// Copyright © 2015 The CefSharp Authors. All rights reserved.

//

// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.

using System;

using System.Text.RegularExpressions;

using System.Threading.Tasks;

namespace CefSharp.Example

{

/// <summary>

/// Methods whose functionaity is mostly implemented by evaluating or

/// executing scripts in the browser.

/// </summary>

public static class ScriptedMethods

{

/// <summary>

/// Determine if the active element in a frame accepts text input.

/// </summary>

/// <param name="frame">Test the active element in this frame.</param>

/// <returns>True if the active element accepts text input.</returns>

public static async Task<bool> ActiveElementAcceptsTextInput(this IFrame frame)

{

if (frame == null)

{

throw new ArgumentException("An IFrame instance is required.", "frame");

}

// Scripts should be minified for production builds. The script

// could also be read from a file...

const string script =

@"(function ()

{

var isText = false;

var activeElement = document.activeElement;

if (activeElement) {

if (activeElement.tagName.toLowerCase() === 'textarea') {

isText = true;

} else {

if (activeElement.tagName.toLowerCase() === 'input') {

if (activeElement.hasAttribute('type')) {

var inputType = activeElement.getAttribute('type').toLowerCase();

if (inputType === 'text' || inputType === 'email' || inputType === 'password' || inputType === 'tel' || inputType === 'number' || inputType === 'range' || inputType === 'search' || inputType === 'url') {

isText = true;

}

}

}

}

}

return isText;

})();";

var response = await frame.EvaluateScriptAsync(script);

if (!response.Success)

{

throw new Exception(response.Message);

}

return (bool)response.Result;

}

/// <summary>

/// Determine if the frame contains an element with the specified id.

/// </summary>

/// <param name="frame">Test the elements in this frame.</param>

/// <param name="id">The id to find.</param>

/// <returns>True if an element with the specified id exists in the frame.</returns>

public static async Task<bool> ElementWithIdExists(this IFrame frame, string id)

{

if (frame == null)

{

throw new ArgumentException("An IFrame instance is required.", "frame");

}

var script =

@"(function () {

var n = document.getElementById('##ID##');

return n !== null && typeof n !== 'undefined';

})();";

// For simple inline scripts you could use String.Format() but

// beware of braces in the javascript code. If reading from a file

// it's probably safer to include tokens that can be replaced via

// regex.

script = Regex.Replace(script, "##ID##", id);

var response = await frame.EvaluateScriptAsync(script);

if (!response.Success)

{

throw new Exception(response.Message);

}

return (bool)response.Result;

}

/// <summary>

/// Set an event listener on the element with the provided id. When the

/// event listener callback is invoked an attempt will be made to pass

/// event information to a .Net class bound to the browser. See

/// ScriptedMethodsBoundObject.

/// </summary>

/// <param name="frame">The element is in this frame.</param>

/// <param name="id">The id of an element that exists in the frame.</param>

/// <param name="eventName">Subscribe to this event. For example 'click'.</param>

public static void ListenForEvent(this IFrame frame, string id, string eventName)

{

if (frame == null)

{

throw new ArgumentException("An IFrame instance is required.", "frame");

}

// Adds a click event listener to a DOM element with the provided

// ID. When the element is clicked the ScriptedMethodsBoundObject's

// RaiseEvent function is invoked. This is one way to get

// asynchronous events from the web page. Typically though the web

// page would be aware of window.boundEvent.RaiseEvent and would

// simply raise it as needed.

//

// Scripts should be minified for production builds. The script

// could also be read from a file...

var script =

@"(async function ()

{

await CefSharp.BindObjectAsync('boundEvent');

var counter = 0;

var elem = document.getElementById('##ID##');

elem.removeAttribute('disabled');

elem.addEventListener('##EVENT##', function(e){

if (!window.boundEvent){

console.log('window.boundEvent does not exist.');

return;

}

counter++;

//NOTE RaiseEvent was converted to raiseEvent in JS (this is configurable when registering the object)

window.boundEvent.raiseEvent('##EVENT##', {count: counter, id: e.target.id, tagName: e.target.tagName});

});

console.log(`Added ##EVENT## listener to ${elem.id}.`);

})();";

// For simple inline scripts you could use String.Format() but

// beware of braces in the javascript code. If reading from a file

// it's probably safer to include tokens that can be replaced via

// regex.

script = Regex.Replace(script, "##ID##", id);

script = Regex.Replace(script, "##EVENT##", eventName);

frame.ExecuteJavaScriptAsync(script);

}

}

}