLightSpotLightRange(Attributes attribs) throws SAXException{
        checkTopNode("light");
        
        float outer = SAXUtil.parseFloat(attribs.getValue("outer"));
        float inner = SAXUtil.parseFloat(attribs.getValue("inner"));
        
        if (!(light instanceof SpotLight)){
            throw new SAXException("dotScene parse error: spotLightRange "
                    + "can only appear under 'spot' light elements");
        }
        
        SpotLight sl = (SpotLight) light;
        sl.setSpotInnerAngle(inner * 0.5f);
        sl.setSpotOuterAngle(outer * 0.5f);
    }
    
    private void parseLight(Attributes attribs) throws SAXException {
        if (node == null || node.getParent() == null)
            throw new SAXException("dotScene parse error: light can only appear under a node");
        
        checkTopNode("node");
        
        String lightType = parseString(attribs.getValue("type"), "point");
        if(lightType.equals("point")) {
            light = new PointLight();
        } else if(lightType.equals("directional") || lightType.equals("sun")) {
            light = new DirectionalLight();
            // Assuming "normal" property is not provided
            ((DirectionalLight)light).setDirection(Vector3f.UNIT_Z);
        } else if(lightType.equals("spotLight") || lightType.equals("spot")) {
            light = new SpotLight();
        } else {
            logger.log(Level.WARNING, "No matching jME3 LightType found for OGRE LightType: {0}", lightType);
        }
        logger.log(Level.FINEST, "{0} created.", light);

        if (!parseBool(attribs.getValue("visible"), true)){
            // set to disabled
        }

        // "attach" it to the parent of this node
        if (light != null)
            node.getParent().addLight(light);
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attribs) throws SAXException{
        if (qName.equals("scene")){
            if (elementStack.size() != 0){
                throw new SAXException("dotScene parse error: 'scene' element must be the root XML element");
            }
            
            String version = attribs.getValue("formatVersion");
            if (version == null && !version.equals("1.0.0") && !version.equals("1.0.1"))
                logger.log(Level.WARNING, "Unrecognized version number"
                        + " in dotScene file: {0}", version);
            
        }else if (qName.equals("nodes")){
            if (root != null){
                throw new SAXException("dotScene parse error: nodes element was specified twice");
            }
            if (sceneName == null)
                root = new Node("OgreDotScene"+(++sceneIdx));
            else
                root = new Node(sceneName+"-scene_node");
            
            node = root;
        }else if (qName.equals("externals")){
            checkTopNode("scene");
            // Not loaded currently
        }else if (qName.equals("item")){
            checkTopNode("externals");
        }else if (qName.equals("file")){
            checkTopNode("item");
            
            // XXX: Currently material file name is based
            // on the scene's filename. THIS IS NOT CORRECT.
            // To solve, port SceneLoader to use DOM instead of SAX
            
            //String matFile = folderName+attribs.getValue("name");
            //try {
            //    materialList = (MaterialList) assetManager.loadAsset(new OgreMaterialKey(matFile));
            //} catch (AssetNotFoundException ex){
            //    materialList = null;
            //    logger.log(Level.WARNING, "Cannot locate material file: {0}", matFile);
            //}
        }else if (qName.equals("node")){
            String curElement = elementStack.peek();
            if (!curElement.equals("node") && !curElement.equals("nodes")){
                throw new SAXException("dotScene parse error: "
                        + "node element can only appear under 'node' or 'nodes'");
            }
            
            String name = attribs.getValue("name");
            if (name == null)
                name = "OgreNode-" + (++nodeIdx);

            Node newNode = new Node(name);
            if (node != null){
                node.attachChild(newNode);
            }
            node = newNode;
        }else if (qName.equals("property")){
            if (node != null){
                String type = attribs.getValue("type");
                String name = attribs.getValue("name");
                String data = attribs.getValue("data");
                if (type.equals("BOOL")){
                    node.setUserData(name, Boolean.parseBoolean(data)||data.equals("1"));
                }else if (type.equals("FLOAT")){
                    node.setUserData(name, Float.parseFloat(data));
                }else if (type.equals("STRING")){
                    node.setUserData(name, data);
                }else if (type.equals("INT")){
                    node.setUserData(name, Integer.parseInt(data));
                }
            }
        }else if (qName.equals("entity")){
            checkTopNode("node");
            
            String name = attribs.getValue("name");
            if (name == null)
                name = "OgreEntity-" + (++nodeIdx);
            else
                name += "-entity";

            String meshFile = attribs.getValue("meshFile");
            if (meshFile == null) {
                throw new SAXException("Required attribute 'meshFile' missing for 'entity' node");
            }

            // TODO: Not currently used
            String materialName = attribs.getValue("materialName");

            if (folderName != null) {
                meshFile = folderName + meshFile;
            }
            
            // NOTE: append "xml" since its assumed mesh files are binary in dotScene
            meshFile += ".xml";
            
            entityNode = new Node(name);
            OgreMeshKey key = new OgreMeshKey(meshFile, materialList);
            Spatial ogreMesh = assetManager.loadModel(key);
            
            entityNode.attachChild(ogreMesh);
            node.attachChild(entityNode);
            node = null;
        }else if (qName.equals("position")){
            if (elementStack.peek().equals("node")){
                node.setLocalTranslation(SAXUtil.parseVector3(attribs));
            }
        }else if (qName.equals("quaternion") || qName.equals("rotation")){
            node.setLocalRotation(parseQuat(attribs));
        }else if (qName.equals("scale")){
            node.setLocalScale(SAXUtil.parseVector3(attribs));
        } else if (qName.equals("light")) {
            parseLight(attribs);
        } else if (qName.equals("colourDiffuse") || qName.equals("colorDiffuse")) {
            if (elementStack.peek().equals("light")){
                if (light != null){
                    light.setColor(parseColor(attribs));
                }
            }else{
                checkTopNode("environment");
            }
        } else if (qName.equals("normal") || qName.equals("direction")) {
            checkTopNode("light");
            parseLightNormal(attribs);
        } else if (qName.equals("lightAttenuation")) {
            parseLightAttenuation(attribs);
        } else if (qName.equals("spotLightRange") || qName.equals("lightRange")) {
            parseLightSpotLightRange(attribs);
        }

        elementStack.push(qName);
    }

    @Override
    public void endElement(String uri, String name, String qName) throws SAXException {
        if (qName.equals("node")){
            node = node.getParent();
        }else if (qName.equals("nodes")){
            node = null;
        }else if (qName.equals("entity")){
            node = entityNode.getParent();
            entityNode = null;
        }else if (qName.equals("light")){
            // apply the node's world transform on the light..
            root.updateGeometricState();
            if (light != null){
                if (light instanceof DirectionalLight){
                    DirectionalLight dl = (DirectionalLight) light;
                    Quaternion q = node.getWorldRotation();
                    Vector3f dir = dl.getDirection();
                    q.multLocal(dir);
                    dl.setDirection(dir);
                }else if (light instanceof PointLight){
                    PointLight pl = (PointLight) light;
                    Vector3f pos = node.getWorldTranslation();
                    pl.setPosition(pos);
                }else if (light instanceof SpotLight){
                    SpotLight sl = (SpotLight) light;
                    
                    Vector3f pos = node.getWorldTranslation();
                    sl.setPosition(pos);
                    
                    Quaternion q = node.getWorldRotation();
                    Vector3f dir = sl.getDirection();
                    q.multLocal(dir);
                    sl.setDirection(dir);
                }
            }
            light = null;
        }
        checkTopNode(qName);
        elementStack.pop();
    }

    @Override
    public void characters(char ch[], int start, int length) {
    }

    public Object load(AssetInfo info) throws IOException {
        try{
            assetManager = info.getManager();
            sceneName = info.getKey().getName();
            String ext = info.getKey().getExtension();
            folderName = info.getKey().getFolder();
            sceneName = sceneName.substring(0, sceneName.length() - ext.length() - 1);

            try {
                materialList = (MaterialList) 
                      assetManager.loadAsset(new OgreMaterialKey(sceneName+".material"));
            } catch (AssetNotFoundException ex){
                logger.log(Level.WARNING, "Cannot locate material file {0}", ex.getMessage());
                materialList = null;
            }

            reset();
            
            // Added by larynx 25.06.2011
            // Android needs the namespace aware flag set to true 
            // Kirill 30.06.2011
            // Now, hack is applied for both desktop and android to avoid
            // checking with JmeSystem.
            SAXParserFactory factory = SAXParserFactory.newInstance();
            factory.setNamespaceAware(true);
            XMLReader xr = factory.newSAXParser().getXMLReader();  
            
            xr.setContentHandler(this);
            xr.setErrorHandler(this);
            
            InputStreamReader r = null;
            
            try {
                r = new InputStreamReader(info.openStream());
                xr.parse(new InputSource(r));
            } finally {
                if (r != null){
                    r.close();
                }
            }
            
            return root;
        }catch (SAXException ex){
            IOException ioEx = new IOException("Error while parsing Ogre3D dotScene");
            ioEx.initCause(ex);
            throw ioEx;
        } catch (ParserConfigurationException ex) {
            IOException ioEx = new IOException("Error while parsing Ogre3D dotScene");
            ioEx.initCause(ex);
            throw ioEx;
        }
    }

}
