/*
 * Copyright 2000-2013 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.intellij.psi.scope.util;

import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.progress.ProgressIndicatorProvider;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiInvalidElementAccessException;
import com.intellij.psi.ResolveState;
import com.intellij.psi.scope.PsiScopeProcessor;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * Some base methods for scopes
 */
public class PsiScopesUtilCore {
  public static final Logger LOGGER = Logger.getInstance(PsiScopesUtilCore.class);

  public static boolean treeWalkUp(@NotNull PsiScopeProcessor processor, @NotNull PsiElement entrance, @Nullable PsiElement maxScope) {
    return treeWalkUp(processor, entrance, maxScope, ResolveState.initial());
  }

  public static boolean treeWalkUp(@NotNull final PsiScopeProcessor processor,
                                   @NotNull final PsiElement entrance,
                                   @Nullable final PsiElement maxScope,
                                   @NotNull final ResolveState state) {
    if (!entrance.isValid()) {
      LOGGER.error(new PsiInvalidElementAccessException(entrance));
    }
    PsiElement prevParent = entrance;
    PsiElement scope = entrance;

    while (scope != null) {
      ProgressIndicatorProvider.checkCanceled();

      if (!scope.processDeclarations(processor, state, prevParent, entrance)) {
        return false; // resolved
      }


      if (scope == maxScope) break;
      prevParent = scope;
      scope = prevParent.getContext();
      if (scope != null && scope != prevParent.getParent() && !scope.isValid()) {
        break;
      }

    }

    return true;
  }

  public static boolean walkChildrenScopes(@NotNull PsiElement thisElement,
                                           @NotNull PsiScopeProcessor processor,
                                           @NotNull ResolveState state,
                                           PsiElement lastParent,
                                           PsiElement place) {
    PsiElement child = null;
    if (lastParent != null && lastParent.getParent() == thisElement) {
      child = lastParent.getPrevSibling();
      if (child == null) return true; // first element
    }

    if (child == null) {
      child = thisElement.getLastChild();
    }

    while (child != null) {
      if (!child.processDeclarations(processor, state, null, place)) return false;
      child = child.getPrevSibling();
    }

    return true;
  }
}