/*******************************************************************************
 * 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
 * <p>
 * Contributors:
 * Jeff Martin - initial API and implementation
 ******************************************************************************/
package cuchaz.enigma;

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 java.io.*;
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 cuchaz.enigma.analysis.*;
import cuchaz.enigma.bytecode.ClassProtectifier;
import cuchaz.enigma.bytecode.ClassPublifier;
import cuchaz.enigma.mapping.*;
import javassist.CtClass;
import javassist.bytecode.Descriptor;

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.");
            }
        }

        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.NONE_PACKAGE)) {
                // 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) {
                // don't crash the whole world here, just log the error and keep going
                // TODO: set up logback via log4j
                System.err.println("Unable to deobfuscate class " + deobfClassEntry.toString() + " (" + obfClassEntry.toString() + ")");
                t.printStackTrace(System.err);
            }
        }
        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, loader::transformClass);
    }

    public void protectifyJar(File out, ProgressListener progress) {
        transformJar(out, progress, ClassProtectifier::protectify);
    }

    public void publifyJar(File out, ProgressListener progress) {
        transformJar(out, progress, ClassPublifier::publify);
    }

    private interface ClassTransformer {
        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<>(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<>(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();
    }
}