/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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.google.errorprone.bugpatterns.collectionincompatibletype;

import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;

import com.google.common.collect.Iterables;
import com.google.errorprone.VisitorState;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.tools.javac.code.Type;
import java.util.Collection;

/**
 * Matches an instance method like {@link Collection#contains}, for which we just need to compare
 * the method argument's type to the receiver's type argument.  This is the common case.
 */
class MethodArgMatcher extends AbstractCollectionIncompatibleTypeMatcher {

  private final Matcher<ExpressionTree> methodMatcher;
  private final String typeName;
  private final int typeArgIndex;
  private final int methodArgIndex;

  /**
   * @param typeName The fully-qualified name of the type whose descendants to match on
   * @param signature The signature of the method to match on
   * @param typeArgIndex The index of the type argument that should match the method argument
   * @param methodArgIndex The index of the method argument that should match the type argument
   */
  public MethodArgMatcher(
      String typeName, String signature, int typeArgIndex, int methodArgIndex) {
    this.methodMatcher = instanceMethod().onDescendantOf(typeName).withSignature(signature);
    this.typeName = typeName;
    this.typeArgIndex = typeArgIndex;
    this.methodArgIndex = methodArgIndex;
  }

  @Override
  Matcher<ExpressionTree> methodMatcher() {
    return methodMatcher;
  }

  @Override
  ExpressionTree extractSourceTree(MethodInvocationTree tree, VisitorState state) {
    return Iterables.get(tree.getArguments(), methodArgIndex);
  }

  @Override
  Type extractSourceType(MethodInvocationTree tree, VisitorState state) {
    return ASTHelpers.getType(extractSourceTree(tree, state));
  }

  @Override
  Type extractTargetType(MethodInvocationTree tree, VisitorState state) {
    return extractTypeArgAsMemberOfSupertype(
        ASTHelpers.getReceiverType(tree),
        state.getSymbolFromString(typeName),
        typeArgIndex,
        state.getTypes());
  }
}