/*
 * [Global.java]
 *
 * Summary: Allows all methods to access the current configuration.
 *
 * Copyright: (c) 2010-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2010-01-23 initial version
 */
package com.mindprod.htmlmacros.macro;

import com.mindprod.common18.BigDate;
import com.mindprod.common18.ST;
import com.mindprod.fastcat.FastCat;
import com.mindprod.htmlmacros.support.AssignCSSClasses;
import com.mindprod.htmlmacros.support.Configuration;
import com.mindprod.htmlmacros.support.ConfigurationForCherokeeObama;
import com.mindprod.htmlmacros.support.ConfigurationForMindprod;
import com.mindprod.htmlmacros.support.ConfigurationForMindprodCa;
import com.mindprod.htmlmacros.support.ConfigurationForMindprodCom;

import java.io.File;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * Allows all methods to access the current configuration.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2010-01-23 initial version.
 * @since 2010-01-23
 */
public class Global
    {
    /**
     * today's date. used to detect anniversaries of birth/deaths.  Keep consistent throughout run over midnight.
     */
    public static final BigDate TODAY = BigDate.localToday();

    public static final BigDate DAY_BEFORE_YESTERDAY = BigDate.localToday().addDays( -2 );

    public static final BigDate YESTERDAY = BigDate.localToday().addDays( -1 );

    public static final int THIS_CALENDAR_YEAR = TODAY.getYYYY();

    /**
     * used to accumulate text to insert at the very bottom of the page just before </body>
     */
    public static final FastCat forBottom = new FastCat( 100 );

    public volatile static boolean gracefulStop = false;

    /**
     * the current configuration.  Known to all methods.
     * Configuration set in Replacer command line, or programmatically
     * by ReplaceMindprod or ReplaceCherokeeObama.
     */
    public static Configuration configuration;

    /**
     * current config for assigning CSS classes to urls
     */
    public static AssignCSSClasses assignCSSClasses;

    /**
     * 5 second periodic timer
     */
    private static ScheduledExecutorService scheduler;

    /**
     * shutdown stop probe
     */
    public static void closeStopMonitoring()
        {
        scheduler.shutdownNow();
        final File stop = new File( configuration.getLocalWebrootWithSlashes() + "/busy/stop.dat" );
        if ( stop.exists() )
            {
            stop.delete();
            }
        }

    /**
     * Installs configuration on the command line as the current configuration.
     *
     * @param args class name of configuration e.g. ConfigurationForMindprod or
     *             ConfigurationForCherokeeObama
     */
    public static void installConfiguration( String[] args )
        {
        if ( args == null || args.length < 1 || ST.isEmpty( args[ 0 ] ) )
            {
            throw new IllegalArgumentException( "The name of the configuration e.g. ConfigurationForMindprod must be first on the commmand line." );
            }
        installConfiguration( args[ 0 ] );
        args[ 0 ] = null;
        }

    /**
     * Installs configuration as the current configuration.
     *
     * @param configurationName class name of configuration e.g. ConfigurationForMindprod or
     *                          ConfigurationForCherokeeObama
     */
    public static void installConfiguration( String configurationName )
        {
        final Configuration c;
        switch ( configurationName )
            {
            case "ConfigurationForMindprodCom":
                c = new ConfigurationForMindprodCom();
                break;
            case "ConfigurationForMindprodCa":
                c = new ConfigurationForMindprodCa();
                break;
            case "ConfigurationForMindprod":
                c = new ConfigurationForMindprod();
                break;
            case "ConfigurationForCherokeeObama":
                c = new ConfigurationForCherokeeObama();
                break;
            default:
                try
                    {
                    // e.g. parm to Class.forName looks like: "ConfigurationForMindprod"
                    final String binaryClassName = "com.mindprod.htmlmacros.support." + configurationName;
                    // Make sure the class we dynamically load implements the Configuration interface.
                    final Class<? extends Configuration> configurationClass = Class.forName( binaryClassName ).asSubclass(
                            Configuration.class );
                    c = configurationClass.newInstance();
                    }
                catch ( ClassCastException e )
                    {
                    // configuration exists but is screwed up, but the code exists.
                    throw new ClassCastException( "Coding bug: The code to process configuration " + configurationName +
                                                  " refused access. It needs a public no-arg constructor." );
                    }
                catch ( Exception e )
                    {
                    // might have been ClassNotFoundException,  NoClassDefFoundException
                    // Any problem is a failure.
                    throw new IllegalArgumentException( "Fatal error: Configuration " + configurationName + " not found" );
                    }
            }  // end switch
        installConfiguration( c );
        }

    /**
     * Installs configuration as the current configuration.
     *
     * @param configuration class name of configuration e.g. new ConfigurationForMindprod()
     *                      ConfigurationForCherokeeObama
     */
    public static void installConfiguration( Configuration configuration )
        {
        Global.configuration = configuration;
        Global.assignCSSClasses = configuration.getAssignCSSClasses();
        }

    /**
     * keep tabs on stop.dat file to request shutdown
     */
    public static void openStopMonitoring()
        {
        final File stop = new File( configuration.getLocalWebrootWithSlashes() + "/busy/stop.dat" );
        // check for request to stop every 5 seconds.
        scheduler = Executors.newSingleThreadScheduledExecutor();
        scheduler.scheduleAtFixedRate( new Runnable()
            {
            public void run()
                {
                if ( stop.exists() )
                    {
                    Global.gracefulStop = true;
                    stop.delete();
                    }
                }
            }, 5, 5, TimeUnit.SECONDS );
        }
    }