package org.codehaus.mojo.animal_sniffer;

/*
 * The MIT License
 *
 * Copyright (c) 2008 Kohsuke Kawaguchi and codehaus.org.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.net.URI;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.regex.Pattern;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

import org.codehaus.mojo.animal_sniffer.logging.Logger;
import org.codehaus.mojo.animal_sniffer.logging.PrintWriterLogger;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * Builds up a signature list from the given classes.
 *
 * @author Kohsuke Kawaguchi
 */
public class SignatureBuilder
    extends ClassFileVisitor
{
    private boolean foundSome;

    private final Logger logger;

    private List<Pattern> includeClasses;

    private List<Pattern> excludeClasses;

    private final Map<String,Clazz> classes = new TreeMap<>();

    public static void main( String[] args )
        throws IOException
    {
        SignatureBuilder builder =
                new SignatureBuilder( new FileOutputStream( "signature" ), new PrintWriterLogger( System.out ) );
        if ( getJavaVersion() > 8 ) {
            builder.process( Paths.get(URI.create("jrt:/modules")) );
        } else {
            builder.process( new File( System.getProperty( "java.home" ), "lib/rt.jar" ) );
        }
        builder.close();
    }

    private final ObjectOutputStream oos;

    public SignatureBuilder( OutputStream out, Logger logger )
        throws IOException
    {
        this( null, out, logger );
    }

    public void addInclude( String className )
    {
        if ( includeClasses == null )
        {
            includeClasses = new ArrayList<>();
        }
        includeClasses.add( RegexUtils.compileWildcard( className ) );
    }

    public void addExclude( String className )
    {
        if ( excludeClasses == null )
        {
            excludeClasses = new ArrayList<>();
        }
        excludeClasses.add( RegexUtils.compileWildcard( className ) );
    }

    public SignatureBuilder( InputStream[] ins, OutputStream out, Logger logger )
        throws IOException
    {
        this.logger = logger;
        if ( ins != null )
        {
            for ( InputStream in : ins )
            {
                try (ObjectInputStream ois = new ObjectInputStream( new GZIPInputStream( in ) ))
                {
                    while ( true )
                    {
                        Clazz c = (Clazz) ois.readObject();
                        if ( c == null )
                        {
                            break; // finished
                        }
                        classes.put( c.getName(), c );
                    }
                }
                catch ( ClassNotFoundException e )
                {
                    throw new IOException( "Could not read base signatures", e );
                }
            }
        }
        oos = new ObjectOutputStream( new GZIPOutputStream( out ) );
    }

    public void close()
        throws IOException
    {
        int count = 0;
        for ( Map.Entry<String,Clazz> entry : classes.entrySet() )
        {
            final String className = entry.getKey().replace( '/', '.' );
            if ( includeClasses != null )
            {
                boolean included = false;
                for( Pattern p : includeClasses )
                {
                    included |= p.matcher( className ).matches();
                }
                if ( !included )
                {
                    continue;
                }
            }
            if ( excludeClasses != null )
            {
                boolean excluded = false;
                for( Pattern p : excludeClasses )
                {
                    excluded |= p.matcher( className ).matches();
                }
                if ( excluded )
                {
                    continue;
                }
            }
            count++;
            logger.debug( className );

            oos.writeObject( entry.getValue() );
        }
        oos.writeObject( null );   // EOF marker
        logger.info( "Wrote signatures for " + count + " classes." );
        oos.close();
        if ( !foundSome )
        {
            throw new IOException( "No index is written" );
        }
    }

    protected void process( String name, InputStream image )
        throws IOException
    {
        logger.debug( name );
        foundSome = true;
        ClassReader cr = new ClassReader( image );
        SignatureVisitor v = new SignatureVisitor();
        cr.accept( v, 0 );
        v.end();
    }

    private class SignatureVisitor
        extends ClassVisitor
    {
        private Clazz clazz;

        public SignatureVisitor() {
            super(Opcodes.ASM9);
        }

        public void visit( int version, int access, String name, String signature, String superName,
                           String[] interfaces )
        {
            this.clazz = new Clazz( name, new HashSet<>(), superName, interfaces );
        }

        public void end()
            throws IOException
        {
            Clazz cur = classes.get( clazz.getName() );
            if ( cur == null )
            {
                classes.put( clazz.getName(), clazz );
            }
            else
            {
                classes.put( clazz.getName(), new Clazz( clazz, cur ) );
            }
        }

        public MethodVisitor visitMethod( int access, String name, String desc, String signature, String[] exceptions )
        {
            clazz.getSignatures().add( name + desc );
            return null;
        }

        public FieldVisitor visitField( int access, String name, String desc, String signature, Object value )
        {
            clazz.getSignatures().add( name + "#" + desc );
            return null;
        }
    }

    public static int getJavaVersion()
    {
        String version = System.getProperty("java.version");
        if ( version.startsWith("1.") )
        {
            version = version.substring(2);
        }
        // Allow these formats:
        // 1.8.0_72-ea
        // 9-ea
        // 9
        // 9.0.1
        int dotPos = version.indexOf( '.' );
        int dashPos = version.indexOf( '-' );
        return Integer.parseInt( version.substring( 0, dotPos > -1 ? dotPos : dashPos > -1 ? dashPos : 1 ) );
    }

}
