///////////////////////////////////////////////////////////////////////////////////////////////
//
//    This File is Part of the CallButler Open Source PBX (http://www.codeplex.com/callbutler
//
//    Copyright (c) 2005-2008, Jim Heising
//    All rights reserved.
//
//    Redistribution and use in source and binary forms, with or without modification,
//    are permitted provided that the following conditions are met:
//
//    * Redistributions of source code must retain the above copyright notice,
//      this list of conditions and the following disclaimer.
//
//    * Redistributions in binary form must reproduce the above copyright notice,
//      this list of conditions and the following disclaimer in the documentation and/or
//      other materials provided with the distribution.
//
//    * Neither the name of Jim Heising nor the names of its contributors may be
//      used to endorse or promote products derived from this software without specific prior
//      written permission.
//
//    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
//    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
//    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
//    IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
//    INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
//    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
//    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
//    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
//    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
//    POSSIBILITY OF SUCH DAMAGE.
//
///////////////////////////////////////////////////////////////////////////////////////////////

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace Controls
{
    public class RichTextBoxEx : RichTextBox
    {
        bool followClickedLinks = true;

        #region Interop-Defines
        [StructLayout(LayoutKind.Sequential)]
        private struct CHARFORMAT2_STRUCT
        {
            public UInt32 cbSize;
            public UInt32 dwMask;
            public UInt32 dwEffects;
            public Int32 yHeight;
            public Int32 yOffset;
            public Int32 crTextColor;
            public byte bCharSet;
            public byte bPitchAndFamily;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
            public char[] szFaceName;
            public UInt16 wWeight;
            public UInt16 sSpacing;
            public int crBackColor; // Color.ToArgb() -> int
            public int lcid;
            public int dwReserved;
            public Int16 sStyle;
            public Int16 wKerning;
            public byte bUnderlineType;
            public byte bAnimation;
            public byte bRevAuthor;
            public byte bReserved1;
        }

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        private const int WM_USER = 0x0400;
        private const int EM_GETCHARFORMAT = WM_USER + 58;
        private const int EM_SETCHARFORMAT = WM_USER + 68;

        private const int SCF_SELECTION = 0x0001;
        private const int SCF_WORD = 0x0002;
        private const int SCF_ALL = 0x0004;

        #region CHARFORMAT2 Flags
        private const UInt32 CFE_BOLD = 0x0001;
        private const UInt32 CFE_ITALIC = 0x0002;
        private const UInt32 CFE_UNDERLINE = 0x0004;
        private const UInt32 CFE_STRIKEOUT = 0x0008;
        private const UInt32 CFE_PROTECTED = 0x0010;
        private const UInt32 CFE_LINK = 0x0020;
        private const UInt32 CFE_AUTOCOLOR = 0x40000000;
        private const UInt32 CFE_SUBSCRIPT = 0x00010000;		/* Superscript and subscript are */
        private const UInt32 CFE_SUPERSCRIPT = 0x00020000;		/*  mutually exclusive			 */

        private const int CFM_SMALLCAPS = 0x0040;			/* (*)	*/
        private const int CFM_ALLCAPS = 0x0080;			/* Displayed by 3.0	*/
        private const int CFM_HIDDEN = 0x0100;			/* Hidden by 3.0 */
        private const int CFM_OUTLINE = 0x0200;			/* (*)	*/
        private const int CFM_SHADOW = 0x0400;			/* (*)	*/
        private const int CFM_EMBOSS = 0x0800;			/* (*)	*/
        private const int CFM_IMPRINT = 0x1000;			/* (*)	*/
        private const int CFM_DISABLED = 0x2000;
        private const int CFM_REVISED = 0x4000;

        private const int CFM_BACKCOLOR = 0x04000000;
        private const int CFM_LCID = 0x02000000;
        private const int CFM_UNDERLINETYPE = 0x00800000;		/* Many displayed by 3.0 */
        private const int CFM_WEIGHT = 0x00400000;
        private const int CFM_SPACING = 0x00200000;		/* Displayed by 3.0	*/
        private const int CFM_KERNING = 0x00100000;		/* (*)	*/
        private const int CFM_STYLE = 0x00080000;		/* (*)	*/
        private const int CFM_ANIMATION = 0x00040000;		/* (*)	*/
        private const int CFM_REVAUTHOR = 0x00008000;


        private const UInt32 CFM_BOLD = 0x00000001;
        private const UInt32 CFM_ITALIC = 0x00000002;
        private const UInt32 CFM_UNDERLINE = 0x00000004;
        private const UInt32 CFM_STRIKEOUT = 0x00000008;
        private const UInt32 CFM_PROTECTED = 0x00000010;
        private const UInt32 CFM_LINK = 0x00000020;
        private const UInt32 CFM_SIZE = 0x80000000;
        private const UInt32 CFM_COLOR = 0x40000000;
        private const UInt32 CFM_FACE = 0x20000000;
        private const UInt32 CFM_OFFSET = 0x10000000;
        private const UInt32 CFM_CHARSET = 0x08000000;
        private const UInt32 CFM_SUBSCRIPT = CFE_SUBSCRIPT | CFE_SUPERSCRIPT;
        private const UInt32 CFM_SUPERSCRIPT = CFM_SUBSCRIPT;

        private const byte CFU_UNDERLINENONE = 0x00000000;
        private const byte CFU_UNDERLINE = 0x00000001;
        private const byte CFU_UNDERLINEWORD = 0x00000002; /* (*) displayed as ordinary underline	*/
        private const byte CFU_UNDERLINEDOUBLE = 0x00000003; /* (*) displayed as ordinary underline	*/
        private const byte CFU_UNDERLINEDOTTED = 0x00000004;
        private const byte CFU_UNDERLINEDASH = 0x00000005;
        private const byte CFU_UNDERLINEDASHDOT = 0x00000006;
        private const byte CFU_UNDERLINEDASHDOTDOT = 0x00000007;
        private const byte CFU_UNDERLINEWAVE = 0x00000008;
        private const byte CFU_UNDERLINETHICK = 0x00000009;
        private const byte CFU_UNDERLINEHAIRLINE = 0x0000000A; /* (*) displayed as ordinary underline	*/

        #endregion

        #endregion

        public RichTextBoxEx()
        {
            // Otherwise, non-standard links get lost when user starts typing
            // next to a non-standard link
            this.DetectUrls = false;
        }

        protected override void OnLinkClicked(LinkClickedEventArgs e)
        {
            if (followClickedLinks)
            {
                // Is the linked text a valid URL?
                try
                {
                    Uri uri = new Uri(e.LinkText);

                    System.Diagnostics.Process.Start(e.LinkText);

                    return;
                }
                catch
                {
                }
            }

            base.OnLinkClicked(e);
        }

        [DefaultValue(false)]
        public new bool DetectUrls
        {
            get { return base.DetectUrls; }
            set { base.DetectUrls = value; }
        }

        public bool FollowClickedLinks
        {
            get
            {
                return followClickedLinks;
            }
            set
            {
                followClickedLinks = value;
            }
        }

        /// <summary>
        /// Insert a given text as a link into the RichTextBox at the current insert position.
        /// </summary>
        /// <param name="text">Text to be inserted</param>
        public void InsertLink(string text)
        {
            InsertLink(text, this.SelectionStart);
        }

        /// <summary>
        /// Insert a given text at a given position as a link. 
        /// </summary>
        /// <param name="text">Text to be inserted</param>
        /// <param name="position">Insert position</param>
        public void InsertLink(string text, int position)
        {
            if (position < 0 || position > this.Text.Length)
                throw new ArgumentOutOfRangeException("position");

            this.SelectionStart = position;
            this.SelectedText = text;
            this.Select(position, text.Length);
            this.SetSelectionLink(true);
            this.Select(position + text.Length, 0);
        }

        /// <summary>
        /// Insert a given text at at the current input position as a link.
        /// The link text is followed by a hash (#) and the given hyperlink text, both of
        /// them invisible.
        /// When clicked on, the whole link text and hyperlink string are given in the
        /// LinkClickedEventArgs.
        /// </summary>
        /// <param name="text">Text to be inserted</param>
        /// <param name="hyperlink">Invisible hyperlink string to be inserted</param>
        public void InsertLink(string text, string hyperlink)
        {
            InsertLink(text, hyperlink, this.SelectionStart);
        }

        /// <summary>
        /// Insert a given text at a given position as a link. The link text is followed by
        /// a hash (#) and the given hyperlink text, both of them invisible.
        /// When clicked on, the whole link text and hyperlink string are given in the
        /// LinkClickedEventArgs.
        /// </summary>
        /// <param name="text">Text to be inserted</param>
        /// <param name="hyperlink">Invisible hyperlink string to be inserted</param>
        /// <param name="position">Insert position</param>
        public void InsertLink(string text, string hyperlink, int position)
        {
            if (position < 0 || position > this.Text.Length)
                throw new ArgumentOutOfRangeException("position");

            this.SelectionStart = position;
            this.SelectedRtf = @"{\rtf1\ansi " + text + @"\v #" + hyperlink + @"\v0}";
            this.Select(position, text.Length + hyperlink.Length + 1);
            this.SetSelectionLink(true);
            this.Select(position + text.Length + hyperlink.Length + 1, 0);
        }

        /// <summary>
        /// Set the current selection's link style
        /// </summary>
        /// <param name="link">true: set link style, false: clear link style</param>
        public void SetSelectionLink(bool link)
        {
            SetSelectionStyle(CFM_LINK, link ? CFE_LINK : 0);
        }
        /// <summary>
        /// Get the link style for the current selection
        /// </summary>
        /// <returns>0: link style not set, 1: link style set, -1: mixed</returns>
        public int GetSelectionLink()
        {
            return GetSelectionStyle(CFM_LINK, CFE_LINK);
        }


        private void SetSelectionStyle(UInt32 mask, UInt32 effect)
        {
            CHARFORMAT2_STRUCT cf = new CHARFORMAT2_STRUCT();
            cf.cbSize = (UInt32)Marshal.SizeOf(cf);
            cf.dwMask = mask;
            cf.dwEffects = effect;

            IntPtr wpar = new IntPtr(SCF_SELECTION);
            IntPtr lpar = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf));
            Marshal.StructureToPtr(cf, lpar, false);

            IntPtr res = SendMessage(Handle, EM_SETCHARFORMAT, wpar, lpar);

            Marshal.FreeCoTaskMem(lpar);
        }

        private int GetSelectionStyle(UInt32 mask, UInt32 effect)
        {
            CHARFORMAT2_STRUCT cf = new CHARFORMAT2_STRUCT();
            cf.cbSize = (UInt32)Marshal.SizeOf(cf);
            cf.szFaceName = new char[32];

            IntPtr wpar = new IntPtr(SCF_SELECTION);
            IntPtr lpar = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf));
            Marshal.StructureToPtr(cf, lpar, false);

            IntPtr res = SendMessage(Handle, EM_GETCHARFORMAT, wpar, lpar);

            cf = (CHARFORMAT2_STRUCT)Marshal.PtrToStructure(lpar, typeof(CHARFORMAT2_STRUCT));

            int state;
            // dwMask holds the information which properties are consistent throughout the selection:
            if ((cf.dwMask & mask) == mask)
            {
                if ((cf.dwEffects & effect) == effect)
                    state = 1;
                else
                    state = 0;
            }
            else
            {
                state = -1;
            }

            Marshal.FreeCoTaskMem(lpar);
            return state;
        }
    }
}
