/*
 * Copyright 2018 The Error Prone Authors.
 *
 * 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;

import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.getStartPosition;
import static com.google.errorprone.util.ASTHelpers.hasExplicitSource;

import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.AnnotationTreeMatcher;
import com.google.errorprone.bugpatterns.BugChecker.ParenthesizedTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.ParenthesizedTree;
import com.sun.source.tree.Tree;

/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
    summary =
        "These parentheses are unnecessary; it is unlikely the code will be misinterpreted without"
            + " them",
    severity = WARNING)
public class UnnecessaryParentheses extends BugChecker
    implements ParenthesizedTreeMatcher, AnnotationTreeMatcher {

  @Override
  public Description matchAnnotation(AnnotationTree tree, VisitorState state) {
    if (!hasExplicitSource(tree, state)) {
      return NO_MATCH;
    }
    return state.getSourceForNode(tree).endsWith("()")
        ? describeMatch(
            tree,
            SuggestedFix.replace(tree, "@" + state.getSourceForNode(tree.getAnnotationType())))
        : NO_MATCH;
  }

  @Override
  public Description matchParenthesized(ParenthesizedTree tree, VisitorState state) {
    ExpressionTree expression = tree.getExpression();
    Tree parent = state.getPath().getParentPath().getLeaf();
    switch (parent.getKind()) {
      case IF, WHILE_LOOP, DO_WHILE_LOOP, FOR_LOOP, SWITCH, SYNCHRONIZED, SWITCH_EXPRESSION -> {
        return NO_MATCH;
      }
      default -> {}
    }
    if (ASTHelpers.requiresParentheses(expression, state)) {
      return NO_MATCH;
    }
    return describeMatch(
        tree,
        SuggestedFix.builder()
            // add an extra leading space to handle e.g. `return(x)`
            .replace(getStartPosition(tree), getStartPosition(expression), " ")
            .replace(state.getEndPosition(expression), state.getEndPosition(tree), "")
            .build());
  }
}
