/*
 * IKA - IcedRobot Kiosk Application
 * Copyright (C) 2011  IcedRobot team
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.icedrobot.ika.runtime;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.icedrobot.ika.output.DefaultWorkerStatus;
import org.icedrobot.ika.output.StatusKeeper;
import org.icedrobot.ika.output.WorkerStatus;


/**
 * Executable command that will report its status to the StatusKeeper.
 */
public class RuntimeCommand {

    private final String[] typeSample = new String[0];


    private Process proc;
    protected final String taskName;
    protected List<String> commandLine;


    /**
     * Initializes a RuntimeCommand
     * @param name          Command name. No other active commands must exist.
     * @param commandLine   Command line used to execute the command.
     */
    public RuntimeCommand(String name, String... commandLine) {
        taskName = name;
        this.commandLine = new LinkedList<String>( Arrays.asList(commandLine) );

        StatusKeeper.getInstance().registerWorker(taskName );
    }


    /**
     * Processes a line of output provided by the external process.
     * @param output    Output of the external process
     * @return          WorkerStatus expressing the same information as output.
     */
    protected WorkerStatus process(String output) {
        return new DefaultWorkerStatus(0f, output);
    }

    /**
     * Starts the external process
     * @param path      Working directory
     * @return          Newly started process.
     */
    protected Process runCommand(File path) {
        return IkaRuntime.exec( path, commandLine.toArray(typeSample) );
    }

    /**
     * Starts the external process
     * @param path      Working directory
     */
    public void execute(File path) {
        proc = runCommand(path);

        BufferedReader input = new BufferedReader(
                                    new InputStreamReader(
                                        proc.getInputStream() ));

        String line;
        WorkerStatus status;

        try {

            while ((line = input.readLine()) != null) {
                status = process(line);
                StatusKeeper.getInstance().reportStatus(taskName, status);
            }

        } catch (IOException ex) {
            Logger.getLogger( RuntimeCommand.class.getName() ).log(
                   Level.SEVERE, taskName + ": error on the input stream", ex );
        }

        do {
            try {

                /*
                 * If the process terminates abnormally, leave its status there
                 * so that it can be clearly seen.
                 */
                if (proc.waitFor() == 0) {
                    StatusKeeper.getInstance().deregisterWorker(taskName);
                }

                proc = null;

            } catch (InterruptedException ex) {
                Logger.getLogger( RuntimeCommand.class.getName() )
                                    .log( Level.INFO,
                                        "Thread was interrupted while waiting "
                                            + "for process termination", ex);
            }

        } while (proc != null);

    }

    @Override
    public String toString() {
        StringBuilder bdr = new StringBuilder(getClass().getSimpleName());

        bdr.append('(');

        for (String s : commandLine) {
            bdr.append(s);
            bdr.append(' ');
        }

        bdr.setCharAt(bdr.length() - 1, ')');

        return bdr.toString();
    }
}