package no.magge.google;

import java.io.*;
import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.message.BasicHeader;
import org.apache.http.params.HttpParams;
import org.apache.log4j.Logger;

// httpclient-3.1 imports
import org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity;
import org.apache.commons.httpclient.methods.multipart.Part;
import org.apache.commons.httpclient.params.HttpMethodParams;


/**
 * MultipartEntityWrapper - this implements the HttpClient-4 HttpEntity interface with the functionality from 
 * HttpClient-3.1's MultipartRequestEntity. Should provide functionality to post multipart/form-data with HttpClient-4.
 * 
 * Followed some instructions written by Roland Webers here:
 *  (http://www.nabble.com/multipart-form-data-in-4.0-td14224819.html)
 *  
 * Note:
 * I tried making a class that extended MultipartRequestEntity at first, but there's at least one conflict in return types of
 * equally named methods in the MultipartRequestEntity class and the HttpEntity interface. Thus we just instantiate a 
 * separate MultipartRequestEntity object and wrap the necessary methods.
 * 
 * @author Magnus Olstad Hansen
 */
public class MultipartEntityWrapper implements HttpEntity {

	private static final Logger log = Logger.getLogger(MultipartEntityWrapper.class);
	
	protected MultipartRequestEntity multipartLegacy;
	
	/**
	 * Constructs a new MultipartRequestEntity compatible with HttpClient-4
	 * 
	 * @param parts The parts to include in the entity
	 * @param params - WARNING, mapping of new parameters to old parameters is -NOT- done
	 */
	public MultipartEntityWrapper(Part[] parts, HttpParams params) {
		HttpMethodParams targetParams = new HttpMethodParams();
		// TODO: map params to httpmethodparams, defaults used here
		multipartLegacy = new MultipartRequestEntity(parts, targetParams);
	}
		
	/**
	 * @see org.apache.http.HttpEntity#getContentLength()
	 */
	@Override
	public long getContentLength() {
		return multipartLegacy.getContentLength();
	}

	/**
	 * @see org.apache.http.HttpEntity#getContentType()
	 */
	@Override
	public Header getContentType() {
		// TODO: Find the constant for Content-Type? :)
		return new BasicHeader("Content-Type", multipartLegacy.getContentType());
	}

	/**
	 * @see org.apache.http.HttpEntity#isChunked()
	 */
	public boolean isChunked() {
		// Roland Webers word is law;
		// (http://www.nabble.com/multipart-form-data-in-4.0-td14224819.html)
		return getContentLength()<0L;
	}

	/**
	 * @see org.apache.http.HttpEntity#isRepeatable()
	 */
	@Override
	public boolean isRepeatable() {
		return multipartLegacy.isRepeatable();
	}

	/**
	 * @see org.apache.http.HttpEntity#writeTo(java.io.OutputStream)
	 */
	@Override
	public void writeTo(OutputStream outstream) throws IOException {
		multipartLegacy.writeRequest(outstream);
	}

	
	
	/**
	 *  Receiving not supported.
	 */
	@Override
	public void consumeContent() throws IOException {
		throw new UnsupportedOperationException("MultipartEntityWrapper has no support for receiving");
	}

	/**
	 *  Receiving not supported.
	 */
	@Override
	public InputStream getContent() throws IOException, IllegalStateException {
		throw new UnsupportedOperationException("MultipartEntityWrapper has no support for receiving");
	}

	/**
	 *  Receiving not supported.
	 */
	@Override
	public Header getContentEncoding() {
		return null;
	}
	
	/**
	 *  Receiving not supported.
	 */
	@Override
	public boolean isStreaming() {
		return false;
	}
}