// Copyright (c) 2009 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

package org.chromium.debug.ui.editors;

import org.chromium.debug.core.model.StackFrame;

import org.chromium.debug.core.util.JsValueStringifier;

import org.chromium.sdk.CallFrame;

import org.chromium.sdk.JsVariable;

import org.eclipse.core.runtime.IAdaptable;

import org.eclipse.debug.ui.DebugUITools;

import org.eclipse.jface.text.IDocument;

import org.eclipse.jface.text.IRegion;

import org.eclipse.jface.text.ITextHover;

import org.eclipse.jface.text.ITextViewer;

/**

 * Supplies a hover for JavaScript expressions while on a breakpoint.

 */

public class JsDebugTextHover implements ITextHover {

  private static final JsValueStringifier STRINGIFIER = new JsValueStringifier();

  public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {

    IDocument doc = textViewer.getDocument();

    String expression = JavascriptUtil.extractSurroundingJsIdentifier(doc, hoverRegion.getOffset());

    if (expression == null) {

      return null;

    }

    IAdaptable context = DebugUITools.getDebugContext();

    if (context == null) { // debugger not active

      return null;

    }

    StackFrame frame = (StackFrame) context.getAdapter(StackFrame.class);

    if (frame == null) { // not a stackframe-related context

      return null;

    }

    final JsVariable[] result = new JsVariable[1];

    frame.getCallFrame().evaluateSync(expression, new CallFrame.EvaluateCallback() {

      public void success(JsVariable var) {

        result[0] = var;

      }

      public void failure(String errorMessage) {

      }

    });

    if (result[0] == null) {

      return null;

    }

    return STRINGIFIER.render(result[0].getValue());

  }

  public IRegion getHoverRegion(ITextViewer textViewer, int offset) {

    IDocument doc = textViewer.getDocument();

    return JavascriptUtil.getSurroundingIdentifierRegion(doc, offset, false);

  }

}