/*******************************************************************************
 * Copyright (c) 2014 Jeff Martin.\
 * 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Contributors:
 *     Jeff Martin - initial API and implementation
 ******************************************************************************/
package cuchaz.enigma;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringWriter;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarOutputStream;

import javassist.CtClass;
import javassist.bytecode.Descriptor;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.strobel.assembler.metadata.MetadataSystem;
import com.strobel.assembler.metadata.TypeDefinition;
import com.strobel.decompiler.DecompilerContext;
import com.strobel.decompiler.DecompilerSettings;
import com.strobel.decompiler.PlainTextOutput;
import com.strobel.decompiler.languages.java.JavaOutputVisitor;
import com.strobel.decompiler.languages.java.ast.AstBuilder;
import com.strobel.decompiler.languages.java.ast.CompilationUnit;
import com.strobel.decompiler.languages.java.ast.InsertParenthesesVisitor;

import cuchaz.enigma.analysis.EntryReference;
import cuchaz.enigma.analysis.JarClassIterator;
import cuchaz.enigma.analysis.JarIndex;
import cuchaz.enigma.analysis.SourceIndex;
import cuchaz.enigma.analysis.SourceIndexVisitor;
import cuchaz.enigma.analysis.Token;
import cuchaz.enigma.analysis.TreeDumpVisitor;
import cuchaz.enigma.mapping.ArgumentEntry;
import cuchaz.enigma.mapping.BehaviorEntry;
import cuchaz.enigma.mapping.BehaviorEntryFactory;
import cuchaz.enigma.mapping.ClassEntry;
import cuchaz.enigma.mapping.ClassMapping;
import cuchaz.enigma.mapping.ConstructorEntry;
import cuchaz.enigma.mapping.Entry;
import cuchaz.enigma.mapping.FieldEntry;
import cuchaz.enigma.mapping.FieldMapping;
import cuchaz.enigma.mapping.Mappings;
import cuchaz.enigma.mapping.MappingsRenamer;
import cuchaz.enigma.mapping.MethodEntry;
import cuchaz.enigma.mapping.MethodMapping;
import cuchaz.enigma.mapping.TranslationDirection;
import cuchaz.enigma.mapping.Translator;

public class Deobfuscator
{
	public interface ProgressListener
	{
		void init( int totalWork, String title );
		void onProgress( int numDone, String message );
	}
	
	private File m_file;
	private JarFile m_jar;
	private DecompilerSettings m_settings;
	private JarIndex m_jarIndex;
	private Mappings m_mappings;
	private MappingsRenamer m_renamer;
	private Map<TranslationDirection,Translator> m_translatorCache;
	
	public Deobfuscator( File file )
	throws IOException
	{
		m_file = file;
		m_jar = new JarFile( m_file );
		
		// build the jar index
		m_jarIndex = new JarIndex();
		m_jarIndex.indexJar( m_jar, true );
		
		// config the decompiler
		m_settings = DecompilerSettings.javaDefaults();
		m_settings.setMergeVariables( true );
		m_settings.setForceExplicitImports( true );
		m_settings.setForceExplicitTypeArguments( true );
		// DEBUG
		//m_settings.setShowSyntheticMembers( true );
		
		// init defaults
		m_translatorCache = Maps.newTreeMap();
		
		// init mappings
		setMappings( new Mappings() );
	}
	
	public String getJarName( )
	{
		return m_file.getName();
	}
	
	public JarIndex getJarIndex( )
	{
		return m_jarIndex;
	}
	
	public Mappings getMappings( )
	{
		return m_mappings;
	}
	public void setMappings( Mappings val )
	{
		if( val == null )
		{
			val = new Mappings();
		}
		
		// pass 1: look for any classes that got moved to inner classes
		Map<String,String> renames = Maps.newHashMap();
		for( ClassMapping classMapping : val.classes() )
		{
			String outerClassName = m_jarIndex.getOuterClass( classMapping.getObfName() );
			if( outerClassName != null )
			{
				// build the composite class name
				String newName = outerClassName + "$" + new ClassEntry( classMapping.getObfName() ).getSimpleName();
				
				// add a rename
				renames.put( classMapping.getObfName(), newName );
				
				System.out.println( String.format( "Converted class mapping %s to %s", classMapping.getObfName(), newName ) );
			}
		}
		for( Map.Entry<String,String> entry : renames.entrySet() )
		{
			val.renameObfClass( entry.getKey(), entry.getValue() );
		}
		
		// pass 2: look for fields/methods that are actually declared in superclasses
		MappingsRenamer renamer = new MappingsRenamer( m_jarIndex, val );
		for( ClassMapping classMapping : val.classes() )
		{
			ClassEntry obfClassEntry = new ClassEntry( classMapping.getObfName() );
			
			// fields
			for( FieldMapping fieldMapping : Lists.newArrayList( classMapping.fields() ) )
			{
				FieldEntry fieldEntry = new FieldEntry( obfClassEntry, fieldMapping.getObfName() );
				ClassEntry resolvedObfClassEntry = m_jarIndex.resolveEntryClass( fieldEntry );
				if( resolvedObfClassEntry != null && !resolvedObfClassEntry.equals( fieldEntry.getClassEntry() ) )
				{
					boolean wasMoved = renamer.moveFieldToObfClass( classMapping, fieldMapping, resolvedObfClassEntry );
					if( wasMoved )
					{
						System.out.println( String.format( "Moved field %s to class %s", fieldEntry, resolvedObfClassEntry ) );
					}
					else
					{
						System.err.println( String.format( "WARNING: Would move field %s to class %s but the field was already there. Dropping instead.", fieldEntry, resolvedObfClassEntry ) );
					}
				}
			}
			
			// methods
			for( MethodMapping methodMapping : Lists.newArrayList( classMapping.methods() ) )
			{
				// skip constructors
				if( methodMapping.isConstructor() )
				{
					continue;
				}
				
				MethodEntry methodEntry = new MethodEntry( obfClassEntry, methodMapping.getObfName(), methodMapping.getObfSignature() );
				ClassEntry resolvedObfClassEntry = m_jarIndex.resolveEntryClass( methodEntry );
				if( resolvedObfClassEntry != null && !resolvedObfClassEntry.equals( methodEntry.getClassEntry() ) )
				{
					boolean wasMoved = renamer.moveMethodToObfClass( classMapping, methodMapping, resolvedObfClassEntry );
					if( wasMoved )
					{
						System.out.println( String.format( "Moved method %s to class %s", methodEntry, resolvedObfClassEntry ) );
					}
					else
					{
						System.err.println( String.format( "WARNING: Would move method %s to class %s but the method was already there. Dropping instead.", methodEntry, resolvedObfClassEntry ) );
					}
				}
			}
			
			// TODO: recurse to inner classes?
		}
		
		// drop mappings that don't match the jar
		List<ClassEntry> unknownClasses = Lists.newArrayList();
		for( ClassMapping classMapping : val.classes() )
		{
			checkClassMapping( unknownClasses, classMapping );
		}
		if( !unknownClasses.isEmpty() )
		{
			throw new Error( "Unable to find classes in jar: " + unknownClasses );
		}
		
		m_mappings = val;
		m_renamer = renamer;
		m_translatorCache.clear();
	}
	
	private void checkClassMapping( List<ClassEntry> unknownClasses, ClassMapping classMapping )
	{
		// check the class
		ClassEntry classEntry = new ClassEntry( classMapping.getObfName() );
		String outerClassName = m_jarIndex.getOuterClass( classMapping.getObfName() );
		if( outerClassName != null )
		{
			classEntry = new ClassEntry( outerClassName + "$" + classEntry.getSimpleName() );
		}
		if( !m_jarIndex.getObfClassEntries().contains( classEntry ) )
		{
			unknownClasses.add( classEntry );
		}
		
		// check the fields
		for( FieldMapping fieldMapping : Lists.newArrayList( classMapping.fields() ) )
		{
			FieldEntry fieldEntry = new FieldEntry( classEntry, fieldMapping.getObfName() );
			if( !m_jarIndex.containsObfField( fieldEntry ) )
			{
				System.err.println( "WARNING: unable to find field " + fieldEntry + ". dropping mapping." );
				classMapping.removeFieldMapping( fieldMapping );
			}
		}
		
		// check methods
		for( MethodMapping methodMapping : Lists.newArrayList( classMapping.methods() ) )
		{
			BehaviorEntry obfBehaviorEntry = BehaviorEntryFactory.createObf( classEntry, methodMapping );
			if( !m_jarIndex.containsObfBehavior( obfBehaviorEntry ) )
			{
				System.err.println( "WARNING: unable to find behavior " + obfBehaviorEntry + ". dropping mapping." );
				classMapping.removeMethodMapping( methodMapping );
			}	
		}
		
		// check inner classes
		for( ClassMapping innerClassMapping : classMapping.innerClasses() )
		{
			checkClassMapping( unknownClasses, innerClassMapping );
		}
	}

	public Translator getTranslator( TranslationDirection direction )
	{
		Translator translator = m_translatorCache.get( direction );
		if( translator == null )
		{
			translator = m_mappings.getTranslator( m_jarIndex.getTranslationIndex(), direction );
			m_translatorCache.put( direction, translator );
		}
		return translator;
	}
	
	public void getSeparatedClasses( List<ClassEntry> obfClasses, List<ClassEntry> deobfClasses )
	{
		for( ClassEntry obfClassEntry : m_jarIndex.getObfClassEntries() )
		{
			// skip inner classes
			if( obfClassEntry.isInnerClass() )
			{
				continue;
			}
			
			// separate the classes
			ClassEntry deobfClassEntry = deobfuscateEntry( obfClassEntry );
			if( !deobfClassEntry.equals( obfClassEntry ) )
			{
				// if the class has a mapping, clearly it's deobfuscated
				deobfClasses.add( deobfClassEntry );
			}
			else if( !obfClassEntry.getPackageName().equals( Constants.NonePackage ) )
			{
				// also call it deobufscated if it's not in the none package
				deobfClasses.add( obfClassEntry );
			}
			else
			{
				// otherwise, assume it's still obfuscated
				obfClasses.add( obfClassEntry );
			}
		}
	}
	
	public CompilationUnit getSourceTree( String obfClassName )
	{
		// is this class deobfuscated?
		// we need to tell the decompiler the deobfuscated name so it doesn't get freaked out
		// the decompiler only sees the deobfuscated class, so we need to load it by the deobfuscated name
		String lookupClassName = obfClassName;
		ClassMapping classMapping = m_mappings.getClassByObf( obfClassName );
		if( classMapping != null && classMapping.getDeobfName() != null )
		{
			lookupClassName = classMapping.getDeobfName();
		}
		
		// is this class even in the jar?
		if( !m_jarIndex.containsObfClass( new ClassEntry( obfClassName ) ) )
		{
			return null;
		}
		
		// set the type loader
		m_settings.setTypeLoader( new TranslatingTypeLoader(
			m_jar,
			m_jarIndex,
			getTranslator( TranslationDirection.Obfuscating ),
			getTranslator( TranslationDirection.Deobfuscating )
		) );
		
		// decompile it!
		TypeDefinition resolvedType = new MetadataSystem( m_settings.getTypeLoader() ).lookupType( lookupClassName ).resolve();
		DecompilerContext context = new DecompilerContext();
		context.setCurrentType( resolvedType );
		context.setSettings( m_settings );
		AstBuilder builder = new AstBuilder( context );
		builder.addType( resolvedType );
		builder.runTransformations( null );
		return builder.getCompilationUnit();
	}
	
	public SourceIndex getSourceIndex( CompilationUnit sourceTree, String source )
	{
		// build the source index
		SourceIndex index = new SourceIndex( source );
		sourceTree.acceptVisitor( new SourceIndexVisitor(), index );
		
		// DEBUG
		//sourceTree.acceptVisitor( new TreeDumpVisitor( new File( "tree.txt" ) ), null );
		
		// resolve all the classes in the source references
		for( Token token : index.referenceTokens() )
		{
			EntryReference<Entry,Entry> deobfReference = index.getDeobfReference( token );
			
			// get the obfuscated entry
			Entry obfEntry = obfuscateEntry( deobfReference.entry );
			
			// try to resolve the class
			ClassEntry resolvedObfClassEntry = m_jarIndex.resolveEntryClass( obfEntry );
			if( resolvedObfClassEntry != null && !resolvedObfClassEntry.equals( obfEntry.getClassEntry() ) )
			{
				// change the class of the entry
				obfEntry = obfEntry.cloneToNewClass( resolvedObfClassEntry );
				
				// save the new deobfuscated reference
				deobfReference.entry = deobfuscateEntry( obfEntry );
				index.replaceDeobfReference( token, deobfReference );
			}
			
			// DEBUG
			//System.out.println( token + " -> " + reference + " -> " + index.getReferenceToken( reference ) );
		}
		
		return index;
	}
	
	public String getSource( CompilationUnit sourceTree )
	{
		// render the AST into source
		StringWriter buf = new StringWriter();
		sourceTree.acceptVisitor( new InsertParenthesesVisitor(), null );
		sourceTree.acceptVisitor( new JavaOutputVisitor( new PlainTextOutput( buf ), m_settings ), null );
		return buf.toString();
	}
	
	public void writeSources( File dirOut, ProgressListener progress )
	throws IOException
	{
		// get the classes to decompile
		Set<ClassEntry> classEntries = Sets.newHashSet();
		for( ClassEntry obfClassEntry : m_jarIndex.getObfClassEntries() )
		{
			// skip inner classes
			if( obfClassEntry.isInnerClass() )
			{
				continue;
			}
			
			classEntries.add( obfClassEntry );
		}
		
		if( progress != null )
		{
			progress.init( classEntries.size(), "Decompiling classes..." );
		}
		
		// DEOBFUSCATE ALL THE THINGS!! @_@
		int i = 0;
		for( ClassEntry obfClassEntry : classEntries )
		{
			ClassEntry deobfClassEntry = deobfuscateEntry( new ClassEntry( obfClassEntry ) );
			if( progress != null )
			{
				progress.onProgress( i++, deobfClassEntry.toString() );
			}
			
			try
			{
				// get the source
				String source = getSource( getSourceTree( obfClassEntry.getName() ) );
				
				// write the file
				File file = new File( dirOut, deobfClassEntry.getName().replace( '.', '/' ) + ".java" );
				file.getParentFile().mkdirs();
				try( FileWriter out = new FileWriter( file ) )
				{
					out.write( source );
				}
			}
			catch( Throwable t )
			{
				throw new Error( "Unable to deobfuscate class " + deobfClassEntry.toString() + " (" + obfClassEntry.toString() + ")", t );
			}
		}
		if( progress != null )
		{
			progress.onProgress( i, "Done!" );
		}
	}
	
	public void writeJar( File out, ProgressListener progress )
	{
		try( JarOutputStream outJar = new JarOutputStream( new FileOutputStream( out ) ) )
		{
			if( progress != null )
			{
				progress.init( JarClassIterator.getClassEntries( m_jar ).size(), "Translating classes..." );
			}
			
			// prep the loader
			TranslatingTypeLoader loader = new TranslatingTypeLoader(
				m_jar,
				m_jarIndex,
				getTranslator( TranslationDirection.Obfuscating ),
				getTranslator( TranslationDirection.Deobfuscating )
			);
			
			int i = 0;
			for( CtClass c : JarClassIterator.classes( m_jar ) )
			{
				if( progress != null )
				{
					progress.onProgress( i++, c.getName() );
				}
				
				try
				{
					c = loader.transformClass( c );
					outJar.putNextEntry( new JarEntry( c.getName().replace( '.', '/' ) + ".class" ) );
					outJar.write( c.toBytecode() );
					outJar.closeEntry();
				}
				catch( Throwable t )
				{
					throw new Error( "Unable to deobfuscate class " + c.getName(), t );
				}
			}
			if( progress != null )
			{
				progress.onProgress( i, "Done!" );
			}
			
			outJar.close();
		}
		catch( IOException ex )
		{
			throw new Error( "Unable to write to Jar file!" );
		}
	}
	
	public <T extends Entry> T obfuscateEntry( T deobfEntry )
	{
		if( deobfEntry == null )
		{
			return null;
		}
		return getTranslator( TranslationDirection.Obfuscating ).translateEntry( deobfEntry );
	}
	
	public <T extends Entry> T deobfuscateEntry( T obfEntry )
	{
		if( obfEntry == null )
		{
			return null;
		}
		return getTranslator( TranslationDirection.Deobfuscating ).translateEntry( obfEntry );
	}
	
	public <E extends Entry,C extends Entry> EntryReference<E,C> obfuscateReference( EntryReference<E,C> deobfReference )
	{
		if( deobfReference == null )
		{
			return null;
		}
		return new EntryReference<E,C>(
			obfuscateEntry( deobfReference.entry ),
			obfuscateEntry( deobfReference.context ),
			deobfReference
		);
	}
	
	public <E extends Entry,C extends Entry> EntryReference<E,C> deobfuscateReference( EntryReference<E,C> obfReference )
	{
		if( obfReference == null )
		{
			return null;
		}
		return new EntryReference<E,C>(
			deobfuscateEntry( obfReference.entry ),
			deobfuscateEntry( obfReference.context ),
			obfReference
		);
	}
	
	public boolean isObfuscatedIdentifier( Entry obfEntry )
	{
		return m_jarIndex.containsObfEntry( obfEntry );
	}
	
	public boolean isRenameable( EntryReference<Entry,Entry> obfReference )
	{
		return obfReference.isNamed() && isObfuscatedIdentifier( obfReference.getNameableEntry() );
	}
	
	
	// NOTE: these methods are a bit messy... oh well

	public boolean hasDeobfuscatedName( Entry obfEntry )
	{
		Translator translator = getTranslator( TranslationDirection.Deobfuscating );
		if( obfEntry instanceof ClassEntry )
		{
			return translator.translate( (ClassEntry)obfEntry ) != null;
		}
		else if( obfEntry instanceof FieldEntry )
		{
			return translator.translate( (FieldEntry)obfEntry ) != null;
		}
		else if( obfEntry instanceof MethodEntry )
		{
			return translator.translate( (MethodEntry)obfEntry ) != null;
		}
		else if( obfEntry instanceof ConstructorEntry )
		{
			// constructors have no names
			return false;
		}
		else if( obfEntry instanceof ArgumentEntry )
		{
			return translator.translate( (ArgumentEntry)obfEntry ) != null;
		}
		else
		{
			throw new Error( "Unknown entry type: " + obfEntry.getClass().getName() );
		}
	}

	public void rename( Entry obfEntry, String newName )
	{
		if( obfEntry instanceof ClassEntry )
		{
			m_renamer.setClassName( (ClassEntry)obfEntry, Descriptor.toJvmName( newName ) );
		}
		else if( obfEntry instanceof FieldEntry )
		{
			m_renamer.setFieldName( (FieldEntry)obfEntry, newName );
		}
		else if( obfEntry instanceof MethodEntry )
		{
			m_renamer.setMethodTreeName( (MethodEntry)obfEntry, newName );
		}
		else if( obfEntry instanceof ConstructorEntry )
		{
			throw new IllegalArgumentException( "Cannot rename constructors" );
		}
		else if( obfEntry instanceof ArgumentEntry )
		{
			m_renamer.setArgumentName( (ArgumentEntry)obfEntry, newName );
		}
		else
		{
			throw new Error( "Unknown entry type: " + obfEntry.getClass().getName() );
		}
		
		// clear caches
		m_translatorCache.clear();
	}
	
	public void removeMapping( Entry obfEntry )
	{
		if( obfEntry instanceof ClassEntry )
		{
			m_renamer.removeClassMapping( (ClassEntry)obfEntry );
		}
		else if( obfEntry instanceof FieldEntry )
		{
			m_renamer.removeFieldMapping( (FieldEntry)obfEntry );
		}
		else if( obfEntry instanceof MethodEntry )
		{
			m_renamer.removeMethodTreeMapping( (MethodEntry)obfEntry );
		}
		else if( obfEntry instanceof ConstructorEntry )
		{
			throw new IllegalArgumentException( "Cannot rename constructors" );
		}
		else if( obfEntry instanceof ArgumentEntry )
		{
			m_renamer.removeArgumentMapping( (ArgumentEntry)obfEntry );
		}
		else
		{
			throw new Error( "Unknown entry type: " + obfEntry );
		}
		
		// clear caches
		m_translatorCache.clear();
	}
	
	public void markAsDeobfuscated( Entry obfEntry )
	{
		if( obfEntry instanceof ClassEntry )
		{
			m_renamer.markClassAsDeobfuscated( (ClassEntry)obfEntry );
		}
		else if( obfEntry instanceof FieldEntry )
		{
			m_renamer.markFieldAsDeobfuscated( (FieldEntry)obfEntry );
		}
		else if( obfEntry instanceof MethodEntry )
		{
			m_renamer.markMethodTreeAsDeobfuscated( (MethodEntry)obfEntry );
		}
		else if( obfEntry instanceof ConstructorEntry )
		{
			throw new IllegalArgumentException( "Cannot rename constructors" );
		}
		else if( obfEntry instanceof ArgumentEntry )
		{
			m_renamer.markArgumentAsDeobfuscated( (ArgumentEntry)obfEntry );
		}
		else
		{
			throw new Error( "Unknown entry type: " + obfEntry );
		}

		// clear caches
		m_translatorCache.clear();
	}
}