/*
 * 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.intellij.codeInsight.daemon.impl;

import com.intellij.lang.Language;
import com.intellij.openapi.extensions.Extensions;
import com.intellij.openapi.progress.ProgressManager;
import com.intellij.openapi.util.Condition;
import com.intellij.openapi.util.ProperTextRange;
import com.intellij.openapi.util.TextRange;
import com.intellij.psi.FileViewProvider;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.util.PsiUtilCore;
import com.intellij.util.containers.Stack;
import gnu.trove.TIntStack;
import org.jetbrains.annotations.NotNull;

import java.util.List;

/**
 * User: cdr
 */
public class Divider {
  private static final int STARTING_TREE_HEIGHT = 10;

  public static void divideInsideAndOutside(@NotNull PsiFile file,
                                            int startOffset,
                                            int endOffset,
                                            @NotNull TextRange range,
                                            @NotNull List<PsiElement> inside,
                                            @NotNull List<ProperTextRange> insideRanges,
                                            @NotNull List<PsiElement> outside,
                                            @NotNull List<ProperTextRange> outsideRanges,
                                            boolean includeParents,
                                            @NotNull Condition<PsiFile> filter) {
    final FileViewProvider viewProvider = file.getViewProvider();
    for (Language language : viewProvider.getLanguages()) {
      final PsiFile psiRoot = viewProvider.getPsi(language);
      if (filter.value(psiRoot)) {
        divideInsideAndOutside(psiRoot, startOffset, endOffset, range, inside, insideRanges, outside, outsideRanges, includeParents);
      }
    }
  }

  private static void divideInsideAndOutside(@NotNull PsiFile root,
                                             int startOffset,
                                             int endOffset,
                                             @NotNull TextRange range,
                                             @NotNull List<PsiElement> inside,
                                             @NotNull List<ProperTextRange> insideRanges,
                                             @NotNull List<PsiElement> outside,
                                             @NotNull List<ProperTextRange> outsideRanges,
                                             boolean includeParents) {
    final int currentOffset = root.getTextRange().getStartOffset();
    final Condition<PsiElement>[] filters = Extensions.getExtensions(CollectHighlightsUtil.EP_NAME);

    int offset = currentOffset;

    final TIntStack starts = new TIntStack(STARTING_TREE_HEIGHT);
    starts.push(startOffset);
    final Stack<PsiElement> elements = new Stack<PsiElement>(STARTING_TREE_HEIGHT);
    final Stack<PsiElement> children = new Stack<PsiElement>(STARTING_TREE_HEIGHT);
    PsiElement element = root;

    PsiElement child = PsiUtilCore.NULL_PSI_ELEMENT;
    while (true) {
      ProgressManager.checkCanceled();

      for (Condition<PsiElement> filter : filters) {
        if (!filter.value(element)) {
          assert child == PsiUtilCore.NULL_PSI_ELEMENT;
          child = null; // do not want to process children
          break;
        }
      }

      boolean startChildrenVisiting;
      if (child == PsiUtilCore.NULL_PSI_ELEMENT) {
        startChildrenVisiting = true;
        child = element.getFirstChild();
      }
      else {
        startChildrenVisiting = false;
      }

      if (child == null) {
        if (startChildrenVisiting) {
          // leaf element
          offset += element.getTextLength();
        }

        int start = starts.pop();
        if (startOffset <= start && offset <= endOffset) {
          if (range.containsRange(start, offset)) {
            inside.add(element);
            insideRanges.add(new ProperTextRange(start, offset));
          }
          else {
            outside.add(element);
            outsideRanges.add(new ProperTextRange(start, offset));
          }
        }

        if (elements.isEmpty()) break;
        element = elements.pop();
        child = children.pop();
      }
      else {
        // composite element
        if (offset > endOffset) break;
        children.push(child.getNextSibling());
        starts.push(offset);
        elements.push(element);
        element = child;
        child = PsiUtilCore.NULL_PSI_ELEMENT;
      }
    }

    if (includeParents) {
      PsiElement parent = !outside.isEmpty() ? outside.get(outside.size() - 1) :
                          !inside.isEmpty() ? inside.get(inside.size() - 1) :
                          CollectHighlightsUtil.findCommonParent(root, startOffset, endOffset);
      while (parent != null && !(parent instanceof PsiFile)) {
        parent = parent.getParent();
        if (parent != null) {
          outside.add(parent);
          TextRange textRange = parent.getTextRange();
          assert textRange != null : "Text range for " + parent + " is null. " + parent.getClass() +"; root: "+root+": "+root.getVirtualFile();
          outsideRanges.add(ProperTextRange.create(textRange));
        }
      }
    }

    assert inside.size() == insideRanges.size();
    assert outside.size() == outsideRanges.size();
  }
}