/*
 * Jalview - A Sequence Alignment Editor and Viewer ($$Version-Rel$$)
 * Copyright (C) $$Year-Rel$$ The Jalview Authors
 * 
 * This file is part of Jalview.
 * 
 * Jalview is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License 
 * as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *  
 * Jalview is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty 
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
 * PURPOSE.  See the GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
 * The Jalview Authors are detailed in the 'AUTHORS' file.
 */
package jalview.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URL;
import java.util.List;

import javax.ws.rs.HttpMethod;

public class HttpUtils
{

  /**
   * Returns true if it is possible to open an input stream at the given URL,
   * else false. The input stream is closed.
   * 
   * @param url
   * @return
   */
  public static boolean isValidUrl(String url)
  {
    InputStream is = null;
    try
    {
      is = new URL(url).openStream();
      if (is != null)
      {
        return true;
      }
    } catch (IOException x)
    {
      // MalformedURLException, FileNotFoundException
      return false;
    } finally
    {
      if (is != null)
      {
        try
        {
          is.close();
        } catch (IOException e)
        {
          // ignore
        }
      }
    }
    return false;
  }
  public static boolean startsWithHttpOrHttps(String file)
  {
    return file.startsWith("http://") || file.startsWith("https://");
  }
  
  /**
   * wrapper to get/post to a URL or check headers
   * @param url
   * @param ids
   * @param readTimeout
   * @return
   * @throws IOException
   * @throws ProtocolException
   */
  public static boolean checkUrlAvailable(URL url,
          int readTimeout) throws IOException, ProtocolException
  {
    // System.out.println(System.currentTimeMillis() + " " + url);

    HttpURLConnection connection = (HttpURLConnection) url.openConnection();

    connection.setRequestMethod(HttpMethod.HEAD);

    connection.setDoInput(true);

    connection.setUseCaches(false);
    connection.setConnectTimeout(300);
    connection.setReadTimeout(readTimeout);
    return connection.getResponseCode() == 200;
  }

  /**
   * download from given URL and return a pointer to temporary file
   */
  public static File fetchURLToTemp(String url) throws OutOfMemoryError,
          IOException
  {
    long time = System.currentTimeMillis();
    URL rcall = new URL(url);

    InputStream is = new BufferedInputStream(rcall.openStream());
    File outFile = null;
    try
    {
      outFile = File.createTempFile("jalview", ".xml");
      outFile.deleteOnExit();
      if (outFile.length() == 0)
      {
        outFile.delete();
        return null;
      }
    } catch (Exception ex)
    {
    }

    if (outFile != null)
    {
      FileOutputStream fio = new FileOutputStream(outFile);
      byte[] bb = new byte[32 * 1024];
      int l;
      while ((l = is.read(bb)) > 0)
      {
        fio.write(bb, 0, l);
      }
      fio.close();
      is.close();
      return outFile;
    }
    else
    {
      return null;
    }
  }
}