package jalview.rest;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.bind.DatatypeConverter;

import jalview.bin.Cache;
import jalview.gui.CutAndPasteTransfer;
import jalview.gui.Desktop;

public class OpenSequenceEndpoint extends EndpointAsync
{
  protected String name = "opensequence";

  private String fileString;

  private String urlString;

  private String method;

  private String dataString;

  private String body;

  private String content;

  private boolean post;

  private boolean data;

  String access = null;

  String ref = null;

  @Override
  protected void initialise(HttpServletRequest request,
          HttpServletResponse response)
  {
    fileString = request.getParameter("file");
    urlString = request.getParameter("url");
    method = request.getMethod().toLowerCase();
    dataString = request.getParameter("data");
    body = null;
    post = method.equalsIgnoreCase("post");
    data = dataString != null;

    if (post)
    {
      access = "post";
      try
      {
        body = getRequestBody(request);
      } catch (IOException e)
      {
        returnError(request, response, "could not read POST body");
        Cache.debug(e);
        return;
      }
      // for ref see md5 later
    }
    else if (data)
    {
      access = "data";
      // for ref see md5 later
    }
    else if (fileString != null)
    {
      access = "file";
      ref = fileString;
    }
    else if (urlString != null)
    {
      access = "url";
      ref = urlString;
    }

    if (access == null)
    {
      returnError(request, response,
              "requires POST body or one of parameters 'data', 'file' or 'url'");
      return;
    }

    // final content used in Future
    final String content;
    if (post || data)
    {
      content = post ? body : dataString;
      try
      {
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        md5.update(content.getBytes());
        byte[] digest = md5.digest();
        ref = DatatypeConverter.printBase64Binary(digest).toLowerCase();
      } catch (NoSuchAlgorithmException e)
      {
        Cache.debug(e);
      }
    }
    else
    {
      content = null;
    }

    setId(request, access + "::" + ref);
  }

  protected void process(HttpServletRequest request,
          HttpServletResponse response)
  {
    if (post || data)
    {
      // Sequence file contents being posted
      // use File -> Input Alignment -> from Textbox
      CutAndPasteTransfer cap = new CutAndPasteTransfer();
      cap.setText(content);
      cap.ok_actionPerformed(null);
      cap.cancel_actionPerformed(null);
    }
    else if (fileString != null)
    {
      // Sequence file on filesystem
      // use File -> Input Alignment -> From File
      URL url = null;
      File file = null;
      try
      {
        url = new URL(fileString);
        file = new File(url.toURI());
      } catch (MalformedURLException | URISyntaxException e)
      {
        returnError(request, response,
                "could not resolve file='" + fileString + "'");
        Cache.debug(e);
        return;
      }
      if (!file.exists())
      {
        returnError(request, response,
                "file='" + fileString + "' does not exist");
        return;
      }
      Desktop.instance.openFile(file, null, null);
    }
    else if (urlString != null)
    {
      boolean success = Desktop.instance.loadUrl(urlString, null);
      if (!success)
      {
        returnError(request, response,
                "url='" + urlString + "' could not be opened");
        return;
      }
    }
  }
}