Added Steam update message box to the launcher

source/Launcher/Enderal Launcher.au3

@@ -51,6 +51,7 @@ Global Const $REG_KEY = "HKEY_CURRENT_USER\Software\SureAI\EnderalSE"
 Global Const $REG_INSTALL_PATH = "Install_Path"
 Global Const $REG_EXE_PATH = "Exe_Path"
 Global Const $REG_START_STEAM = "Start_Steam"
+Global Const $REG_STEAM_UPDATE_NOTICE_SHOWN = "Steam_Update_Notice_Shown"
 Global Const $AA_TAA = "TAA (Best quality)"
 Global Const $AA_FXAA = "FXAA (Low)"
 Global Const $AA_OFF = "Off (Best performance)"
@@ -358,9 +359,9 @@ Func GetEnderalVersion()
 EndFunc
 
 ; ============================================
-; Update Function
+; Update Functions
 ; ============================================
-Func CheckAndApplyUpdate()
+Func CheckAndApplyGOGUpdate()
     ; Check if update is needed: SkyrimSE.exe is not 1.6.659 AND skse64_1_6_659.dll exists
     Local $skyrimVersion = GetSkyrimVersion()
     Local $oldSkseDll = $LAUNCHER_DIR & "\skse64_1_6_659.dll"
@@ -509,6 +510,71 @@ Func CheckAndApplyUpdate()
     EndIf
 EndFunc
 
+Func CheckAndNotifySteamUpdate()
+    ; 2.1+ uses a new savegame location, the savegames in the old one are playable on the 2.0.12.4 branch only
+    If Not FileExists($LAUNCHER_DIR & "\steam_api64.dll") Then Return
+    If Not FileExists($LAUNCHER_DIR & "\Data\SKSE\Plugins\SkyrimRedirector.dll") Then Return
+    If GetEnderalVersion() = "2.0.12.4" Then Return
+    If RegRead($REG_KEY, $REG_STEAM_UPDATE_NOTICE_SHOWN) = 1 Then Return
+
+    Local $oldSavesDir = GetDocumentsPath() & "\My Games\Enderal Special Edition\Saves\"
+    Local $hSearch = FileFindFirstFile($oldSavesDir & "*.ess")
+    If $hSearch = -1 Then Return
+    FileClose($hSearch)
+
+    Local $iButton = ShowTwoButtonDialog("Enderal Special Edition", _
+        "Enderal SE has been updated. To continue playing your old savegames in " & $oldSavesDir & _
+        ", please, switch to the 2.0.12.4 branch on Steam.", "OK", "Never show again")
+    If $iButton = 2 Then RegWrite($REG_KEY, $REG_STEAM_UPDATE_NOTICE_SHOWN, "REG_DWORD", 1)
+EndFunc
+
+Func ShowTwoButtonDialog($sTitle, $sText, $sButton1, $sButton2)
+    ; Warning message box with custom button labels, which MsgBox does not support.
+    ; Returns 1 or 2 for the clicked button, 0 when the dialog was closed with Esc or the close button.
+    Local Const $TDF_ALLOW_DIALOG_CANCELLATION = 0x0008
+    Local Const $TD_WARNING_ICON = 0xFFFF
+    ; Distinct from IDOK/IDCANCEL, which TaskDialogIndirect returns when the dialog is cancelled
+    Local Const $BUTTON_ID_BASE = 100
+
+    Local $tStrings = DllStructCreate("wchar Title[" & StringLen($sTitle) + 1 & "];wchar Text[" & StringLen($sText) + 1 & _
+        "];wchar Button1[" & StringLen($sButton1) + 1 & "];wchar Button2[" & StringLen($sButton2) + 1 & "]")
+    DllStructSetData($tStrings, "Title", $sTitle)
+    DllStructSetData($tStrings, "Text", $sText)
+    DllStructSetData($tStrings, "Button1", $sButton1)
+    DllStructSetData($tStrings, "Button2", $sButton2)
+
+    ; TASKDIALOG_BUTTON and TASKDIALOGCONFIG are packed (pshpack1.h)
+    Local $tButtons = DllStructCreate("align 1;int Id1;ptr Text1;int Id2;ptr Text2")
+    DllStructSetData($tButtons, "Id1", $BUTTON_ID_BASE + 1)
+    DllStructSetData($tButtons, "Text1", DllStructGetPtr($tStrings, "Button1"))
+    DllStructSetData($tButtons, "Id2", $BUTTON_ID_BASE + 2)
+    DllStructSetData($tButtons, "Text2", DllStructGetPtr($tStrings, "Button2"))
+
+    Local $tConfig = DllStructCreate("align 1;uint Size;hwnd Parent;handle Instance;dword Flags;dword CommonButtons;" & _
+        "ptr WindowTitle;ptr MainIcon;ptr MainInstruction;ptr Content;uint ButtonCount;ptr Buttons;int DefaultButton;" & _
+        "uint RadioButtonCount;ptr RadioButtons;int DefaultRadioButton;ptr VerificationText;ptr ExpandedInformation;" & _
+        "ptr ExpandedControlText;ptr CollapsedControlText;ptr FooterIcon;ptr Footer;ptr Callback;ptr CallbackData;uint Width")
+    DllStructSetData($tConfig, "Size", DllStructGetSize($tConfig))
+    DllStructSetData($tConfig, "Flags", $TDF_ALLOW_DIALOG_CANCELLATION)
+    DllStructSetData($tConfig, "WindowTitle", DllStructGetPtr($tStrings, "Title"))
+    DllStructSetData($tConfig, "MainIcon", $TD_WARNING_ICON)
+    DllStructSetData($tConfig, "Content", DllStructGetPtr($tStrings, "Text"))
+    DllStructSetData($tConfig, "ButtonCount", 2)
+    DllStructSetData($tConfig, "Buttons", DllStructGetPtr($tButtons))
+    DllStructSetData($tConfig, "DefaultButton", $BUTTON_ID_BASE + 1)
+
+    Local $aCall = DllCall("comctl32.dll", "long", "TaskDialogIndirect", "struct*", $tConfig, "int*", 0, "ptr", 0, "ptr", 0)
+    If @error Or $aCall[0] <> 0 Then
+        ; Fallback without the custom buttons, so that the message is not lost
+        MsgBox(48, $sTitle, $sText)
+        Return 1
+    EndIf
+
+    Local $iButton = $aCall[2] - $BUTTON_ID_BASE
+    If $iButton = 1 Or $iButton = 2 Then Return $iButton
+    Return 0
+EndFunc
+
 ; ============================================
 ; Main Entry Point
 ; ============================================
@@ -516,7 +582,8 @@ Main()
 
 Func Main()
     ; Check and apply update if needed
-    CheckAndApplyUpdate()
+    CheckAndApplyGOGUpdate()
+    CheckAndNotifySteamUpdate()
 
     ; Check if SkyrimRedirector is installed
     Local $redirectorDll = $LAUNCHER_DIR & "\Data\SKSE\Plugins\SkyrimRedirector.dll"