Convert implementation and build script to Kotlin

13 files changed, 736 insertions, 861 deletions

diff --git a/src/main/java/com/replaymod/gradle/remap/PsiMapper.java b/src/main/java/com/replaymod/gradle/remap/PsiMapper.java
deleted file mode 100644
index c1b2d41..0000000
--- a/src/main/java/com/replaymod/gradle/remap/PsiMapper.java
+++ /dev/null
@@ -1,429 +0,0 @@
-package com.replaymod.gradle.remap;
-
-import com.intellij.openapi.util.TextRange;
-import com.intellij.openapi.util.text.StringUtil;
-import com.intellij.psi.JavaRecursiveElementVisitor;
-import com.intellij.psi.PsiAnnotation;
-import com.intellij.psi.PsiAnnotationMemberValue;
-import com.intellij.psi.PsiClass;
-import com.intellij.psi.PsiClassObjectAccessExpression;
-import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiField;
-import com.intellij.psi.PsiFile;
-import com.intellij.psi.PsiIdentifier;
-import com.intellij.psi.PsiJavaCodeReferenceElement;
-import com.intellij.psi.PsiMethod;
-import com.intellij.psi.PsiNameValuePair;
-import com.intellij.psi.PsiPackage;
-import com.intellij.psi.PsiQualifiedNamedElement;
-import com.intellij.psi.PsiSwitchLabelStatement;
-import com.intellij.psi.PsiTypeElement;
-import org.cadixdev.bombe.type.signature.MethodSignature;
-import org.cadixdev.lorenz.MappingSet;
-import org.cadixdev.lorenz.model.ClassMapping;
-import org.cadixdev.lorenz.model.Mapping;
-import org.cadixdev.lorenz.model.MethodMapping;
-
-import java.util.ArrayDeque;
-import java.util.Arrays;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.TreeMap;
-
-import static com.replaymod.gradle.remap.PsiUtils.getSignature;
-
-class PsiMapper {
-    private static final String CLASS_MIXIN = "org.spongepowered.asm.mixin.Mixin";
-    private static final String CLASS_ACCESSOR = "org.spongepowered.asm.mixin.gen.Accessor";
-    private static final String CLASS_AT = "org.spongepowered.asm.mixin.injection.At";
-    private static final String CLASS_INJECT = "org.spongepowered.asm.mixin.injection.Inject";
-    private static final String CLASS_REDIRECT = "org.spongepowered.asm.mixin.injection.Redirect";
-
-    private final MappingSet map;
-    private final Map<String, ClassMapping<?, ?>> mixinMappings = new HashMap<>();
-    private final PsiFile file;
-    private boolean error;
-    private TreeMap<TextRange, String> changes = new TreeMap<>(Comparator.comparing(TextRange::getStartOffset));
-
-    PsiMapper(MappingSet map, PsiFile file) {
-        this.map = map;
-        this.file = file;
-    }
-
-    private void error(PsiElement at, String message) {
-        int line = StringUtil.offsetToLineNumber(file.getText(), at.getTextOffset());
-        System.err.println(file.getName() + ":" + line + ": " + message);
-        error = true;
-    }
-
-    private void replace(PsiElement e, String with) {
-        changes.put(e.getTextRange(), with);
-    }
-
-    private void replaceIdentifier(PsiElement parent, String with) {
-        for (PsiElement child : parent.getChildren()) {
-            if (child instanceof PsiIdentifier) {
-                replace(child, with);
-                return;
-            }
-        }
-    }
-
-    private boolean valid(PsiElement e) {
-        TextRange range = e.getTextRange();
-        TextRange before = changes.ceilingKey(range);
-        return before == null || !before.intersects(range);
-    }
-
-    private String getResult(String text) {
-        if (error) {
-            return null;
-        }
-        for (Map.Entry<TextRange, String> change : changes.descendingMap().entrySet()) {
-            text = change.getKey().replace(text, change.getValue());
-        }
-        return text;
-    }
-
-    private static boolean isSwitchCase(PsiElement e) {
-        if (e instanceof PsiSwitchLabelStatement) {
-            return true;
-        }
-        PsiElement parent = e.getParent();
-        return parent != null && isSwitchCase(parent);
-    }
-
-    private void map(PsiElement expr, PsiField field) {
-        PsiClass declaringClass = field.getContainingClass();
-        if (declaringClass == null) return;
-        String name = declaringClass.getQualifiedName();
-        if (name == null) return;
-        ClassMapping<?, ?> mapping = this.mixinMappings.get(name);
-        if (mapping == null) {
-            mapping = map.getClassMapping(name).orElse(null);
-        }
-        if (mapping == null) return;
-        String mapped = mapping.getFieldMapping(field.getName()).map(Mapping::getDeobfuscatedName).orElse(null);
-        if (mapped == null || mapped.equals(field.getName())) return;
-        replaceIdentifier(expr, mapped);
-
-        if (expr instanceof PsiJavaCodeReferenceElement
-                && !((PsiJavaCodeReferenceElement) expr).isQualified() // qualified access is fine
-                && !isSwitchCase(expr) // referencing constants in case statements is fine
-        ) {
-            error(expr, "Implicit member reference to remapped field \"" + field.getName() + "\". " +
-                    "This can cause issues if the remapped reference becomes shadowed by a local variable and is therefore forbidden. " +
-                    "Use \"this." + field.getName() + "\" instead.");
-        }
-    }
-
-    private void map(PsiElement expr, PsiMethod method) {
-        if (method.isConstructor()) return;
-
-        PsiClass declaringClass = method.getContainingClass();
-        if (declaringClass == null) return;
-        ArrayDeque<PsiClass> parentQueue = new ArrayDeque<>();
-        parentQueue.offer(declaringClass);
-        ClassMapping<?, ?> mapping = null;
-
-        String name = declaringClass.getQualifiedName();
-        if (name != null) {
-            mapping = mixinMappings.get(name);
-        }
-        while (true) {
-            if (mapping != null) {
-                String mapped = mapping.getMethodMapping(getSignature(method)).map(Mapping::getDeobfuscatedName).orElse(null);
-                if (mapped != null) {
-                    if (!mapped.equals(method.getName())) {
-                        replaceIdentifier(expr, mapped);
-                    }
-                    return;
-                }
-                mapping = null;
-            }
-            while (mapping == null) {
-                declaringClass = parentQueue.poll();
-                if (declaringClass == null) return;
-
-                PsiClass superClass = declaringClass.getSuperClass();
-                if (superClass != null) {
-                    parentQueue.offer(superClass);
-                }
-                for (PsiClass anInterface : declaringClass.getInterfaces()) {
-                    parentQueue.offer(anInterface);
-                }
-
-                name = declaringClass.getQualifiedName();
-                if (name == null) continue;
-                mapping = map.getClassMapping(name).orElse(null);
-            }
-        }
-    }
-
-    private void map(PsiElement expr, PsiQualifiedNamedElement resolved) {
-        String name = resolved.getQualifiedName();
-        if (name == null) return;
-        ClassMapping<?, ?> mapping = map.getClassMapping(name).orElse(null);
-        if (mapping == null) return;
-        String mapped = mapping.getDeobfuscatedName();
-        if (mapped.equals(name)) return;
-        mapped = mapped.replace('/', '.');
-
-        if (expr.getText().equals(name)) {
-            replace(expr, mapped);
-            return;
-        }
-        replaceIdentifier(expr, mapped.substring(mapped.lastIndexOf('.') + 1));
-    }
-
-    private void map(PsiElement expr, PsiElement resolved) {
-        if (resolved instanceof PsiField) {
-            map(expr, (PsiField) resolved);
-        } else if (resolved instanceof PsiMethod) {
-            map(expr, (PsiMethod) resolved);
-        } else if (resolved instanceof PsiClass || resolved instanceof PsiPackage) {
-            map(expr, (PsiQualifiedNamedElement) resolved);
-        }
-    }
-
-    // Note: Supports only Mixins with a single target (ignores others) and only ones specified via class literals
-    private PsiClass getMixinTarget(PsiAnnotation annotation) {
-        for (PsiNameValuePair pair : annotation.getParameterList().getAttributes()) {
-            String name = pair.getName();
-            if (name != null && !"value".equals(name)) continue;
-            PsiAnnotationMemberValue value = pair.getValue();
-            if (!(value instanceof PsiClassObjectAccessExpression)) continue;
-            PsiTypeElement type = ((PsiClassObjectAccessExpression) value).getOperand();
-            PsiJavaCodeReferenceElement reference = type.getInnermostComponentReferenceElement();
-            if (reference == null) continue;
-            return (PsiClass) reference.resolve();
-        }
-        return null;
-    }
-
-    private void remapAccessors(ClassMapping<?, ?> mapping) {
-        file.accept(new JavaRecursiveElementVisitor() {
-            @Override
-            public void visitMethod(PsiMethod method) {
-                PsiAnnotation annotation = method.getAnnotation(CLASS_ACCESSOR);
-                if (annotation == null) return;
-
-                String targetByName = method.getName();
-                if (targetByName.startsWith("is")) {
-                    targetByName = targetByName.substring(2);
-                } else if (targetByName.startsWith("get") || targetByName.startsWith("set")) {
-                    targetByName = targetByName.substring(3);
-                } else {
-                    targetByName = null;
-                }
-                if (targetByName != null) {
-                    targetByName = targetByName.substring(0, 1).toLowerCase() + targetByName.substring(1);
-                }
-
-                String target = Arrays.stream(annotation.getParameterList().getAttributes())
-                        .filter(it -> it.getName() == null || it.getName().equals("value"))
-                        .map(PsiNameValuePair::getLiteralValue)
-                        .findAny()
-                        .orElse(targetByName);
-
-                if (target == null) {
-                    throw new IllegalArgumentException("Cannot determine accessor target for " + method);
-                }
-
-                String mapped = mapping.getFieldMapping(target).map(Mapping::getDeobfuscatedName).orElse(null);
-                if (mapped != null && !mapped.equals(target)) {
-                    // Update accessor target
-                    String parameterList;
-                    if (mapped.equals(targetByName)) {
-                        // Mapped name matches implied target, can just remove the explict target
-                        parameterList = "";
-                    } else {
-                        // Mapped name does not match implied target, need to set the target as annotation value
-                        parameterList = "(\"" + StringUtil.escapeStringCharacters(mapped) + "\")";
-                    }
-                    replace(annotation.getParameterList(), parameterList);
-                }
-            }
-        });
-    }
-
-    private void remapInjectsAndRedirects(ClassMapping<?, ?> mapping) {
-        file.accept(new JavaRecursiveElementVisitor() {
-            @Override
-            public void visitMethod(PsiMethod method) {
-                PsiAnnotation annotation = method.getAnnotation(CLASS_INJECT);
-                if (annotation == null) {
-                    annotation = method.getAnnotation(CLASS_REDIRECT);
-                }
-                if (annotation == null) return;
-
-                for (PsiNameValuePair attribute : annotation.getParameterList().getAttributes()) {
-                    if (!"method".equals(attribute.getName())) continue;
-                    // Note: mixin supports multiple targets, we do not (yet)
-                    String literalValue = attribute.getLiteralValue();
-                    if (literalValue == null) continue;
-                    String mapped;
-                    if (literalValue.contains("(")) {
-                        mapped = mapping.getMethodMapping(MethodSignature.of(literalValue)).map(Mapping::getDeobfuscatedName).orElse(null);
-                    } else {
-                        mapped = null;
-                        for (MethodMapping methodMapping : mapping.getMethodMappings()) {
-                            if (methodMapping.getObfuscatedName().equals(literalValue)) {
-                                String name = methodMapping.getDeobfuscatedName();
-                                if (mapped != null && !mapped.equals(name)) {
-                                    error(attribute, "Ambiguous mixin method \"" + literalValue + "\" maps to \"" + mapped + "\" and \"" + name + "\"");
-                                }
-                                mapped = name;
-                            }
-                        }
-                    }
-                    if (mapped != null && !mapped.equals(literalValue)) {
-                        PsiAnnotationMemberValue value = attribute.getValue();
-                        assert value != null;
-                        replace(value, '"' + mapped + '"');
-                    }
-                }
-            }
-        });
-    }
-
-    private ClassMapping<?, ?> remapInternalType(String internalType, StringBuilder result) {
-        if (internalType.charAt(0) == 'L') {
-            String type = internalType.substring(1, internalType.length() - 1).replace('/', '.');
-            ClassMapping<?, ?> mapping = map.getClassMapping(type).orElse(null);
-            if (mapping != null) {
-                result.append('L').append(mapping.getFullDeobfuscatedName()).append(';');
-                return mapping;
-            }
-        }
-        result.append(internalType);
-        return null;
-    }
-
-    private String remapFullyQualifiedMethodOrField(String signature) {
-        int ownerEnd = signature.indexOf(';');
-        int argsBegin = signature.indexOf('(');
-        int argsEnd = signature.indexOf(')');
-        boolean method = argsBegin != -1;
-        if (!method) {
-            argsBegin = argsEnd = signature.indexOf(':');
-        }
-        String owner = signature.substring(0, ownerEnd + 1);
-        String name = signature.substring(ownerEnd + 1, argsBegin);
-        String returnType = signature.substring(argsEnd + 1);
-
-        StringBuilder builder = new StringBuilder(signature.length() + 32);
-        ClassMapping<?, ?> mapping = remapInternalType(owner, builder);
-        String mapped = null;
-        if (mapping != null) {
-            mapped = (method
-                    ? mapping.getMethodMapping(MethodSignature.of(signature.substring(ownerEnd + 1)))
-                    : mapping.getFieldMapping(name))
-                    .map(Mapping::getDeobfuscatedName)
-                    .orElse(null);
-        }
-        builder.append(mapped != null ? mapped : name);
-        if (method) {
-            builder.append('(');
-            String args = signature.substring(argsBegin + 1, argsEnd);
-            for (int i = 0; i < args.length(); i++) {
-                char c = args.charAt(i);
-                if (c != 'L') {
-                    builder.append(c);
-                    continue;
-                }
-                int end = args.indexOf(';', i);
-                String arg = args.substring(i, end + 1);
-                remapInternalType(arg, builder);
-                i = end;
-            }
-            builder.append(')');
-        } else {
-            builder.append(':');
-        }
-        remapInternalType(returnType, builder);
-        return builder.toString();
-    }
-
-    private void remapAtTargets() {
-        file.accept(new JavaRecursiveElementVisitor() {
-            @Override
-            public void visitAnnotation(PsiAnnotation annotation) {
-                if (!CLASS_AT.equals(annotation.getQualifiedName())) {
-                    super.visitAnnotation(annotation);
-                    return;
-                }
-
-                for (PsiNameValuePair attribute : annotation.getParameterList().getAttributes()) {
-                    if (!"target".equals(attribute.getName())) continue;
-                    String signature = attribute.getLiteralValue();
-                    if (signature == null) continue;
-                    String newSignature = remapFullyQualifiedMethodOrField(signature);
-                    if (!newSignature.equals(signature)) {
-                        PsiAnnotationMemberValue value = attribute.getValue();
-                        assert value != null;
-                        replace(value, '"' + newSignature + '"');
-                    }
-                }
-            }
-        });
-    }
-
-    String remapFile() {
-        file.accept(new JavaRecursiveElementVisitor() {
-            @Override
-            public void visitClass(PsiClass psiClass) {
-                PsiAnnotation annotation = psiClass.getAnnotation(CLASS_MIXIN);
-                if (annotation == null) return;
-
-                remapAtTargets();
-
-                PsiClass target = getMixinTarget(annotation);
-                if (target == null) return;
-                String qualifiedName = target.getQualifiedName();
-                if (qualifiedName == null) return;
-
-                ClassMapping<?, ?> mapping = map.getClassMapping(qualifiedName).orElse(null);
-                if (mapping == null) return;
-
-                mixinMappings.put(psiClass.getQualifiedName(), mapping);
-
-                if (!mapping.getFieldMappings().isEmpty()) {
-                    remapAccessors(mapping);
-                }
-                if (!mapping.getMethodMappings().isEmpty()) {
-                    remapInjectsAndRedirects(mapping);
-                }
-            }
-        });
-
-        file.accept(new JavaRecursiveElementVisitor() {
-            @Override
-            public void visitField(PsiField field) {
-                if (valid(field)) {
-                    map(field, field);
-                }
-                super.visitField(field);
-            }
-
-            @Override
-            public void visitMethod(PsiMethod method) {
-                if (valid(method)) {
-                    map(method, method);
-                }
-                super.visitMethod(method);
-            }
-
-            @Override
-            public void visitReferenceElement(PsiJavaCodeReferenceElement reference) {
-                if (valid(reference)) {
-                    map(reference, reference.resolve());
-                }
-                super.visitReferenceElement(reference);
-            }
-        });
-
-        return getResult(file.getText());
-    }
-}
diff --git a/src/main/java/com/replaymod/gradle/remap/PsiUtils.java b/src/main/java/com/replaymod/gradle/remap/PsiUtils.java
deleted file mode 100644
index ec4d1c8..0000000
--- a/src/main/java/com/replaymod/gradle/remap/PsiUtils.java
+++ /dev/null
@@ -1,61 +0,0 @@
-package com.replaymod.gradle.remap;
-
-import com.intellij.psi.PsiArrayType;
-import com.intellij.psi.PsiClass;
-import com.intellij.psi.PsiClassType;
-import com.intellij.psi.PsiMethod;
-import com.intellij.psi.PsiPrimitiveType;
-import com.intellij.psi.PsiType;
-import com.intellij.psi.util.TypeConversionUtil;
-import org.cadixdev.bombe.type.ArrayType;
-import org.cadixdev.bombe.type.FieldType;
-import org.cadixdev.bombe.type.MethodDescriptor;
-import org.cadixdev.bombe.type.ObjectType;
-import org.cadixdev.bombe.type.Type;
-import org.cadixdev.bombe.type.VoidType;
-import org.cadixdev.bombe.type.signature.MethodSignature;
-
-import java.util.Arrays;
-import java.util.stream.Collectors;
-
-class PsiUtils {
-    static MethodSignature getSignature(PsiMethod method) {
-        return new MethodSignature(method.getName(), getDescriptor(method));
-    }
-
-    private static MethodDescriptor getDescriptor(PsiMethod method) {
-        return new MethodDescriptor(
-                Arrays.stream(method.getParameterList().getParameters())
-                        .map(it -> getFieldType(it.getType()))
-                        .collect(Collectors.toList()),
-                getType(method.getReturnType())
-        );
-    }
-
-    private static FieldType getFieldType(PsiType type) {
-        type = TypeConversionUtil.erasure(type);
-        if (type instanceof PsiPrimitiveType) {
-            return FieldType.of(((PsiPrimitiveType) type).getKind().getBinaryName());
-        } else if (type instanceof PsiArrayType) {
-            PsiArrayType array = (PsiArrayType) type;
-            return new ArrayType(array.getArrayDimensions(), getFieldType(array.getDeepComponentType()));
-        } else if (type instanceof PsiClassType) {
-            PsiClass resolved = ((PsiClassType) type).resolve();
-            if (resolved == null) throw new NullPointerException("Failed to resolve type " + type);
-            String qualifiedName = resolved.getQualifiedName();
-            if (qualifiedName == null) throw new NullPointerException("Type " + type + " has no qualified name.");
-            return new ObjectType(qualifiedName);
-        } else {
-            throw new IllegalArgumentException("Cannot translate type " + type);
-        }
-    }
-
-    private static Type getType(PsiType type) {
-        if (TypeConversionUtil.isVoidType(type)) {
-            return VoidType.INSTANCE;
-        } else {
-            return getFieldType(type);
-        }
-    }
-
-}
diff --git a/src/main/java/com/replaymod/gradle/remap/Transformer.java b/src/main/java/com/replaymod/gradle/remap/Transformer.java
deleted file mode 100644
index 5b25856..0000000
--- a/src/main/java/com/replaymod/gradle/remap/Transformer.java
+++ /dev/null
@@ -1,173 +0,0 @@
-package com.replaymod.gradle.remap;
-
-import com.intellij.codeInsight.CustomExceptionHandler;
-import com.intellij.mock.MockProject;
-import com.intellij.openapi.extensions.ExtensionPoint;
-import com.intellij.openapi.extensions.Extensions;
-import com.intellij.openapi.extensions.ExtensionsArea;
-import com.intellij.openapi.util.Disposer;
-import com.intellij.openapi.vfs.StandardFileSystems;
-import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.openapi.vfs.VirtualFileManager;
-import com.intellij.openapi.vfs.local.CoreLocalFileSystem;
-import com.intellij.psi.PsiFile;
-import com.intellij.psi.PsiManager;
-import com.replaymod.gradle.remap.legacy.LegacyMapping;
-import org.cadixdev.lorenz.MappingSet;
-import org.jetbrains.kotlin.cli.common.CLIConfigurationKeys;
-import org.jetbrains.kotlin.cli.common.config.KotlinSourceRoot;
-import org.jetbrains.kotlin.cli.common.messages.MessageRenderer;
-import org.jetbrains.kotlin.cli.common.messages.PrintingMessageCollector;
-import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles;
-import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment;
-import org.jetbrains.kotlin.cli.jvm.compiler.NoScopeRecordCliBindingTrace;
-import org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM;
-import org.jetbrains.kotlin.cli.jvm.config.JavaSourceRoot;
-import org.jetbrains.kotlin.cli.jvm.config.JvmClasspathRoot;
-import org.jetbrains.kotlin.config.CommonConfigurationKeys;
-import org.jetbrains.kotlin.config.CompilerConfiguration;
-
-import java.io.BufferedReader;
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStreamReader;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.StandardOpenOption;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Map.Entry;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
-
-public class Transformer {
-    private MappingSet map;
-    private String[] classpath;
-    private boolean fail;
-
-    public static void main(String[] args) throws IOException {
-        MappingSet mappings;
-        if (args[0].isEmpty()) {
-            mappings = MappingSet.create();
-        } else {
-            mappings = LegacyMapping.readMappingSet(new File(args[0]).toPath(), args[1].equals("true"));
-        }
-        Transformer transformer = new Transformer(mappings);
-
-        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
-
-        String[] classpath = new String[Integer.parseInt(args[2])];
-        for (int i = 0; i < classpath.length; i++) {
-            classpath[i] = reader.readLine();
-        }
-        transformer.setClasspath(classpath);
-
-        Map<String, String> sources = new HashMap<>();
-        while (true) {
-            String name = reader.readLine();
-            if (name == null || name.isEmpty()) {
-                break;
-            }
-
-            String[] lines = new String[Integer.parseInt(reader.readLine())];
-            for (int i = 0; i < lines.length; i++) {
-                lines[i] = reader.readLine();
-            }
-            String source = String.join("\n", lines);
-
-            sources.put(name, source);
-        }
-
-        Map<String, String> results = transformer.remap(sources);
-
-        for (String name : sources.keySet()) {
-            System.out.println(name);
-            String[] lines = results.get(name).split("\n");
-            System.out.println(lines.length);
-            for (String line : lines) {
-                System.out.println(line);
-            }
-        }
-
-        if (transformer.fail) {
-            System.exit(1);
-        }
-    }
-
-    public Transformer(MappingSet mappings) {
-        this.map = mappings;
-    }
-
-    public String[] getClasspath() {
-        return classpath;
-    }
-
-    public void setClasspath(String[] classpath) {
-        this.classpath = classpath;
-    }
-
-    public Map<String, String> remap(Map<String, String> sources) throws IOException {
-        Path tmpDir = Files.createTempDirectory("remap");
-        try {
-            for (Entry<String, String> entry : sources.entrySet()) {
-                String unitName = entry.getKey();
-                String source = entry.getValue();
-
-                Path path = tmpDir.resolve(unitName);
-                Files.createDirectories(path.getParent());
-                Files.write(path, source.getBytes(StandardCharsets.UTF_8), StandardOpenOption.CREATE);
-            }
-
-            CompilerConfiguration config = new CompilerConfiguration();
-            config.put(CommonConfigurationKeys.MODULE_NAME, "main");
-            config.add(CLIConfigurationKeys.CONTENT_ROOTS, new JavaSourceRoot(tmpDir.toFile(), ""));
-            config.add(CLIConfigurationKeys.CONTENT_ROOTS, new KotlinSourceRoot(tmpDir.toAbsolutePath().toString(), false));
-            config.put(CLIConfigurationKeys.MESSAGE_COLLECTOR_KEY, new PrintingMessageCollector(System.err, MessageRenderer.GRADLE_STYLE, true));
-
-            KotlinCoreEnvironment environment = KotlinCoreEnvironment.createForProduction(
-                    Disposer.newDisposable(),
-                    config,
-                    EnvironmentConfigFiles.JVM_CONFIG_FILES
-            );
-            ExtensionsArea rootArea = Extensions.getRootArea();
-            if (!rootArea.hasExtensionPoint(CustomExceptionHandler.KEY)) {
-                rootArea.registerExtensionPoint(CustomExceptionHandler.KEY.getName(), CustomExceptionHandler.class.getName(), ExtensionPoint.Kind.INTERFACE);
-            }
-
-            MockProject project = (MockProject) environment.getProject();
-
-            environment.updateClasspath(Stream.of(getClasspath()).map(it -> new JvmClasspathRoot(new File(it))).collect(Collectors.toList()));
-
-            TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(
-                    project,
-                    Collections.emptyList(),
-                    new NoScopeRecordCliBindingTrace(),
-                    environment.getConfiguration(),
-                    environment::createPackagePartProvider
-            );
-
-            CoreLocalFileSystem vfs = (CoreLocalFileSystem) VirtualFileManager.getInstance().getFileSystem(StandardFileSystems.FILE_PROTOCOL);
-            Map<String, String> results = new HashMap<>();
-            for (String name : sources.keySet()) {
-                VirtualFile file = vfs.findFileByIoFile(tmpDir.resolve(name).toFile());
-                assert file != null;
-                PsiFile psiFile = PsiManager.getInstance(project).findFile(file);
-                assert psiFile != null;
-
-                String mapped = new PsiMapper(map, psiFile).remapFile();
-                if (mapped == null) {
-                    fail = true;
-                    continue;
-                }
-                results.put(name, mapped);
-            }
-            return results;
-        } finally {
-            Files.walk(tmpDir).map(Path::toFile).sorted(Comparator.reverseOrder()).forEach(File::delete);
-        }
-    }
-
-}
diff --git a/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMapping.java b/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMapping.java
deleted file mode 100644
index 05a85d9..0000000
--- a/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMapping.java
+++ /dev/null
@@ -1,118 +0,0 @@
-package com.replaymod.gradle.remap.legacy;
-
-import org.cadixdev.lorenz.MappingSet;
-
-import java.io.IOException;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.function.Function;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
-
-public class LegacyMapping {
-    public static MappingSet readMappingSet(Path mappingFile, boolean invert) throws IOException {
-        return new LegacyMappingsReader(readMappings(mappingFile, invert)).read();
-    }
-
-    public static Map<String, LegacyMapping> readMappings(Path mappingFile, boolean invert) throws IOException {
-        Map<String, LegacyMapping> mappings = new HashMap<>();
-        Map<String, LegacyMapping> revMappings = new HashMap<>();
-        int lineNumber = 0;
-        for (String line : Files.readAllLines(mappingFile, StandardCharsets.UTF_8)) {
-            lineNumber++;
-            if (line.trim().startsWith("#") || line.trim().isEmpty()) continue;
-
-            String[] parts = line.split(" ");
-            if (parts.length < 2 || line.contains(";")) {
-                throw new IllegalArgumentException("Failed to parse line " + lineNumber + " in " + mappingFile + ".");
-            }
-
-            LegacyMapping mapping = mappings.get(parts[0]);
-            if (mapping == null) {
-                mapping = new LegacyMapping();
-                mapping.oldName = mapping.newName = parts[0];
-                mappings.put(mapping.oldName, mapping);
-            }
-
-            if (parts.length == 2) {
-                // Class mapping
-                mapping.newName = parts[1];
-                // Possibly merge with reverse mapping
-                LegacyMapping revMapping = revMappings.remove(mapping.newName);
-                if (revMapping != null) {
-                    mapping.fields.putAll(revMapping.fields);
-                    mapping.methods.putAll(revMapping.methods);
-                }
-                revMappings.put(mapping.newName, mapping);
-            } else if (parts.length == 3 || parts.length == 4) {
-                String fromName = parts[1];
-                String toName;
-                LegacyMapping revMapping;
-                if (parts.length == 4) {
-                    toName = parts[3];
-                    revMapping = revMappings.get(parts[2]);
-                    if (revMapping == null) {
-                        revMapping = new LegacyMapping();
-                        revMapping.oldName = revMapping.newName = parts[2];
-                        revMappings.put(revMapping.newName, revMapping);
-                    }
-                } else {
-                    toName = parts[2];
-                    revMapping = mapping;
-                }
-                if (fromName.endsWith("()")) {
-                    // Method mapping
-                    fromName = fromName.substring(0, fromName.length() - 2);
-                    toName = toName.substring(0, toName.length() - 2);
-                    mapping.methods.put(fromName, toName);
-                    revMapping.methods.put(fromName, toName);
-                } else {
-                    // Field mapping
-                    mapping.fields.put(fromName, toName);
-                    revMapping.fields.put(fromName, toName);
-                }
-            } else {
-                throw new IllegalArgumentException("Failed to parse line " + lineNumber + " in " + mappingFile + ".");
-            }
-        }
-        if (invert) {
-            Stream.concat(
-                    mappings.values().stream(),
-                    revMappings.values().stream()
-            ).distinct().forEach(it -> {
-                String oldName = it.oldName;
-                it.oldName = it.newName;
-                it.newName = oldName;
-                it.fields = it.fields.entrySet().stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
-                it.methods = it.methods.entrySet().stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
-            });
-        }
-        return Stream.concat(
-                mappings.values().stream(),
-                revMappings.values().stream()
-        ).collect(Collectors.toMap(mapping -> mapping.oldName, Function.identity(), (mapping, other) -> {
-            if (!other.oldName.equals(other.newName)) {
-                if (!mapping.oldName.equals(mapping.newName)
-                        && !other.oldName.equals(mapping.oldName)
-                        && !other.newName.equals(mapping.newName)) {
-                    throw new IllegalArgumentException("Conflicting mappings: "
-                            + mapping.oldName + " -> " + mapping.newName
-                            + " and " + other.oldName + " -> " + other.newName);
-                }
-                mapping.oldName = other.oldName;
-                mapping.newName = other.newName;
-            }
-            mapping.fields.putAll(other.fields);
-            mapping.methods.putAll(other.methods);
-            return mapping;
-        }));
-    }
-
-    public String oldName;
-    public String newName;
-    public Map<String, String> fields = new HashMap<>();
-    public Map<String, String> methods = new HashMap<>();
-}
diff --git a/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMappingSetModelFactory.java b/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMappingSetModelFactory.java
deleted file mode 100644
index eb72788..0000000
--- a/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMappingSetModelFactory.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.replaymod.gradle.remap.legacy;
-
-import org.cadixdev.bombe.type.signature.MethodSignature;
-import org.cadixdev.lorenz.MappingSet;
-import org.cadixdev.lorenz.impl.MappingSetModelFactoryImpl;
-import org.cadixdev.lorenz.impl.model.TopLevelClassMappingImpl;
-import org.cadixdev.lorenz.model.MethodMapping;
-import org.cadixdev.lorenz.model.TopLevelClassMapping;
-
-import java.util.Optional;
-
-public class LegacyMappingSetModelFactory extends MappingSetModelFactoryImpl {
-    @Override
-    public TopLevelClassMapping createTopLevelClassMapping(MappingSet parent, String obfuscatedName, String deobfuscatedName) {
-        return new TopLevelClassMappingImpl(parent, obfuscatedName, deobfuscatedName) {
-            private MethodSignature stripDesc(MethodSignature signature) {
-                // actual descriptor isn't included in legacy format
-                return MethodSignature.of(signature.getName(), "()V");
-            }
-
-            @Override
-            public boolean hasMethodMapping(MethodSignature signature) {
-                return super.hasMethodMapping(signature) || super.hasMethodMapping(stripDesc(signature));
-            }
-
-            @Override
-            public Optional<MethodMapping> getMethodMapping(MethodSignature signature) {
-                Optional<MethodMapping> maybeMapping = super.getMethodMapping(signature);
-                if (!maybeMapping.isPresent() || !maybeMapping.get().hasMappings()) {
-                    maybeMapping = super.getMethodMapping(stripDesc(signature));
-                }
-                return maybeMapping;
-            }
-        };
-    }
-}
diff --git a/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMappingsReader.java b/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMappingsReader.java
deleted file mode 100644
index 502f7ba..0000000
--- a/src/main/java/com/replaymod/gradle/remap/legacy/LegacyMappingsReader.java
+++ /dev/null
@@ -1,44 +0,0 @@
-package com.replaymod.gradle.remap.legacy;
-
-import org.cadixdev.lorenz.MappingSet;
-import org.cadixdev.lorenz.io.MappingsReader;
-import org.cadixdev.lorenz.model.ClassMapping;
-
-import java.util.Map;
-
-public class LegacyMappingsReader extends MappingsReader {
-    private final Map<String, LegacyMapping> map;
-
-    public LegacyMappingsReader(Map<String, LegacyMapping> map) {
-        this.map = map;
-    }
-
-    @Override
-    public MappingSet read() {
-        return read(MappingSet.create(new LegacyMappingSetModelFactory()));
-    }
-
-    @Override
-    public MappingSet read(MappingSet mappings) {
-        if (!(mappings.getModelFactory() instanceof LegacyMappingSetModelFactory)) {
-            throw new IllegalArgumentException("legacy mappings must use legacy model factory, use read() instead");
-        }
-        for (LegacyMapping legacyMapping : map.values()) {
-            ClassMapping classMapping = mappings.getOrCreateClassMapping(legacyMapping.oldName)
-                    .setDeobfuscatedName(legacyMapping.newName);
-            for (Map.Entry<String, String> entry : legacyMapping.fields.entrySet()) {
-                classMapping.getOrCreateFieldMapping(entry.getKey())
-                        .setDeobfuscatedName(entry.getValue());
-            }
-            for (Map.Entry<String, String> entry : legacyMapping.methods.entrySet()) {
-                classMapping.getOrCreateMethodMapping(entry.getKey(), "()V")
-                        .setDeobfuscatedName(entry.getValue());
-            }
-        }
-        return mappings;
-    }
-
-    @Override
-    public void close() {
-    }
-}
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/LorenzExtensions.kt b/src/main/kotlin/com/replaymod/gradle/remap/LorenzExtensions.kt
new file mode 100644
index 0000000..cd04918
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/LorenzExtensions.kt
@@ -0,0 +1,11 @@
+package com.replaymod.gradle.remap
+
+import org.cadixdev.bombe.type.signature.MethodSignature
+import org.cadixdev.lorenz.MappingSet
+import org.cadixdev.lorenz.model.ClassMapping
+import org.cadixdev.lorenz.model.FieldMapping
+import org.cadixdev.lorenz.model.MethodMapping
+
+fun MappingSet.findClassMapping(obfuscatedName: String): ClassMapping<*, *>? = getClassMapping(obfuscatedName).orElse(null)
+fun ClassMapping<*, *>.findFieldMapping(obfuscatedName: String): FieldMapping? = getFieldMapping(obfuscatedName).orElse(null)
+fun ClassMapping<*, *>.findMethodMapping(signature: MethodSignature): MethodMapping? = getMethodMapping(signature).orElse(null)
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt b/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt
new file mode 100644
index 0000000..95ee858
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt
@@ -0,0 +1,365 @@
+package com.replaymod.gradle.remap
+
+import com.intellij.openapi.util.TextRange
+import com.intellij.openapi.util.text.StringUtil
+import com.intellij.psi.*
+import com.replaymod.gradle.remap.PsiUtils.getSignature
+import org.cadixdev.bombe.type.signature.MethodSignature
+import org.cadixdev.lorenz.MappingSet
+import org.cadixdev.lorenz.model.ClassMapping
+import java.util.*
+
+internal class PsiMapper(private val map: MappingSet, private val file: PsiFile) {
+    private val mixinMappings = mutableMapOf<String, ClassMapping<*, *>>()
+    private var error: Boolean = false
+    private val changes = TreeMap<TextRange, String>(Comparator.comparing<TextRange, Int> { it.startOffset })
+
+    private fun error(at: PsiElement, message: String) {
+        val line = StringUtil.offsetToLineNumber(file.text, at.textOffset)
+        System.err.println(file.name + ":" + line + ": " + message)
+        error = true
+    }
+
+    private fun replace(e: PsiElement, with: String) {
+        changes[e.textRange] = with
+    }
+
+    private fun replaceIdentifier(parent: PsiElement, with: String) {
+        for (child in parent.children) {
+            if (child is PsiIdentifier) {
+                replace(child, with)
+                return
+            }
+        }
+    }
+
+    private fun valid(e: PsiElement): Boolean {
+        val range = e.textRange
+        val before = changes.ceilingKey(range)
+        return before == null || !before.intersects(range)
+    }
+
+    private fun getResult(text: String): String? {
+        if (error) {
+            return null
+        }
+        var result = text
+        for ((key, value) in changes.descendingMap()) {
+            result = key.replace(result, value)
+        }
+        return result
+    }
+
+    private fun map(expr: PsiElement, field: PsiField) {
+        val fieldName = field.name ?: return
+        val declaringClass = field.containingClass ?: return
+        val name = declaringClass.qualifiedName ?: return
+        var mapping: ClassMapping<*, *>? = this.mixinMappings[name]
+        if (mapping == null) {
+            mapping = map.findClassMapping(name)
+        }
+        if (mapping == null) return
+        val mapped = mapping.findFieldMapping(fieldName)?.deobfuscatedName
+        if (mapped == null || mapped == fieldName) return
+        replaceIdentifier(expr, mapped)
+
+        if (expr is PsiJavaCodeReferenceElement
+                && !expr.isQualified // qualified access is fine
+                && !isSwitchCase(expr) // referencing constants in case statements is fine
+        ) {
+            error(expr, "Implicit member reference to remapped field \"$fieldName\". " +
+                    "This can cause issues if the remapped reference becomes shadowed by a local variable and is therefore forbidden. " +
+                    "Use \"this.$fieldName\" instead.")
+        }
+    }
+
+    private fun map(expr: PsiElement, method: PsiMethod) {
+        if (method.isConstructor) return
+
+        var declaringClass: PsiClass? = method.containingClass ?: return
+        val parentQueue = ArrayDeque<PsiClass>()
+        parentQueue.offer(declaringClass)
+        var mapping: ClassMapping<*, *>? = null
+
+        var name = declaringClass!!.qualifiedName
+        if (name != null) {
+            mapping = mixinMappings[name]
+        }
+        while (true) {
+            if (mapping != null) {
+                val mapped = mapping.findMethodMapping(getSignature(method))?.deobfuscatedName
+                if (mapped != null) {
+                    if (mapped != method.name) {
+                        replaceIdentifier(expr, mapped)
+                    }
+                    return
+                }
+                mapping = null
+            }
+            while (mapping == null) {
+                declaringClass = parentQueue.poll()
+                if (declaringClass == null) return
+
+                val superClass = declaringClass.superClass
+                if (superClass != null) {
+                    parentQueue.offer(superClass)
+                }
+                for (anInterface in declaringClass.interfaces) {
+                    parentQueue.offer(anInterface)
+                }
+
+                name = declaringClass.qualifiedName
+                if (name == null) continue
+                mapping = map.findClassMapping(name)
+            }
+        }
+    }
+
+    private fun map(expr: PsiElement, resolved: PsiQualifiedNamedElement) {
+        val name = resolved.qualifiedName ?: return
+        val mapping = map.findClassMapping(name) ?: return
+        var mapped = mapping.deobfuscatedName
+        if (mapped == name) return
+        mapped = mapped.replace('/', '.')
+
+        if (expr.text == name) {
+            replace(expr, mapped)
+            return
+        }
+        replaceIdentifier(expr, mapped.substring(mapped.lastIndexOf('.') + 1))
+    }
+
+    private fun map(expr: PsiElement, resolved: PsiElement?) {
+        when (resolved) {
+            is PsiField -> map(expr, resolved)
+            is PsiMethod -> map(expr, resolved)
+            is PsiClass, is PsiPackage -> map(expr, resolved as PsiQualifiedNamedElement)
+        }
+    }
+
+    // Note: Supports only Mixins with a single target (ignores others) and only ones specified via class literals
+    private fun getMixinTarget(annotation: PsiAnnotation): PsiClass? {
+        for (pair in annotation.parameterList.attributes) {
+            val name = pair.name
+            if (name != null && "value" != name) continue
+            val value = pair.value
+            if (value !is PsiClassObjectAccessExpression) continue
+            val type = value.operand
+            val reference = type.innermostComponentReferenceElement ?: continue
+            return reference.resolve() as PsiClass?
+        }
+        return null
+    }
+
+    private fun remapAccessors(mapping: ClassMapping<*, *>) {
+        file.accept(object : JavaRecursiveElementVisitor() {
+            override fun visitMethod(method: PsiMethod) {
+                val annotation = method.getAnnotation(CLASS_ACCESSOR) ?: return
+
+                val methodName = method.name
+                val targetByName = when {
+                    methodName.startsWith("is") -> methodName.substring(2)
+                    methodName.startsWith("get") || methodName.startsWith("set") -> methodName.substring(3)
+                    else -> null
+                }?.decapitalize()
+
+                val target = annotation.parameterList.attributes.find {
+                    it.name == null || it.name == "value"
+                }?.literalValue ?: targetByName ?: throw IllegalArgumentException("Cannot determine accessor target for $method")
+
+                val mapped = mapping.findFieldMapping(target)?.deobfuscatedName
+                if (mapped != null && mapped != target) {
+                    // Update accessor target
+                    replace(annotation.parameterList, if (mapped == targetByName) {
+                        // Mapped name matches implied target, can just remove the explict target
+                        ""
+                    } else {
+                        // Mapped name does not match implied target, need to set the target as annotation value
+                        "(\"" + StringUtil.escapeStringCharacters(mapped) + "\")"
+                    })
+                }
+            }
+        })
+    }
+
+    private fun remapInjectsAndRedirects(mapping: ClassMapping<*, *>) {
+        file.accept(object : JavaRecursiveElementVisitor() {
+            override fun visitMethod(method: PsiMethod) {
+                val annotation = method.getAnnotation(CLASS_INJECT) ?: method.getAnnotation(CLASS_REDIRECT) ?: return
+
+                for (attribute in annotation.parameterList.attributes) {
+                    if ("method" != attribute.name) continue
+                    // Note: mixin supports multiple targets, we do not (yet)
+                    val literalValue = attribute.literalValue ?: continue
+                    var mapped: String?
+                    if (literalValue.contains("(")) {
+                        mapped = mapping.findMethodMapping(MethodSignature.of(literalValue))?.deobfuscatedName
+                    } else {
+                        mapped = null
+                        for (methodMapping in mapping.methodMappings) {
+                            if (methodMapping.obfuscatedName == literalValue) {
+                                val name = methodMapping.deobfuscatedName
+                                if (mapped != null && mapped != name) {
+                                    error(attribute, "Ambiguous mixin method \"$literalValue\" maps to \"$mapped\" and \"$name\"")
+                                }
+                                mapped = name
+                            }
+                        }
+                    }
+                    if (mapped != null && mapped != literalValue) {
+                        val value = attribute.value!!
+                        replace(value, '"'.toString() + mapped + '"'.toString())
+                    }
+                }
+            }
+        })
+    }
+
+    private fun remapInternalType(internalType: String, result: StringBuilder): ClassMapping<*, *>? {
+        if (internalType[0] == 'L') {
+            val type = internalType.substring(1, internalType.length - 1).replace('/', '.')
+            val mapping = map.findClassMapping(type)
+            if (mapping != null) {
+                result.append('L').append(mapping.fullDeobfuscatedName).append(';')
+                return mapping
+            }
+        }
+        result.append(internalType)
+        return null
+    }
+
+    private fun remapFullyQualifiedMethodOrField(signature: String): String {
+        val ownerEnd = signature.indexOf(';')
+        var argsBegin = signature.indexOf('(')
+        var argsEnd = signature.indexOf(')')
+        val method = argsBegin != -1
+        if (!method) {
+            argsEnd = signature.indexOf(':')
+            argsBegin = argsEnd
+        }
+        val owner = signature.substring(0, ownerEnd + 1)
+        val name = signature.substring(ownerEnd + 1, argsBegin)
+        val returnType = signature.substring(argsEnd + 1)
+
+        val builder = StringBuilder(signature.length + 32)
+        val mapping = remapInternalType(owner, builder)
+        var mapped: String? = null
+        if (mapping != null) {
+            mapped = (if (method) {
+                mapping.findMethodMapping(MethodSignature.of(signature.substring(ownerEnd + 1)))
+            } else {
+                mapping.findFieldMapping(name)
+            })?.deobfuscatedName
+        }
+        builder.append(mapped ?: name)
+        if (method) {
+            builder.append('(')
+            val args = signature.substring(argsBegin + 1, argsEnd)
+            var i = 0
+            while (i < args.length) {
+                val c = args[i]
+                if (c != 'L') {
+                    builder.append(c)
+                    i++
+                    continue
+                }
+                val end = args.indexOf(';', i)
+                val arg = args.substring(i, end + 1)
+                remapInternalType(arg, builder)
+                i = end
+                i++
+            }
+            builder.append(')')
+        } else {
+            builder.append(':')
+        }
+        remapInternalType(returnType, builder)
+        return builder.toString()
+    }
+
+    private fun remapAtTargets() {
+        file.accept(object : JavaRecursiveElementVisitor() {
+            override fun visitAnnotation(annotation: PsiAnnotation) {
+                if (CLASS_AT != annotation.qualifiedName) {
+                    super.visitAnnotation(annotation)
+                    return
+                }
+
+                for (attribute in annotation.parameterList.attributes) {
+                    if ("target" != attribute.name) continue
+                    val signature = attribute.literalValue ?: continue
+                    val newSignature = remapFullyQualifiedMethodOrField(signature)
+                    if (newSignature != signature) {
+                        val value = attribute.value!!
+                        replace(value, "\"$newSignature\"")
+                    }
+                }
+            }
+        })
+    }
+
+    fun remapFile(): String? {
+        file.accept(object : JavaRecursiveElementVisitor() {
+            override fun visitClass(psiClass: PsiClass) {
+                val annotation = psiClass.getAnnotation(CLASS_MIXIN) ?: return
+
+                remapAtTargets()
+
+                val target = getMixinTarget(annotation) ?: return
+                val qualifiedName = target.qualifiedName ?: return
+
+                val mapping = map.findClassMapping(qualifiedName) ?: return
+
+                mixinMappings[psiClass.qualifiedName!!] = mapping
+
+                if (!mapping.fieldMappings.isEmpty()) {
+                    remapAccessors(mapping)
+                }
+                if (!mapping.methodMappings.isEmpty()) {
+                    remapInjectsAndRedirects(mapping)
+                }
+            }
+        })
+
+        file.accept(object : JavaRecursiveElementVisitor() {
+            override fun visitField(field: PsiField) {
+                if (valid(field)) {
+                    map(field, field)
+                }
+                super.visitField(field)
+            }
+
+            override fun visitMethod(method: PsiMethod) {
+                if (valid(method)) {
+                    map(method, method)
+                }
+                super.visitMethod(method)
+            }
+
+            override fun visitReferenceElement(reference: PsiJavaCodeReferenceElement) {
+                if (valid(reference)) {
+                    map(reference, reference.resolve())
+                }
+                super.visitReferenceElement(reference)
+            }
+        })
+
+        return getResult(file.text)
+    }
+
+    companion object {
+        private const val CLASS_MIXIN = "org.spongepowered.asm.mixin.Mixin"
+        private const val CLASS_ACCESSOR = "org.spongepowered.asm.mixin.gen.Accessor"
+        private const val CLASS_AT = "org.spongepowered.asm.mixin.injection.At"
+        private const val CLASS_INJECT = "org.spongepowered.asm.mixin.injection.Inject"
+        private const val CLASS_REDIRECT = "org.spongepowered.asm.mixin.injection.Redirect"
+
+        private fun isSwitchCase(e: PsiElement): Boolean {
+            if (e is PsiSwitchLabelStatement) {
+                return true
+            }
+            val parent = e.parent
+            return parent != null && isSwitchCase(parent)
+        }
+    }
+}
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/PsiUtils.kt b/src/main/kotlin/com/replaymod/gradle/remap/PsiUtils.kt
new file mode 100644
index 0000000..de29956
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/PsiUtils.kt
@@ -0,0 +1,41 @@
+package com.replaymod.gradle.remap
+
+import com.intellij.psi.*
+import com.intellij.psi.util.TypeConversionUtil
+import org.cadixdev.bombe.type.ArrayType
+import org.cadixdev.bombe.type.FieldType
+import org.cadixdev.bombe.type.MethodDescriptor
+import org.cadixdev.bombe.type.ObjectType
+import org.cadixdev.bombe.type.Type
+import org.cadixdev.bombe.type.VoidType
+import org.cadixdev.bombe.type.signature.MethodSignature
+
+internal object PsiUtils {
+    fun getSignature(method: PsiMethod): MethodSignature = MethodSignature(method.name, getDescriptor(method))
+
+    private fun getDescriptor(method: PsiMethod): MethodDescriptor = MethodDescriptor(
+            method.parameterList.parameters.map { getFieldType(it.type) },
+            getType(method.returnType)
+    )
+
+    private fun getFieldType(type: PsiType?): FieldType = when (val erasedType = TypeConversionUtil.erasure(type)) {
+        is PsiPrimitiveType -> FieldType.of(erasedType.kind.binaryName)
+        is PsiArrayType -> {
+            val array = erasedType as PsiArrayType?
+            ArrayType(array!!.arrayDimensions, getFieldType(array.deepComponentType))
+        }
+        is PsiClassType -> {
+            val resolved = erasedType.resolve() ?: throw NullPointerException("Failed to resolve type $erasedType")
+            val qualifiedName = resolved.qualifiedName
+                    ?: throw NullPointerException("Type $erasedType has no qualified name.")
+            ObjectType(qualifiedName)
+        }
+        else -> throw IllegalArgumentException("Cannot translate type " + erasedType!!)
+    }
+
+    private fun getType(type: PsiType?): Type = if (TypeConversionUtil.isVoidType(type)) {
+        VoidType.INSTANCE
+    } else {
+        getFieldType(type)
+    }
+}
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/Transformer.kt b/src/main/kotlin/com/replaymod/gradle/remap/Transformer.kt
new file mode 100644
index 0000000..303ee42
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/Transformer.kt
@@ -0,0 +1,149 @@
+package com.replaymod.gradle.remap
+
+import com.intellij.codeInsight.CustomExceptionHandler
+import com.intellij.mock.MockProject
+import com.intellij.openapi.extensions.ExtensionPoint
+import com.intellij.openapi.extensions.Extensions
+import com.intellij.openapi.util.Disposer
+import com.intellij.openapi.vfs.StandardFileSystems
+import com.intellij.openapi.vfs.VirtualFileManager
+import com.intellij.openapi.vfs.local.CoreLocalFileSystem
+import com.intellij.psi.PsiManager
+import com.intellij.psi.search.GlobalSearchScope
+import com.replaymod.gradle.remap.legacy.LegacyMapping
+import org.cadixdev.lorenz.MappingSet
+import org.jetbrains.kotlin.cli.common.CLIConfigurationKeys
+import org.jetbrains.kotlin.cli.common.config.ContentRoot
+import org.jetbrains.kotlin.cli.common.config.KotlinSourceRoot
+import org.jetbrains.kotlin.cli.common.messages.MessageCollector
+import org.jetbrains.kotlin.cli.common.messages.MessageRenderer
+import org.jetbrains.kotlin.cli.common.messages.PrintingMessageCollector
+import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles
+import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
+import org.jetbrains.kotlin.cli.jvm.compiler.NoScopeRecordCliBindingTrace
+import org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM
+import org.jetbrains.kotlin.cli.jvm.config.JavaSourceRoot
+import org.jetbrains.kotlin.cli.jvm.config.JvmClasspathRoot
+import org.jetbrains.kotlin.config.CommonConfigurationKeys
+import org.jetbrains.kotlin.config.CompilerConfiguration
+import java.io.BufferedReader
+import java.io.File
+import java.io.IOException
+import java.io.InputStreamReader
+import java.nio.charset.StandardCharsets
+import java.nio.file.Files
+import java.nio.file.StandardOpenOption
+import java.util.*
+import kotlin.system.exitProcess
+
+class Transformer(private val map: MappingSet) {
+    var classpath: Array<String>? = null
+    private var fail: Boolean = false
+
+    @Throws(IOException::class)
+    fun remap(sources: Map<String, String>): Map<String, String> {
+        val tmpDir = Files.createTempDirectory("remap")
+        try {
+            for ((unitName, source) in sources) {
+                val path = tmpDir.resolve(unitName)
+                Files.createDirectories(path.parent)
+                Files.write(path, source.toByteArray(StandardCharsets.UTF_8), StandardOpenOption.CREATE)
+            }
+
+            val config = CompilerConfiguration()
+            config.put(CommonConfigurationKeys.MODULE_NAME, "main")
+            config.add<ContentRoot>(CLIConfigurationKeys.CONTENT_ROOTS, JavaSourceRoot(tmpDir.toFile(), ""))
+            config.add<ContentRoot>(CLIConfigurationKeys.CONTENT_ROOTS, KotlinSourceRoot(tmpDir.toAbsolutePath().toString(), false))
+            config.put<MessageCollector>(CLIConfigurationKeys.MESSAGE_COLLECTOR_KEY, PrintingMessageCollector(System.err, MessageRenderer.GRADLE_STYLE, true))
+
+            val environment = KotlinCoreEnvironment.createForProduction(
+                    Disposer.newDisposable(),
+                    config,
+                    EnvironmentConfigFiles.JVM_CONFIG_FILES
+            )
+            val rootArea = Extensions.getRootArea()
+            if (!rootArea.hasExtensionPoint(CustomExceptionHandler.KEY)) {
+                rootArea.registerExtensionPoint(CustomExceptionHandler.KEY.name, CustomExceptionHandler::class.java.name, ExtensionPoint.Kind.INTERFACE)
+            }
+
+            val project = environment.project as MockProject
+
+            environment.updateClasspath(classpath!!.map { JvmClasspathRoot(File(it)) })
+
+            TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(
+                    project,
+                    emptyList(),
+                    NoScopeRecordCliBindingTrace(),
+                    environment.configuration,
+                    { scope: GlobalSearchScope -> environment.createPackagePartProvider(scope) }
+            )
+
+            val vfs = VirtualFileManager.getInstance().getFileSystem(StandardFileSystems.FILE_PROTOCOL) as CoreLocalFileSystem
+            val results = HashMap<String, String>()
+            for (name in sources.keys) {
+                val file = vfs.findFileByIoFile(tmpDir.resolve(name).toFile())!!
+                val psiFile = PsiManager.getInstance(project).findFile(file)!!
+
+                val mapped = PsiMapper(map, psiFile).remapFile()
+                if (mapped == null) {
+                    fail = true
+                    continue
+                }
+                results[name] = mapped
+            }
+            return results
+        } finally {
+            Files.walk(tmpDir).map<File> { it.toFile() }.sorted(Comparator.reverseOrder()).forEach { it.delete() }
+        }
+    }
+
+    companion object {
+
+        @Throws(IOException::class)
+        @JvmStatic
+        fun main(args: Array<String>) {
+            val mappings: MappingSet = if (args[0].isEmpty()) {
+                MappingSet.create()
+            } else {
+                LegacyMapping.readMappingSet(File(args[0]).toPath(), args[1] == "true")
+            }
+            val transformer = Transformer(mappings)
+
+            val reader = BufferedReader(InputStreamReader(System.`in`))
+
+            transformer.classpath = (1..Integer.parseInt(args[2])).map { reader.readLine() }.toTypedArray()
+
+            val sources = mutableMapOf<String, String>()
+            while (true) {
+                val name = reader.readLine()
+                if (name == null || name.isEmpty()) {
+                    break
+                }
+
+                val lines = arrayOfNulls<String>(Integer.parseInt(reader.readLine()))
+                for (i in lines.indices) {
+                    lines[i] = reader.readLine()
+                }
+                val source = lines.joinToString("\n")
+
+                sources[name] = source
+            }
+
+            val results = transformer.remap(sources)
+
+            for (name in sources.keys) {
+                println(name)
+                val lines = results.getValue(name).split("\n").dropLastWhile { it.isEmpty() }.toTypedArray()
+                println(lines.size)
+                for (line in lines) {
+                    println(line)
+                }
+            }
+
+            if (transformer.fail) {
+                exitProcess(1)
+            }
+        }
+    }
+
+}
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMapping.kt b/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMapping.kt
new file mode 100644
index 0000000..389b1c9
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMapping.kt
@@ -0,0 +1,109 @@
+package com.replaymod.gradle.remap.legacy
+
+import org.cadixdev.lorenz.MappingSet
+
+import java.io.IOException
+import java.nio.charset.StandardCharsets
+import java.nio.file.Files
+import java.nio.file.Path
+import java.util.HashMap
+
+class LegacyMapping(var oldName: String, var newName: String) {
+    var fields: MutableMap<String, String> = mutableMapOf()
+    var methods: MutableMap<String, String> = mutableMapOf()
+
+    companion object {
+        @Throws(IOException::class)
+        fun readMappingSet(mappingFile: Path, invert: Boolean): MappingSet {
+            return LegacyMappingsReader(readMappings(mappingFile, invert)).read()
+        }
+
+        @Throws(IOException::class)
+        fun readMappings(mappingFile: Path, invert: Boolean): Map<String, LegacyMapping> {
+            val mappings = HashMap<String, LegacyMapping>()
+            val revMappings = HashMap<String, LegacyMapping>()
+            var lineNumber = 0
+            for (line in Files.readAllLines(mappingFile, StandardCharsets.UTF_8)) {
+                lineNumber++
+                if (line.trim { it <= ' ' }.startsWith("#") || line.trim { it <= ' ' }.isEmpty()) continue
+
+                val parts = line.split(" ".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
+                require(!(parts.size < 2 || line.contains(";"))) { "Failed to parse line $lineNumber in $mappingFile." }
+
+                var mapping: LegacyMapping? = mappings[parts[0]]
+                if (mapping == null) {
+                    mapping = LegacyMapping(parts[0], parts[0])
+                    mappings[mapping.oldName] = mapping
+                }
+
+                if (parts.size == 2) {
+                    // Class mapping
+                    mapping.newName = parts[1]
+                    // Possibly merge with reverse mapping
+                    val revMapping = revMappings.remove(mapping.newName)
+                    if (revMapping != null) {
+                        mapping.fields.putAll(revMapping.fields)
+                        mapping.methods.putAll(revMapping.methods)
+                    }
+                    revMappings[mapping.newName] = mapping
+                } else if (parts.size == 3 || parts.size == 4) {
+                    var fromName = parts[1]
+                    var toName: String
+                    var revMapping: LegacyMapping?
+                    if (parts.size == 4) {
+                        toName = parts[3]
+                        revMapping = revMappings[parts[2]]
+                        if (revMapping == null) {
+                            revMapping = LegacyMapping(parts[2], parts[2])
+                            revMappings[revMapping.newName] = revMapping
+                        }
+                    } else {
+                        toName = parts[2]
+                        revMapping = mapping
+                    }
+                    if (fromName.endsWith("()")) {
+                        // Method mapping
+                        fromName = fromName.substring(0, fromName.length - 2)
+                        toName = toName.substring(0, toName.length - 2)
+                        mapping.methods[fromName] = toName
+                        revMapping.methods[fromName] = toName
+                    } else {
+                        // Field mapping
+                        mapping.fields[fromName] = toName
+                        revMapping.fields[fromName] = toName
+                    }
+                } else {
+                    throw IllegalArgumentException("Failed to parse line $lineNumber in $mappingFile.")
+                }
+            }
+            if (invert) {
+
+                (mappings.values + revMappings.values).distinct().forEach { mapping ->
+                    mapping.oldName = mapping.newName.also { mapping.newName = mapping.oldName }
+                    mapping.fields = mapping.fields.map { it.value to it.key }.toMap(mutableMapOf())
+                    mapping.methods = mapping.methods.map { it.value to it.key }.toMap(mutableMapOf())
+                }
+            }
+            val result = mutableMapOf<String, LegacyMapping>()
+            for (mapping in (mappings.values + revMappings.values)) {
+                val key = mapping.oldName
+                val other = result[key]
+                result[key] = if (other != null) {
+                    if (other.oldName != other.newName) {
+                        require(mapping.oldName == mapping.newName || other.oldName == mapping.oldName || other.newName == mapping.newName) {
+                            "Conflicting mappings: ${mapping.oldName} -> ${mapping.newName} and ${other.oldName} -> ${other.newName}"
+                        }
+                        mapping.oldName = other.oldName
+                        mapping.newName = other.newName
+                    }
+                    mapping.fields.putAll(other.fields)
+                    mapping.methods.putAll(other.methods)
+                    mapping
+                } else {
+                    mapping
+                }
+            }
+            return result
+        }
+    }
+}
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMappingSetModelFactory.kt b/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMappingSetModelFactory.kt
new file mode 100644
index 0000000..7737200
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMappingSetModelFactory.kt
@@ -0,0 +1,33 @@
+package com.replaymod.gradle.remap.legacy
+
+import org.cadixdev.bombe.type.signature.MethodSignature
+import org.cadixdev.lorenz.MappingSet
+import org.cadixdev.lorenz.impl.MappingSetModelFactoryImpl
+import org.cadixdev.lorenz.impl.model.TopLevelClassMappingImpl
+import org.cadixdev.lorenz.model.MethodMapping
+import org.cadixdev.lorenz.model.TopLevelClassMapping
+
+import java.util.Optional
+
+class LegacyMappingSetModelFactory : MappingSetModelFactoryImpl() {
+    override fun createTopLevelClassMapping(parent: MappingSet, obfuscatedName: String, deobfuscatedName: String): TopLevelClassMapping {
+        return object : TopLevelClassMappingImpl(parent, obfuscatedName, deobfuscatedName) {
+            private fun stripDesc(signature: MethodSignature): MethodSignature {
+                // actual descriptor isn't included in legacy format
+                return MethodSignature.of(signature.name, "()V")
+            }
+
+            override fun hasMethodMapping(signature: MethodSignature): Boolean {
+                return super.hasMethodMapping(signature) || super.hasMethodMapping(stripDesc(signature))
+            }
+
+            override fun getMethodMapping(signature: MethodSignature): Optional<MethodMapping> {
+                var maybeMapping = super.getMethodMapping(signature)
+                if (!maybeMapping.isPresent || !maybeMapping.get().hasMappings()) {
+                    maybeMapping = super.getMethodMapping(stripDesc(signature))
+                }
+                return maybeMapping
+            }
+        }
+    }
+}
diff --git a/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMappingsReader.kt b/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMappingsReader.kt
new file mode 100644
index 0000000..8a6144e
--- /dev/null
+++ b/src/main/kotlin/com/replaymod/gradle/remap/legacy/LegacyMappingsReader.kt
@@ -0,0 +1,28 @@
+package com.replaymod.gradle.remap.legacy
+
+import org.cadixdev.lorenz.MappingSet
+import org.cadixdev.lorenz.io.MappingsReader
+
+class LegacyMappingsReader(private val map: Map<String, LegacyMapping>) : MappingsReader() {
+
+    override fun read(): MappingSet {
+        return read(MappingSet.create(LegacyMappingSetModelFactory()))
+    }
+
+    override fun read(mappings: MappingSet): MappingSet {
+        require(mappings.modelFactory is LegacyMappingSetModelFactory) { "legacy mappings must use legacy model factory, use read() instead" }
+        for (legacyMapping in map.values) {
+            val classMapping = mappings.getOrCreateClassMapping(legacyMapping.oldName)
+                    .setDeobfuscatedName(legacyMapping.newName)
+            for ((key, value) in legacyMapping.fields) {
+                classMapping.getOrCreateFieldMapping(key).deobfuscatedName = value
+            }
+            for ((key, value) in legacyMapping.methods) {
+                classMapping.getOrCreateMethodMapping(key, "()V").deobfuscatedName = value
+            }
+        }
+        return mappings
+    }
+
+    override fun close() {}
+}