/*
 * 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 org.jetbrains.plugins.groovy.intentions.conversions.strings;

import com.intellij.lang.ASTNode;
import com.intellij.openapi.editor.Editor;
import com.intellij.openapi.project.Project;
import com.intellij.psi.PsiElement;
import com.intellij.psi.tree.IElementType;
import com.intellij.util.IncorrectOperationException;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.plugins.groovy.intentions.base.Intention;
import org.jetbrains.plugins.groovy.intentions.base.PsiElementPredicate;
import org.jetbrains.plugins.groovy.lang.lexer.GroovyTokenTypes;
import org.jetbrains.plugins.groovy.lang.parser.GroovyElementTypes;
import org.jetbrains.plugins.groovy.lang.psi.GroovyPsiElementFactory;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrExpression;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.literals.GrLiteral;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.literals.GrString;
import org.jetbrains.plugins.groovy.lang.psi.util.GrStringUtil;

/**
 * @author Max Medvedev
 */
public class GrBreakStringOnLineBreaksIntention extends Intention {
  @Override
  protected void processIntention(@NotNull PsiElement element, Project project, Editor editor) throws IncorrectOperationException {
    final String text = invokeImpl(element);
    final GrExpression newExpr = GroovyPsiElementFactory.getInstance(project).createExpressionFromText(text);
    ((GrExpression)element).replaceWithExpression(newExpr, true);
  }

  @NotNull
  @Override
  protected PsiElementPredicate getElementPredicate() {
    return new PsiElementPredicate() {
      @Override
      public boolean satisfiedBy(PsiElement element) {
        return element instanceof GrLiteral && !element.getText().equals(invokeImpl(element));
      }
    };
  }

  private static String invokeImpl(PsiElement element) {
    final String text = element.getText();
    final String quote = GrStringUtil.getStartQuote(text);

    if (!("'".equals(quote) || "\"".equals(quote))) return text;
    if (!text.contains("\\n")) return text;

    String value = GrStringUtil.removeQuotes(text);

    StringBuilder buffer = new StringBuilder();
    if (element instanceof GrString) {
      processGString(element, quote, value, buffer);
    }
    else {
      processSimpleString(quote, value, buffer);
    }

    final String result = buffer.toString();
    if (result.endsWith("+\n\"\"")) return result.substring(0, result.length() - 4);

    return result;
  }

  private static void processGString(PsiElement element, String quote, String value, StringBuilder buffer) {
    final ASTNode node = element.getNode();

    for (ASTNode child = node.getFirstChildNode(); child != null; child = child.getTreeNext()) {
      final IElementType type = child.getElementType();
      if (type == GroovyTokenTypes.mGSTRING_BEGIN || type == GroovyTokenTypes.mGSTRING_END) continue;
      if (type == GroovyElementTypes.GSTRING_INJECTION) {
        buffer.append(child.getText());
      }
      else {
        value = child.getText();
        int prev = 0;
        if (!isInjection(child.getTreePrev())) {
          buffer.append(quote);
        }
        for (int pos = value.indexOf("\\n"); pos >= 0; pos = value.indexOf("\\n", prev)) {
          int end = checkForR(value, pos);
          buffer.append(value.substring(prev, end));
          prev = end;
          buffer.append(quote);
          buffer.append("+\n");
          buffer.append(quote);
        }
        buffer.append(value.substring(prev, value.length()));
        if (!isInjection(child.getTreeNext())) {
          buffer.append(quote);
        }
      }
    }
  }

  private static boolean isInjection(ASTNode next) {
    return next != null && next.getElementType() == GroovyElementTypes.GSTRING_INJECTION;
  }

  private static void processSimpleString(String quote, String value, StringBuilder buffer) {
    int prev = 0;
    for (int pos = value.indexOf("\\n"); pos >= 0; pos = value.indexOf("\\n", prev)) {
      buffer.append(quote);
      int end = checkForR(value, pos);
      buffer.append(value.substring(prev, end));
      prev = end;
      buffer.append(quote);
      buffer.append("+\n");
    }
    buffer.append(quote);
    buffer.append(value.substring(prev, value.length()));
    buffer.append(quote);
  }

  private static int checkForR(String value, int pos) {
    pos += 2;
    if (value.length() > pos + 2 && "\r".equals(value.substring(pos, pos + 2))) return pos + 2;
    return pos;
  }


}