/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.uiautomator.tree;

import java.awt.Rectangle;

import org.apache.log4j.Logger;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

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

public class UiHierarchyXmlLoader {

	private BasicTreeNode mRootNode;
	private List<Rectangle> mNafNodes;

	public UiHierarchyXmlLoader() {
	}

	/**
	 * Uses a SAX parser to process XML dump
	 * @param xmlPath
	 * @return
	 */
	public BasicTreeNode parseXml(String xmlPath) {
		mRootNode = null;
		mNafNodes = new ArrayList<Rectangle>();
		// standard boilerplate to get a SAX parser
		SAXParserFactory factory = SAXParserFactory.newInstance();
		SAXParser parser = null;
		try {
			parser = factory.newSAXParser();
		} catch (ParserConfigurationException e) {
			Logger.getLogger(this.getClass() ).debug("/****UiHierarchyXmlLoader.Error while parsing XML file***/ "+ e.getMessage());
			return null;
		} catch (SAXException e) {
			Logger.getLogger(this.getClass() ).debug("/****UiHierarchyXmlLoader.Error while parsing XML file***/ "+ e.getMessage());
			return null;
		}
		// handler class for SAX parser to receiver standard parsing events:
		// e.g. on reading "<foo>", startElement is called, on reading "</foo>",
		// endElement is called
		DefaultHandler handler = new DefaultHandler(){
			BasicTreeNode mParentNode;
			BasicTreeNode mWorkingNode;
			@Override
			public void startElement(String uri, String localName, String qName,
					Attributes attributes) throws SAXException {
				boolean nodeCreated = false;
				// starting an element implies that the element that has not yet been closed
				// will be the parent of the element that is being started here
				mParentNode = mWorkingNode;
				if ("hierarchy".equals(qName)) {
					int rotation = 0;
					for (int i = 0; i < attributes.getLength(); i++) {
						if ("rotation".equals(attributes.getQName(i)))
							try {
								rotation = Integer.parseInt(attributes.getValue(i));
							}
						catch (NumberFormatException nfe) {
							Logger.getLogger(this.getClass() ).debug("/****UiHierarchyXmlLoader.Error while parsing XML file***/ "+ nfe.getMessage());
						}
					}
					this.mWorkingNode = new RootWindowNode(attributes.getValue("windowName"), rotation);
					nodeCreated = true;
				} else if ("node".equals(qName)) {
					UiNode tmpNode = new UiNode();
					for (int i = 0; i < attributes.getLength(); i++) {
						tmpNode.addAtrribute(attributes.getQName(i), attributes.getValue(i));
					}
					mWorkingNode = tmpNode;
					nodeCreated = true;
					// check if current node is NAF
					String naf = tmpNode.getAttribute("NAF");
					if ("true".equals(naf)) {
						mNafNodes.add(new Rectangle(tmpNode.x, tmpNode.y,
								tmpNode.width, tmpNode.height));
					}
				}
				// nodeCreated will be false if the element started is neither
				// "hierarchy" nor "node"
				if (nodeCreated) {
					if (mRootNode == null) {
						// this will only happen once
						mRootNode = mWorkingNode;
					}
					if (mParentNode != null) {
						mParentNode.addChild(mWorkingNode);
					}
				}
			}

			@Override
			public void endElement(String uri, String localName, String qName) throws SAXException {
				//mParentNode should never be null here in a well formed XML
				if (mParentNode != null) {
					// closing an element implies that we are back to working on
					// the parent node of the element just closed, i.e. continue to
					// parse more child nodes
					mWorkingNode = mParentNode;
					mParentNode = mParentNode.getParent();
				}
			}
		};
		try {
			parser.parse(new File(xmlPath), handler);
		} catch (SAXException e) {
			Logger.getLogger(this.getClass() ).debug("/****UiHierarchyXmlLoader.Error while parsing XML file***/ "+ e.getMessage());
			return null;
		} catch (IOException e) {
			Logger.getLogger(this.getClass() ).debug("/****UiHierarchyXmlLoader.Error while parsing XML file***/ "+ e.getMessage());
			return null;
		}
		return mRootNode;
	}

	/**
	 * Returns the list of "Not Accessibility Friendly" nodes found during parsing.
	 *
	 * Call this function after parsing
	 *
	 * @return
	 */
	public List<Rectangle> getNafNodes() {
		return Collections.unmodifiableList(mNafNodes);
	}
}