using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Resources;
using IO = System.IO;
using System.Windows.Forms;
using System.Windows;
using System.Windows.Interop;
using Yaulw.Process;
using Diag = System.Diagnostics;

namespace Yaulw.File
{
    /// <summary>
    /// CHM Help File Wrapper
    /// </summary>
    public class CHMFile
    {
        #region Private Members

        /// <summary>
        /// The Full File Name and Path to the CHM File
        /// </summary>
        private string _FileNameNPath = "";

        /// <summary>
        /// The File Stream that created the CHM File (if used)
        /// </summary>
        private IO.Stream _FileStream = null;

        /// <summary>
        /// Internally we keep track of each Form to Help Context ID
        /// </summary>
        private Dictionary<Form, int> s_FormContextMap = new Dictionary<Form, int>();

        #endregion

        #region Construction

        /// <summary>
        /// Construct a CHMFile object with the specified chm file
        /// </summary>
        /// <param name="FileNameNPath">a full path to a valid chm file</param>
        public CHMFile(string FileNameNPath)
        {
            if (!String.IsNullOrEmpty(FileNameNPath) && IO.File.Exists(FileNameNPath) && (IO.Path.GetExtension(FileNameNPath).ToLower() == "chm"))
                _FileNameNPath = FileNameNPath;
            else
                throw new ArgumentException("Invalid chm File or File does not exist");
        }

        /// <summary>
        /// Construct a CHMFile object from the specified stream (will construct a chm file in 
        /// a temporary location from the specified stream)
        /// </summary>
        /// <param name="stream">stream to construct the chm file from</param>
        /// <param name="ApplicationName">The name of the application (will be used when creating the .chm file)</param>
        /// <param name="ForceNewFile">if true, will force a new file to be written out, false will only write file if not exists</param>
        public CHMFile(IO.Stream stream, string ApplicationName, bool ForceNewFile)
        {
            if (stream != null && !String.IsNullOrEmpty(ApplicationName))
            {
                _FileStream = stream;
                _FileNameNPath = IO.Path.GetTempPath() + ApplicationName + ".chm";
                EnsureCHMFileExistance(ForceNewFile);
            }
            else
                throw new ArgumentNullException("Resource can not be null. ApplicationName can not be empty");
        }

        #endregion

        #region Public Consts

        /// <summary>
        /// Legacy MFC View Context offset
        /// </summary>
        public const int MNU = 0x10000;

        /// <summary>
        /// Legacy MFC Dialog Context offset
        /// </summary>
        public const int DLG = 0x20000;

        #endregion

        #region Public Methods

        /// <summary>
        /// Attaches the HelpRequest Handler as well as shows the HelpButton on the CaptionBar
        /// </summary>
        /// <param name="form">WinForm to Attach Help Button to</param>
        /// <param name="dwContextId">the Help Topic Context Id to attach to the specified WinForm</param>
        public void AttachHelpCaptionButtonToWinForm(Form form, int dwContextId)
        {
            // Set the HelpButton to be displayed
            form.MinimizeBox = false;
            form.MaximizeBox = false;
            form.HelpButton = true;

            // add the form / contextID to the map
            s_FormContextMap[form] = (int)dwContextId;

            // Subscribe to the Help Requested Handler
            form.HelpRequested += new HelpEventHandler(form_HelpRequested);

            // Subscribe to the Destroyed Event Handler *to remove the form from the list*
            form.HandleDestroyed += new EventHandler(form_HandleDestroyed);
        }

        /// <summary>
        /// Launch CHM Help
        /// </summary>
        public void LaunchHelp()
        {
            int bHelpIsAlreadyRunning_Pid = 0;
            Diag.Process[] ps = ProcessW.AllRunningProcessesOf("hh", false, true);
            if (ps != null && ps.Length >= 1)
            {
                foreach (Diag.Process p in ps)
                {
                    string ProcessName = "";
                    string CommandLine = "";
                    ProcessW.GetCommandLineArgumentsForProcessPID(p.Id, out ProcessName, out CommandLine);
                    if (CommandLine.Contains(_FileNameNPath))
                    {
                        bHelpIsAlreadyRunning_Pid = p.Id;
                        break;
                    }
                }
            }

            // No need to launch a second time
            if (bHelpIsAlreadyRunning_Pid != 0)
            {
                // Set Focus
                IntPtr hWnd = Yaulw.Win32.Functions.GetFirstTopLevelWindowForProcess(bHelpIsAlreadyRunning_Pid);
                if (hWnd != IntPtr.Zero)
                    Yaulw.Win32.User32.SetActiveWindow(hWnd);
            }
            else
            {
                // Launch
                EnsureCHMFileExistance(false);
                PStarter.StartProcess(PStartInfo.CreateProcess(_FileNameNPath, "", "", false, System.Diagnostics.ProcessWindowStyle.Normal, true), false, false);
            }
        }

        /// <summary>
        /// Launch CHM Help 
        /// </summary>
        /// <param name="form">form which will be the parent of the CHM File</param>
        public void LaunchHelp(Form form)
        {
            if (form != null)
            {
                Control control = Control.FromHandle(form.Handle);
                if (control != null)
                {
                    EnsureCHMFileExistance(false);
                    Help.ShowHelp(control, _FileNameNPath);
                }
            }
        }

        /// <summary>
        /// aunch CHM Help
        /// </summary>
        /// <param name="window">Window which will be the parent for the CHM file</param>
        public void LaunchHelp(Window window)
        {
            if (window != null)
            {
                Control control = Control.FromHandle(GetHandleForWPFWindow(window));
                if (control != null)
                {
                    EnsureCHMFileExistance(false);
                    Help.ShowHelp(control, _FileNameNPath);
                }
            }
        }

        /// <summary>
        /// Launch CHM Help for the specified Context
        /// </summary>
        /// <param name="form">form which will be the parent of the CHM File</param>
        /// <param name="dwContextId">Context Id to launch chm file with</param>
        public void LaunchHelp(Form form, int dwContextId)
        {
            if (form != null)
            {
                Control control = Control.FromHandle(form.Handle);
                if (control != null)
                {
                    EnsureCHMFileExistance(false);
                    Help.ShowHelp(control, _FileNameNPath, HelpNavigator.TopicId, dwContextId.ToString());
                }
            }
        }

        /// <summary>
        /// aunch CHM Help for the specified Context
        /// </summary>
        /// <param name="window">Window which will be the parent for the CHM file</param>
        /// <param name="dwContextId">Context Id to launch chm file with</param>
        public void LaunchHelp(Window window, int dwContextId)
        {
            if (window != null)
            {
               EnsureCHMFileExistance(false);
               Help.ShowHelp(null, _FileNameNPath, HelpNavigator.TopicId, dwContextId.ToString());
            }
        }

        #endregion

        #region Private WinForm Help Event Handlers

        /// <summary>
        /// Handle HelpRequests
        /// </summary>
        private void form_HelpRequested(object sender, HelpEventArgs hlpevent)
        {
            Form form = sender as Form;
            if (form != null)
            {
                int dwContextId = s_FormContextMap[form];
                Help.ShowHelp(form, _FileNameNPath, HelpNavigator.TopicId, dwContextId.ToString());
            }
        }

        /// <summary>
        /// Handle Form Destroys
        /// </summary>
        private void form_HandleDestroyed(object sender, EventArgs e)
        {
            Form form = sender as Form;
            if (form != null)
                s_FormContextMap.Remove(form);
        }

        #endregion

        #region Private Helpers

        /// <summary>
        /// Creates the CHMFile from the stream (if a stream was used)
        /// </summary>
        /// <param name="ForceCreationOfFile">true to force re-creation of the file, false otherwise</param>
        private void EnsureCHMFileExistance(bool ForceCreationOfFile)
        {
            if (_FileStream != null)
            {
                if (ForceCreationOfFile || !IO.File.Exists(_FileNameNPath))
                {
                    using (IO.FileStream fs = new IO.FileStream(_FileNameNPath, IO.FileMode.Create))
                    {
                        using (IO.BinaryWriter writer = new IO.BinaryWriter(fs))
                        {
                            // Read from the Resource
                            Byte[] streamData = new Byte[_FileStream.Length];
                            _FileStream.Read(streamData, 0, streamData.Length);

                            // Write to File
                            writer.Write(streamData);
                            writer.Close();
                        }
                    }
                }
            }
        }

        /// <summary>
        /// Uses the InteropHelper to get the Handle of a WPF Window
        /// </summary>
        /// <param name="window">a WPF Window</param>
        /// <returns>an hWnd for the specified WPF Window</returns>
        private IntPtr GetHandleForWPFWindow(Window window)
        {
            WindowInteropHelper InteropHelper = new WindowInteropHelper(window);
            return InteropHelper.Handle;
        }

        #endregion
    }
}