using FastReport.Forms;
using FastReport.Utils;
using System.Drawing;
using System.IO;
using System.Windows.Documents;
using System.Windows;
using System.Windows.Forms;
using System.Windows.Media.Imaging;
using System.Windows.Media;
using System.Text;
using System;

namespace FastReport
{
    partial class RichObject : IHasEditor
    {
        private string cachedText;
        private SizeF cachedSize;
        private FlowDocument cachedDocument;
        private Image cachedImage;

        private BitmapSource FlowDocumentToBitmap(FlowDocument document, System.Windows.Size size)
        {
            document.ColumnWidth = size.Width;
            document.PagePadding = new Thickness(Padding.Left, Padding.Top, Padding.Right, Padding.Bottom);
            var paginator = ((IDocumentPaginatorSource)document).DocumentPaginator;
            paginator.PageSize = size;

            var visual = new DrawingVisual();
            using (var ctx = visual.RenderOpen())
            {
                // draw white background
                ctx.DrawRectangle(System.Windows.Media.Brushes.White, null, new Rect(size));
            }
            visual.Children.Add(paginator.GetPage(0).Visual);

            var dpi = Report.Designer.ZoomDpi;
            var bitmap = new RenderTargetBitmap((int)(size.Width * dpi), (int)(size.Height * dpi), 96 * dpi, 96 * dpi, PixelFormats.Pbgra32);
            bitmap.Render(visual);
            visual.Children.Clear();

            return bitmap;
        }

        private FlowDocument RtfToFlowDocument(string text)
        {
            var document = new FlowDocument();
            var textRange = new TextRange(document.ContentStart, document.ContentEnd);
            using (var stream = new MemoryStream(Encoding.Default.GetBytes(text)))
                textRange.Load(stream, System.Windows.DataFormats.Rtf);
            return document;
        }

        private void DrawRich(FRPaintEventArgs e)
        {
            if (Width <= 0 || Height <= 0)
                return;

            if (Text != cachedText || cachedDocument == null)
            {
                cachedDocument = RtfToFlowDocument(Text);
                cachedText = Text;
                cachedSize = System.Drawing.Size.Empty;
            }

            var width = Width * e.ScaleX - Padding.Horizontal;
            var height = Height * e.ScaleY - Padding.Vertical;
            if (width != cachedSize.Width || height != cachedSize.Height || cachedImage == null)
            {
                var bitmap = FlowDocumentToBitmap(cachedDocument, new System.Windows.Size(Width, Height));
                cachedImage?.Dispose();
                cachedImage = Helper.GetImage(bitmap);
                cachedSize = new SizeF(width, height);
            }

            e.Graphics.DrawImage(cachedImage, AbsLeft * e.ScaleX, AbsTop * e.ScaleY, Width * e.ScaleX, Height * e.ScaleY);
        }

        #region Public Methods
        internal void DrawDesign(FRPaintEventArgs e)
        {
            if (IsDesigning)
            {
                if (string.IsNullOrEmpty(this.Text))
                {
                    e.Graphics.DrawString(Res.Get("Forms,RichTextEditor,Invoke"), DrawUtils.DefaultReportFont, System.Drawing.Brushes.Gray,
                        new RectangleF(AbsLeft * e.ScaleX, AbsTop * e.ScaleY, Width * e.ScaleX, Height * e.ScaleY));
                }
                else
                {
                    try
                    {
                        DrawRich(e);
                    }
                    catch (Exception ex)
                    {
                        e.Graphics.DrawString(ex.Message, DrawUtils.DefaultReportFont, System.Drawing.Brushes.Red,
                            new RectangleF(AbsLeft * e.ScaleX, AbsTop * e.ScaleY, Width * e.ScaleX, Height * e.ScaleY));
                    }
                }
                DrawMarkers(e);
            }
        }

        /// <inheritdoc/>
        public bool InvokeEditor()
        {
            using (var form = new RichEditorForm(this))
            {
                if (form.ShowDialog() == DialogResult.OK)
                {
                    actualTextStart = 0;
                    actualTextLength = 0;
                    return true;
                }
            }

            return false;
        }

        /// <inheritdoc/>
        public override SmartTagBase GetSmartTag()
        {
            return new RichObjectSmartTag(this);
        }

        /// <inheritdoc/>
        public override ContextMenuBase GetContextMenu()
        {
            return new TextObjectBaseMenu(Report.Designer);
        }
        #endregion

    }
}