// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#nullable disable

using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Text;
using System.Xml;

namespace System.Windows.Forms.Layout
{
    public class TableLayoutSettingsTypeConverter : TypeConverter
    {
        /// <summary>
        ///  Determines if this converter can convert an object in the given source
        ///  type to the native type of the converter.
        /// </summary>
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            if (sourceType == typeof(string))
            {
                return true;
            }

            return base.CanConvertFrom(context, sourceType);
        }

        /// <summary>
        ///  Gets a value indicating whether this converter can
        ///  convert an object to the given destination type using the context.
        /// </summary>
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor) || destinationType == typeof(string))
            {
                return true;
            }

            return base.CanConvertTo(context, destinationType);
        }

        /// <summary>
        ///  Converts the given object to the converter's native type.
        /// </summary>
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value is string)
            {
                XmlDocument tableLayoutSettingsXml = new XmlDocument();
                tableLayoutSettingsXml.LoadXml(value as string);

                TableLayoutSettings settings = new TableLayoutSettings();

                ParseControls(settings, tableLayoutSettingsXml.GetElementsByTagName("Control"));
                ParseStyles(settings, tableLayoutSettingsXml.GetElementsByTagName("Columns"), /*isColumn=*/true);
                ParseStyles(settings, tableLayoutSettingsXml.GetElementsByTagName("Rows"), /*isColumn=*/false);
                return settings;
            }

            return base.ConvertFrom(context, culture, value);
        }

        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (value is TableLayoutSettings && (destinationType == typeof(string)))
            {
                TableLayoutSettings tableLayoutSettings = value as TableLayoutSettings;

                StringBuilder xmlStringBuilder = new StringBuilder();
                XmlWriter xmlWriter = XmlWriter.Create(xmlStringBuilder);
                xmlWriter.WriteStartElement("TableLayoutSettings");

                //
                // write controls
                //
                xmlWriter.WriteStartElement("Controls");

                foreach (TableLayoutSettings.ControlInformation c in tableLayoutSettings.GetControlsInformation())
                {
                    if (c.Name is null)
                    {
                        throw new InvalidOperationException(SR.TableLayoutSettingsConverterNoName);
                    }

                    xmlWriter.WriteStartElement("Control");
                    xmlWriter.WriteAttributeString("Name", c.Name.ToString());
                    xmlWriter.WriteAttributeString("Row", c.Row.ToString(CultureInfo.CurrentCulture));
                    xmlWriter.WriteAttributeString("RowSpan", c.RowSpan.ToString(CultureInfo.CurrentCulture));

                    xmlWriter.WriteAttributeString("Column", c.Column.ToString(CultureInfo.CurrentCulture));
                    xmlWriter.WriteAttributeString("ColumnSpan", c.ColumnSpan.ToString(CultureInfo.CurrentCulture));

                    xmlWriter.WriteEndElement();
                }

                xmlWriter.WriteEndElement(); // end Controls

                //
                // write columns
                //
                xmlWriter.WriteStartElement("Columns");
                StringBuilder columnStyles = new StringBuilder();
                foreach (ColumnStyle colStyle in tableLayoutSettings.ColumnStyles)
                {
                    columnStyles.AppendFormat("{0},{1},", colStyle.SizeType, colStyle.Width);
                }

                if (columnStyles.Length > 0)
                {
                    columnStyles.Remove(columnStyles.Length - 1, 1);
                }

                xmlWriter.WriteAttributeString("Styles", columnStyles.ToString());
                xmlWriter.WriteEndElement(); // end columns

                //
                // write rows
                //
                xmlWriter.WriteStartElement("Rows");
                StringBuilder rowStyles = new StringBuilder();
                foreach (RowStyle rowStyle in tableLayoutSettings.RowStyles)
                {
                    rowStyles.AppendFormat("{0},{1},", rowStyle.SizeType, rowStyle.Height);
                }

                if (rowStyles.Length > 0)
                {
                    rowStyles.Remove(rowStyles.Length - 1, 1);
                }

                xmlWriter.WriteAttributeString("Styles", rowStyles.ToString());
                xmlWriter.WriteEndElement(); // end Rows

                xmlWriter.WriteEndElement(); // end TableLayoutSettings

                xmlWriter.Close();
                return xmlStringBuilder.ToString();
            }

            return base.ConvertTo(context, culture, value, destinationType);
        }

        private string GetAttributeValue(XmlNode node, string attribute)
        {
            XmlAttribute attr = node.Attributes[attribute];
            if (attr is not null)
            {
                return attr.Value;
            }

            return null;
        }

        private int GetAttributeValue(XmlNode node, string attribute, int valueIfNotFound)
        {
            string attributeValue = GetAttributeValue(node, attribute);
            if (!string.IsNullOrEmpty(attributeValue))
            {
                if (int.TryParse(attributeValue, out int result))
                {
                    return result;
                }
            }

            return valueIfNotFound;
        }

        private void ParseControls(TableLayoutSettings settings, XmlNodeList controlXmlFragments)
        {
            foreach (XmlNode controlXmlNode in controlXmlFragments)
            {
                string name = GetAttributeValue(controlXmlNode, "Name");

                if (!string.IsNullOrEmpty(name))
                {
                    int row = GetAttributeValue(controlXmlNode, "Row",       /*default*/-1);
                    int rowSpan = GetAttributeValue(controlXmlNode, "RowSpan",   /*default*/1);
                    int column = GetAttributeValue(controlXmlNode, "Column",    /*default*/-1);
                    int columnSpan = GetAttributeValue(controlXmlNode, "ColumnSpan",/*default*/1);

                    settings.SetRow(name, row);
                    settings.SetColumn(name, column);
                    settings.SetRowSpan(name, rowSpan);
                    settings.SetColumnSpan(name, columnSpan);
                }
            }
        }

        private void ParseStyles(TableLayoutSettings settings, XmlNodeList controlXmlFragments, bool columns)
        {
            foreach (XmlNode styleXmlNode in controlXmlFragments)
            {
                string styleString = GetAttributeValue(styleXmlNode, "Styles");
                Type sizeTypeType = typeof(SizeType);

                // styleString will consist of N Column/Row styles serialized in the following format
                // (Percent | Absolute | AutoSize), (24 | 24.4 | 24,4)
                // Two examples:
                // Percent,23.3,Percent,46.7,Percent,30
                // Percent,23,3,Percent,46,7,Percent,30
                // Note we get either . or , based on the culture the TableLayoutSettings were serialized in

                if (!string.IsNullOrEmpty(styleString))
                {
                    int currentIndex = 0;
                    int nextIndex;
                    while (currentIndex < styleString.Length)
                    {
                        // ---- SizeType Parsing -----------------
                        nextIndex = currentIndex;
                        while (char.IsLetter(styleString[nextIndex]))
                        {
                            nextIndex++;
                        }

                        SizeType type = (SizeType)Enum.Parse(sizeTypeType, styleString.Substring(currentIndex, nextIndex - currentIndex), true);

                        // ----- Float Parsing --------------
                        // Find the next Digit (start of the float)
                        while (!char.IsDigit(styleString[nextIndex]))
                        {
                            nextIndex++;
                        }

                        // Append digits left of the decimal delimiter(s)
                        StringBuilder floatStringBuilder = new StringBuilder();
                        while ((nextIndex < styleString.Length) && (char.IsDigit(styleString[nextIndex])))
                        {
                            floatStringBuilder.Append(styleString[nextIndex]);
                            nextIndex++;
                        }

                        // Append culture invariant delimiter
                        floatStringBuilder.Append('.');
                        // Append digits right of the decimal delimiter(s)
                        while ((nextIndex < styleString.Length) && (!char.IsLetter(styleString[nextIndex])))
                        {
                            if (char.IsDigit(styleString[nextIndex]))
                            {
                                floatStringBuilder.Append(styleString[nextIndex]);
                            }

                            nextIndex++;
                        }

                        string floatString = floatStringBuilder.ToString();
                        if (!float.TryParse(floatString, NumberStyles.Float, CultureInfo.InvariantCulture.NumberFormat, out float width))
                        {
                            width = 0F;
                        }

                        // Add new Column/Row Style
                        if (columns)
                        {
                            settings.ColumnStyles.Add(new ColumnStyle(type, width));
                        }
                        else
                        {
                            settings.RowStyles.Add(new RowStyle(type, width));
                        }

                        // Go to the next Column/Row Style
                        currentIndex = nextIndex;
                    }
                }
            }
        }
    }
}
