/*
 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.sun.tools.sjavac.server;

import java.io.File;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.Socket;
import java.net.URI;
import java.util.List;
import java.util.Set;

import com.sun.tools.sjavac.Log;

/**
 * A RequestHandler handles requests performed over a socket. Specifically it
 *  - Reads the command string specifying which method is to be invoked
 *  - Reads the appropriate arguments
 *  - Delegates the actual invocation to the given sjavac implementation
 *  - Writes the result back to the socket output stream
 *
 * None of the work performed by this class is really bound by the CPU. It
 * should be completely fine to have a large number of RequestHandlers active.
 * To limit the number of concurrent compilations, use PooledSjavac.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class RequestHandler implements Runnable {

    private final Socket socket;
    private final Sjavac sjavac;

    public RequestHandler(Socket socket, Sjavac sjavac) {
        this.socket = socket;
        this.sjavac = sjavac;
    }

    @Override
    public void run() {
        try (ObjectOutputStream oout = new ObjectOutputStream(socket.getOutputStream());
             ObjectInputStream oin = new ObjectInputStream(socket.getInputStream())) {
            String id = (String) oin.readObject();
            String cmd = (String) oin.readObject();
            Log.info("Handling request, id: " + id + " cmd: " + cmd);
            switch (cmd) {
            case SjavacServer.CMD_SYS_INFO: handleSysInfoRequest(oin, oout); break;
            case SjavacServer.CMD_COMPILE:  handleCompileRequest(oin, oout); break;
            default: Log.error("Unknown command: " + cmd);
            }
        } catch (Exception ex) {
            // Not much to be done at this point. The client side request
            // code will most likely throw an IOException and the
            // compilation will fail.
            StringWriter sw = new StringWriter();
            ex.printStackTrace(new PrintWriter(sw));
            Log.error(sw.toString());
        }
    }

    private void handleSysInfoRequest(ObjectInputStream oin,
                                      ObjectOutputStream oout) throws IOException {
        oout.writeObject(sjavac.getSysInfo());
        oout.flush();
    }

    @SuppressWarnings("unchecked")
    private void handleCompileRequest(ObjectInputStream oin,
                                      ObjectOutputStream oout) throws IOException {
        try {
            // Read request arguments
            String protocolId = (String) oin.readObject();
            String invocationId = (String) oin.readObject();
            String[] args = (String[]) oin.readObject();
            List<File> explicitSources = (List<File>) oin.readObject();
            Set<URI> sourcesToCompile = (Set<URI>) oin.readObject();
            Set<URI> visibleSources = (Set<URI>) oin.readObject();

            // Perform compilation
            CompilationResult cr = sjavac.compile(protocolId,
                                                  invocationId,
                                                  args,
                                                  explicitSources,
                                                  sourcesToCompile,
                                                  visibleSources);
            // Write request response
            oout.writeObject(cr);
            oout.flush();
        } catch (ClassNotFoundException cnfe) {
            throw new IOException(cnfe);
        }
    }
}