using FastReport.Utils;
using System.Drawing;
using System.Globalization;
using System.Text;
using System.Windows.Forms;

namespace FastReport.Controls
{
    internal class HtmlDescriptionTextBlock : System.Windows.Controls.TextBlock
    {
        public System.Windows.Media.ImageSource Image { get; set; }

        public string Description { get; set; }

        public void ParseDescription()
        {
            Inlines.Clear();
            if (Image != null)
            {
                Inlines.Add(
                    new System.Windows.Documents.InlineUIContainer(
                        new System.Windows.Controls.Image() { Source = Image, Width = 16, Height = 16, Margin = new System.Windows.Thickness(0, 0, 4, 0) })
                    { BaselineAlignment = System.Windows.BaselineAlignment.Center });
            }
            ConvertHtml(Description, new StyleDescriptor(DrawUtils.DefaultFont));
        }

        private enum BaseLine
        {
            Normal,
            Subscript,
            Superscript
        }

        private class StyleDescriptor
        {
            public string FontName;
            public float FontSize;
            public FontStyle FontStyle;
            public Color Color;
            public BaseLine BaseLine;

            public StyleDescriptor(string fontName, float fontSize, FontStyle fontStyle, Color color, BaseLine baseLine)
            {
                FontName = fontName;
                FontStyle = fontStyle;
                FontSize = fontSize;
                Color = color;
                BaseLine = baseLine;
            }

            public StyleDescriptor(Font font) : this(font.Name, font.Size, FontStyle.Regular, Color.Black, BaseLine.Normal) { }

            public StyleDescriptor(StyleDescriptor other) : this(other.FontName, other.FontSize, other.FontStyle, other.Color, other.BaseLine) { }
        }

        private void AddRun(string text, StyleDescriptor s)
        {
            var run = new System.Windows.Documents.Run();
            run.Text = text;
            Helper.SetFont(s.FontName, s.FontSize, s.FontStyle, Helper.GetDpiScale(this), out var family, out var size, out var style, out var weight, out var deco);
            run.FontFamily = family;
            run.FontSize = size;
            run.FontStyle = style;
            run.FontWeight = weight;
            run.TextDecorations = deco;
            run.Foreground = Helper.GetBrush(s.Color);
            Inlines.Add(run);
        }

        private void AddLineBreak()
        {
            Inlines.Add(new System.Windows.Documents.LineBreak());
        }

        private void ConvertHtml(string text, StyleDescriptor defaultStyle)
        {
            StringBuilder currentWord = new StringBuilder(100);
            StyleDescriptor style = new StyleDescriptor(defaultStyle);

            for (int i = 0; i < text.Length; i++)
            {
                char lastChar = text[i];
                if (lastChar == '<')
                {
                    // probably html tag
                    StyleDescriptor newStyle = new StyleDescriptor(style);
                    string tag = "";
                    bool match = false;

                    // <b>, <i>, <u>
                    if (i + 3 <= text.Length)
                    {
                        match = true;
                        tag = text.Substring(i, 3).ToLower();
                        if (tag == "<b>")
                            newStyle.FontStyle |= System.Drawing.FontStyle.Bold;
                        else if (tag == "<i>")
                            newStyle.FontStyle |= System.Drawing.FontStyle.Italic;
                        else if (tag == "<u>")
                            newStyle.FontStyle |= System.Drawing.FontStyle.Underline;
                        else
                            match = false;

                        if (match)
                            i += 3;
                    }

                    // </b>, </i>, </u>
                    if (!match && i + 4 <= text.Length && text[i + 1] == '/')
                    {
                        match = true;
                        tag = text.Substring(i, 4).ToLower();
                        if (tag == "</b>")
                            newStyle.FontStyle &= ~System.Drawing.FontStyle.Bold;
                        else if (tag == "</i>")
                            newStyle.FontStyle &= ~System.Drawing.FontStyle.Italic;
                        else if (tag == "</u>")
                            newStyle.FontStyle &= ~System.Drawing.FontStyle.Underline;
                        else
                            match = false;

                        if (match)
                            i += 4;
                    }

                    // <sub>, <sup>, <font
                    if (!match && i + 5 <= text.Length)
                    {
                        match = true;
                        tag = text.Substring(i, 5).ToLower();
                        if (tag == "<sub>")
                            newStyle.BaseLine = BaseLine.Subscript;
                        else if (tag == "<sup>")
                            newStyle.BaseLine = BaseLine.Superscript;
                        else if (tag == "<font")
                        {
                            //try to found end of open tag
                            int right = text.IndexOf('>', i + 5);
                            if (right <= 0) match = false;
                            else
                            {
                                //found font and parse them
                                string color = null;
                                string face = null;
                                string size = null;
                                int color_ind = text.IndexOf("color=\"", i + 5);
                                if (color_ind < right && color_ind >= 0)
                                {
                                    color_ind += 7;
                                    int color_end = text.IndexOf("\"", color_ind);
                                    if (color_end < right && color_end >= 0)
                                    {
                                        color = text.Substring(color_ind, color_end - color_ind);
                                    }
                                }

                                int face_ind = text.IndexOf("face=\"", i + 5);
                                if (face_ind < right && face_ind >= 0)
                                {
                                    face_ind += 6;
                                    int face_end = text.IndexOf("\"", face_ind);
                                    if (face_end < right && face_end >= 0)
                                    {
                                        face = text.Substring(face_ind, face_end - face_ind);
                                    }
                                }

                                int size_ind = text.IndexOf("size=\"", i + 5);
                                if (size_ind < right && size_ind >= 0)
                                {
                                    size_ind += 6;
                                    int size_end = text.IndexOf("\"", size_ind);
                                    if (size_end < right && size_end >= 0)
                                    {
                                        size = text.Substring(size_ind, size_end - size_ind);
                                    }
                                }

                                if (color != null)
                                {
                                    if (color.StartsWith("\"") && color.EndsWith("\""))
                                        color = color.Substring(1, color.Length - 2);
                                    if (color.StartsWith("#"))
                                    {
                                        newStyle.Color = Color.FromArgb((int)(0xFF000000 + uint.Parse(color.Substring(1), NumberStyles.HexNumber)));
                                    }
                                    else
                                    {
                                        newStyle.Color = Color.FromName(color);
                                    }
                                }
                                if (face != null)
                                    newStyle.FontName = face;
                                if (size != null)
                                {

                                    try
                                    {
                                        size = size.Trim(' ');
                                        newStyle.FontSize = (float)Converter.FromString(typeof(float), size);
                                    }
                                    catch { }
                                }
                                i = right - 4;
                            }
                        }
                        else
                            match = false;

                        if (match)
                            i += 5;
                    }

                    // </sub>, </sup>
                    if (!match && i + 6 <= text.Length && text[i + 1] == '/')
                    {
                        match = true;
                        tag = text.Substring(i, 6).ToLower();
                        if (tag == "</sub>")
                            newStyle.BaseLine = BaseLine.Normal;
                        else if (tag == "</sup>")
                            newStyle.BaseLine = BaseLine.Normal;
                        else
                            match = false;

                        if (match)
                            i += 6;
                    }

                    // <strike>
                    if (!match && i + 8 <= text.Length && text.Substring(i, 8).ToLower() == "<strike>")
                    {
                        newStyle.FontStyle |= System.Drawing.FontStyle.Strikeout;
                        match = true;
                        i += 8;
                    }

                    // </strike>
                    if (!match && i + 9 <= text.Length && text.Substring(i, 9).ToLower() == "</strike>")
                    {
                        newStyle.FontStyle &= ~System.Drawing.FontStyle.Strikeout;
                        match = true;
                        i += 9;
                    }
                    // </font>
                    if (!match && i + 7 <= text.Length && text.Substring(i, 7).ToLower() == "</font>")
                    {
                        newStyle = new StyleDescriptor(defaultStyle);
                        match = true;
                        i += 7;
                    }
                    // <br/>
                    if (!match && i + 5 <= text.Length && text.Substring(i, 5).ToLower() == "<br/>")
                    {
                        i += 5 - 1;
                        lastChar = '\n';
                    }

                    if (match)
                    {
                        if (currentWord.Length != 0)
                        {
                            // finish the word
                            AddRun(currentWord.ToString(), style);
                        }

                        currentWord.Clear();
                        style = newStyle;
                        i--;

                        continue;
                    }
                }

                if (lastChar == '&')
                {
                    if (Converter.FromHtmlEntities(text, ref i, currentWord))
                    {
                        if (i >= text.Length - 1)
                        {
                            AddRun(currentWord.ToString(), style);
                            break;
                        }
                        else
                        {
                            continue;
                        }
                    }
                }

                // skip r, handle n
                if (lastChar == '\r')
                    continue;
                if (lastChar == '\n')
                {
                    if (currentWord.Length != 0)
                        AddRun(currentWord.ToString(), style);
                    currentWord.Clear();
                    AddLineBreak();
                    continue;
                }

                currentWord.Append(lastChar);
                if (i == text.Length - 1)
                {
                    // finish the last word
                    if (currentWord.Length != 0)
                        AddRun(currentWord.ToString(), style);
                }
            }
        }
    }
}