/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.net.finger;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedOutputStream;
import java.io.DataOutputStream;

import org.apache.commons.net.SocketClient;
import org.apache.commons.net.util.Charsets;

/***
 * The FingerClient class implements the client side of the Internet Finger
 * Protocol defined in RFC 1288.  To finger a host you create a
 * FingerClient instance, connect to the host, query the host, and finally
 * disconnect from the host.  If the finger service you want to query is on
 * a non-standard port, connect to the host at that port.
 * Here's a sample use:
 * <pre>
 *    FingerClient finger;
 *
 *    finger = new FingerClient();
 *
 *    try {
 *      finger.connect("foo.bar.com");
 *      System.out.println(finger.query("foobar", false));
 *      finger.disconnect();
 *    } catch(IOException e) {
 *      System.err.println("Error I/O exception: " + e.getMessage());
 *      return;
 *    }
 * </pre>
 *
 ***/

public class FingerClient extends SocketClient
{
    /***
     * The default FINGER port.  Set to 79 according to RFC 1288.
     ***/
    public static final int DEFAULT_PORT = 79;

    private static final String __LONG_FLAG = "/W ";

    private transient char[] __buffer = new char[1024];

    /***
     * The default FingerClient constructor.  Initializes the
     * default port to <code> DEFAULT_PORT </code>.
     ***/
    public FingerClient()
    {
        setDefaultPort(DEFAULT_PORT);
    }


    /***
     * Fingers a user at the connected host and returns the output
     * as a String.  You must first connect to a finger server before
     * calling this method, and you should disconnect afterward.
     *
     * @param longOutput Set to true if long output is requested, false if not.
     * @param username  The name of the user to finger.
     * @return The result of the finger query.
     * @exception IOException If an I/O error occurs while reading the socket.
     ***/
    public String query(boolean longOutput, String username) throws IOException
    {
        int read;
        StringBuilder result = new StringBuilder(__buffer.length);
        BufferedReader input;

        input =
            new BufferedReader(new InputStreamReader(getInputStream(longOutput,
                               username), getCharsetName())); // Java 1.6 can use getCharset()

        try {
            while (true)
            {
                read = input.read(__buffer, 0, __buffer.length);
                if (read <= 0) {
                    break;
                }
                result.append(__buffer, 0, read);
            }
        } finally {
            input.close();
        }

        return result.toString();
    }


    /***
     * Fingers the connected host and returns the output
     * as a String.  You must first connect to a finger server before
     * calling this method, and you should disconnect afterward.
     * This is equivalent to calling <code> query(longOutput, "") </code>.
     *
     * @param longOutput Set to true if long output is requested, false if not.
     * @return The result of the finger query.
     * @exception IOException If an I/O error occurs while reading the socket.
     ***/
    public String query(boolean longOutput) throws IOException
    {
        return query(longOutput, "");
    }


    /***
     * Fingers a user and returns the input stream from the network connection
     * of the finger query.  You must first connect to a finger server before
     * calling this method, and you should disconnect after finishing reading
     * the stream.
     *
     * @param longOutput Set to true if long output is requested, false if not.
     * @param username  The name of the user to finger.
     * @return The InputStream of the network connection of the finger query.
     *         Can be read to obtain finger results.
     * @exception IOException If an I/O error during the operation.
     ***/
    public InputStream getInputStream(boolean longOutput, String username)
    throws IOException
    {
        return getInputStream(longOutput, username, null);
    }

    /***
     * Fingers a user and returns the input stream from the network connection
     * of the finger query.  You must first connect to a finger server before
     * calling this method, and you should disconnect after finishing reading
     * the stream.
     *
     * @param longOutput Set to true if long output is requested, false if not.
     * @param username  The name of the user to finger.
     * @param encoding the character encoding that should be used for the query,
     *        null for the platform's default encoding
     * @return The InputStream of the network connection of the finger query.
     *         Can be read to obtain finger results.
     * @exception IOException If an I/O error during the operation.
     ***/
    public InputStream getInputStream(boolean longOutput, String username, String encoding)
    throws IOException
    {
        DataOutputStream output;
        StringBuilder buffer = new StringBuilder(64);
        if (longOutput) {
            buffer.append(__LONG_FLAG);
        }
        buffer.append(username);
        buffer.append(SocketClient.NETASCII_EOL);

        // Note: Charsets.toCharset() returns the platform default for null input
        byte[] encodedQuery = buffer.toString().getBytes(Charsets.toCharset(encoding).name()); // Java 1.6 can use charset directly

        output = new DataOutputStream(new BufferedOutputStream(_output_, 1024));
        output.write(encodedQuery, 0, encodedQuery.length);
        output.flush();

        return _input_;
    }


    /***
     * Fingers the connected host and returns the input stream from
     * the network connection of the finger query.  This is equivalent to
     * calling getInputStream(longOutput, "").  You must first connect to a
     * finger server before calling this method, and you should disconnect
     * after finishing reading the stream.
     *
     * @param longOutput Set to true if long output is requested, false if not.
     * @return The InputStream of the network connection of the finger query.
     *         Can be read to obtain finger results.
     * @exception IOException If an I/O error during the operation.
     ***/
    public InputStream getInputStream(boolean longOutput) throws IOException
    {
        return getInputStream(longOutput, "");
    }

}
