// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.

using System;
using System.Diagnostics;
using System.ComponentModel.Design;
using System.IO;
using Microsoft.VisualStudio;
using Microsoft.VisualStudio.Shell;
using Microsoft.VisualStudio.Shell.Interop;
using Microsoft.VisualStudio.OLE.Interop;
using EnvDTE;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using EnvDTE80;


namespace UnrealVS
{
	class GenerateProjectFiles
	{
		const int GenerateProjectFilesButtonID = 0x1100;


		public GenerateProjectFiles()
		{
			// GenerateProjectFilesButton
			{
				var CommandID = new CommandID( GuidList.UnrealVSCmdSet, GenerateProjectFilesButtonID );
				GenerateProjectFilesButtonCommand = new MenuCommand( new EventHandler( GenerateProjectFilesButtonHandler ), CommandID );
				UnrealVSPackage.Instance.MenuCommandService.AddCommand( GenerateProjectFilesButtonCommand );
			}


			// Register to find out when the solution is closed or opened
			UnrealVSPackage.Instance.OnSolutionOpened += OnSolutionOpened;
			UnrealVSPackage.Instance.OnSolutionClosing += OnSolutionClosing;

			UpdateGenerateProjectFilesButtonState();
		}



		/// Called when 'GenerateProjectFiles' button is clicked
		void GenerateProjectFilesButtonHandler( object Sender, EventArgs Args )
		{
			// Don't allow a regen if we're already generating projects
			if( GenerateProjectFilesProcess == null )
			{
				// Figure out which project to rebuild
				string BatchFileName = GetBatchFileName();

				if( !String.IsNullOrEmpty( BatchFileName ) )
				{
					// Make sure the Output window is visible
					UnrealVSPackage.Instance.DTE.ExecuteCommand( "View.Output" );

					// Activate the output pane
					var Pane = UnrealVSPackage.Instance.GetOutputPane();
					if( Pane != null )
					{
						// Clear and activate the output pane.
						Pane.Clear();

						// @todo: Activating doesn't seem to really bring the pane to front like we would expect it to.
						Pane.Activate();
					}

					GenerateProjectFilesProcess = UnrealVSPackage.Instance.LaunchProgram(
                        "cmd.exe", "/C " + GetSafeFilePath(BatchFileName),
						OnGenerateProjectFilesProcessExit,
						OnOutputFromGenerateProjectFilesProcess );
				}

				UpdateGenerateProjectFilesButtonState();
			}
		}


		/// Called when the GenerateProjectFiles process terminates
		void OnGenerateProjectFilesProcessExit( object Sender, EventArgs Args )
		{
			GenerateProjectFilesProcess = null;

			UpdateGenerateProjectFilesButtonState();
		}


		/// <summary>
		/// Updates the enabled/disabled state of the 'Generate Project Files' button
		/// </summary>
		void UpdateGenerateProjectFilesButtonState( bool ShouldForceDisable = false )
		{
			var CanGenerateProjects = false;

			if( !ShouldForceDisable )
			{
				// Can't launch when a process is already running
				if( GenerateProjectFilesProcess == null )
				{
					string BatchFileName = GetBatchFileName();
					if ( BatchFileName != null )
					{
						CanGenerateProjects = true;
					}
					else
					{
						// No solution loaded, or solution doesn't look like UE4
					}
				}
			}

			GenerateProjectFilesButtonCommand.Enabled = CanGenerateProjects;
		}


		/// <summary>
		/// Called when a solution is opened
		/// </summary>
		public void OnSolutionOpened()
		{
			UpdateGenerateProjectFilesButtonState();
		}


		/// <summary>
		/// Called when the solution is closed
		/// </summary>
		public void OnSolutionClosing()
		{
			UpdateGenerateProjectFilesButtonState( ShouldForceDisable:true );
		}


		/// <summary>
		/// Called when data is received from the GenerateProjectFiles process
		/// </summary>
		public void OnOutputFromGenerateProjectFilesProcess( object Sender, DataReceivedEventArgs Args )
		{
			var Pane = UnrealVSPackage.Instance.GetOutputPane();
			if( Pane != null )
			{
				Pane.OutputString( Args.Data + "\n" );
			}
		}

		private string GetBatchFileName()
		{
			// Check to see if we have UE4.sln loaded
			if (UnrealVSPackage.Instance.IsUE4Loaded)
			{ 
				// We expect "GenerateProjectFiles.bat" to live in the same directory as the solution
				return Path.Combine(Path.GetDirectoryName(UnrealVSPackage.Instance.SolutionFilepath), "GenerateProjectFiles.bat");
			}
			return null;
		}

        /// <summary>
        /// Wraps a file path in quotes if it contains a space character
        /// </summary>
        /// <param name="InPath"></param>
        /// <returns></returns>
        private string GetSafeFilePath( string InPath )
        {
            string WorkingPath = InPath;

            if (WorkingPath.Contains(" ") && !WorkingPath.Contains("\""))
            {
                WorkingPath = "\"" + WorkingPath + "\"";
            }
            return WorkingPath;
        }

		/// Active process for the "generate project files" command
		System.Diagnostics.Process GenerateProjectFilesProcess;

		/// Command for 'Generate Project Files' button
		MenuCommand GenerateProjectFilesButtonCommand;
	}

}