#region License Information (GPL v3)

/*
    ShareX - A program that allows you to take screenshots and share any file type
    Copyright (c) 2007-2018 ShareX Team

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

    Optionally you can also view the license at <http://www.gnu.org/licenses/>.
*/

#endregion License Information (GPL v3)

using ShareX.HelpersLib;
using System;
using System.Drawing;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ShareX.ScreenCaptureLib
{
    public class WebpageCapture : IDisposable
    {
        public event Action<Bitmap> CaptureCompleted;

        public int CaptureDelay { get; set; }

        private WebBrowser webBrowser;

        public WebpageCapture()
        {
            webBrowser = new WebBrowser();
            webBrowser.AllowNavigation = true;
            webBrowser.ScriptErrorsSuppressed = true;
            webBrowser.ScrollBarsEnabled = false;
            webBrowser.DocumentCompleted += webBrowser_DocumentCompleted;
        }

        public void CapturePage(string url)
        {
            CapturePage(url, Screen.PrimaryScreen.Bounds.Size);
        }

        public void CapturePage(string url, Size browserSize)
        {
            if (!string.IsNullOrEmpty(url))
            {
                webBrowser.Size = browserSize;
                webBrowser.Navigate(url);
            }
        }

        public void Stop()
        {
            webBrowser.Stop();
        }

        private async void webBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            await Task.Delay(CaptureDelay);

            GetWebpageBitmap();
        }

        private void GetWebpageBitmap()
        {
            if (webBrowser.Document != null && webBrowser.Document.Body != null)
            {
                Rectangle rect = webBrowser.Document.Body.ScrollRectangle;
                webBrowser.Size = new Size(rect.Width, rect.Height);
                Bitmap bmp = new Bitmap(rect.Width, rect.Height);

                try
                {
                    GetImage(webBrowser.ActiveXInstance, bmp, Color.White);
                    OnCaptureCompleted(bmp);
                    return;
                }
                catch (Exception ex)
                {
                    DebugHelper.WriteException(ex);

                    if (bmp != null)
                    {
                        bmp.Dispose();
                    }
                }
            }

            OnCaptureCompleted(null);
        }

        private static void GetImage(object obj, Image destination, Color backgroundColor)
        {
            using (Graphics graphics = Graphics.FromImage(destination))
            {
                IntPtr deviceContextHandle = IntPtr.Zero;
                RECT rectangle = new RECT();

                rectangle.Right = destination.Width;
                rectangle.Bottom = destination.Height;

                graphics.Clear(backgroundColor);

                try
                {
                    deviceContextHandle = graphics.GetHdc();

                    IViewObject viewObject = obj as IViewObject;
                    viewObject.Draw(1, -1, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, deviceContextHandle, ref rectangle, IntPtr.Zero, IntPtr.Zero, 0);
                }
                finally
                {
                    if (deviceContextHandle != IntPtr.Zero)
                    {
                        graphics.ReleaseHdc(deviceContextHandle);
                    }
                }
            }
        }

        protected void OnCaptureCompleted(Bitmap bmp)
        {
            if (CaptureCompleted != null)
            {
                CaptureCompleted(bmp);
            }
            else if (bmp != null)
            {
                bmp.Dispose();
            }
        }

        public void Dispose()
        {
            if (webBrowser != null)
            {
                webBrowser.Dispose();
            }
        }
    }
}