/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx;

import com.android.dx.rop.cst.CstMethodRef;
import com.android.dx.rop.cst.CstNat;
import com.android.dx.rop.cst.CstString;
import com.android.dx.rop.type.Prototype;

import java.util.List;

/**
 * Identifies a method or constructor.
 *
 * @param <D> the type declaring this field
 * @param <R> the return type of this method
 */
public final class MethodId<D, R> {
  final TypeId<D> declaringType;
  final TypeId<R> returnType;
  final String name;
  final TypeList parameters;

  /** cached converted state */
  final CstNat nat;

  final CstMethodRef constant;

  MethodId(TypeId<D> declaringType, TypeId<R> returnType, String name, TypeList parameters) {
    if (declaringType == null || returnType == null || name == null || parameters == null) {
      throw new NullPointerException();
    }
    this.declaringType = declaringType;
    this.returnType = returnType;
    this.name = name;
    this.parameters = parameters;
    this.nat = new CstNat(new CstString(name), new CstString(descriptor(false)));
    this.constant = new CstMethodRef(declaringType.constant, nat);
  }

  public TypeId<D> getDeclaringType() {
    return declaringType;
  }

  public TypeId<R> getReturnType() {
    return returnType;
  }

  /** Returns true if this method is a constructor for its declaring class. */
  public boolean isConstructor() {
    return name.equals("<init>");
  }

  /** Returns true if this method is the static initializer for its declaring class. */
  public boolean isStaticInitializer() {
    return name.equals("<clinit>");
  }

  /**
   * Returns the method's name. This is "&lt;init&gt;" if this is a constructor or "&lt;clinit&gt;"
   * if a static initializer
   */
  public String getName() {
    return name;
  }

  public List<TypeId<?>> getParameters() {
    return parameters.asList();
  }

  /** Returns a descriptor like "(Ljava/lang/Class;[I)Ljava/lang/Object;". */
  String descriptor(boolean includeThis) {
    StringBuilder result = new StringBuilder();
    result.append("(");
    if (includeThis) {
      result.append(declaringType.name);
    }
    for (TypeId t : parameters.types) {
      result.append(t.name);
    }
    result.append(")");
    result.append(returnType.name);
    return result.toString();
  }

  Prototype prototype(boolean includeThis) {
    return Prototype.intern(descriptor(includeThis));
  }

  @Override
  public boolean equals(Object o) {
    return o instanceof MethodId
        && ((MethodId<?, ?>) o).declaringType.equals(declaringType)
        && ((MethodId<?, ?>) o).name.equals(name)
        && ((MethodId<?, ?>) o).parameters.equals(parameters)
        && ((MethodId<?, ?>) o).returnType.equals(returnType);
  }

  @Override
  public int hashCode() {
    int result = 17;
    result = 31 * result + declaringType.hashCode();
    result = 31 * result + name.hashCode();
    result = 31 * result + parameters.hashCode();
    result = 31 * result + returnType.hashCode();
    return result;
  }

  @Override
  public String toString() {
    return declaringType + "." + name + "(" + parameters + ")";
  }
}
