/*
 * Copyright 2000-2012 JetBrains s.r.o.
 *
 * 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 org.jetbrains.idea.devkit.inspections;

import com.intellij.codeInspection.InspectionManager;
import com.intellij.codeInspection.ProblemDescriptor;
import com.intellij.codeInspection.ProblemHighlightType;
import com.intellij.codeInspection.ProblemsHolder;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.NullUtils;
import com.intellij.psi.*;
import com.intellij.psi.impl.JavaConstantExpressionEvaluator;
import com.intellij.psi.search.GlobalSearchScope;
import com.intellij.ui.Gray;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.idea.devkit.inspections.quickfix.ConvertToGrayQuickFix;

/**
 * @author Konstantin Bulenkov
 */
public class UseGrayInspection extends DevKitInspectionBase {
  @NotNull
  @Override
  public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder holder, final boolean isOnTheFly) {
    return new JavaElementVisitor() {
      @Override
      public void visitNewExpression(PsiNewExpression expression) {
        final ProblemDescriptor descriptor = checkNewExpression(expression, holder.getManager(), isOnTheFly);
        if (descriptor != null) {
          holder.registerProblem(descriptor);
        }
      }
    };
  }

  @Nullable
  private static ProblemDescriptor checkNewExpression(PsiNewExpression expression, InspectionManager manager, boolean isOnTheFly) {
    final Project project = manager.getProject();
    final JavaPsiFacade facade = JavaPsiFacade.getInstance(project);
    final PsiClass grayClass = facade.findClass(Gray.class.getName(), GlobalSearchScope.allScope(project));
    final PsiType type = expression.getType();
    if (type != null && grayClass != null) {
      final PsiExpressionList arguments = expression.getArgumentList();
      if (arguments != null) {
        final PsiExpression[] expressions = arguments.getExpressions();
        if (expressions.length == 3 && "java.awt.Color".equals(type.getCanonicalText())) {
          if (! facade.getResolveHelper().isAccessible(grayClass, expression, grayClass)) return null;
          final PsiExpression r = expressions[0];
          final PsiExpression g = expressions[1];
          final PsiExpression b = expressions[2];
          if (r instanceof PsiLiteralExpression 
            && g instanceof PsiLiteralExpression
            && b instanceof PsiLiteralExpression) {
            final Object red = JavaConstantExpressionEvaluator.computeConstantExpression(r, false);
            final Object green = JavaConstantExpressionEvaluator.computeConstantExpression(g, false);
            final Object blue = JavaConstantExpressionEvaluator.computeConstantExpression(b, false);
            if (NullUtils.notNull(red, green, blue)) {
              try {
                int rr = Integer.parseInt(red.toString());
                int gg = Integer.parseInt(green.toString());
                int bb = Integer.parseInt(blue.toString());
                if (rr == gg && gg == bb && 0 <= rr && rr < 256) {
                  return manager.createProblemDescriptor(expression, "Convert to Gray._" + rr, new ConvertToGrayQuickFix(rr), ProblemHighlightType.GENERIC_ERROR_OR_WARNING, isOnTheFly);
                }
              } catch (Exception ignore){}
            }
          }
        } else if (expressions.length == 1 && "com.intellij.ui.Gray".equals(type.getCanonicalText())) {
          final PsiExpression e = expressions[0];
          if (e instanceof PsiLiteralExpression) {
            final Object literal = JavaConstantExpressionEvaluator.computeConstantExpression(e, false);
            if (literal != null) {
              try {
                int num = Integer.parseInt(literal.toString());
                if (0 <= num && num < 256) {
                  return manager.createProblemDescriptor(expression, "Convert to Gray_" + num, new ConvertToGrayQuickFix(num), ProblemHighlightType.GENERIC_ERROR_OR_WARNING, isOnTheFly);
                }
              } catch (Exception ignore){}
            }
          }
        }
      }
    }
    return null;
  }

  @Nls
  @NotNull
  @Override
  public String getDisplayName() {
    return "Using new Color(a,a,a)";
  }

  @NotNull
  @Override
  public String getShortName() {
    return "InspectionUsingGrayColors";
  }
}