//Source: http://www.codeproject.com/KB/edit/SyntaxRichTextBox/SyntaxRichTextBox_src.zip

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Windows.Forms;
using System.ComponentModel;
using System.Text.RegularExpressions;
using System.Drawing;

namespace ShiftOS
{
    public class SyntaxRichTextBox : System.Windows.Forms.RichTextBox
    {
        private SyntaxSettings m_settings = new SyntaxSettings();
        private static bool m_bPaint = true;
        private string m_strLine = "";
        private int m_nContentLength = 0;
        private int m_nLineLength = 0;
        private int m_nLineStart = 0;
        private int m_nLineEnd = 0;
        private string m_strKeywords = "";
        private int m_nCurSelection = 0;

        /// <summary>
        /// The settings.
        /// </summary>
        public SyntaxSettings Settings
        {
            get { return m_settings; }
        }

        /// <summary>
        /// WndProc
        /// </summary>
        /// <param name="m"></param>
        protected override void WndProc(ref System.Windows.Forms.Message m)
        {
            if (m.Msg == 0x00f)
            {
                if (m_bPaint)
                    base.WndProc(ref m);
                else
                    m.Result = IntPtr.Zero;
            }
            else
                base.WndProc(ref m);
        }

        public void SetLanguage(SyntaxSettings.Language lang)
        {
            Color white = Color.Black;
            Color keyword = Color.Red;
            Color integer = Color.LightGreen;
            Color comment = Color.DarkGray;
            Color str = Color.Orange;
            Settings.EnableComments = true;
            Settings.EnableIntegers = true;
            Settings.EnableStrings = true;
            if (API.Upgrades["limitlesscustomshades"])
            {
                Settings.CommentColor = comment;
                Settings.KeywordColor = keyword;
                Settings.StringColor = str;
                Settings.IntegerColor = integer;
            }
            else
            {
                Settings.CommentColor = white;
                Settings.KeywordColor = white;
                Settings.StringColor = white;
                Settings.IntegerColor = white;
            }

            switch (lang)
            {
                case SyntaxSettings.Language.Lua:
                    var kw = new List<string>() { "function", "local", "return", "if", "else", "elseif", "while", "true", "do", "next", "end", "for", "pairs", "in", "{", "}", "false", "=", "+", "-", "/", "*", "..", "," };
                    Settings.Keywords.Clear();
                    foreach (var k in kw)
                    {
                        Settings.Keywords.Add(k);
                    }
                    Settings.Comment = "--";
                    break;
                case SyntaxSettings.Language.CSharp:
                    var cskw = new List<string>() { "public", "private", "internal", "static", "dynamic", "namespace", "typeof", "(", ")", "[", "]", "{", "}", "sizeof", "int", "using", "<", ">", ";", "this", "base", ":", "class", "interface", "string", "double", "single", "char", "new", "if", "else", "while", "for", "foreach", "in", "var", "as", "is", "object", "~" };
                    Settings.Keywords.Clear();
                    foreach (var k in cskw)
                    {
                        Settings.Keywords.Add(k);
                    }
                    Settings.Comment = "//";
                    break;
            }
            CompileKeywords();
            ProcessAllLines();
        }

        /// <summary>
        /// OnTextChanged
        /// </summary>
        /// <param name="e"></param>
        protected override void OnTextChanged(EventArgs e)
        {
            // Calculate shit here. (NO. I didn't write this. This was there in codeproject... - Michael)
            m_nContentLength = this.TextLength;

            int nCurrentSelectionStart = SelectionStart;
            int nCurrentSelectionLength = SelectionLength;

            m_bPaint = false;

            // Find the start of the current line.
            m_nLineStart = nCurrentSelectionStart;
            while ((m_nLineStart > 0) && (Text[m_nLineStart - 1] != '\n'))
                m_nLineStart--;
            // Find the end of the current line.
            m_nLineEnd = nCurrentSelectionStart;
            while ((m_nLineEnd < Text.Length) && (Text[m_nLineEnd] != '\n'))
                m_nLineEnd++;
            // Calculate the length of the line.
            m_nLineLength = m_nLineEnd - m_nLineStart;
            // Get the current line.
            m_strLine = Text.Substring(m_nLineStart, m_nLineLength);

            // Process this line.
            ProcessLine();

            m_bPaint = true;
        }
        /// <summary>
        /// Process a line.
        /// </summary>
        private void ProcessLine()
        {
            // Save the position and make the whole line black
            int nPosition = SelectionStart;
            SelectionStart = m_nLineStart;
            SelectionLength = m_nLineLength;
            SelectionColor = ForeColor;

            // Process the keywords
            ProcessRegex(m_strKeywords, Settings.KeywordColor);
            // Process numbers
            if (Settings.EnableIntegers)
                ProcessRegex("\\b(?:[0-9]*\\.)?[0-9]+\\b", Settings.IntegerColor);
            // Process strings
            if (Settings.EnableStrings)
                ProcessRegex("\"[^\"\\\\\\r\\n]*(?:\\\\.[^\"\\\\\\r\\n]*)*\"", Settings.StringColor);
            // Process comments
            if (Settings.EnableComments && !string.IsNullOrEmpty(Settings.Comment))
                ProcessRegex(Settings.Comment + ".*$", Settings.CommentColor);

            SelectionStart = nPosition;
            SelectionLength = 0;
            SelectionColor = Color.Black;

            m_nCurSelection = nPosition;
        }
        /// <summary>
        /// Process a regular expression.
        /// </summary>
        /// <param name="strRegex">The regular expression.</param>
        /// <param name="color">The color.</param>
        private void ProcessRegex(string strRegex, Color color)
        {
            Regex regKeywords = new Regex(strRegex, RegexOptions.IgnoreCase | RegexOptions.Compiled);
            Match regMatch;

            for (regMatch = regKeywords.Match(m_strLine); regMatch.Success; regMatch = regMatch.NextMatch())
            {
                // Process the words
                int nStart = m_nLineStart + regMatch.Index;
                int nLenght = regMatch.Length;
                SelectionStart = nStart;
                SelectionLength = nLenght;
                SelectionColor = color;
            }
        }
        /// <summary>
        /// Compiles the keywords as a regular expression.
        /// </summary>
        public void CompileKeywords()
        {
            for (int i = 0; i < Settings.Keywords.Count; i++)
            {
                string strKeyword = Settings.Keywords[i];

                if (i == Settings.Keywords.Count - 1)
                    m_strKeywords += "\\b" + strKeyword + "\\b";
                else
                    m_strKeywords += "\\b" + strKeyword + "\\b|";
            }
        }

        public void ProcessAllLines()
        {
            m_bPaint = false;

            int nStartPos = 0;
            int i = 0;
            int nOriginalPos = SelectionStart;
            while (i < Lines.Length)
            {
                m_strLine = Lines[i];
                m_nLineStart = nStartPos;
                m_nLineEnd = m_nLineStart + m_strLine.Length;

                ProcessLine();
                i++;

                nStartPos += m_strLine.Length + 1;
            }

            m_bPaint = true;
        }
    }

    /// <summary>
    /// Class to store syntax objects in.
    /// </summary>
    public class SyntaxList
    {
        public List<string> m_rgList = new List<string>();
        public Color m_color = new Color();
    }

    /// <summary>
    /// Settings for the keywords and colors.
    /// </summary>
    public class SyntaxSettings
    {
        SyntaxList m_rgKeywords = new SyntaxList();
        string m_strComment = "";
        Color m_colorComment = Color.Green;
        Color m_colorString = Color.Gray;
        Color m_colorInteger = Color.Red;
        bool m_bEnableComments = true;
        bool m_bEnableIntegers = true;
        bool m_bEnableStrings = true;

        #region Properties
        /// <summary>
        /// A list containing all keywords.
        /// </summary>
        public List<string> Keywords
        {
            get { return m_rgKeywords.m_rgList; }
        }
        /// <summary>
        /// The color of keywords.
        /// </summary>
        public Color KeywordColor
        {
            get { return m_rgKeywords.m_color; }
            set { m_rgKeywords.m_color = value; }
        }
        /// <summary>
        /// A string containing the comment identifier.
        /// </summary>
        public string Comment
        {
            get { return m_strComment; }
            set { m_strComment = value; }
        }
        /// <summary>
        /// The color of comments.
        /// </summary>
        public Color CommentColor
        {
            get { return m_colorComment; }
            set { m_colorComment = value; }
        }
        /// <summary>
        /// Enables processing of comments if set to true.
        /// </summary>
        public bool EnableComments
        {
            get { return m_bEnableComments; }
            set { m_bEnableComments = value; }
        }
        /// <summary>
        /// Enables processing of integers if set to true.
        /// </summary>
        public bool EnableIntegers
        {
            get { return m_bEnableIntegers; }
            set { m_bEnableIntegers = value; }
        }
        /// <summary>
        /// Enables processing of strings if set to true.
        /// </summary>
        public bool EnableStrings
        {
            get { return m_bEnableStrings; }
            set { m_bEnableStrings = value; }
        }
        /// <summary>
        /// The color of strings.
        /// </summary>
        public Color StringColor
        {
            get { return m_colorString; }
            set { m_colorString = value; }
        }
        /// <summary>
        /// The color of integers.
        /// </summary>
        public Color IntegerColor
        {
            get { return m_colorInteger; }
            set { m_colorInteger = value; }
        }
        #endregion

        public enum Language
        {
            Lua,
            CSharp,
        }
    }
}