/*
  KeePass Password Safe - The Open-Source Password Manager
  Copyright (C) 2003-2017 Dominik Reichl <dominik.reichl@t-online.de>

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.IO;
using System.Security.Cryptography;

using Microsoft.Win32;

using KeePass.App;
using KeePass.Native;
using KeePass.Resources;
using KeePass.Util.Spr;

using KeePassLib;
using KeePassLib.Serialization;
using KeePassLib.Utility;

using NativeLib = KeePassLib.Native.NativeLib;

namespace KeePass.Util
{
	public static class WinUtil
	{
		private const int ERROR_ACCESS_DENIED = 5;

		private static bool m_bIsWindows9x = false;
		private static bool m_bIsWindows2000 = false;
		private static bool m_bIsWindowsXP = false;
		private static bool m_bIsAtLeastWindows2000 = false;
		private static bool m_bIsAtLeastWindowsVista = false;
		private static bool m_bIsAtLeastWindows7 = false;
		private static bool m_bIsAtLeastWindows8 = false;
		private static bool m_bIsAtLeastWindows10 = false;

		private static string m_strExePath = null;

		private static ulong m_uFrameworkVersion = 0;

		public static bool IsWindows9x
		{
			get { return m_bIsWindows9x; }
		}

		public static bool IsWindows2000
		{
			get { return m_bIsWindows2000; }
		}

		public static bool IsWindowsXP
		{
			get { return m_bIsWindowsXP; }
		}

		public static bool IsAtLeastWindows2000
		{
			get { return m_bIsAtLeastWindows2000; }
		}

		public static bool IsAtLeastWindowsVista
		{
			get { return m_bIsAtLeastWindowsVista; }
		}

		public static bool IsAtLeastWindows7
		{
			get { return m_bIsAtLeastWindows7; }
		}

		public static bool IsAtLeastWindows8
		{
			get { return m_bIsAtLeastWindows8; }
		}

		public static bool IsAtLeastWindows10
		{
			get { return m_bIsAtLeastWindows10; }
		}

		static WinUtil()
		{
			OperatingSystem os = Environment.OSVersion;
			Version v = os.Version;

			m_bIsWindows9x = (os.Platform == PlatformID.Win32Windows);
			m_bIsWindows2000 = ((v.Major == 5) && (v.Minor == 0));
			m_bIsWindowsXP = ((v.Major == 5) && (v.Minor == 1));

			m_bIsAtLeastWindows2000 = (v.Major >= 5);
			m_bIsAtLeastWindowsVista = (v.Major >= 6);
			m_bIsAtLeastWindows7 = ((v.Major >= 7) || ((v.Major == 6) && (v.Minor >= 1)));
			m_bIsAtLeastWindows8 = ((v.Major >= 7) || ((v.Major == 6) && (v.Minor >= 2)));

			// Environment.OSVersion is reliable only up to version 6.2;
			// https://msdn.microsoft.com/library/windows/desktop/ms724832.aspx
			RegistryKey rk = null;
			try
			{
				rk = Registry.LocalMachine.OpenSubKey(
					"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion", false);
				if(rk != null)
				{
					string str = rk.GetValue("CurrentMajorVersionNumber",
						string.Empty).ToString();
					uint u;
					if(uint.TryParse(str, out u))
						m_bIsAtLeastWindows10 = (u >= 10);
					else { Debug.Assert(string.IsNullOrEmpty(str)); }
				}
				else { Debug.Assert(NativeLib.IsUnix()); }
			}
			catch(Exception) { Debug.Assert(NativeLib.IsUnix()); }
			finally { if(rk != null) rk.Close(); }
		}

		public static void OpenEntryUrl(PwEntry pe)
		{
			Debug.Assert(pe != null);
			if(pe == null) throw new ArgumentNullException("pe");

			string strUrl = pe.Strings.ReadSafe(PwDefs.UrlField);

			if(pe.OverrideUrl.Length > 0)
				WinUtil.OpenUrl(pe.OverrideUrl, pe, true, strUrl);
			else
			{
				string strOverride = Program.Config.Integration.UrlOverride;
				if(strOverride.Length > 0)
					WinUtil.OpenUrl(strOverride, pe, true, strUrl);
				else
					WinUtil.OpenUrl(strUrl, pe, true);
			}
		}

		public static void OpenUrl(string strUrlToOpen, PwEntry peDataSource)
		{
			OpenUrl(strUrlToOpen, peDataSource, true, null);
		}

		public static void OpenUrl(string strUrlToOpen, PwEntry peDataSource,
			bool bAllowOverride)
		{
			OpenUrl(strUrlToOpen, peDataSource, bAllowOverride, null);
		}

		public static void OpenUrl(string strUrlToOpen, PwEntry peDataSource,
			bool bAllowOverride, string strBaseRaw)
		{
			// If URL is null, return, do not throw exception.
			Debug.Assert(strUrlToOpen != null); if(strUrlToOpen == null) return;

			string strPrevWorkDir = WinUtil.GetWorkingDirectory();
			string strThisExe = WinUtil.GetExecutable();
			
			string strExeDir = UrlUtil.GetFileDirectory(strThisExe, false, true);
			WinUtil.SetWorkingDirectory(strExeDir);

			string strUrlFlt = strUrlToOpen;
			strUrlFlt = strUrlFlt.TrimStart(new char[]{ ' ', '\t', '\r', '\n' });

			PwDatabase pwDatabase = null;
			try
			{
				pwDatabase = Program.MainForm.DocumentManager.SafeFindContainerOf(
					peDataSource);
			}
			catch(Exception) { Debug.Assert(false); }

			bool bCmdQuotes = WinUtil.IsCommandLineUrl(strUrlFlt);

			SprContext ctx = new SprContext(peDataSource, pwDatabase,
				SprCompileFlags.All, false, bCmdQuotes);
			ctx.Base = strBaseRaw;
			ctx.BaseIsEncoded = false;

			string strUrl = SprEngine.Compile(strUrlFlt, ctx);

			string strOvr = Program.Config.Integration.UrlSchemeOverrides.GetOverrideForUrl(
				strUrl);
			if(!bAllowOverride) strOvr = null;
			if(strOvr != null)
			{
				bool bCmdQuotesOvr = WinUtil.IsCommandLineUrl(strOvr);

				SprContext ctxOvr = new SprContext(peDataSource, pwDatabase,
					SprCompileFlags.All, false, bCmdQuotesOvr);
				ctxOvr.Base = strUrl;
				ctxOvr.BaseIsEncoded = bCmdQuotes;

				strUrl = SprEngine.Compile(strOvr, ctxOvr);
			}

			if(WinUtil.IsCommandLineUrl(strUrl))
			{
				string strApp, strArgs;
				StrUtil.SplitCommandLine(WinUtil.GetCommandLineFromUrl(strUrl),
					out strApp, out strArgs);

				try
				{
					if((strArgs != null) && (strArgs.Length > 0))
						Process.Start(strApp, strArgs);
					else
						Process.Start(strApp);
				}
				catch(Win32Exception)
				{
					StartWithoutShellExecute(strApp, strArgs);
				}
				catch(Exception exCmd)
				{
					string strInf = KPRes.FileOrUrl + ": " + strApp;
					if((strArgs != null) && (strArgs.Length > 0))
						strInf += MessageService.NewParagraph +
							KPRes.Arguments + ": " + strArgs;

					MessageService.ShowWarning(strInf, exCmd);
				}
			}
			else // Standard URL
			{
				try { Process.Start(strUrl); }
				catch(Exception exUrl)
				{
					MessageService.ShowWarning(strUrl, exUrl);
				}
			}

			// Restore previous working directory
			WinUtil.SetWorkingDirectory(strPrevWorkDir);

			// SprEngine.Compile might have modified the database
			Program.MainForm.UpdateUI(false, null, false, null, false, null, false);
		}

		public static void OpenUrlWithApp(string strUrlToOpen, PwEntry peDataSource,
			string strAppPath)
		{
			if(string.IsNullOrEmpty(strUrlToOpen)) return;
			if(string.IsNullOrEmpty(strAppPath)) return;

			char[] vPathTrim = new char[]{ ' ', '\t', '\r', '\n',
				'\"', '\'' };

			string strUrl = strUrlToOpen.Trim(vPathTrim);
			if(strUrl.Length == 0) { Debug.Assert(false); return; }

			string strApp = strAppPath.Trim(vPathTrim);
			if(strApp.Length == 0) { Debug.Assert(false); return; }

			string str = "cmd://\"" + strApp + "\" \"" + strUrl + "\"";
			OpenUrl(str, peDataSource, false);
		}

		private static void StartWithoutShellExecute(string strApp, string strArgs)
		{
			try
			{
				ProcessStartInfo psi = new ProcessStartInfo();

				psi.FileName = strApp;

				if((strArgs != null) && (strArgs.Length > 0))
					psi.Arguments = strArgs;

				psi.UseShellExecute = false;

				Process.Start(psi);
			}
			catch(Exception exCmd)
			{
				string strInf = KPRes.FileOrUrl + ": " + strApp;
				if((strArgs != null) && (strArgs.Length > 0))
					strInf += MessageService.NewParagraph +
						KPRes.Arguments + ": " + strArgs;

				MessageService.ShowWarning(strInf, exCmd);
			}
		}

		public static void Restart()
		{
			try { Process.Start(WinUtil.GetExecutable()); }
			catch(Exception exRestart)
			{
				MessageService.ShowWarning(exRestart);
			}
		}

		public static string GetExecutable()
		{
			if(m_strExePath != null) return m_strExePath;

			try { m_strExePath = Assembly.GetExecutingAssembly().Location; }
			catch(Exception) { }

			if(string.IsNullOrEmpty(m_strExePath))
			{
				m_strExePath = Assembly.GetExecutingAssembly().GetName().CodeBase;
				m_strExePath = UrlUtil.FileUrlToPath(m_strExePath);
			}

			return m_strExePath;
		}

		/// <summary>
		/// Shorten a path.
		/// </summary>
		/// <param name="strPath">Path to make shorter.</param>
		/// <param name="nMaxChars">Maximum number of characters in the returned string.</param>
		/// <returns>Shortened path.</returns>
		public static string CompactPath(string strPath, int nMaxChars)
		{
			Debug.Assert(strPath != null);
			if(strPath == null) throw new ArgumentNullException("strPath");
			Debug.Assert(nMaxChars >= 0);
			if(nMaxChars < 0) throw new ArgumentOutOfRangeException("nMaxChars");

			if(nMaxChars == 0) return string.Empty;
			if(strPath.Length <= nMaxChars) return strPath;

			try
			{
				StringBuilder sb = new StringBuilder(strPath.Length * 2 + 4);

				if(NativeMethods.PathCompactPathEx(sb, strPath, (uint)nMaxChars, 0) == false)
					return StrUtil.CompactString3Dots(strPath, nMaxChars);

				Debug.Assert(sb.Length <= nMaxChars);
				if((sb.Length <= nMaxChars) && (sb.Length != 0))
					return sb.ToString();
				else
					return StrUtil.CompactString3Dots(strPath, nMaxChars);
			}
			catch(Exception) { Debug.Assert(false); }

			return StrUtil.CompactString3Dots(strPath, nMaxChars);
		}

		public static bool FlushStorageBuffers(char chDriveLetter, bool bOnlyIfRemovable)
		{
			string strDriveLetter = new string(chDriveLetter, 1);
			bool bResult = true;

			try
			{
				if(bOnlyIfRemovable)
				{
					DriveInfo di = new DriveInfo(strDriveLetter);
					if(di.DriveType != DriveType.Removable) return true;
				}

				string strDevice = "\\\\.\\" + strDriveLetter + ":";

				IntPtr hDevice = NativeMethods.CreateFile(strDevice,
					NativeMethods.EFileAccess.GenericRead | NativeMethods.EFileAccess.GenericWrite,
					NativeMethods.EFileShare.Read | NativeMethods.EFileShare.Write,
					IntPtr.Zero, NativeMethods.ECreationDisposition.OpenExisting,
					0, IntPtr.Zero);
				if(NativeMethods.IsInvalidHandleValue(hDevice))
				{
					Debug.Assert(false);
					return false;
				}

				string strDir = FreeDriveIfCurrent(chDriveLetter);

				uint dwDummy;
				if(NativeMethods.DeviceIoControl(hDevice, NativeMethods.FSCTL_LOCK_VOLUME,
					IntPtr.Zero, 0, IntPtr.Zero, 0, out dwDummy, IntPtr.Zero) != false)
				{
					if(NativeMethods.DeviceIoControl(hDevice, NativeMethods.FSCTL_UNLOCK_VOLUME,
						IntPtr.Zero, 0, IntPtr.Zero, 0, out dwDummy, IntPtr.Zero) == false)
					{
						Debug.Assert(false);
					}
				}
				else bResult = false;

				if(strDir.Length > 0) WinUtil.SetWorkingDirectory(strDir);

				if(!NativeMethods.CloseHandle(hDevice)) { Debug.Assert(false); }
			}
			catch(Exception)
			{
				Debug.Assert(false);
				return false;
			}

			return bResult;
		}

		public static bool FlushStorageBuffers(string strFileOnStorage, bool bOnlyIfRemovable)
		{
			if(strFileOnStorage == null) { Debug.Assert(false); return false; }
			if(strFileOnStorage.Length < 3) return false;
			if(strFileOnStorage[1] != ':') return false;
			if(strFileOnStorage[2] != '\\') return false;

			return FlushStorageBuffers(char.ToUpper(strFileOnStorage[0]), bOnlyIfRemovable);
		}

		private static string FreeDriveIfCurrent(char chDriveLetter)
		{
			try
			{
				string strCur = WinUtil.GetWorkingDirectory();
				if((strCur == null) || (strCur.Length < 3)) return string.Empty;
				if(strCur[1] != ':') return string.Empty;
				if(strCur[2] != '\\') return string.Empty;

				char chPar = char.ToUpper(chDriveLetter);
				char chCur = char.ToUpper(strCur[0]);
				if(chPar != chCur) return string.Empty;

				string strTemp = UrlUtil.GetTempPath();
				WinUtil.SetWorkingDirectory(strTemp);

				return strCur;
			}
			catch(Exception) { Debug.Assert(false); }

			return string.Empty;
		}

		private static readonly string[] m_vIE7Windows = new string[] {
			"Windows Internet Explorer", "Maxthon"
		};

		public static bool IsInternetExplorer7Window(string strWindowTitle)
		{
			if(strWindowTitle == null) return false; // No assert or throw
			if(strWindowTitle.Length == 0) return false; // No assert or throw

			foreach(string str in m_vIE7Windows)
			{
				if(strWindowTitle.IndexOf(str) >= 0) return true;
			}

			return false;
		}

		public static byte[] HashFile(IOConnectionInfo iocFile)
		{
			if(iocFile == null) { Debug.Assert(false); return null; } // Assert only

			Stream sIn;
			try
			{
				sIn = IOConnection.OpenRead(iocFile);
				if(sIn == null) throw new FileNotFoundException();
			}
			catch(Exception) { return null; }

			byte[] pbHash;
			try
			{
				using(SHA256Managed sha256 = new SHA256Managed())
				{
					pbHash = sha256.ComputeHash(sIn);
				}
			}
			catch(Exception) { Debug.Assert(false); sIn.Close(); return null; }

			sIn.Close();
			return pbHash;
		}

		// See GetCommandLineFromUrl when editing this method
		public static bool IsCommandLineUrl(string strUrl)
		{
			if(strUrl == null) { Debug.Assert(false); return false; }

			string strLower = strUrl.ToLower();

			if(strLower.StartsWith("cmd://")) return true;
			if(strLower.StartsWith("\\\\")) return true; // UNC path support

			return false;
		}

		// See IsCommandLineUrl when editing this method
		public static string GetCommandLineFromUrl(string strUrl)
		{
			if(strUrl == null) { Debug.Assert(false); return string.Empty; }

			string strLower = strUrl.ToLower();

			if(strLower.StartsWith("cmd://")) return strUrl.Remove(0, 6);
			if(strLower.StartsWith("\\\\")) return strUrl; // UNC path support

			return strUrl;
		}

		public static bool RunElevated(string strExe, string strArgs,
			bool bShowMessageIfFailed)
		{
			if(strExe == null) throw new ArgumentNullException("strExe");

			try
			{
				ProcessStartInfo psi = new ProcessStartInfo();
				if(strArgs != null) psi.Arguments = strArgs;
				psi.FileName = strExe;
				psi.UseShellExecute = true;
				psi.WindowStyle = ProcessWindowStyle.Normal;

				// Elevate on Windows Vista and higher
				if(WinUtil.IsAtLeastWindowsVista) psi.Verb = "runas";

				Process.Start(psi);
			}
			catch(Exception ex)
			{
				if(bShowMessageIfFailed) MessageService.ShowWarning(ex);

				return false;
			}

			return true;
		}

		public static ulong GetMaxNetFrameworkVersion()
		{
			if(m_uFrameworkVersion != 0) return m_uFrameworkVersion;

			try { m_uFrameworkVersion = GetMaxNetVersionPriv(); }
			catch(Exception) { Debug.Assert(false); }

			if(m_uFrameworkVersion == 0)
			{
				Version v = Environment.Version;
				if(v.Major > 0) m_uFrameworkVersion |= (uint)v.Major;
				m_uFrameworkVersion <<= 16;
				if(v.Minor > 0) m_uFrameworkVersion |= (uint)v.Minor;
				m_uFrameworkVersion <<= 16;
				if(v.Build > 0) m_uFrameworkVersion |= (uint)v.Build;
				m_uFrameworkVersion <<= 16;
				if(v.Revision > 0) m_uFrameworkVersion |= (uint)v.Revision;
			}

			return m_uFrameworkVersion;
		}

		private static ulong GetMaxNetVersionPriv()
		{
			RegistryKey kNdp = Registry.LocalMachine.OpenSubKey(
				"SOFTWARE\\Microsoft\\NET Framework Setup\\NDP", false);
			if(kNdp == null) { Debug.Assert(false); return 0; }

			ulong uMaxVer = 0;

			string[] vInNdp = kNdp.GetSubKeyNames();
			foreach(string strInNdp in vInNdp)
			{
				if(strInNdp == null) { Debug.Assert(false); continue; }
				if(!strInNdp.StartsWith("v", StrUtil.CaseIgnoreCmp)) continue;

				RegistryKey kVer = kNdp.OpenSubKey(strInNdp, false);
				if(kVer != null)
				{
					UpdateNetVersionFromRegKey(kVer, ref uMaxVer);

					string[] vProfiles = kVer.GetSubKeyNames();
					foreach(string strProfile in vProfiles)
					{
						if(string.IsNullOrEmpty(strProfile)) { Debug.Assert(false); continue; }

						RegistryKey kPro = kVer.OpenSubKey(strProfile, false);
						UpdateNetVersionFromRegKey(kPro, ref uMaxVer);
						if(kPro != null) kPro.Close();
					}

					kVer.Close();
				}
				else { Debug.Assert(false); }
			}

			kNdp.Close();
			return uMaxVer;
		}

		private static void UpdateNetVersionFromRegKey(RegistryKey k, ref ulong uMaxVer)
		{
			if(k == null) { Debug.Assert(false); return; }

			try
			{
				// https://msdn.microsoft.com/en-us/library/hh925568.aspx
				string strInstall = k.GetValue("Install", string.Empty).ToString();
				if((strInstall.Length > 0) && (strInstall != "1")) return;

				string strVer = k.GetValue("Version", string.Empty).ToString();
				if(strVer.Length > 0)
				{
					ulong uVer = StrUtil.ParseVersion(strVer);
					if(uVer > uMaxVer) uMaxVer = uVer;
				}
			}
			catch(Exception) { Debug.Assert(false); }
		}

		/* private static ulong GetMaxNetVersionPriv()
		{
			string strSysRoot = Environment.GetEnvironmentVariable("SystemRoot");
			string strFrameworks = UrlUtil.EnsureTerminatingSeparator(strSysRoot,
				false) + "Microsoft.NET" + Path.DirectorySeparatorChar + "Framework";
			if(!Directory.Exists(strFrameworks)) { Debug.Assert(false); return 0; }

			ulong uFrameworkVersion = 0;
			DirectoryInfo diFrameworks = new DirectoryInfo(strFrameworks);
			foreach(DirectoryInfo di in diFrameworks.GetDirectories("v*",
				SearchOption.TopDirectoryOnly))
			{
				string strVer = di.Name.TrimStart('v', 'V');
				ulong uVer = StrUtil.ParseVersion(strVer);
				if(uVer > uFrameworkVersion) uFrameworkVersion = uVer;
			}

			return uFrameworkVersion;
		} */

		public static string GetOSStr()
		{
			if(NativeLib.IsUnix()) return "Unix";
			return "Windows";
		}

		public static void RemoveZoneIdentifier(string strFilePath)
		{
			// No throw
			if(string.IsNullOrEmpty(strFilePath)) { Debug.Assert(false); return; }

			try
			{
				string strZoneId = strFilePath + ":Zone.Identifier";

				if(NativeMethods.FileExists(strZoneId))
					NativeMethods.DeleteFile(strZoneId);
			}
			catch(Exception) { Debug.Assert(NativeLib.IsUnix()); }
		}

		[Obsolete]
		public static string RunConsoleApp(string strAppPath, string strParams)
		{
			return NativeLib.RunConsoleApp(strAppPath, strParams);
		}

		public static string LocateSystemApp(string strExeName)
		{
			if(strExeName == null) { Debug.Assert(false); return string.Empty; }
			if(strExeName.Length == 0) return strExeName;

			if(NativeLib.IsUnix()) return strExeName;

			try
			{
				string str = null;
				for(int i = 0; i < 3; ++i)
				{
					if(i == 0)
						str = Environment.GetFolderPath(
							Environment.SpecialFolder.System);
					else if(i == 1)
						str = Environment.GetEnvironmentVariable("WinDir");
					else if(i == 2)
						str = Environment.GetEnvironmentVariable("SystemRoot");

					if(!string.IsNullOrEmpty(str))
					{
						str = UrlUtil.EnsureTerminatingSeparator(str, false);
						str += strExeName;

						if(File.Exists(str)) return str;
					}
				}
			}
			catch(Exception) { Debug.Assert(false); }

			return strExeName;
		}

		public static string GetHomeDirectory()
		{
			string str = null;
			try
			{
				str = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
			}
			catch(Exception) { Debug.Assert(false); }

			if(string.IsNullOrEmpty(str))
			{
				try
				{
					str = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
				}
				catch(Exception) { Debug.Assert(false); }
			}

			if(string.IsNullOrEmpty(str)) { Debug.Assert(false); return string.Empty; }

			return str;
		}

		public static string GetWorkingDirectory()
		{
			string strWorkDir = null;
			try { strWorkDir = Directory.GetCurrentDirectory(); }
			catch(Exception) { Debug.Assert(false); }

			return (!string.IsNullOrEmpty(strWorkDir) ? strWorkDir : GetHomeDirectory());
		}

		public static void SetWorkingDirectory(string strWorkDir)
		{
			string str = strWorkDir; // May be null

			if(!string.IsNullOrEmpty(str))
			{
				try { if(!Directory.Exists(str)) str = null; }
				catch(Exception) { Debug.Assert(false); str = null; }
			}

			if(string.IsNullOrEmpty(str))
				str = GetHomeDirectory(); // Not app dir

			try { Directory.SetCurrentDirectory(str); }
			catch(Exception) { Debug.Assert(false); }
		}
	}
}