/*
 * Copyright 2000-2014 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 com.jetbrains.python.inspections;

import com.intellij.codeInspection.LocalInspectionToolSession;
import com.intellij.codeInspection.ProblemsHolder;
import com.intellij.psi.PsiElementVisitor;
import com.jetbrains.python.PyBundle;
import com.jetbrains.python.PyNames;
import com.jetbrains.python.inspections.quickfix.PyMoveAttributeToInitQuickFix;
import com.jetbrains.python.psi.Property;
import com.jetbrains.python.psi.PyClass;
import com.jetbrains.python.psi.PyFunction;
import com.jetbrains.python.psi.PyTargetExpression;
import com.jetbrains.python.psi.impl.PyClassImpl;
import com.jetbrains.python.testing.PythonUnitTestUtil;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * User: ktisha
 *
 * Inspection to detect situations, where instance attribute
 * defined outside __init__ function
 */
public class PyAttributeOutsideInitInspection extends PyInspection {
  @Nls
  @NotNull
  @Override
  public String getDisplayName() {
    return PyBundle.message("INSP.NAME.attribute.outside.init");
  }

  @NotNull
  @Override
  public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder,
                                        boolean isOnTheFly,
                                        @NotNull LocalInspectionToolSession session) {
    return new Visitor(holder, session);
  }


  private static class Visitor extends PyInspectionVisitor {
    public Visitor(@Nullable ProblemsHolder holder, @NotNull LocalInspectionToolSession session) {
      super(holder, session);
    }

    @Override
    public void visitPyFunction(PyFunction node) {
      final PyClass containingClass = node.getContainingClass();
      if (containingClass == null) return;
      final String name = node.getName();
      if (name != null && name.startsWith("_")) return;
      if (!isApplicable(containingClass)) {
        return;
      }

      final PyFunction.Modifier modifier = node.getModifier();
      if (modifier != null) return;
      final List<PyTargetExpression> classAttributes = containingClass.getClassAttributes();

      Map<String, PyTargetExpression> attributesInInit = new HashMap<String, PyTargetExpression>();
      for (PyTargetExpression classAttr : classAttributes) {
        attributesInInit.put(classAttr.getName(), classAttr);
      }

      final PyFunction initMethod = containingClass.findMethodByName(PyNames.INIT, false);
      if (initMethod != null) {
        PyClassImpl.collectInstanceAttributes(initMethod, attributesInInit);
      }
      for (PyClass superClass : containingClass.getAncestorClasses(myTypeEvalContext)) {
        final PyFunction superInit = superClass.findMethodByName(PyNames.INIT, false);
        if (superInit != null)
          PyClassImpl.collectInstanceAttributes(superInit, attributesInInit);

        for (PyTargetExpression classAttr : superClass.getClassAttributes()) {
          attributesInInit.put(classAttr.getName(), classAttr);
        }
      }

      Map<String, PyTargetExpression> attributes = new HashMap<String, PyTargetExpression>();
      PyClassImpl.collectInstanceAttributes(node, attributes);

      for (Map.Entry<String, PyTargetExpression> attribute : attributes.entrySet()) {
        String attributeName = attribute.getKey();
        if (attributeName == null) continue;
        final Property property = containingClass.findProperty(attributeName, true);
        if (!attributesInInit.containsKey(attributeName) && property == null) {
          registerProblem(attribute.getValue(), PyBundle.message("INSP.attribute.$0.outside.init", attributeName),
                          new PyMoveAttributeToInitQuickFix());
        }
      }
    }
  }

  private static boolean isApplicable(@NotNull final PyClass containingClass) {
    return !PythonUnitTestUtil.isUnitTestCaseClass(containingClass) && !containingClass.isSubclass("django.db.models.base.Model");
  }
}