/*
    * Copyright (c) 2006 JMockit developers
    * This file is subject to the terms of the MIT license (see LICENSE.txt).
    */
   package mockit.internal.expectations.mocking;
   
   import static java.lang.reflect.Modifier.isStatic;
   
   import static mockit.asm.jvmConstants.Access.FINAL;
  import static mockit.asm.jvmConstants.Access.PUBLIC;
  import static mockit.asm.jvmConstants.Access.isSynthetic;
  import static mockit.asm.jvmConstants.Opcodes.ALOAD;
  import static mockit.asm.jvmConstants.Opcodes.INVOKESPECIAL;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  
  import java.lang.reflect.Type;
  import java.util.ArrayList;
  import java.util.EnumSet;
  import java.util.List;
  
  import mockit.asm.annotations.AnnotationVisitor;
  import mockit.asm.classes.ClassInfo;
  import mockit.asm.classes.ClassReader;
  import mockit.asm.fields.FieldVisitor;
  import mockit.asm.metadata.ClassMetadataReader;
  import mockit.asm.metadata.ClassMetadataReader.Attribute;
  import mockit.asm.metadata.ClassMetadataReader.MethodInfo;
  import mockit.asm.methods.MethodVisitor;
  import mockit.internal.BaseClassModifier;
  import mockit.internal.ClassFile;
  import mockit.internal.classGeneration.MockedTypeInfo;
  import mockit.internal.reflection.GenericTypeReflection;
  import mockit.internal.reflection.GenericTypeReflection.GenericSignature;
  
  public final class InterfaceImplementationGenerator extends BaseClassModifier {
      private static final int CLASS_ACCESS = PUBLIC + FINAL;
      private static final EnumSet<Attribute> SIGNATURE = EnumSet.of(Attribute.Signature);
  
      @NonNull
      private final MockedTypeInfo mockedTypeInfo;
      @NonNull
      private final String implementationClassDesc;
      @NonNull
      private final List<String> implementedMethods;
      private String interfaceName;
      private String methodOwner;
      @Nullable
      private String[] initialSuperInterfaces;
  
      public InterfaceImplementationGenerator(@NonNull ClassReader cr, @NonNull Type mockedType,
              @NonNull String implementationClassName) {
          super(cr);
          mockedTypeInfo = new MockedTypeInfo(mockedType);
          implementationClassDesc = implementationClassName.replace('.', '/');
          implementedMethods = new ArrayList<>();
      }
  
      @Override
      public void visit(int version, int access, @NonNull String name, @NonNull ClassInfo additionalInfo) {
          interfaceName = name;
          methodOwner = name;
          initialSuperInterfaces = additionalInfo.interfaces;
  
          ClassInfo implementationClassInfo = new ClassInfo();
          String signature = additionalInfo.signature;
          implementationClassInfo.signature = signature == null ? null
                  : signature + mockedTypeInfo.implementationSignature;
          implementationClassInfo.interfaces = new String[] { name };
          implementationClassInfo.superName = additionalInfo.superName;
  
          super.visit(version, CLASS_ACCESS, implementationClassDesc, implementationClassInfo);
  
          generateNoArgsConstructor();
      }
  
      private void generateNoArgsConstructor() {
          mw = cw.visitMethod(PUBLIC, "<init>", "()V", null, null);
          mw.visitVarInsn(ALOAD, 0);
          mw.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
          generateEmptyImplementation();
      }
  
      @Override
      public AnnotationVisitor visitAnnotation(@NonNull String desc) {
          return null;
      }
  
      @Override
      public void visitInnerClass(@NonNull String name, String outerName, String innerName, int access) {
      }
  
      @Nullable
      @Override
      public FieldVisitor visitField(int access, @NonNull String name, @NonNull String desc, @Nullable String signature,
              @Nullable Object value) {
          return null;
      }
 
     @Nullable
     @Override
     public MethodVisitor visitMethod(int access, @NonNull String name, @NonNull String desc, @Nullable String signature,
             @Nullable String[] exceptions) {
         if (!isSynthetic(access)) {
             generateMethodImplementation(access, name, desc, signature, exceptions);
         }
 
         return null;
     }
 
     private void generateMethodImplementation(int access, @NonNull String name, @NonNull String desc,
             @Nullable String signature, @Nullable String[] exceptions) {
         if (!isStatic(access)) {
             String methodNameAndDesc = name + desc;
 
             if (!implementedMethods.contains(methodNameAndDesc)) {
                 generateMethodBody(access, name, desc, signature, exceptions);
                 implementedMethods.add(methodNameAndDesc);
             }
         }
     }
 
     private void generateMethodBody(int access, @NonNull String name, @NonNull String desc, @Nullable String signature,
             @Nullable String[] exceptions) {
         mw = cw.visitMethod(PUBLIC, name, desc, signature, exceptions);
 
         String className = null;
 
         if (signature != null) {
             String subInterfaceOverride = getSubInterfaceOverride(mockedTypeInfo.genericTypeMap, name, signature);
 
             if (subInterfaceOverride != null) {
                 className = interfaceName;
                 // noinspection AssignmentToMethodParameter
                 desc = subInterfaceOverride.substring(name.length());
                 // noinspection AssignmentToMethodParameter
                 signature = null;
             }
         }
 
         if (className == null) {
             className = isOverrideOfMethodFromSuperInterface(name, desc) ? interfaceName : methodOwner;
         }
 
         generateDirectCallToHandler(className, access, name, desc, signature);
         generateReturnWithObjectAtTopOfTheStack(desc);
         mw.visitMaxStack(1);
     }
 
     @Nullable
     private String getSubInterfaceOverride(@NonNull GenericTypeReflection genericTypeMap, @NonNull String name,
             @NonNull String genericSignature) {
         if (!implementedMethods.isEmpty()) {
             GenericSignature parsedSignature = genericTypeMap.parseSignature(genericSignature);
 
             for (String implementedMethod : implementedMethods) {
                 if (sameMethodName(implementedMethod, name) && parsedSignature.satisfiesSignature(implementedMethod)) {
                     return implementedMethod;
                 }
             }
         }
 
         return null;
     }
 
     private static boolean sameMethodName(@NonNull String implementedMethod, @NonNull String name) {
         return implementedMethod.startsWith(name) && implementedMethod.charAt(name.length()) == '(';
     }
 
     private boolean isOverrideOfMethodFromSuperInterface(@NonNull String name, @NonNull String desc) {
         if (!implementedMethods.isEmpty()) {
             int p = desc.lastIndexOf(')');
             String descNoReturnType = desc.substring(0, p + 1);
 
             for (String implementedMethod : implementedMethods) {
                 if (sameMethodName(implementedMethod, name) && implementedMethod.contains(descNoReturnType)) {
                     return true;
                 }
             }
         }
 
         return false;
     }
 
     @Override
     public void visitEnd() {
         assert initialSuperInterfaces != null;
 
         for (String superInterface : initialSuperInterfaces) {
             generateImplementationsForInterfaceMethodsRecurringToSuperInterfaces(superInterface);
         }
     }
 
     private void generateImplementationsForInterfaceMethodsRecurringToSuperInterfaces(@NonNull String anInterface) {
         methodOwner = anInterface;
 
         byte[] interfaceBytecode = ClassFile.getClassFile(anInterface);
         ClassMetadataReader cmr = new ClassMetadataReader(interfaceBytecode, SIGNATURE);
         String[] superInterfaces = cmr.getInterfaces();
 
         for (MethodInfo method : cmr.getMethods()) {
             generateMethodImplementation(method.accessFlags, method.name, method.desc, method.signature, null);
         }
 
         if (superInterfaces != null) {
             for (String superInterface : superInterfaces) {
                 generateImplementationsForInterfaceMethodsRecurringToSuperInterfaces(superInterface);
             }
         }
     }
 }