python/src/com/jetbrains/python/codeInsight/completion/PyDocstringCompletionContributor.java

/*
 * 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.jetbrains.python.codeInsight.completion;

import com.intellij.codeInsight.completion.*;
import com.intellij.codeInsight.lookup.AutoCompletionPolicy;
import com.intellij.codeInsight.lookup.LookupElementBuilder;
import com.intellij.openapi.module.Module;
import com.intellij.openapi.module.ModuleUtilCore;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.util.ProcessingContext;
import com.jetbrains.python.psi.PyDocStringOwner;
import com.jetbrains.python.psi.PyStringLiteralExpression;
import com.jetbrains.python.refactoring.PyRefactoringUtil;
import org.jetbrains.annotations.NotNull;

import java.util.Collection;

import static com.intellij.patterns.PlatformPatterns.psiComment;
import static com.intellij.patterns.PlatformPatterns.psiElement;
import static com.intellij.patterns.StandardPatterns.or;

/**
 * User : ktisha
 */
public class PyDocstringCompletionContributor extends CompletionContributor {
  public PyDocstringCompletionContributor() {
    extend(CompletionType.BASIC,
           or(psiElement().inside(PyStringLiteralExpression.class), psiComment()),
           new IdentifierCompletionProvider());
  }

  private static class IdentifierCompletionProvider extends CompletionProvider<CompletionParameters> {

    private IdentifierCompletionProvider() {
    }

    @Override
    protected void addCompletions(@NotNull CompletionParameters parameters,
                                  ProcessingContext context,
                                  @NotNull CompletionResultSet result) {
      if (parameters.isAutoPopup()) return;
      final PsiElement element = parameters.getOriginalPosition();
      if (element == null) return;
      final PsiFile file = element.getContainingFile();
      if (file.findReferenceAt(parameters.getOffset()) != null) return;
      final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(element, PyDocStringOwner.class);
      final Module module = ModuleUtilCore.findModuleForPsiElement(element);
      if (module != null) {
        result = result.withPrefixMatcher(getPrefix(parameters.getOffset(), file));
        final Collection<String> identifiers = PyRefactoringUtil.collectUsedNames(docStringOwner);
        for (String identifier : identifiers)
          result.addElement(LookupElementBuilder.create(identifier).withAutoCompletionPolicy(AutoCompletionPolicy.NEVER_AUTOCOMPLETE));


        final Collection<String> fileIdentifiers = PyRefactoringUtil.collectUsedNames(parameters.getOriginalFile());
        for (String identifier : fileIdentifiers)
          result.addElement(LookupElementBuilder.create(identifier).withAutoCompletionPolicy(AutoCompletionPolicy.NEVER_AUTOCOMPLETE));
      }
    }
  }

  private static String getPrefix(int offset, PsiFile file) {
    if (offset > 0) {
      offset--;
    }
    final String text = file.getText();
    StringBuilder prefixBuilder = new StringBuilder();
    while(offset > 0 && Character.isLetterOrDigit(text.charAt(offset))) {
      prefixBuilder.insert(0, text.charAt(offset));
      offset--;
    }
    return prefixBuilder.toString();
  }

  @Override
  public boolean invokeAutoPopup(@NotNull PsiElement position, char typeChar) {
    return false;
  }
}