/*
 * Copyright 2003-2006 Dave Griffith, Bas Leijdekkers
 *
 * 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.siyeh.ipp.junit;

import com.intellij.psi.*;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.psi.tree.IElementType;
import com.intellij.util.IncorrectOperationException;
import com.intellij.codeInsight.AnnotationUtil;
import com.siyeh.ig.PsiReplacementUtil;
import com.siyeh.ipp.base.Intention;
import com.siyeh.ipp.base.PsiElementPredicate;
import com.siyeh.ipp.psiutils.BoolUtils;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.NonNls;

public class CreateAssertIntention extends Intention {

  @NotNull
  public PsiElementPredicate getElementPredicate() {
    return new CreateAssertPredicate();
  }

  public void processIntention(PsiElement element)
    throws IncorrectOperationException {
    final PsiExpressionStatement statement =
      (PsiExpressionStatement)element;
    assert statement != null;
    final PsiExpression expression = statement.getExpression();
    final PsiMethod containingMethod =
      PsiTreeUtil.getParentOfType(statement, PsiMethod.class);
    final String specifierString;
    if (containingMethod != null &&
        AnnotationUtil.isAnnotated(containingMethod,
                                   "org.junit.Test", true)) {
      specifierString = "org.junit.Assert.";
    }
    else {
      specifierString = "";
    }
    if (BoolUtils.isNegation(expression)) {
      @NonNls final String newExpression =
        specifierString + "assertFalse(" +
        BoolUtils.getNegatedExpressionText(expression) + ");";
      PsiReplacementUtil.replaceStatementAndShortenClassNames(statement, newExpression);
    }
    else if (isNullComparison(expression)) {
      final PsiBinaryExpression binaryExpression =
        (PsiBinaryExpression)expression;
      final PsiExpression lhs = binaryExpression.getLOperand();
      final PsiExpression rhs = binaryExpression.getROperand();
      final PsiExpression comparedExpression;
      if (isNull(lhs)) {
        comparedExpression = rhs;
      }
      else {
        comparedExpression = lhs;
      }
      assert comparedExpression != null;
      @NonNls final String newExpression = specifierString +
                                           "assertNull(" + comparedExpression.getText() + ");";
      PsiReplacementUtil.replaceStatementAndShortenClassNames(statement, newExpression);
    }
    else if (isEqualityComparison(expression)) {
      final PsiBinaryExpression binaryExpression =
        (PsiBinaryExpression)expression;
      final PsiExpression lhs = binaryExpression.getLOperand();
      final PsiExpression rhs = binaryExpression.getROperand();
      final PsiExpression comparedExpression;
      final PsiExpression comparingExpression;
      if (rhs instanceof PsiLiteralExpression) {
        comparedExpression = rhs;
        comparingExpression = lhs;
      }
      else {
        comparedExpression = lhs;
        comparingExpression = rhs;
      }
      assert comparingExpression != null;
      final PsiType type = lhs.getType();
      @NonNls final String newExpression;
      if (PsiType.DOUBLE.equals(type) || PsiType.FLOAT.equals(type)) {
        newExpression = specifierString + "assertEquals(" +
                        comparedExpression.getText() + ", " +
                        comparingExpression.getText() + ", 0.0);";
      }
      else if (type instanceof PsiPrimitiveType) {
        newExpression = specifierString + "assertEquals(" +
                        comparedExpression.getText() + ", " +
                        comparingExpression.getText() + ");";
      }
      else {
        newExpression = specifierString + "assertSame(" +
                        comparedExpression.getText() + ", " +
                        comparingExpression.getText() + ");";
      }
      PsiReplacementUtil.replaceStatementAndShortenClassNames(statement, newExpression);
    }
    else if (isEqualsExpression(expression)) {
      final PsiMethodCallExpression call =
        (PsiMethodCallExpression)expression;
      final PsiReferenceExpression methodExpression =
        call.getMethodExpression();
      final PsiExpression comparedExpression =
        methodExpression.getQualifierExpression();
      assert comparedExpression != null;
      final PsiExpressionList argList = call.getArgumentList();
      final PsiExpression comparingExpression =
        argList.getExpressions()[0];
      @NonNls final String newExpression;
      if (comparingExpression instanceof PsiLiteralExpression) {
        newExpression = specifierString + "assertEquals(" +
                        comparingExpression.getText() + ", " +
                        comparedExpression.getText() + ");";
      }
      else {
        newExpression = specifierString + "assertEquals(" +
                        comparedExpression.getText() + ", " +
                        comparingExpression.getText() + ");";
      }
      PsiReplacementUtil.replaceStatementAndShortenClassNames(statement, newExpression);
    }
    else {
      @NonNls final String newExpression =
        specifierString + "assertTrue(" + expression.getText() + ");";
      PsiReplacementUtil.replaceStatementAndShortenClassNames(statement, newExpression);
    }
  }

  private static boolean isEqualsExpression(PsiExpression expression) {
    if (!(expression instanceof PsiMethodCallExpression)) {
      return false;
    }
    final PsiMethodCallExpression call =
      (PsiMethodCallExpression)expression;
    final PsiReferenceExpression methodExpression =
      call.getMethodExpression();
    @NonNls final String methodName = methodExpression.getReferenceName();
    if (!"equals".equals(methodName)) {
      return false;
    }
    final PsiExpression qualifier =
      methodExpression.getQualifierExpression();
    if (qualifier == null) {
      return false;
    }
    final PsiExpressionList argList = call.getArgumentList();
    final PsiExpression[] expressions = argList.getExpressions();
    return expressions.length == 1 && expressions[0] != null;
  }

  private static boolean isEqualityComparison(PsiExpression expression) {
    if (!(expression instanceof PsiBinaryExpression)) {
      return false;
    }
    final PsiBinaryExpression binaryExpression =
      (PsiBinaryExpression)expression;
    final IElementType tokenType = binaryExpression.getOperationTokenType();
    return JavaTokenType.EQEQ.equals(tokenType);
  }

  private static boolean isNullComparison(PsiExpression expression) {
    if (!(expression instanceof PsiBinaryExpression)) {
      return false;
    }
    final PsiBinaryExpression binaryExpression =
      (PsiBinaryExpression)expression;
    final IElementType tokenType = binaryExpression.getOperationTokenType();
    if (!JavaTokenType.EQEQ.equals(tokenType)) {
      return false;
    }
    final PsiExpression lhs = binaryExpression.getLOperand();
    if (isNull(lhs)) {
      return true;
    }
    final PsiExpression Rhs = binaryExpression.getROperand();
    return isNull(Rhs);
  }

  private static boolean isNull(PsiExpression expression) {
    if (!(expression instanceof PsiLiteralExpression)) {
      return false;
    }
    @NonNls final String text = expression.getText();
    return PsiKeyword.NULL.equals(text);
  }
}