//   Copyright 2012 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.autoquest.plugin.html;

import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.xml.sax.SAXException;

import de.ugoe.cs.autoquest.eventcore.Event;
import de.ugoe.cs.autoquest.eventcore.IEventType;
import de.ugoe.cs.autoquest.eventcore.guimodel.GUIModel;
import de.ugoe.cs.autoquest.eventcore.guimodel.GUIModelException;
import de.ugoe.cs.autoquest.eventcore.guimodel.IGUIElement;
import de.ugoe.cs.autoquest.plugin.html.eventcore.HTMLEventTypeFactory;
import de.ugoe.cs.autoquest.plugin.html.guimodel.HTMLDocumentSpec;
import de.ugoe.cs.autoquest.plugin.html.guimodel.HTMLGUIElement;
import de.ugoe.cs.autoquest.plugin.html.guimodel.HTMLGUIElementSpec;
import de.ugoe.cs.autoquest.plugin.html.guimodel.HTMLPageElementSpec;
import de.ugoe.cs.autoquest.plugin.html.guimodel.HTMLServerSpec;

/**
 * <p>
 * This class provides the functionality to parse XML log files generated by the HTMLMonitor of
 * AutoQUEST. The result of parsing a file is a collection of event sequences and a GUI model
 * </p>
 * 
 * @author Fabian Glaser, Patrick Harms
 * @version 1.0
 * 
 */
public class HTMLLogParser extends AbstractDefaultLogParser {
    
    /**
     *
     */
    private Pattern htmlElementPattern =
        Pattern.compile("(\\w+)(\\[(\\d+)\\]|\\(htmlId=([\\w-]+)\\))");

    /* (non-Javadoc)
     * @see de.ugoe.cs.autoquest.plugin.html.AbstractDefaultLogParser#handleGUIElement(java.lang.String, java.util.Map)
     */
    @Override
    protected boolean handleGUIElement(String id, Map<String, String> parameters)
        throws SAXException
    {
        HTMLGUIElementSpec specification = null;
        
        String parentId = parameters.get("parent");
        IGUIElement parent = super.getGUIElementTree().find(parentId);

        if (parameters.containsKey("host")) {
            // this is a server specification
            int port = 80;
            String portStr = parameters.get(port);
            
            if (portStr != null) {
                port = Integer.parseInt(portStr);
            }
            
            specification = new HTMLServerSpec(parameters.get("host"), port);
        }
        else if (parameters.containsKey("path")) {
            // this is a document specification
            
            if (parent != null) {
                if (!(parent.getSpecification() instanceof HTMLServerSpec)) {
                    throw new SAXException
                        ("invalid log: parent GUI element of a document is not of type server");
                }
                
                specification = new HTMLDocumentSpec
                    ((HTMLServerSpec) parent.getSpecification(), parameters.get("path"),
                     parameters.get("query"), parameters.get("title"));
            }
            else if (parentId == null) {
                throw new SAXException("invalid log: a document has no parent id");
            }
        }
        else if (parameters.containsKey("tagname")) {
            String tagName = parameters.get("tagname");
            
            if (!tagNameMustBeConsidered(tagName)) {
                return true;
            }

            if (parent != null) {
                IGUIElement document = parent;
                
                while ((document != null) &&
                       (!(document.getSpecification() instanceof HTMLDocumentSpec)))
                {
                    document = document.getParent();
                }
                
                if (document == null) {
                    throw new SAXException
                        ("invalid log: parent hierarchy of a page element does not contain a " +
                         "document");
                }
                
                int index = -1;
                String indexStr = parameters.get("index");

                if ((indexStr != null) && (!"".equals(indexStr))) {
                    index = Integer.parseInt(indexStr);
                }

                specification = new HTMLPageElementSpec
                    ((HTMLDocumentSpec) document.getSpecification(), tagName,
                     parameters.get("htmlid"), index);
            }
            else if (parentId == null) {
                throw new SAXException("invalid log: a page element has no parent id");
            }
        }
        else {
            throw new SAXException("invalid log: unknown GUI element");
        }

        if (specification != null) {
            try {
                super.getGUIElementTree().add(id, parentId, specification);
            }
            catch (GUIModelException e) {
                throw new SAXException("could not handle GUI element with id " +
                                       id + ": " + e.getMessage(), e);
            }
            return true;
        }
        else {
            return false;
        }
    }

    /* (non-Javadoc)
     * @see de.ugoe.cs.autoquest.plugin.html.AbstractDefaultLogParser#handleEvent(java.lang.String, java.util.Map)
     */
    @Override
    protected boolean handleEvent(String type, Map<String, String> parameters) throws SAXException {
        String targetId = parameters.get("target");
        
        if (targetId == null) {
            String targetDocument = parameters.get("targetDocument");
            String targetDOMPath = parameters.get("targetDOMPath");
            
            if ((targetDocument == null) || (targetDOMPath == null)) {
                throw new SAXException("event has no target defined");
            }
            
            targetId = determineTargetId(targetDocument, targetDOMPath);
            
            if (targetId == null) {
                // the target id can not be determined yet
                return false;
            }
        }
        
        IGUIElement target = super.getGUIElementTree().find(targetId);
        
        if (target == null) {
            // event not processible yet
            return false;
        }

        IEventType eventType =
            HTMLEventTypeFactory.getInstance().getEventType(type, parameters, target);
        
        if (eventType != null) {
            Event event = new Event(eventType, target);

            String timestampStr = parameters.get("timestamp");
        
            if (timestampStr != null) {
                event.setTimestamp(Long.parseLong(timestampStr));
            }

            ((HTMLGUIElement) event.getTarget()).markUsed();
        
            super.addToSequence(event);
        }
        // else ignore unknown event type

        return true;
    }

    /**
     * <p>
     * TODO: comment
     * </p>
     *
     * @param targetDocument
     * @param targetDOMPath
     * @return
     */
    private String determineTargetId(String targetDocument, String targetDOMPath)
        throws SAXException
    {
        IGUIElement document = super.getGUIElementTree().find(targetDocument);
        
        if (document == null) {
            return null;
        }
        
        if (!(document.getSpecification() instanceof HTMLDocumentSpec)) {
            throw new SAXException("an id that should refer to an HTML document refers to" +
                                   "something else");
        }
        
        GUIModel model = super.getGUIElementTree().getGUIModel();
        IGUIElement child = document;
        String[] pathElements = targetDOMPath.split("/");
        int pathIndex = 0;
        
        HTMLPageElementSpec compareSpec;
        String tagName;
        int index;
        String htmlId;
        
        while ((pathIndex < pathElements.length) && (child != null)) {
            if ((pathElements[pathIndex] != null) && (!"".equals(pathElements[pathIndex]))) {           
                Matcher matcher = htmlElementPattern.matcher(pathElements[pathIndex]);
                if (!matcher.matches()) {
                    throw new SAXException
                        ("could not parse target DOM path element " + pathElements[pathIndex]);
                }

                tagName = matcher.group(1);
                String indexStr = matcher.group(3);
                htmlId = matcher.group(4);

                index = -1;
                if ((indexStr != null) && (!"".equals(indexStr))) {
                    index = Integer.parseInt(indexStr);
                }

                compareSpec = new HTMLPageElementSpec
                    ((HTMLDocumentSpec) document.getSpecification(), tagName, htmlId, index);

                List<IGUIElement> children = model.getChildren(child);
                child = null;

                for (IGUIElement candidate : children) {
                    if (compareSpec.getSimilarity(candidate.getSpecification())) {
                        child = candidate;
                        break;
                    }
                }
            }
            
            pathIndex++;
        }
        
        if (child != null) {
            return super.getGUIElementTree().find(child);
        }
        else {
            return null;
        }
    }

    /**
     * <p>
     * checks if tags with the provided name must be handled in the GUI model. As an example,
     * it is not necessary to handle "head" tags and anything included in them. 
     * </p>
     *
     * @param tagName
     * @return
     */
    private boolean tagNameMustBeConsidered(String tagName) {
        return
            !"head".equals(tagName) && !"title".equals(tagName) && !"script".equals(tagName) &&
            !"style".equals(tagName) && !"link".equals(tagName) && !"meta".equals(tagName) &&
            !"iframe".equals(tagName) && !"input_hidden".equals(tagName) &&
            !"option".equals(tagName) && !"tt".equals(tagName) && !"br".equals(tagName) &&
            !"colgroup".equals(tagName) && !"col".equals(tagName);

    }

}
