/*
 * Autopsy Forensic Browser
 *
 * Copyright 2012 Basis Technology Corp.
 * Contact: carrier <at> sleuthkit <dot> org
 *
 * 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 org.sleuthkit.autopsy.keywordsearch;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.util.List;
import java.util.logging.Level;
import org.sleuthkit.autopsy.coreutils.Logger;
import net.htmlparser.jericho.Attributes;
import net.htmlparser.jericho.Renderer;
import net.htmlparser.jericho.Source;
import net.htmlparser.jericho.StartTag;
import net.htmlparser.jericho.StartTagType;

/**
 * Uses Jericho HTML Parser to create a Reader for output, consisting of the
 * text, comments, tag attributes, and other important information found in the
 * HTML.
 */
class JerichoParserWrapper {

    private static final Logger logger = Logger.getLogger(JerichoParserWrapper.class.getName());
    private InputStream in;
    private StringBuilder out;
    private Reader reader;

    JerichoParserWrapper(InputStream in) {
        this.in = in;
    }

    /**
     * Returns the reader, initialized in parse(), which will be null if parse()
     * is not called or if parse() throws an error.
     *
     * @return Reader
     */
    public Reader getReader() {
        return reader;
    }

    /**
     * Initialize the reader by parsing the InputStream, adding it to
     * StringBuilder, and creating a StringReader from it.
     */
    public void parse() {
        out = new StringBuilder();

        try {
            Source source = new Source(in);
            source.fullSequentialParse();

            String text;
            StringBuilder scripts = new StringBuilder();
            StringBuilder links = new StringBuilder();
            StringBuilder images = new StringBuilder();
            StringBuilder comments = new StringBuilder();
            StringBuilder others = new StringBuilder();
            int numScripts = 1;
            int numLinks = 1;
            int numImages = 1;
            int numComments = 1;
            int numOthers = 1;

            text = renderHTMLAsPlainText(source);

            // Get all the tags in the source
            List<StartTag> tags = source.getAllStartTags();
            for (StartTag tag : tags) {
                if (tag.getName().equals("script")) { //NON-NLS
                    // If the <script> tag has attributes
                    scripts.append(numScripts).append(") ");
                    if (tag.getTagContent().length() > 0) {
                        scripts.append(tag.getTagContent()).append(" ");
                    }
                    // Get whats between the <script> .. </script> tags
                    scripts.append(tag.getElement().getContent()).append("\n");
                    numScripts++;
                } else if (tag.getName().equals("a")) { //NON-NLS
                    links.append(numLinks).append(") ");
                    links.append(tag.getTagContent()).append("\n");
                    numLinks++;
                } else if (tag.getName().equals("img")) { //NON-NLS
                    images.append(numImages).append(") ");
                    images.append(tag.getTagContent()).append("\n");
                    numImages++;
                } else if (tag.getTagType().equals(StartTagType.COMMENT)) {
                    comments.append(numComments).append(") ");
                    comments.append(tag.getTagContent()).append("\n");
                    numComments++;
                } else {
                    // Make sure it has an attribute
                    Attributes atts = tag.getAttributes();
                    if (atts != null && atts.length() > 0) {
                        others.append(numOthers).append(") ");
                        others.append(tag.getName()).append(":");
                        others.append(tag.getTagContent()).append("\n");
                        numOthers++;
                    }
                }
            }

            out.append(text).append("\n\n");

            out.append("----------NONVISIBLE TEXT----------\n\n"); //NON-NLS
            if (numScripts > 1) {
                out.append("---Scripts---\n"); //NON-NLS
                out.append(scripts.toString()).append("\n");
            }
            if (numLinks > 1) {
                out.append("---Links---\n"); //NON-NLS
                out.append(links.toString()).append("\n");
            }
            if (numImages > 1) {
                out.append("---Images---\n"); //NON-NLS
                out.append(images.toString()).append("\n");
            }
            if (numComments > 1) {
                out.append("---Comments---\n"); //NON-NLS
                out.append(comments.toString()).append("\n");
            }
            if (numOthers > 1) {
                out.append("---Others---\n"); //NON-NLS
                out.append(others.toString()).append("\n");
            }
            // All done, now make it a reader
            reader = new StringReader(out.toString());
        } catch (IOException ex) {
            logger.log(Level.WARNING, "Unable to parse the HTML file", ex); //NON-NLS
        }
    }

    // Extract text from the source, nicely formatted with whitespace and
    // newlines where appropriate.
    private String renderHTMLAsPlainText(Source source) {
        Renderer renderer = source.getRenderer();
        renderer.setNewLine("\n");
        renderer.setIncludeHyperlinkURLs(false);
        renderer.setDecorateFontStyles(false);
        renderer.setIncludeAlternateText(false);
        return renderer.toString();
    }
}