using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
    
public static class ClipboardFusionHelper
{
    public static string ProcessText(string text)
    {
        // takes a string of text (typically multiline text) and converts it to a HTML list
        // it tries to be smart enough to identify either a ordered list, or unordered list, but
        // it only detects ordered lists if they start at the beginning (ie.a, i, A, I, 0, or 1)
        // it also tries to account for cut'n'pasting lists out of MS Word
        // I've been having trouble with Regex $ - it seems to think the $ is between the \r and the \n, which isn't very helpful
        // this code isn't perfect, but it works well for me
        // use at your own discretion

        char chrLineIndent = '\t';        // default to a tab "\t"
        int intLineIndentSize = 1;
        string strListType = "ul";        // default to an unordered list
        string strListCSS = "";
        string strOutput = text.Trim();

        // remove multiple white spaces characters and replace them with a single space
        strOutput = Regex.Replace(strOutput, @"[ \t]+", " ");

        // remove empty lines ($ doesn't seem to work very well)
        strOutput = Regex.Replace(strOutput, @"(?<linebreak>[\r\n]{1,2})+", "${linebreak}");

        // trim the start and end of each line (Regex $ doesn't seem to work very well)
        strOutput = Regex.Replace(strOutput, @"(?:^[ \t]*)|(?:[ \t]*(?<linebreak>[\r\n]{1,2}))", "${linebreak}", RegexOptions.Multiline);

        if (Regex.IsMatch(strOutput , @"^[aiAI01][^\w0-9]+"))
        {
            // it looks like we are dealing with some sort of ordered list
            strListType = "ol";

            // lets work out what type of ordered list it is
            switch (strOutput[0].ToString())
            {
                case "a": strListCSS = "lower-alpha"; break;
                case "i": strListCSS = "lower-roman"; break;
                case "A": strListCSS = "upper-alpha"; break;
                case "I": strListCSS = "upper-roman"; break;
                case "0": strListCSS = "decimal-leading-zero"; break;
                case "1": strListCSS = "decimal"; break;
            }
            strListCSS = "list-style-type:" + strListCSS + ";";

            // remove the list item indicators
            strOutput = Regex.Replace(strOutput, @"^[a-zA-Z0-9]+[^\w0-9]+", "", RegexOptions.Multiline);

        }

        else if (Regex.IsMatch(strOutput, @"^[^a-np-zA-NP-Z0-9]+[^\w0-9]+"))
        {
            // it looks like we have some sort of bulleted unordered list
            // typical bullets include •, o, §, #, *, -, ->, =, Ø, etc
            strListType = "ul";

            // remove the list item indicators
            strOutput = Regex.Replace(strOutput, @"^[^a-np-zA-NP-Z0-9]+[^\w0-9]+", "", RegexOptions.Multiline);
        }

        string strLineIndent = new string(chrLineIndent, intLineIndentSize);

        // replace line breaks with <li>s (Regex $ doesn't seem to work very well)
        strOutput = Regex.Replace(strOutput, @"(?<linebreak>[\r\n]{1,2})", "</li>${linebreak}" + strLineIndent + "<li>");

        strOutput = String.Format(
            "<{0}{1}>\r\n{2}<li>{3}</li>\r\n</{0}>",
            strListType,
            (strListCSS.Length > 0 ? " style=\"" + strListCSS + "\"" : ""),
            strLineIndent,
            strOutput
            );

        return strOutput;
    }
}