// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
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// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
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package io.ebean.enhance.asm.commons;

import java.util.HashMap;
import java.util.Map;
import io.ebean.enhance.asm.Type;

/**
 * A named method descriptor.
 *
 * @author Juozas Baliuka
 * @author Chris Nokleberg
 * @author Eric Bruneton
 */
public class Method {

  /** The method name. */
  private final String name;

  /** The method descriptor. */
  private final String descriptor;

  /** The descriptors of the primitive Java types (plus void). */
  private static final Map<String, String> PRIMITIVE_TYPE_DESCRIPTORS;

  static {
    HashMap<String, String> descriptors = new HashMap<>();
    descriptors.put("void", "V");
    descriptors.put("byte", "B");
    descriptors.put("char", "C");
    descriptors.put("double", "D");
    descriptors.put("float", "F");
    descriptors.put("int", "I");
    descriptors.put("long", "J");
    descriptors.put("short", "S");
    descriptors.put("boolean", "Z");
    PRIMITIVE_TYPE_DESCRIPTORS = descriptors;
  }

  /**
   * Constructs a new {@link Method}.
   *
   * @param name the method's name.
   * @param descriptor the method's descriptor.
   */
  public Method(final String name, final String descriptor) {
    this.name = name;
    this.descriptor = descriptor;
  }

  /**
   * Constructs a new {@link Method}.
   *
   * @param name the method's name.
   * @param returnType the method's return type.
   * @param argumentTypes the method's argument types.
   */
  public Method(final String name, final Type returnType, final Type[] argumentTypes) {
    this(name, Type.getMethodDescriptor(returnType, argumentTypes));
  }

  /**
   * Creates a new {@link Method}.
   *
   * @param method a java.lang.reflect method descriptor
   * @return a {@link Method} corresponding to the given Java method declaration.
   */
  public static Method getMethod(final java.lang.reflect.Method method) {
    return new Method(method.getName(), Type.getMethodDescriptor(method));
  }

  /**
   * Creates a new {@link Method}.
   *
   * @param constructor a java.lang.reflect constructor descriptor
   * @return a {@link Method} corresponding to the given Java constructor declaration.
   */
  public static Method getMethod(final java.lang.reflect.Constructor<?> constructor) {
    return new Method("<init>", Type.getConstructorDescriptor(constructor));
  }

  /**
   * Returns a {@link Method} corresponding to the given Java method declaration.
   *
   * @param method a Java method declaration, without argument names, of the form "returnType name
   *     (argumentType1, ... argumentTypeN)", where the types are in plain Java (e.g. "int",
   *     "float", "java.util.List", ...). Classes of the java.lang package can be specified by their
   *     unqualified name; all other classes names must be fully qualified.
   * @return a {@link Method} corresponding to the given Java method declaration.
   * @throws IllegalArgumentException if <code>method</code> could not get parsed.
   */
  public static Method getMethod(final String method) {
    return getMethod(method, false);
  }

  /**
   * Returns a {@link Method} corresponding to the given Java method declaration.
   *
   * @param method a Java method declaration, without argument names, of the form "returnType name
   *     (argumentType1, ... argumentTypeN)", where the types are in plain Java (e.g. "int",
   *     "float", "java.util.List", ...). Classes of the java.lang package may be specified by their
   *     unqualified name, depending on the defaultPackage argument; all other classes names must be
   *     fully qualified.
   * @param defaultPackage true if unqualified class names belong to the default package, or false
   *     if they correspond to java.lang classes. For instance "Object" means "Object" if this
   *     option is true, or "java.lang.Object" otherwise.
   * @return a {@link Method} corresponding to the given Java method declaration.
   * @throws IllegalArgumentException if <code>method</code> could not get parsed.
   */
  public static Method getMethod(final String method, final boolean defaultPackage) {
    final int spaceIndex = method.indexOf(' ');
    int currentArgumentStartIndex = method.indexOf('(', spaceIndex) + 1;
    final int endIndex = method.indexOf(')', currentArgumentStartIndex);
    if (spaceIndex == -1 || currentArgumentStartIndex == 0 || endIndex == -1) {
      throw new IllegalArgumentException();
    }
    final String returnType = method.substring(0, spaceIndex);
    final String methodName =
        method.substring(spaceIndex + 1, currentArgumentStartIndex - 1).trim();
    StringBuilder stringBuilder = new StringBuilder();
    stringBuilder.append('(');
    int currentArgumentEndIndex;
    do {
      String argumentDescriptor;
      currentArgumentEndIndex = method.indexOf(',', currentArgumentStartIndex);
      if (currentArgumentEndIndex == -1) {
        argumentDescriptor =
            getDescriptorInternal(
                method.substring(currentArgumentStartIndex, endIndex).trim(), defaultPackage);
      } else {
        argumentDescriptor =
            getDescriptorInternal(
                method.substring(currentArgumentStartIndex, currentArgumentEndIndex).trim(),
                defaultPackage);
        currentArgumentStartIndex = currentArgumentEndIndex + 1;
      }
      stringBuilder.append(argumentDescriptor);
    } while (currentArgumentEndIndex != -1);
    stringBuilder.append(')').append(getDescriptorInternal(returnType, defaultPackage));
    return new Method(methodName, stringBuilder.toString());
  }

  /**
   * Returns the descriptor corresponding to the given type name.
   *
   * @param type a Java type name.
   * @param defaultPackage true if unqualified class names belong to the default package, or false
   *     if they correspond to java.lang classes. For instance "Object" means "Object" if this
   *     option is true, or "java.lang.Object" otherwise.
   * @return the descriptor corresponding to the given type name.
   */
  private static String getDescriptorInternal(final String type, final boolean defaultPackage) {
    if ("".equals(type)) {
      return type;
    }

    StringBuilder stringBuilder = new StringBuilder();
    int arrayBracketsIndex = 0;
    while ((arrayBracketsIndex = type.indexOf("[]", arrayBracketsIndex) + 1) > 0) {
      stringBuilder.append('[');
    }

    String elementType = type.substring(0, type.length() - stringBuilder.length() * 2);
    String descriptor = PRIMITIVE_TYPE_DESCRIPTORS.get(elementType);
    if (descriptor != null) {
      stringBuilder.append(descriptor);
    } else {
      stringBuilder.append('L');
      if (elementType.indexOf('.') < 0) {
        if (!defaultPackage) {
          stringBuilder.append("java/lang/");
        }
        stringBuilder.append(elementType);
      } else {
        stringBuilder.append(elementType.replace('.', '/'));
      }
      stringBuilder.append(';');
    }
    return stringBuilder.toString();
  }

  /**
   * Returns the name of the method described by this object.
   *
   * @return the name of the method described by this object.
   */
  public String getName() {
    return name;
  }

  /**
   * Returns the descriptor of the method described by this object.
   *
   * @return the descriptor of the method described by this object.
   */
  public String getDescriptor() {
    return descriptor;
  }

  /**
   * Returns the return type of the method described by this object.
   *
   * @return the return type of the method described by this object.
   */
  public Type getReturnType() {
    return Type.getReturnType(descriptor);
  }

  /**
   * Returns the argument types of the method described by this object.
   *
   * @return the argument types of the method described by this object.
   */
  public Type[] getArgumentTypes() {
    return Type.getArgumentTypes(descriptor);
  }

  @Override
  public String toString() {
    return name + descriptor;
  }

  @Override
  public boolean equals(final Object other) {
    if (!(other instanceof Method)) {
      return false;
    }
    Method otherMethod = (Method) other;
    return name.equals(otherMethod.name) && descriptor.equals(otherMethod.descriptor);
  }

  @Override
  public int hashCode() {
    return name.hashCode() ^ descriptor.hashCode();
  }
}