/*
 * [Which.java]
 *
 * Summary: Finds exe, dll, class, jar on path and identifies type.
 *
 * Copyright: (c) 2012-2017 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 2012-01-09 initial version.
 *  1.1 2012-05-07 update Jet version signature. add debugging code.
 *  1.2 2012-11-15 update Jet version signature for MP5
 *  1.3 2013-04-19 update Jet version signature for 8.0
 *  1.4 2014-07-25 update Jet version signature for 9.0
 *  1.5 2014-07-27 update Jet version signature for 10.0 and 11.0
 *  1.6 2016-06-20 update to Jet 11.0 mp3
 */
package com.mindprod.which;

import com.mindprod.common18.EIO;
import com.mindprod.common18.ST;

import java.io.File;
import java.io.FilenameFilter;
import java.util.regex.Pattern;

import static java.lang.System.*;

/**
 * Finds exe, dll, class, jar on path and identifies type.
 * <p/>
 * Recognises 16-bit DOS, 16-bit Windows 32-bit Windows, 32-bit Jet, 64-bit Jet.
 * <p/>
 * Determines if a file is a Jet executable. Searches the Java library path for file mentioned on the command line.
 * I composed this program in a dream, waking up a dozen times
 * to discover I had not hit a single keystroke.   I composed this
 * not so much because I think anyone will need this, but because
 * I want to shut up the damn dream.
 * Searches for exe, dll and identifies type
 * <p/>
 * Put file you want to examine on command line.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.6 2016-06-20 update to Jet 11.0 mp3
 * @see com.mindprod.which.FileType
 * @see FileType#classifyJet
 * @since 2012-01-09
 */
public class Which
    {
    /**
     * true if want extra debug output. also change FileType.DEBUGGING
     */
    private static final boolean DEBUGGING = false;

    private static final int FIRST_COPYRIGHT_YEAR = 2012;

    /**
     * undisplayed copyright notice
     */
    @SuppressWarnings( { "UnusedDeclaration" } )
    private static final String EMBEDDED_COPYRIGHT =
            "Copyright: (c) 2012-2017 Roedy Green, Canadian Mind Products, http://mindprod.com";

    @SuppressWarnings( { "UnusedDeclaration" } )
    private static final String RELEASE_DATE = "2016-06-20";

    /**
     * how to use this utility.
     */
    private static final String USAGE = "\nUsage: Which.exe someprog.exe (Where someprog.exe is somewhere on the path.).";

    /**
     * embedded version string.
     */
    private static final String VERSION_STRING = "1.6";

    /**
     * used to split out various legs of the path
     */
    private static final Pattern PATH_SPLITTER = Pattern.compile( System.getProperty( "path.separator" ) );

    /**
     * Search path for DLL or exe, and identify types of files found.
     *
     * @param fileToExamine DLL or exe to search for.
     */
    private static void searchForDLLorExe( final String fileToExamine )
        {
        final String path = System.getProperty( "java.library.path" );
        boolean first = true;
        int firstRetCode = 91;
        if ( path != null )
            {
            String[] legs = PATH_SPLITTER.split( path );
            if ( DEBUGGING )
                {
                int count = 1;
                out.println( "Raw java.library.path:" );
                for ( String leg : legs )
                    {
                    if ( !ST.isEmpty( leg ) )
                        {
                        out.println( count++ + " [" + leg + "]" );
                        }
                    }
                }
            // get rid of dups.  We cannot sort or would find wrong instance first.
            for ( int i = 1; i < legs.length; i++ )
                {
                for ( int j = 0; j < i; j++ )
                    {
                    assert legs[ i ] != null : "null leg";
                    if ( ST.isEmpty( legs[ i ] ) )
                        {
                        legs[ i ] = null;
                        }
                    else if ( legs[ i ].equalsIgnoreCase( legs[ j ] ) )
                        {
                        if ( DEBUGGING )
                            {
                            out.println( "Duplicate on path " + legs[ i ] );
                            }
                        // get rid of dup so we won't report exe twice
                        legs[ i ] = null;
                        break;
                        }
                    }
                }
            final FilenameFilter onlyMatch = new OnlyMatch( fileToExamine );
            // leg is one element of the path, text between semicolons.
            int legNo = 0;
            for ( String leg : legs )
                {
                // ignore nulled dups
                if ( leg == null )
                    {
                    continue;
                    }
                legNo++;
                // no jars on path, just dirs. Only Classpath has jars.
                final File dir = new File( leg );
                if ( !dir.isDirectory() )
                    {
                    // C:\WINDOWS\Sun\Java\bin  does not exist, but that is expected.
                    if ( !EIO.getCanOrAbsPath( dir ).equalsIgnoreCase( "C:\\Windows\\Sun\\Java\\bin" ) )
                        {
                        err.println( "Warning: non existent " + legNo + "th dir [" + leg + "] found on path" );
                        }
                    continue;
                    }
                String[] candidates = dir.list( onlyMatch );
                for ( String candidate : candidates )
                    {
                    final File hit = new File( dir, candidate );
                    FileType type = FileType.classify( hit );
                    out.println( "found: " + EIO.getCanOrAbsPath( hit ) + " : " + type );
                    if ( first )
                        {
                        first = false;
                        firstRetCode = type.getRetCode();
                        }
                    }
                }
            }
        if ( first )
            {
            out.println( "not found: " + fileToExamine );
            }
        System.exit( firstRetCode );
        }

    /**
     * Determine if a file in an ordinary exe or a Jet exe.
     *
     * @param args name of an exe file to be found somewhere on the path
     */
    public static void main( String[] args )
        {
        if ( args.length != 1 )
            {
            err.println( "Must have exactly one unqualified (no dir) .exe or .dll file name on the command line.\n" +
                         USAGE );
            System.exit( 99 );
            }
        final String fileToExamine = args[ 0 ];
        if ( fileToExamine.contains( "/" ) || fileToExamine.contains( "\\" ) || fileToExamine.contains( ":" ) )
            {
            err.println( "Must have exactly one unqualified (no dir) .exe or .dll file name on the command line.\n" +
                         USAGE );
            System.exit( 99 );
            }
        if ( ( fileToExamine.endsWith( ".exe" ) || fileToExamine.endsWith( ".dll" ) ) )
            {
            searchForDLLorExe( fileToExamine );
            }
        err.println( "Filename must end in .exe or .dl\n" + USAGE );
        System.exit( 99 );
        }
    }