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package simpleserver;

import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.CharacterCodingException;
import java.util.Date;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 *
 * @author Michael
 */
public class Request
{
    
    private static Pattern pattern = Pattern.compile("GET /.*\r?\n");
    private RequestListener context;
    
    private SocketChannel socket;
    private SelectionKey  key;
    
    private ByteBuffer    request;
    private FileChannel   file = null;
    private ByteBuffer    response = null;
    private ByteBuffer    contents = null;
    
    
    public Request(RequestListener context, Selector selector, SocketChannel sc) throws IOException
    {
        this.context = context;
        
        sc.configureBlocking(false);
        socket = sc;
        
        key = sc.register(selector, SelectionKey.OP_READ, this);
        request = ByteBuffer.allocate(4096);
    }
    
    public void process()
    {
        try
        {
            if (file == null)
            {
                /* Reading request. Change selection to OP_WRITE when done.
                 */
                if (socket.read(request) < 0)
                {
                    close();
                }
                else if (isComplete(request))
                {
                    key.interestOps(SelectionKey.OP_WRITE);
                    request.flip();
                    decodeRequest(context.decoder.decode(request).toString());
                }
            }
            else
            {
                /* Delivering file. Cancel this key when done.
                 */
                if (response != null)
                {
                    socket.write(response);
                    if (!response.hasRemaining())
                        response = null;
                }
                else
                {
                    socket.write(contents);
                    if (!contents.hasRemaining())
                        close();
                }
            }
        }
        catch (IOException ioe)
        {
            ioe.printStackTrace();
            close();
        }
    }
    
    private boolean isComplete(ByteBuffer r)
    {
        int index = r.position();
        return index >= 4 && r.get(index-4)=='\r' && r.get(index-3)=='\n' && r.get(index-2)=='\r' && r.get(index-1)=='\n';
    }
    
    public void close()
    {
        key.cancel();
        try {socket.close();}catch(IOException e){}
        if (file != null) try{file.close();}catch(IOException e){}
        
        response = null;
        contents = null;
    }
    
    private void decodeRequest(String request) throws IOException
    {
        if (!request.startsWith("GET "))
        {
            respond(405, "Invalid method");
        }
        else
        {
            int sp = request.indexOf(' ', 4);
            if (sp < 0) sp = request.indexOf('\r');
            else if (sp < 0) sp = request.indexOf('\n');
            else if (sp < 0) sp = request.length();
            
            String path = request.substring(4, sp);
            System.err.println("PATH = " + path);
            
            file = new FileInputStream(Main.BASE_PATH + path).getChannel();
            respond(200, "OK");
            contents = file.map(FileChannel.MapMode.READ_ONLY, 0, file.size());
        }
    }
    
    private void respond(int code, String message)
    {
        try
        {
            response = context.encoder.encode(CharBuffer.wrap("1.1 " + code + " " + message + "\r\n\r\n"));
        }
        catch (CharacterCodingException e)
        {
            throw new RuntimeException(e);
        }
    }
}