HTML2Md.java

package com.pnikosis.html2markdown;

import com.pnikosis.html2markdown.md.MDLine;
import com.pnikosis.html2markdown.md.MDLine.MDLineType;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.nodes.Entities.EscapeMode;
import org.jsoup.nodes.Node;
import org.jsoup.nodes.TextNode;
import org.jsoup.parser.Tag;
import org.jsoup.safety.Cleaner;
import org.jsoup.safety.Whitelist;

/**
 * Convert Html to MarkDown
 */
public class HTML2Md {
  private static int indentation = -1;
  private static boolean orderedList = false;

  public static String convert(String theHTML, String baseURL) {
    Document doc = Jsoup.parse(theHTML, baseURL);

    return parseDocument(doc);
  }

  public static String convert(URL url, int timeoutMillis) throws IOException {
    Document doc = Jsoup.parse(url, timeoutMillis);

    return parseDocument(doc);
  }

  public static String convertHtml(String html, String charset) throws IOException {
    Document doc = Jsoup.parse(html, charset);

    return parseDocument(doc);
  }

  public static String convertFile(File file, String charset) throws IOException {
    Document doc = Jsoup.parse(file, charset);

    return parseDocument(doc);
  }

  public static void htmlToJekyllMd(String htmlPath, String mdPath, String charset) {
    try {
      List<File> fileList = FilesUtil.getAllFiles(htmlPath, "html");
      for (File file : fileList) {
        String mdName = file.getAbsolutePath().replace(htmlPath, mdPath).replace("html", "md");
        String hmPath = mdName.substring(0, mdName.lastIndexOf("/")) + "/";
        String separator = System.getProperty("line.separator");
        String head = "---" + separator +
            "layout: post" + separator +
            "title: \"" + file.getName() + "\"" + separator +
            "description: \"" + file.getName() + "\"" + separator +
            "category: pages\"" + separator +
            "tags: [blog]\"" + separator +
            "--- " + separator +
            "{% include JB/setup %}" + separator
            + separator;
        FilesUtil.isExist(hmPath);
        String parsedText = convertFile(file, charset);
        Calendar calendar = Calendar.getInstance();
        String dateName = DateUtil.dateToShortString(calendar.getTime());
        String newName = dateName + "-" + hmPath.replace(mdPath, "").replace("/", "-") + "-" + file.getName();
        String mmName = (hmPath + newName.replace("html", "md")).replaceAll("\\s*", "");
        FilesUtil.newFile(mmName, head + parsedText, charset);
      }
    } catch (MalformedURLException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  public static void htmlToHexoMd(String htmlPath, String mdPath, String charset) {
    try {
      List<File> fileList = FilesUtil.getAllFiles(htmlPath, "html");
      for (File file : fileList) {
        String mdName = file.getAbsolutePath().replace(htmlPath, mdPath).replace("html", "md");
        String hmPath = mdName.substring(0, mdName.lastIndexOf("/")) + "/";
        String separator = System.getProperty("line.separator");
        String[] strings = hmPath.replace(mdPath, "").split("/");
        Calendar calendar = Calendar.getInstance();
        String dateName = DateUtil.dateToShortString(calendar.getTime());
        String dateString = DateUtil.dateToLongString(calendar.getTime());
        StringBuilder blog = new StringBuilder();
        StringBuilder categories = new StringBuilder();
        Map<String, String> stringMap = new TreeMap<String, String>();
        for (String value : strings) {
          stringMap.put(value, value);
        }
        for (String tag : stringMap.keySet()) {
          blog.append(" - ").append(tag).append(separator);
        }
        categories.append(strings[0]);
        String head = "---" + separator +
            "layout: post" + separator +
            "title: \"" + file.getName().replace(".html", "").split("-")[0] + "\"" + separator +
            "date: " + dateString + separator +
            "categories: " + categories + separator +
            "tags: " + separator +
            blog.toString() +
            "--- " + separator +
            separator;
        FilesUtil.isExist(hmPath);
        String parsedText = HTML2Md.convertFile(file, "utf-8");
        String newName = dateName + "-" + hmPath.replace(mdPath, "").replace("/", "-") + "-" + file.getName();
        String mmName = (hmPath + newName.replace("html", "md")).replaceAll("\\s*", "");
        FilesUtil.newFile(mmName, head + parsedText, charset);
      }
    } catch (MalformedURLException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  private static String parseDocument(Document dirtyDoc) {
    indentation = -1;

    String title = dirtyDoc.title();

    Whitelist whitelist = Whitelist.relaxed();
    Cleaner cleaner = new Cleaner(whitelist);

    Document doc = cleaner.clean(dirtyDoc);
    doc.outputSettings().escapeMode(EscapeMode.xhtml);

    String trimmedTitle = title.trim();
    if (!"".equals(trimmedTitle)) {
      return "# " + trimmedTitle + "\n\n" + getTextContent(doc);
    } else {
      return getTextContent(doc);
    }
  }

  private static String getTextContent(Element element) {
    ArrayList<MDLine> lines = new ArrayList<>();

    List<Node> children = element.childNodes();
    for (Node child : children) {
      if (TextNode.class.isInstance(child)) {
        TextNode textNode = (TextNode) child;
        MDLine line = getLastLine(lines);
        if (line.getContent().equals("")) {
          if (!textNode.isBlank()) {
            line.append(textNode.text().replaceAll("#", "/#").replaceAll("\\*", "/\\*"));
          }
        } else {
          line.append(textNode.text().replaceAll("#", "/#").replaceAll("\\*", "/\\*"));
        }

      } else if (child instanceof Element) {
        Element childElement = (Element) child;
        processElement(childElement, lines);
      } else {
        System.out.println();
      }
    }

    int blankLines = 0;
    StringBuilder result = new StringBuilder();
    for (int i = 0; i < lines.size(); i++) {
      String line = lines.get(i).toString().trim();
      if (line.equals("")) {
        blankLines++;
      } else {
        blankLines = 0;
      }
      if (blankLines < 2) {
        result.append(line);
        if (i < lines.size() - 1) {
          result.append("\n");
        }
      }
    }

    return result.toString();
  }

  private static void processElement(Element element, ArrayList<MDLine> lines) {
    Tag tag = element.tag();

    String tagName = tag.getName();
    if (tagName.equals("div")) {
      div(element, lines);
    } else if (tagName.equals("p")) {
      p(element, lines);
    } else if (tagName.equals("br")) {
      br(lines);
    } else if (tagName.matches("^h[0-9]+$")) {
      h(element, lines);
    } else if (tagName.equals("strong") || tagName.equals("b")) {
      strong(element, lines);
    } else if (tagName.equals("em")) {
      em(element, lines);
    } else if (tagName.equals("hr")) {
      hr(lines);
    } else if (tagName.equals("a")) {
      a(element, lines);
    } else if (tagName.equals("img")) {
      img(element, lines);
    } else if (tagName.equals("code")) {
      code(element, lines);
    } else if (tagName.equals("ul")) {
      ul(element, lines);
    } else if (tagName.equals("ol")) {
      ol(element, lines);
    } else if (tagName.equals("li")) {
      li(element, lines);
    } else {
      MDLine line = getLastLine(lines);
      line.append(getTextContent(element));
    }
  }

  private static MDLine getLastLine(ArrayList<MDLine> lines) {
    MDLine line;
    if (lines.size() > 0) {
      line = lines.get(lines.size() - 1);
    } else {
      line = new MDLine(MDLineType.None, 0, "");
      lines.add(line);
    }

    return line;
  }

  private static void div(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    String content = getTextContent(element);
    if (!content.equals("")) {
      if (!line.getContent().trim().equals("")) {
        lines.add(new MDLine(MDLineType.None, 0, ""));
        lines.add(new MDLine(MDLineType.None, 0, content));
        lines.add(new MDLine(MDLineType.None, 0, ""));
      } else {
        if (!content.trim().equals(""))
          line.append(content);
      }
    }
  }

  private static void p(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    if (!line.getContent().trim().equals(""))
      lines.add(new MDLine(MDLineType.None, 0, ""));
    lines.add(new MDLine(MDLineType.None, 0, ""));
    lines.add(new MDLine(MDLineType.None, 0, getTextContent(element)));
    lines.add(new MDLine(MDLineType.None, 0, ""));
    if (!line.getContent().trim().equals(""))
      lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void br(ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    if (!line.getContent().trim().equals(""))
      lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void h(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    if (!line.getContent().trim().equals(""))
      lines.add(new MDLine(MDLineType.None, 0, ""));

    int level = Integer.valueOf(element.tagName().substring(1));
    switch (level) {
      case 1:
        lines.add(new MDLine(MDLineType.Head1, 0, getTextContent(element)));
        break;
      case 2:
        lines.add(new MDLine(MDLineType.Head2, 0, getTextContent(element)));
        break;
      default:
        lines.add(new MDLine(MDLineType.Head3, 0, getTextContent(element)));
        break;
    }

    lines.add(new MDLine(MDLineType.None, 0, ""));
    lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void strong(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    line.append("**");
    line.append(getTextContent(element));
    line.append("**");
  }

  private static void em(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    line.append("*");
    line.append(getTextContent(element));
    line.append("*");
  }

  private static void hr(ArrayList<MDLine> lines) {
    lines.add(new MDLine(MDLineType.None, 0, ""));
    lines.add(new MDLine(MDLineType.HR, 0, ""));
    lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void a(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);
    line.append("[");
    line.append(getTextContent(element));
    line.append("]");
    line.append("(");
    String url = element.attr("href");
    line.append(url);
    String title = element.attr("title");
    if (!title.equals("")) {
      line.append(" \"");
      line.append(title);
      line.append("\"");
    }
    line.append(")");
  }

  private static void img(Element element, ArrayList<MDLine> lines) {
    MDLine line = getLastLine(lines);

    line.append("![");
    String alt = element.attr("alt");
    line.append(alt);
    line.append("]");
    line.append("(");
    String url = element.attr("src");
    line.append(url);
    String title = element.attr("title");
    if (!title.equals("")) {
      line.append(" \"");
      line.append(title);
      line.append("\"");
    }
    line.append(")");
  }

  private static void code(Element element, ArrayList<MDLine> lines) {
    lines.add(new MDLine(MDLineType.None, 0, ""));
    MDLine line = new MDLine(MDLineType.None, 0, "    ");
    line.append(getTextContent(element).replace("\n", "    "));
    lines.add(line);
    lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void ul(Element element, ArrayList<MDLine> lines) {
    lines.add(new MDLine(MDLineType.None, 0, ""));
    indentation++;
    orderedList = false;
    MDLine line = new MDLine(MDLineType.None, 0, "");
    line.append(getTextContent(element));
    lines.add(line);
    indentation--;
    lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void ol(Element element, ArrayList<MDLine> lines) {
    lines.add(new MDLine(MDLineType.None, 0, ""));
    indentation++;
    orderedList = true;
    MDLine line = new MDLine(MDLineType.None, 0, "");
    line.append(getTextContent(element));
    lines.add(line);
    indentation--;
    lines.add(new MDLine(MDLineType.None, 0, ""));
  }

  private static void li(Element element, ArrayList<MDLine> lines) {
    MDLine line;
    if (orderedList) {
      line = new MDLine(MDLineType.Ordered, indentation,
          getTextContent(element));
    } else {
      line = new MDLine(MDLineType.Unordered, indentation,
          getTextContent(element));
    }
    lines.add(line);
  }
}