using System;
using System.ComponentModel;
using System.Windows.Forms;
using Bevelstone.EditVoicepack.InstallerApi;
using Microsoft.Win32;

namespace Bevelstone.EditVoicepack.ExampleInstaller
{
    public partial class MainForm : Form
    {
        private VoicepackUpdater updater;

        public MainForm()
        {
            InitializeComponent();
        }

        /// <summary>
        ///     Called once the form is shown on the screen.
        /// </summary>
        /// <param name="sender">
        ///     The sender.
        /// </param>
        /// <param name="e">
        ///     The EventArgs instance containing the event data.
        /// </param>
        /// <remarks>
        ///     Waiting until the form is shown allows it to be used
        ///     as the parent window for the UAC dialog in case
        ///     it needs to be displayed.
        /// </remarks>
        private void FormShownHandler(object sender, EventArgs e)
        {
            string flightSimFolder = FindFlightSimDirectoryFromRegistry();
            if (flightSimFolder == null)
            {
                MessageBox.Show(this, "Unable to locate Flight Simulator X from the registry.",
                                "ATC Voicepack Installer", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Close();
                return;
            }

            // Instantiate and start the update process.
            updater = new VoicepackUpdater(flightSimFolder);
            updater.PropertyChanged += PropertyChangedHandler;
            try
            {
                updater.Execute(Handle);
            }
            catch (Win32Exception ex)
            {
                updater.Dispose();
                updater = null;
                // Check if it is a normal UAC cancel
                if (ex.NativeErrorCode == 1223) Close();
                else throw;
            }
        }

        /// <summary>
        ///     Called when the user click the cancel button.
        /// </summary>
        /// <param name="sender">
        ///     The sender.
        /// </param>
        /// <param name="e">
        ///     The EventArgs instance containing the event data.
        /// </param>
        /// <remarks>
        ///     If the update is already completed close the form.
        ///     If the update is not completed request the updater to cancel
        ///     but do not close the form until the cancelation is completed.
        /// </remarks>
        private void CancelButtonClickHandler(object sender, EventArgs e)
        {
            if (updater == null || updater.IsCompleted) Close();
            else updater.Cancel();
        }

        /// <summary>
        ///     Called by the VoicepackUpdater as it's properties are changed.
        /// </summary>
        /// <param name="sender">
        ///     The sender.
        /// </param>
        /// <param name="e">
        ///     The PropertyChangedEventArgs instance containing the event data.
        /// </param>
        void PropertyChangedHandler(object sender, PropertyChangedEventArgs e)
        {
            switch (e.PropertyName)
            {
                case "ProgressText":
                    progressTextLabel.Text = updater.ProgressText;
                    break;
                case "ProgressPercentage":
                    progressBar.Value = updater.ProgressPercentage;
                    break;
                case "IsCancelAllowed":
                    // Ensure the user can use the cancel button to close once the
                    // update is completed.
                    cancelButton.Enabled = updater.IsCancelAllowed || updater.IsCompleted;
                    break;
                case "IsCompleted":
                    if (updater.IsCompleted) UpdateCompleted();
                    break;
            }
        }

        /// <summary>
        ///     Executed once the voicepack update is completed.
        /// </summary>
        private void UpdateCompleted()
        {
            if (updater.IsCanceled)
            {
                // The user requested a cancel, so close the window.
                Close();
            }
            else if (updater.UpdateError == null)
            {
                // Normal termination
                cancelButton.Text = "Close";
                cancelButton.Enabled = true;
            }
            else
            {
                // Termination with error
                string errorMsg = "Updating the ATC voicepack failed with the following error:" + Environment.NewLine;
                if (updater.UpdateError is UpdateVoicepackException)
                {
                    errorMsg += ((UpdateVoicepackException)updater.UpdateError).BaseExceptionMessage;
                }
                else
                {
                    errorMsg += updater.UpdateError.GetBaseException().Message;
                }
                MessageBox.Show(this, errorMsg, "ATC Voicepack Installer", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Close();
            }
        }

        /// <summary>
        ///     Called when the Form is being closed.
        /// </summary>
        /// <param name="sender">
        ///     The sender.
        /// </param>
        /// <param name="e">
        ///     The FormClosingEventArgs instance containing the event data.
        /// </param>
        /// <remarks>
        ///     If the update is in progress cancel it but keep the window open.
        /// </remarks>
        private void FormClosingHandler(object sender, FormClosingEventArgs e)
        {
            if (updater != null && !updater.IsCompleted)
            {
                updater.Cancel();
                e.Cancel = true;
            }
        }

        /// <summary>
        ///     Called when the form has been closed
        /// </summary>
        /// <param name="sender">
        ///     The sender.
        /// </param>
        /// <param name="e">
        ///     The FormClosedEventArgs instance containing the event data.
        /// </param>
        /// <remarks>
        ///     Ensure Dispose is called on the VoicepackUpdater.
        /// </remarks>
        private void FormCloseHandler(object sender, FormClosedEventArgs e)
        {
            if (updater != null) updater.Dispose();
        }

        /// <summary>
        ///     Finds the root directory of Flight Simulator X based on the registry
        ///     key created by the installer.
        /// </summary>
        /// <returns>
        ///     The location of the root folder; or <c>null</c> if the registry key
        ///     indicating the root folder could not be found.
        /// </returns>
        /// <remarks>
        ///     Supports both 32 and 64 bit environments.
        /// </remarks>
        private static string FindFlightSimDirectoryFromRegistry()
        {
            string result;
            RegistryKey key = null;

            string keyPath = @"SOFTWARE\Microsoft\Microsoft Games\Flight Simulator\10.0";
            if (IntPtr.Size == 8) keyPath = @"SOFTWARE\Wow6432Node\Microsoft\Microsoft Games\Flight Simulator\10.0";

            try
            {
                key = Registry.LocalMachine.OpenSubKey(keyPath, false);
                if (key == null) return null;

                result = (string)key.GetValue("SetupPath");
            }
            finally
            {
                if (key != null) key.Close();
            }

            return result;
        }
    }
}