/*
 * 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.stubs;

import com.intellij.lang.*;
import com.intellij.openapi.diagnostic.LogUtil;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.fileTypes.FileType;
import com.intellij.openapi.fileTypes.LanguageFileType;
import com.intellij.psi.PsiFile;
import com.intellij.psi.StubBuilder;
import com.intellij.psi.tree.IElementType;
import com.intellij.psi.tree.IFileElementType;
import com.intellij.psi.tree.ILightStubFileElementType;
import com.intellij.util.containers.Stack;
import gnu.trove.TIntStack;
import org.jetbrains.annotations.NotNull;

import java.util.List;

public class LightStubBuilder implements StubBuilder {
  private static final Logger LOG = Logger.getInstance("#com.intellij.psi.stubs.LightStubBuilder");
  public static final ThreadLocal<LighterAST> FORCED_AST = new ThreadLocal<LighterAST>();

  @Override
  public StubElement buildStubTree(@NotNull PsiFile file) {
    LighterAST tree = FORCED_AST.get();
    if (tree == null) {
      FileType fileType = file.getFileType();
      if (!(fileType instanceof LanguageFileType)) {
        LOG.error("File is not of LanguageFileType: " + fileType + ", " + file);
        return null;
      }
      Language language = ((LanguageFileType)fileType).getLanguage();
      final IFileElementType contentType = LanguageParserDefinitions.INSTANCE.forLanguage(language).getFileNodeType();
      if (!(contentType instanceof ILightStubFileElementType)) {
        LOG.error("File is not of ILightStubFileElementType: " + contentType + ", " + file);
        return null;
      }
      tree = file.getNode().getLighterAST();
    } else {
      FORCED_AST.set(null);
    }
    if (tree == null) return null;

    final StubElement rootStub = createStubForFile(file, tree);
    buildStubTree(tree, tree.getRoot(), rootStub);
    return rootStub;
  }

  @NotNull
  @SuppressWarnings("unchecked")
  protected StubElement createStubForFile(@NotNull PsiFile file, @NotNull LighterAST tree) {
    return new PsiFileStubImpl(file);
  }

  protected void buildStubTree(@NotNull LighterAST tree, @NotNull LighterASTNode root, @NotNull StubElement rootStub) {
    final Stack<LighterASTNode> parents = new Stack<LighterASTNode>();
    final TIntStack childNumbers = new TIntStack();
    final Stack<List<LighterASTNode>> kinderGarden = new Stack<List<LighterASTNode>>();
    final Stack<StubElement> parentStubs = new Stack<StubElement>();

    LighterASTNode parent = null;
    LighterASTNode element = root;
    List<LighterASTNode> children = null;
    int childNumber = 0;
    StubElement parentStub = rootStub;

    nextElement:
    while (element != null) {
      final StubElement stub = createStub(tree, element, parentStub);

      if (parent == null || !skipNode(tree, parent, element)) {
        final List<LighterASTNode> kids = tree.getChildren(element);
        if (!kids.isEmpty()) {
          if (parent != null) {
            parents.push(parent);
            childNumbers.push(childNumber);
            kinderGarden.push(children);
            parentStubs.push(parentStub);
          }
          parent = element;
          element = (children = kids).get(childNumber = 0);
          parentStub = stub;
          if (!skipNode(tree, parent, element)) continue nextElement;
        }
      }

      while (children != null && ++childNumber < children.size()) {
        element = children.get(childNumber);
        if (!skipNode(tree, parent, element)) continue nextElement;
      }

      element = null;
      while (!parents.isEmpty()) {
        parent = parents.pop();
        childNumber = childNumbers.pop();
        children = kinderGarden.pop();
        parentStub = parentStubs.pop();
        while (++childNumber < children.size()) {
          element = children.get(childNumber);
          if (!skipNode(tree, parent, element)) continue nextElement;
        }
        element = null;
      }
    }
  }

  @SuppressWarnings({"MethodMayBeStatic"})
  protected StubElement createStub(final LighterAST tree, final LighterASTNode element, final StubElement parentStub) {
    final IElementType elementType = element.getTokenType();
    if (elementType instanceof IStubElementType) {
      if (elementType instanceof ILightStubElementType) {
        final ILightStubElementType lightElementType = (ILightStubElementType)elementType;
        if (lightElementType.shouldCreateStub(tree, element, parentStub)) {
          return lightElementType.createStub(tree, element, parentStub);
        }
      }
      else {
        LOG.error("Element is not of ILightStubElementType: " + LogUtil.objectAndClass(elementType) + ", " + element);
      }
    }

    return parentStub;
  }

  private boolean skipNode(@NotNull LighterAST tree, @NotNull LighterASTNode parent, @NotNull LighterASTNode node) {
    if (tree instanceof TreeBackedLighterAST) {
      return skipChildProcessingWhenBuildingStubs(((TreeBackedLighterAST)tree).unwrap(parent), ((TreeBackedLighterAST)tree).unwrap(node));
    }
    else {
      return skipChildProcessingWhenBuildingStubs(tree, parent, node);
    }
  }

  /**
   * Note to implementers: always keep in sync with {@linkplain #skipChildProcessingWhenBuildingStubs(LighterAST, LighterASTNode, LighterASTNode)}.
   */
  @Override
  public boolean skipChildProcessingWhenBuildingStubs(@NotNull ASTNode parent, @NotNull ASTNode node) {
    return false;
  }

  /**
   * Note to implementers: always keep in sync with {@linkplain #skipChildProcessingWhenBuildingStubs(ASTNode, ASTNode)}.
   */
  protected boolean skipChildProcessingWhenBuildingStubs(@NotNull LighterAST tree, @NotNull LighterASTNode parent, @NotNull LighterASTNode node) {
    return false;
  }
}

@@ -1062,32 +1062,83 @@
 ileElementType;%0A
+import com.intellij.psi.tree.IStubFileElementType;%0A
 import com.intel
@@ -2071,29 +2071,24 @@
 instanceof I
-Light
 StubFileElem
@@ -2130,29 +2130,24 @@
  is not of I
-Light
 StubFileElem
@@ -2220,52 +2220,230 @@
   %7D%0A
+%0A
       
-tree = file.getNode().getLighterAST();
+final FileASTNode node = file.getNode();%0A      if (contentType instanceof ILightStubFileElementType) %7B%0A        tree = node.getLighterAST();%0A      %7D%0A      else %7B%0A        tree = new TreeBackedLighterAST(node);%0A      %7D
 %0A   

use real AST when building stub tree with light stub builder (e.g. for java in jsp)