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/**
 * Copyright (C) 2011 Ovea 
 *
 * Licensed 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 com.ovea.tadjin.util;

import com.ovea.tadjin.util.logging.JdkOverLog4j;
import com.ovea.tadjin.util.logging.Logging;
import com.ovea.tadjin.util.properties.PropertyPlaceholderResolver;
import com.ovea.tadjin.util.properties.PropertySettings;
import org.apache.commons.cli.*;

import java.io.*;
import java.lang.management.ManagementFactory;
import java.util.Properties;

public final class Program {

    private static final Options OPTIONS = new Options()
        .addOption(new Option("c", "conf", true, "Property configuration file (required). I.e. file:./program.properties"))
        .addOption(new Option("h", "help", false, "This help"));

    private final Class mainClass;
    private final String[] args;
    private PropertySettings propertySettings;

    private Program(Class mainClass, String... args) {
        this.mainClass = mainClass;
        this.args = args;
    }

    public void validate() {
        try {
            CommandLine commandLine = new PosixParser().parse(OPTIONS, args);
            if (commandLine.hasOption("help"))
                helpAndExit();
            else if (!commandLine.hasOption("conf"))
                helpAndExit();
        } catch (ParseException e) {
            helpAndExit();
        }
    }

    public void prepare() {
        final PropertySettings settings = getOptions();
        Properties properties = settings.getProperties();
        for (String key : properties.stringPropertyNames())
            if (System.getProperty(key) == null)
                System.setProperty(key, properties.getProperty(key));
        Logging.setupLog4j(settings.getResource("log4j.config"));
        JdkOverLog4j.install();
        final File pidFile = settings.getPath("pid.file");
        if (pidFile.exists()) {
            System.err.println("PID file already exists: " + pidFile);
            System.exit(2);
        }
        pidFile.getParentFile().mkdirs();
        String pidStr = System.getProperty("pid");
        if (pidStr == null) {
            pidStr = ManagementFactory.getRuntimeMXBean().getName();
            pidStr = pidStr.substring(0, pidStr.indexOf('@'));
        }
        final int pid = Integer.parseInt(pidStr);
        try {
            PrintWriter pw = new PrintWriter(pidFile);
            pw.print(pid);
            pw.close();
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e.getMessage(), e);
        }
        pidFile.deleteOnExit();
    }

    private void helpAndExit() {
        new HelpFormatter().printHelp(mainClass.getName(), OPTIONS);
        System.exit(1);
    }

    public PropertySettings getOptions() {
        try {
            if (propertySettings == null) {
                CommandLine commandLine = new PosixParser().parse(OPTIONS, args);
                Properties properties = load(Resource.from("file:" + commandLine.getOptionValue("conf")));
                PropertyPlaceholderResolver resolver = new PropertyPlaceholderResolver();
                propertySettings = new PropertySettings(resolver.resolveAll(System.getProperties(), SystemInfo.asProperties(), properties));
            }
            return propertySettings;
        } catch (ParseException e) {
            throw new IllegalArgumentException("bad program parameters");
        }
    }

    private static Properties load(Resource propertyFile) {
        Properties p = new Properties();
        InputStream in = propertyFile.read();
        try {
            p.load(in);
            return p;
        } catch (IOException e) {
            throw new RuntimeException(e.getMessage(), e);
        } finally {
            try {
                in.close();
            } catch (IOException ignored) {
            }
        }
    }

    public static Program from(Class mainClass, String... args) {
        return new Program(mainClass, args);
    }

}