package tk.eclipse.plugin.jspeditor.editors;

import java.util.HashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import jp.aonir.fuzzyxml.FuzzyXMLAttribute;
import jp.aonir.fuzzyxml.FuzzyXMLDocument;
import jp.aonir.fuzzyxml.FuzzyXMLElement;
import jp.aonir.fuzzyxml.FuzzyXMLNode;
import jp.aonir.fuzzyxml.FuzzyXMLParser;
import jp.aonir.fuzzyxml.internal.RenderContext;

import org.eclipse.ui.IFileEditorInput;

import tk.eclipse.plugin.htmleditor.HTMLPlugin;
import tk.eclipse.plugin.htmleditor.HTMLUtil;
import tk.eclipse.plugin.htmleditor.ICustomTagConverter;
import tk.eclipse.plugin.htmleditor.ICustomTagConverterContributer;

/**
 * This class provides some utility methods to convert JSP to HTML for preview.
 */
public class JSPPreviewConverter {

  private static Pattern petternScript = Pattern.compile("<%(.*?)%>", Pattern.DOTALL);
  private static Pattern petternTagBegin = Pattern.compile("<(|/)((\\w+?):(.*?))>");

  /**
   * Converts JSP to HTML for preview.
   * 
   * @param jsp JSP
   * @return converted HTML
   */
  public static String convertJSP(IFileEditorInput input, String jsp) {
    // get JSPInfo
    JSPInfo info = JSPInfo.getJSPInfo(input.getFile(), jsp);

    // remove JSP comments
    //jsp = jsp.replaceAll("<%--(.|\n|\r)*?--%>","");
    jsp = HTMLUtil.comment2space(jsp, false);

    // split by <body>
    String lower = jsp.toLowerCase();
    int index = lower.indexOf("<body");
    int end = lower.indexOf("</body>");

    // if <body> doesn't exist, remove all
    if (index == -1) {
      jsp = petternScript.matcher(jsp).replaceAll("");
      jsp = petternTagBegin.matcher(jsp).replaceAll("");
      return jsp;
    }
    if (end == -1) {
      end = jsp.length();
    }
    else {
      end = end + 7;
    }

    String head = jsp.substring(0, index);
    String body = jsp.substring(index, end);

    // before <body>
    head = petternScript.matcher(head).replaceAll("");
    head = petternTagBegin.matcher(head).replaceAll("");

    // after <body>
    body = processScript(body);
    body = processTag(body, info);
    body = body.replaceAll("&nbsp;", " ");
    body = body.replaceAll("'", "'");

    return "<html>" + head + body + "</html>";
  }

  /**
   * Process scriptlet.
   * 
   * @param jsp JSP
   * @return converted JSP
   */
  private static String processScript(String jsp) {
    StringBuffer sb = new StringBuffer();
    Matcher matcher = petternScript.matcher(jsp);
    int index = 0;
    while (matcher.find()) {
      sb.append(jsp.substring(index, matcher.start()));
      sb.append(HTMLUtil.escapeHTML(matcher.group(0)));
      index = matcher.end();
    }
    if (index < jsp.length() - 1) {
      sb.append(jsp.substring(index));
    }
    return sb.toString();
  }

  /**
   * This method should be private, but it's required to be public...
   * 
   * @param element
   * @param info
   * @return
   */
  public static String processElement(FuzzyXMLElement element, JSPInfo info) {
    StringBuffer sb = new StringBuffer();

    if (element.getName().indexOf(":") != -1) {
      String tagName = element.getName();
      String[] dim = tagName.split(":");

      // get URI from prefix
      String uri = info.getTaglibUri(dim[0]);
      // get converter
      ICustomTagConverter converter = null;
      if (uri != null) {
        ICustomTagConverterContributer contributer = HTMLPlugin.getDefault().getCustomTagContributer(uri);
        if (contributer != null) {
          converter = contributer.getConverter(dim[1]);
        }
      }
      if (converter != null) {
        HashMap<String, String> attrMap = new HashMap<String, String>();
        FuzzyXMLAttribute[] attrs = element.getAttributes();
        for (int i = 0; i < attrs.length; i++) {
          attrMap.put(attrs[i].getName(), attrs[i].getValue());
        }
        sb.append(converter.process(attrMap, element.getChildren(), info));
        return sb.toString();
      }
    }

    if (element.getChildren().length == 0) {
      sb.append(element.toXMLString(new RenderContext(true)));
    }
    else {
      sb.append(element2startTag(element));
      FuzzyXMLNode[] node = element.getChildren();
      for (int i = 0; i < node.length; i++) {
        if (node[i] instanceof FuzzyXMLElement) {
          sb.append(processElement((FuzzyXMLElement) node[i], info));
        }
        else {
          sb.append(node[i].toXMLString(new RenderContext(true)));
        }
      }
      sb.append(element2closeTag(element));
    }

    return sb.toString();
  }

  private static String element2startTag(FuzzyXMLElement e) {
    StringBuffer sb = new StringBuffer();
    sb.append("<" + e.getName());
    FuzzyXMLAttribute[] attr = e.getAttributes();
    for (int i = 0; i < attr.length; i++) {
      sb.append(" " + attr[i].getName() + "=\"" + attr[i].getValue() + "\"");
    }
    sb.append(">");
    return sb.toString();
  }

  private static String element2closeTag(FuzzyXMLElement e) {
    return "</" + e.getName() + ">";
  }

  /**
   * Process taglibs.
   * 
   * @param jsp  JSP
   * @param info JSPInfo
   * @return processed JSP
   */
  private static String processTag(String jsp, JSPInfo info) {
    FuzzyXMLDocument doc = new FuzzyXMLParser(false).parse(jsp);
    FuzzyXMLNode[] nodes = doc.getDocumentElement().getChildren();
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < nodes.length; i++) {
      if (nodes[i] instanceof FuzzyXMLElement) {
        sb.append(processElement((FuzzyXMLElement) nodes[i], info));
      }
    }
    return sb.toString();
  }

}