/*******************************************************************************
 * Copyright (c) 2015 Jeff Martin.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser General Public
 * License v3.0 which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/lgpl.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.Maps;
import com.google.common.collect.Sets;
import com.strobel.assembler.metadata.MetadataSystem;
import com.strobel.assembler.metadata.TypeDefinition;
import com.strobel.assembler.metadata.TypeReference;
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.bytecode.ClassProtectifier;
import cuchaz.enigma.bytecode.ClassPublifier;
import cuchaz.enigma.mapping.ArgumentEntry;
import cuchaz.enigma.mapping.BehaviorEntry;
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.MappingsChecker;
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 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(JarFile jar) throws IOException {
		m_jar = jar;
		
		// 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);
		m_settings.setShowDebugLineNumbers(true);
		// DEBUG
		//m_settings.setShowSyntheticMembers(true);
		
		// init defaults
		m_translatorCache = Maps.newTreeMap();
		
		// init mappings
		setMappings(new Mappings());
	}
	
	public JarFile getJar() {
		return m_jar;
	}
	
	public String getJarName() {
		return m_jar.getName();
	}
	
	public JarIndex getJarIndex() {
		return m_jarIndex;
	}
	
	public Mappings getMappings() {
		return m_mappings;
	}
	
	public void setMappings(Mappings val) {
		setMappings(val, true);
	}
	
	public void setMappings(Mappings val, boolean warnAboutDrops) {
		if (val == null) {
			val = new Mappings();
		}
		
		// drop mappings that don't match the jar
		MappingsChecker checker = new MappingsChecker(m_jarIndex);
		checker.dropBrokenMappings(val);
		if (warnAboutDrops) {
			for (java.util.Map.Entry<ClassEntry,ClassMapping> mapping : checker.getDroppedClassMappings().entrySet()) {
				System.out.println("WARNING: Couldn't find class entry " + mapping.getKey() + " (" + mapping.getValue().getDeobfName() + ") in jar. Mapping was dropped.");
			}
			for (java.util.Map.Entry<ClassEntry,ClassMapping> mapping : checker.getDroppedInnerClassMappings().entrySet()) {
				System.out.println("WARNING: Couldn't find inner class entry " + mapping.getKey() + " (" + mapping.getValue().getDeobfName() + ") in jar. Mapping was dropped.");
			}
			for (java.util.Map.Entry<FieldEntry,FieldMapping> mapping : checker.getDroppedFieldMappings().entrySet()) {
				System.out.println("WARNING: Couldn't find field entry " + mapping.getKey() + " (" + mapping.getValue().getDeobfName() + ") in jar. Mapping was dropped.");
			}
			for (java.util.Map.Entry<BehaviorEntry,MethodMapping> mapping : checker.getDroppedMethodMappings().entrySet()) {
				System.out.println("WARNING: Couldn't find behavior entry " + mapping.getKey() + " (" + mapping.getValue().getDeobfName() + ") in jar. Mapping was dropped.");
			}
		}
		
		// check for related method inconsistencies
		if (checker.getRelatedMethodChecker().hasProblems()) {
			throw new Error("Related methods are inconsistent! Need to fix the mappings manually.\n" + checker.getRelatedMethodChecker().getReport());
		}
		
		m_mappings = val;
		m_renamer = new MappingsRenamer(m_jarIndex, val);
		m_translatorCache.clear();
	}
	
	public Translator getTranslator(TranslationDirection direction) {
		Translator translator = m_translatorCache.get(direction);
		if (translator == null) {
			translator = m_mappings.getTranslator(direction, m_jarIndex.getTranslationIndex());
			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 className) {
		
		// we don't know if this class name is obfuscated or deobfuscated
		// we need to tell the decompiler the deobfuscated name so it doesn't get freaked out
		// the decompiler only sees classes after deobfuscation, so we need to load it by the deobfuscated name if there is one
		
		// first, assume class name is deobf
		String deobfClassName = className;
		
		// if it wasn't actually deobf, then we can find a mapping for it and get the deobf name
		ClassMapping classMapping = m_mappings.getClassByObf(className);
		if (classMapping != null && classMapping.getDeobfName() != null) {
			deobfClassName = classMapping.getDeobfName();
		}
		
		// set the type loader
		TranslatingTypeLoader loader = new TranslatingTypeLoader(
			m_jar,
			m_jarIndex,
			getTranslator(TranslationDirection.Obfuscating),
			getTranslator(TranslationDirection.Deobfuscating)
		); 
		m_settings.setTypeLoader(loader);

		// see if procyon can find the type
		TypeReference type = new MetadataSystem(loader).lookupType(deobfClassName);
		if (type == null) {
			throw new Error(String.format("Unable to find type: %s (deobf: %s)\nTried class names: %s",
				className, deobfClassName, loader.getClassNamesToTry(deobfClassName)
			));
		}
		TypeDefinition resolvedType = type.resolve();
		
		// decompile it!
		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) {
		return getSourceIndex(sourceTree, source, null);
	}
	
	public SourceIndex getSourceIndex(CompilationUnit sourceTree, String source, Boolean ignoreBadTokens) {
		
		// build the source index
		SourceIndex index;
		if (ignoreBadTokens != null) {
			index = new SourceIndex(source, ignoreBadTokens);
		} else {
			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.getTranslationIndex().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) {
		final TranslatingTypeLoader loader = new TranslatingTypeLoader(
			m_jar,
			m_jarIndex,
			getTranslator(TranslationDirection.Obfuscating),
			getTranslator(TranslationDirection.Deobfuscating)
		);
		transformJar(out, progress, new ClassTransformer() {

			@Override
			public CtClass transform(CtClass c) throws Exception {
				return loader.transformClass(c);
			}
		});
	}
	
	public void protectifyJar(File out, ProgressListener progress) {
		transformJar(out, progress, new ClassTransformer() {

			@Override
			public CtClass transform(CtClass c) throws Exception {
				return ClassProtectifier.protectify(c);
			}
		});
	}
	
	public void publifyJar(File out, ProgressListener progress) {
		transformJar(out, progress, new ClassTransformer() {

			@Override
			public CtClass transform(CtClass c) throws Exception {
				return ClassPublifier.publify(c);
			}
		});
	}
	
	private interface ClassTransformer {
		public CtClass transform(CtClass c) throws Exception;
	}
	private void transformJar(File out, ProgressListener progress, ClassTransformer transformer) {
		try (JarOutputStream outJar = new JarOutputStream(new FileOutputStream(out))) {
			if (progress != null) {
				progress.init(JarClassIterator.getClassEntries(m_jar).size(), "Transforming classes...");
			}
			
			int i = 0;
			for (CtClass c : JarClassIterator.classes(m_jar)) {
				if (progress != null) {
					progress.onProgress(i++, c.getName());
				}
				
				try {
					c = transformer.transform(c);
					outJar.putNextEntry(new JarEntry(c.getName().replace('.', '/') + ".class"));
					outJar.write(c.toBytecode());
					outJar.closeEntry();
				} catch (Throwable t) {
					throw new Error("Unable to transform 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) {
		
		if (obfEntry instanceof MethodEntry) {
			
			// HACKHACK: Object methods are not obfuscated identifiers
			MethodEntry obfMethodEntry = (MethodEntry)obfEntry;
			String name = obfMethodEntry.getName();
			String sig = obfMethodEntry.getSignature().toString();
			if (name.equals("clone") && sig.equals("()Ljava/lang/Object;")) {
				return false;
			} else if (name.equals("equals") && sig.equals("(Ljava/lang/Object;)Z")) {
				return false;
			} else if (name.equals("finalize") && sig.equals("()V")) {
				return false;
			} else if (name.equals("getClass") && sig.equals("()Ljava/lang/Class;")) {
				return false;
			} else if (name.equals("hashCode") && sig.equals("()I")) {
				return false;
			} else if (name.equals("notify") && sig.equals("()V")) {
				return false;
			} else if (name.equals("notifyAll") && sig.equals("()V")) {
				return false;
			} else if (name.equals("toString") && sig.equals("()Ljava/lang/String;")) {
				return false;
			} else if (name.equals("wait") && sig.equals("()V")) {
				return false;
			} else if (name.equals("wait") && sig.equals("(J)V")) {
				return false;
			} else if (name.equals("wait") && sig.equals("(JI)V")) {
				return false;
			}
		}
		
		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) {
			ClassEntry obfClass = (ClassEntry)obfEntry;
			List<ClassMapping> mappingChain = m_mappings.getClassMappingChain(obfClass);
			ClassMapping classMapping = mappingChain.get(mappingChain.size() - 1);
			return classMapping != null && classMapping.getDeobfName() != 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();
	}
}