/*
Taken from forum.java.sun.com

License

Copyright 1994-2007 Sun Microsystems, Inc. All Rights Reserved.
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 * Redistribution of source code must retain the above copyright notice, this list
      of conditions and the following disclaimer.

 * Redistribution in binary form must reproduce the above copyright notice, this
      list of conditions and the following disclaimer in the documentation and/or other
      materials provided with the distribution.

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 */

package org.openstreetmap.josm.io;

import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

/**
 * <code>MultiPartFormOutputStream</code> is used to write
 * "multipart/form-data" to a <code>java.net.URLConnection</code> for
 * POSTing.  This is primarily for file uploading to HTTP servers.
 *
 * @since  JDK1.3
 */
public class MultiPartFormOutputStream extends OsmConnection {
    /**
     * The line end characters.
     */
    private static final String NEWLINE = "\r\n";

    /**
     * The boundary prefix.
     */
    private static final String PREFIX = "--";

    /**
     * The output stream to write to.
     */
    private DataOutputStream out = null;

    /**
     * The multipart boundary string.
     */
    private String boundary = null;

    /**
     * Creates a new <code>MultiPartFormOutputStream</code> object using
     * the specified output stream and boundary.  The boundary is required
     * to be created before using this method, as described in the
     * description for the <code>getContentType(String)</code> method.
     * The boundary is only checked for <code>null</code> or empty string,
     * but it is recommended to be at least 6 characters.  (Or use the
     * static createBoundary() method to create one.)
     *
     * @param  os        the output stream
     * @param  boundary  the boundary
     * @see  #createBoundary()
     * @see  #getContentType(String)
     */
    public MultiPartFormOutputStream(OutputStream os, String boundary) {
        if(os == null)
            throw new IllegalArgumentException("Output stream is required.");
        if(boundary == null || boundary.length() == 0)
            throw new IllegalArgumentException("Boundary stream is required.");
        this.out = new DataOutputStream(os);
        this.boundary = boundary;
    }

    /**
     * Writes an boolean field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, boolean value)
    throws java.io.IOException {
        writeField(name, Boolean.valueOf(value).toString());
    }

    /**
     * Writes an double field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, double value)
    throws java.io.IOException {
        writeField(name, Double.toString(value));
    }

    /**
     * Writes an float field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, float value)
    throws java.io.IOException {
        writeField(name, Float.toString(value));
    }

    /**
     * Writes an long field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, long value)
    throws java.io.IOException {
        writeField(name, Long.toString(value));
    }

    /**
     * Writes an int field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, int value)
    throws java.io.IOException {
        writeField(name, Integer.toString(value));
    }

    /**
     * Writes an short field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, short value)
    throws java.io.IOException {
        writeField(name, Short.toString(value));
    }

    /**
     * Writes an char field value.
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, char value)
    throws java.io.IOException {
        writeField(name, Character.valueOf(value).toString());
    }

    /**
     * Writes an string field value.  If the value is null, an empty string
     * is sent ("").
     *
     * @param  name   the field name (required)
     * @param  value  the field value
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeField(String name, String value)
    throws java.io.IOException {
        if(name == null)
            throw new IllegalArgumentException("Name cannot be null or empty.");
        if(value == null) {
            value = "";
        }
        /*
            --boundary\r\n
            Content-Disposition: form-data; name="<fieldName>"\r\n
            \r\n
            <value>\r\n
         */
        // write boundary
        out.writeBytes(PREFIX);
        out.writeBytes(boundary);
        out.writeBytes(NEWLINE);
        // write content header
        out.writeBytes("Content-Disposition: form-data; name=\"" + name + "\"");
        out.writeBytes(NEWLINE);
        out.writeBytes(NEWLINE);
        // write content
        out.writeBytes(value);
        out.writeBytes(NEWLINE);
        out.flush();
    }

    /**
     * Writes a file's contents.  If the file is null, does not exists, or
     * is a directory, a <code>java.lang.IllegalArgumentException</code>
     * will be thrown.
     *
     * @param  name      the field name
     * @param  mimeType  the file content type (optional, recommended)
     * @param  file      the file (the file must exist)
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeFile(String name, String mimeType, java.io.File file)
    throws java.io.IOException {
        if(file == null)
            throw new IllegalArgumentException("File cannot be null.");
        if(!file.exists())
            throw new IllegalArgumentException("File does not exist.");
        if(file.isDirectory())
            throw new IllegalArgumentException("File cannot be a directory.");
        writeFile(name, mimeType, file.getCanonicalPath(), new FileInputStream(file));
    }

    /**
     * Writes a input stream's contents.  If the input stream is null, a
     * <code>java.lang.IllegalArgumentException</code> will be thrown.
     *
     * @param  name      the field name
     * @param  mimeType  the file content type (optional, recommended)
     * @param  fileName  the file name (required)
     * @param  is        the input stream
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeFile(String name, String mimeType,
            String fileName, InputStream is)
    throws java.io.IOException {
        if(is == null)
            throw new IllegalArgumentException("Input stream cannot be null.");
        if(fileName == null || fileName.length() == 0)
            throw new IllegalArgumentException("File name cannot be null or empty.");
        /*
            --boundary\r\n
            Content-Disposition: form-data; name="<fieldName>"; filename="<filename>"\r\n
            Content-Type: <mime-type>\r\n
            \r\n
            <file-data>\r\n
         */
        // write boundary
        out.writeBytes(PREFIX);
        out.writeBytes(boundary);
        out.writeBytes(NEWLINE);
        // write content header
        out.writeBytes("Content-Disposition: form-data; name=\"" + name +
                "\"; filename=\"" + fileName + "\"");
        out.writeBytes(NEWLINE);
        if(mimeType != null) {
            out.writeBytes("Content-Type: " + mimeType);
            out.writeBytes(NEWLINE);
        }
        out.writeBytes(NEWLINE);
        // write content
        byte[] data = new byte[1024];
        int r = 0;
        while((r = is.read(data, 0, data.length)) != -1) {
            out.write(data, 0, r);
        }
        // close input stream, but ignore any possible exception for it
        try {
            is.close();
        } catch(Exception e) {}
        out.writeBytes(NEWLINE);
        out.flush();
    }

    /**
     * Writes the given bytes.  The bytes are assumed to be the contents
     * of a file, and will be sent as such.  If the data is null, a
     * <code>java.lang.IllegalArgumentException</code> will be thrown.
     *
     * @param  name      the field name
     * @param  mimeType  the file content type (optional, recommended)
     * @param  fileName  the file name (required)
     * @param  data      the file data
     * @throws  java.io.IOException  on input/output errors
     */
    public void writeFile(String name, String mimeType,
            String fileName, byte[] data)
    throws java.io.IOException {
        if(data == null)
            throw new IllegalArgumentException("Data cannot be null.");
        if(fileName == null || fileName.length() == 0)
            throw new IllegalArgumentException("File name cannot be null or empty.");
        /*
            --boundary\r\n
            Content-Disposition: form-data; name="<fieldName>"; filename="<filename>"\r\n
            Content-Type: <mime-type>\r\n
            \r\n
            <file-data>\r\n
         */
        // write boundary
        out.writeBytes(PREFIX);
        out.writeBytes(boundary);
        out.writeBytes(NEWLINE);
        // write content header
        out.writeBytes("Content-Disposition: form-data; name=\"" + name +
                "\"; filename=\"" + fileName + "\"");
        out.writeBytes(NEWLINE);
        if(mimeType != null) {
            out.writeBytes("Content-Type: " + mimeType);
            out.writeBytes(NEWLINE);
        }
        out.writeBytes(NEWLINE);
        // write content
        out.write(data, 0, data.length);
        out.writeBytes(NEWLINE);
        out.flush();
    }

    /**
     * Flushes the stream.  Actually, this method does nothing, as the only
     * write methods are highly specialized and automatically flush.
     */
    public void flush() {
        // out.flush();
    }

    /**
     * Closes the stream.  <br/>
     * <br/>
     * <b>NOTE:</b> This method <b>MUST</b> be called to finalize the
     * multipart stream.
     *
     * @throws  java.io.IOException  on input/output errors
     */
    public void close() throws java.io.IOException {
        // write final boundary
        out.writeBytes(PREFIX);
        out.writeBytes(boundary);
        out.writeBytes(PREFIX);
        out.writeBytes(NEWLINE);
        out.flush();
        out.close();
    }

    /**
     * Gets the multipart boundary string being used by this stream.
     *
     * @return  the boundary
     */
    public String getBoundary() {
        return this.boundary;
    }

    /**
     * Creates a new <code>java.net.URLConnection</code> object from the
     * specified <code>java.net.URL</code>.  This is a convenience method
     * which will set the <code>doInput</code>, <code>doOutput</code>,
     * <code>useCaches</code> and <code>defaultUseCaches</code> fields to
     * the appropriate settings in the correct order.
     *
     * @return  a <code>java.net.URLConnection</code> object for the URL
     * @throws  java.io.IOException  on input/output errors
     */
    public static URLConnection createConnection(URL url)
    throws java.io.IOException {
        URLConnection urlConn = url.openConnection();
        if(urlConn instanceof HttpURLConnection) {
            HttpURLConnection httpConn = (HttpURLConnection)urlConn;
            httpConn.setRequestMethod("POST");
        }
        urlConn.setDoInput(true);
        urlConn.setDoOutput(true);
        urlConn.setUseCaches(false);
        urlConn.setDefaultUseCaches(false);
        return urlConn;
    }

    /**
     * Creates a multipart boundary string by concatenating 20 hyphens (-)
     * and the hexadecimal (base-16) representation of the current time in
     * milliseconds.
     *
     * @return  a multipart boundary string
     * @see  #getContentType(String)
     */
    public static String createBoundary() {
        return "--------------------" +
        Long.toString(System.currentTimeMillis(), 16);
    }

    /**
     * Gets the content type string suitable for the
     * <code>java.net.URLConnection</code> which includes the multipart
     * boundary string.  <br/>
     * <br/>
     * This method is static because, due to the nature of the
     * <code>java.net.URLConnection</code> class, once the output stream
     * for the connection is acquired, it's too late to set the content
     * type (or any other request parameter).  So one has to create a
     * multipart boundary string first before using this class, such as
     * with the <code>createBoundary()</code> method.
     *
     * @param  boundary  the boundary string
     * @return  the content type string
     * @see  #createBoundary()
     */
    public static String getContentType(String boundary) {
        return "multipart/form-data; boundary=" + boundary;
    }
}