package org.apidesign.deadlock.startuplock;

import java.io.DataOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.net.ServerSocket;

import java.util.logging.Level;

import java.util.logging.Logger;

public final class CLIHandlerBlocking {

    // BEGIN: cli.real

    public static int start(File lockFile) throws IOException {

        enterState(10);

        if (lockFile.exists ()) {

            // read the port number and connect to it

            enterState(11);

            int alive = readPortNumber(lockFile);

            if (alive != -1) {

                // exit

                return alive;

            }

        }

        // otherwise try to create the file yourself

        enterState(20);

        lockFile.createNewFile();

        DataOutputStream os = new DataOutputStream(

            new FileOutputStream(lockFile)

        );

        ServerSocket server = new ServerSocket();

        enterState(21);

        int p = server.getLocalPort();

        enterState(22);

        os.writeInt(p);

        enterState(23);

        return p;

    }

    // END: cli.real

    private static Logger LOG = Logger.getLogger(CLIHandlerBlocking.class.getName());

    private static void enterState(int state) {

        LOG.log(Level.FINEST, "enterState {0}", state);

    }

    private static int readPortNumber(File lockFile) throws IOException {

        return -1;

    }

}