// <file>
//     <copyright see="prj:///doc/copyright.txt"/>
//     <license see="prj:///doc/license.txt"/>
//     <author name="Daniel Grunwald"/>
//     <version>$Revision: 2522 $</version>
// </file>

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Xml;
using ICSharpCode.TextEditor;
using ICSharpCode.TextEditor.Document;

namespace ICSharpCode.HtmlSyntaxColorizer
{
    public class HtmlWriter
    {
        public bool AlternateLineBackground;
        public bool ShowLineNumbers;

        public string MainStyle = "font-size: small; font-family: Consolas, \"Courier New\", Courier, Monospace;";
        public string LineStyle = "margin: 0em;";
        public string AlternateLineStyle = "margin: 0em; width: 100%; background-color: #f0f0f0;";

        #region Stylesheet cache
        /// <summary>
        /// Specifies whether a CSS stylesheet should be created to reduce the size of the created code.
        /// The default value is true.
        /// </summary>
        public bool CreateStylesheet = true;

        /// <summary>
        /// Specifies the prefix to use in front of generate style class names.
        /// </summary>
        public string StyleClassPrefix = "code";

        Dictionary<string, string> stylesheetCache = new Dictionary<string, string>();

        /// <summary>
        /// Resets the CSS stylesheet cache. Stylesheet classes will be cached on GenerateHtml calls.
        /// If you want to reuse the HtmlWriter for multiple
        /// </summary>
        public void ResetStylesheetCache()
        {
            stylesheetCache.Clear();
        }

        string GetClass(string style)
        {
            return stylesheetCache[style];
        }

        void CacheClass(string style, StringBuilder b)
        {
            if (style == null) return;
            if (!stylesheetCache.ContainsKey(style))
            {
                string styleName = StyleClassPrefix + stylesheetCache.Count;
                stylesheetCache[style] = styleName;
                b.Append('.');
                b.Append(styleName);
                b.Append(" { ");
                b.Append(style);
                b.AppendLine(" }");
            }
        }
        #endregion

        public string GenerateHtml(string code, string highlighterName)
        {
            IDocument doc = new DocumentFactory().CreateDocument();
            doc.HighlightingStrategy = HighlightingManager.Manager.FindHighlighter(highlighterName);
            doc.TextContent = code;
            return GenerateHtml(doc);
        }

        HighlightColor currentDefaultTextColor;

        public string GenerateHtml(IDocument document)
        {
            string myMainStyle = MainStyle;
            currentDefaultTextColor = document.HighlightingStrategy.GetColorFor("Default");
            myMainStyle += " color: " + ColorToString(currentDefaultTextColor.Color) + ";"
                + " background-color: " + ColorToString(currentDefaultTextColor.BackgroundColor) + ";";

            string LineNumberStyle;
            HighlightColor lineNumbersColor = document.HighlightingStrategy.GetColorFor("LineNumbers");
            if (lineNumbersColor != null)
            {
                LineNumberStyle = "color: " + ColorToString(lineNumbersColor.Color) + ";"
                    + " background-color: " + ColorToString(lineNumbersColor.BackgroundColor) + ";";
            }
            else
            {
                LineNumberStyle = "color: #606060;";
            }

            StringBuilder b = new StringBuilder();
            if (CreateStylesheet)
            {
                b.AppendLine("<style type=\"text/css\">");
                if (ShowLineNumbers || AlternateLineBackground)
                {
                    CacheClass(myMainStyle, b);
                    CacheClass(LineStyle, b);
                }
                else
                {
                    CacheClass(myMainStyle + LineStyle, b);
                }
                if (AlternateLineBackground) CacheClass(AlternateLineStyle, b);
                if (ShowLineNumbers) CacheClass(LineNumberStyle, b);
                foreach (LineSegment ls in document.LineSegmentCollection)
                {
                    foreach (TextWord word in ls.Words)
                    {
                        CacheClass(GetStyle(word), b);
                    }
                }
                b.AppendLine("</style>");
            }
            if (ShowLineNumbers || AlternateLineBackground)
            {
                b.Append("<div");
                WriteStyle(myMainStyle, b);
                b.AppendLine(">");

                int longestNumberLength = 1 + (int)Math.Log10(document.TotalNumberOfLines);

                int lineNumber = 1;
                foreach (LineSegment lineSegment in document.LineSegmentCollection)
                {
                    b.Append("<pre");
                    if (AlternateLineBackground && (lineNumber % 2) == 0)
                    {
                        WriteStyle(AlternateLineStyle, b);
                    }
                    else
                    {
                        WriteStyle(LineStyle, b);
                    }
                    b.Append(">");

                    if (ShowLineNumbers)
                    {
                        b.Append("<span");
                        WriteStyle(LineNumberStyle, b);
                        b.Append('>');
                        b.Append(lineNumber.ToString().PadLeft(longestNumberLength));
                        b.Append(":  ");
                        b.Append("</span>");
                    }


                    if (lineSegment.Words.Count == 0)
                    {
                        b.Append("&nbsp;");
                    }
                    else
                    {
                        PrintWords(lineSegment, b);
                    }
                    b.AppendLine("</pre>");

                    lineNumber++;
                }
                b.AppendLine("</div>");
            }
            else
            {
                b.Append("<pre");
                WriteStyle(myMainStyle + LineStyle, b);
                b.AppendLine(">");
                foreach (LineSegment lineSegment in document.LineSegmentCollection)
                {
                    PrintWords(lineSegment, b);
                    b.AppendLine();
                }
                b.AppendLine("</pre>");
            }
            return b.ToString();
        }

        void PrintWords(LineSegment lineSegment, StringBuilder b)
        {
            string currentSpan = null;
            foreach (TextWord word in lineSegment.Words)
            {
                if (word.Type == TextWordType.Space)
                {
                    b.Append(' ');
                }
                else if (word.Type == TextWordType.Tab)
                {
                    b.Append('\t');
                }
                else
                {
                    string newSpan = GetStyle(word);
                    if (currentSpan != newSpan)
                    {
                        if (currentSpan != null) b.Append("</span>");
                        if (newSpan != null)
                        {
                            b.Append("<span");
                            WriteStyle(newSpan, b);
                            b.Append('>');
                        }
                        currentSpan = newSpan;
                    }
                    b.Append(HtmlEncode(word.Word));
                }
            }
            if (currentSpan != null) b.Append("</span>");
        }

        static string HtmlEncode(string word)
        {
            return word.Replace("&", "&amp;").Replace("<", "&lt;").Replace(">", "&gt;");
        }

        void WriteStyle(string style, StringBuilder b)
        {
            if (CreateStylesheet)
            {
                b.Append(" class=\"");
                b.Append(GetClass(style));
                b.Append('"');
            }
            else
            {
                b.Append(" style='");
                b.Append(style);
                b.Append("'");
            }
        }

        string GetStyle(TextWord word)
        {
            if (word.SyntaxColor == null || word.SyntaxColor.ToString() == currentDefaultTextColor.ToString())
                return null;

            string style = "color: " + ColorToString(word.Color) + ";";
            if (word.Bold)
            {
                style += " font-weight: bold;";
            }
            if (word.Italic)
            {
                style += "  font-style: italic;";
            }
            if (word.SyntaxColor.HasBackground)
            {
                style += "  background-color: " + ColorToString(word.SyntaxColor.BackgroundColor) + ";";
            }
            return style;
        }

        static string ColorToString(System.Drawing.Color color)
        {
            return "#" + color.R.ToString("x2") + color.G.ToString("x2") + color.B.ToString("x2");
        }
    }
}