!define APPNAME "OpenTTD"   ; Define application name
!define APPVERSION "0.7.1"  ; Define application version
!define APPVERSIONINTERNAL "0.7.1.0" ; Define application version in X.X.X.X
!define INSTALLERVERSION 62 ; NEED TO UPDATE THIS FOR EVERY RELEASE!!!
!include ${VERSION_INCLUDE}

!define APPURLLINK "http://www.openttd.org"
!define APPNAMEANDVERSION "${APPNAME} ${APPVERSION}"

!define MUI_ICON "..\..\..\media\openttd.ico"
!define MUI_UNICON "..\..\..\media\openttd.ico"
!define MUI_WELCOMEFINISHPAGE_BITMAP "welcome.bmp"
!define MUI_HEADERIMAGE
!define MUI_HEADERIMAGE_BITMAP "top.bmp"

BrandingText "OpenTTD Installer"
SetCompressor LZMA

; Version Info
Var AddWinPrePopulate
VIProductVersion "${APPVERSIONINTERNAL}"
VIAddVersionKey "ProductName" "OpenTTD Installer ${APPBITS} bits version ${EXTRA_VERSION}"
VIAddVersionKey "Comments" "Installs ${APPNAMEANDVERSION}"
VIAddVersionKey "CompanyName" "OpenTTD Developers"
VIAddVersionKey "FileDescription" "Installs ${APPNAMEANDVERSION}"
VIAddVersionKey "ProductVersion" "${APPVERSION}"
VIAddVersionKey "InternalName" "InstOpenTTD-${APPARCH}"
VIAddVersionKey "FileVersion" "${APPVERSION}-${APPARCH}"
VIAddVersionKey "LegalCopyright" " "
; Main Install settings
Name "${APPNAMEANDVERSION} ${APPBITS} bits version ${EXTRA_VERSION}"

; NOTE: Keep trailing backslash!
InstallDirRegKey HKLM "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Install Folder"
OutFile "openttd-${APPVERSION}-${APPARCH}.exe"
CRCCheck force

ShowInstDetails show
ShowUninstDetails show

Var SHORTCUTS
Var CDDRIVE

; Modern interface settings
!include "MUI.nsh"

!define MUI_ABORTWARNING
!define MUI_WELCOMEPAGE_TITLE_3LINES
!insertmacro MUI_PAGE_WELCOME

!define MUI_LICENSEPAGE_RADIOBUTTONS
!insertmacro MUI_DEFAULT MUI_LICENSEPAGE_RADIOBUTTONS_TEXT_ACCEPT "I &accept this agreement"
!insertmacro MUI_DEFAULT MUI_LICENSEPAGE_RADIOBUTTONS_TEXT_DECLINE "I &do not accept this agreement"
!insertmacro MUI_PAGE_LICENSE "..\..\..\COPYING"

!insertmacro MUI_PAGE_COMPONENTS

;---------------------------------
; Custom page for finding TTDLX CD
Page custom SelectCDEnter SelectCDExit ": TTD folder"

!insertmacro MUI_PAGE_DIRECTORY

;Start Menu Folder Page Configuration
!define MUI_STARTMENUPAGE_DEFAULTFOLDER $SHORTCUTS
!define MUI_STARTMENUPAGE_REGISTRY_ROOT "HKEY_LOCAL_MACHINE"
!define MUI_STARTMENUPAGE_REGISTRY_KEY "Software\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD"
!define MUI_STARTMENUPAGE_REGISTRY_VALUENAME "Shortcut Folder"

!insertmacro MUI_PAGE_STARTMENU "OpenTTD" $SHORTCUTS

!insertmacro MUI_PAGE_INSTFILES

;-----------------------------------------------------
; New custom page to show UNICODE and MSLU information
Page custom ShowWarningsPage

!define MUI_FINISHPAGE_TITLE_3LINES
!define MUI_FINISHPAGE_RUN_TEXT "Run ${APPNAMEANDVERSION} now!"
!define MUI_FINISHPAGE_RUN "$INSTDIR\openttd.exe"
!define MUI_FINISHPAGE_LINK "Visit the OpenTTD site for latest news, FAQs and downloads"
!define MUI_FINISHPAGE_LINK_LOCATION "${APPURLLINK}"
!define MUI_FINISHPAGE_NOREBOOTSUPPORT
!define MUI_FINISHPAGE_SHOWREADME "$INSTDIR\readme.txt"
!define MUI_FINISHPAGE_SHOWREADME_NOTCHECKED
!define MUI_WELCOMEFINISHPAGE_CUSTOMFUNCTION_INIT DisableBack

!insertmacro MUI_PAGE_FINISH
!define MUI_PAGE_HEADER_TEXT "Uninstall ${APPNAMEANDVERSION}"
!insertmacro MUI_UNPAGE_CONFIRM
!insertmacro MUI_UNPAGE_INSTFILES

; Set languages (first is default language)
!insertmacro MUI_LANGUAGE "English"
!insertmacro MUI_RESERVEFILE_LANGDLL

;--------------------------------------------------------------
; (Core) OpenTTD install section. Copies all internal game data
Section "!OpenTTD" Section1
	; Overwrite files by default, but don't complain on failure
	SetOverwrite try

	; Define root variable relative to installer
	!define PATH_ROOT "..\..\..\"

	; Copy language files
	SetOutPath "$INSTDIR\lang\"
	File ${PATH_ROOT}bin\lang\*.lng

	; Copy data files
	SetOutPath "$INSTDIR\data\"
	File ${PATH_ROOT}bin\data\*.grf
	File ${PATH_ROOT}bin\data\*.obg
	File ${PATH_ROOT}bin\data\*.obs
	File ${PATH_ROOT}bin\data\opntitle.dat

	; Copy the scripts
	SetOutPath "$INSTDIR\scripts\"
	File ${PATH_ROOT}bin\scripts\*.*

	; Copy the rest of the stuff
	SetOutPath "$INSTDIR\"

	; Copy text files
	File ${PATH_ROOT}changelog.txt
	File ${PATH_ROOT}COPYING
	File ${PATH_ROOT}readme.txt
	File ${PATH_ROOT}known-bugs.txt

	; Copy executable
	File /oname=openttd.exe ${BINARY_DIR}\openttd.exe


	; Delete old files from the main dir. they are now placed in data/ and lang/
	Delete "$INSTDIR\*.lng"
	Delete "$INSTDIR\*.grf"
	Delete "$INSTDIR\*.obg"
	Delete "$INSTDIR\*.obs"
	Delete "$INSTDIR\sample.cat"
	Delete "$INSTDIR\ttd.exe"


	; Create the Registry Entries
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Comments" "Visit ${APPURLLINK}"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "DisplayIcon" "$INSTDIR\openttd.exe,0"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "DisplayName" "OpenTTD ${APPVERSION}"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "DisplayVersion" "${APPVERSION}"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "HelpLink" "${APPURLLINK}"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Install Folder" "$INSTDIR"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Publisher" "OpenTTD"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Shortcut Folder" "$SHORTCUTS"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "UninstallString" "$INSTDIR\uninstall.exe"
	WriteRegStr HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "URLInfoAbout" "${APPURLLINK}"
	; This key sets the Version DWORD that new installers will check against
	WriteRegDWORD HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Version" ${INSTALLERVERSION}

	!insertmacro MUI_STARTMENU_WRITE_BEGIN "OpenTTD"
	CreateShortCut "$DESKTOP\OpenTTD.lnk" "$INSTDIR\openttd.exe"
	CreateDirectory "$SMPROGRAMS\$SHORTCUTS"
	CreateShortCut "$SMPROGRAMS\$SHORTCUTS\OpenTTD.lnk" "$INSTDIR\openttd.exe"
	CreateShortCut "$SMPROGRAMS\$SHORTCUTS\Uninstall.lnk" "$INSTDIR\uninstall.exe"
	CreateShortCut "$SMPROGRAMS\$SHORTCUTS\Readme.lnk" "$INSTDIR\Readme.txt"
	CreateShortCut "$SMPROGRAMS\$SHORTCUTS\Changelog.lnk" "$INSTDIR\Changelog.txt"
	CreateShortCut "$SMPROGRAMS\$SHORTCUTS\Known-bugs.lnk" "$INSTDIR\known-bugs.txt"
	!insertmacro MUI_STARTMENU_WRITE_END
SectionEnd

;----------------------------------------------------------------------------------
; TTDLX files install section. Copies all needed TTDLX files from CD or install dir
Section "Copy Game Graphics" Section2
	; Let's copy the files with size approximation
	SetOutPath "$INSTDIR\gm"
	CopyFiles "$CDDRIVE\gm\*.gm" "$INSTDIR\gm\" 1028
	SetOutPath "$INSTDIR\data\"
	CopyFiles "$CDDRIVE\sample.cat" "$INSTDIR\data\sample.cat" 1566
	; Copy Windows files
	CopyFiles "$CDDRIVE\trg1r.grf" "$INSTDIR\data\trg1r.grf" 2365
	CopyFiles "$CDDRIVE\trgcr.grf" "$INSTDIR\data\trgcr.grf" 260
	CopyFiles "$CDDRIVE\trghr.grf" "$INSTDIR\data\trghr.grf" 400
	CopyFiles "$CDDRIVE\trgir.grf" "$INSTDIR\data\trgir.grf" 334
	CopyFiles "$CDDRIVE\trgtr.grf" "$INSTDIR\data\trgtr.grf" 546
	; Copy DOS files
	CopyFiles "$CDDRIVE\trg1.grf" "$INSTDIR\data\trg1.grf" 2365
	CopyFiles "$CDDRIVE\trgc.grf" "$INSTDIR\data\trgc.grf" 260
	CopyFiles "$CDDRIVE\trgh.grf" "$INSTDIR\data\trgh.grf" 400
	CopyFiles "$CDDRIVE\trgi.grf" "$INSTDIR\data\trgi.grf" 334
	CopyFiles "$CDDRIVE\trgt.grf" "$INSTDIR\data\trgt.grf" 546
	SetOutPath "$INSTDIR\"
SectionEnd

;-------------------------------------------
; Install the uninstaller (option is hidden)
Section -FinishSection
	WriteUninstaller "$INSTDIR\uninstall.exe"
SectionEnd

; Modern install component descriptions
!insertmacro MUI_FUNCTION_DESCRIPTION_BEGIN
	!insertmacro MUI_DESCRIPTION_TEXT ${Section1} "OpenTTD is a fully functional clone of TTD and is very playable."
	!insertmacro MUI_DESCRIPTION_TEXT ${Section2} "Copies the game graphics. Requires TTD (for Windows)."
!insertmacro MUI_FUNCTION_DESCRIPTION_END

;-----------------------------------------------
; Uninstall section, deletes all installed files
Section "Uninstall"
	MessageBox MB_YESNO|MB_ICONQUESTION \
		"Remove the save game folders located at $\"$INSTDIR\save?$\"$\n \
		If you choose Yes, your saved games will be deleted." \
		IDYES RemoveSavedGames IDNO NoRemoveSavedGames
	RemoveSavedGames:
		Delete "$INSTDIR\save\autosave\*"
		RMDir "$INSTDIR\save\autosave"
		Delete "$INSTDIR\save\*"
		RMDir "$INSTDIR\save"
	NoRemoveSavedGames:

	MessageBox MB_YESNO|MB_ICONQUESTION \
		"Remove the scenario folders located at $\"$INSTDIR\scenario?$\"$\n \
		If you choose Yes, your scenarios will be deleted." \
		IDYES RemoveScen IDNO NoRemoveScen
	RemoveScen:
		Delete "$INSTDIR\scenario\heightmap*"
		RMDir "$INSTDIR\scenario\heightmap"
		Delete "$INSTDIR\scenario\*"
		RMDir "$INSTDIR\scenario"
	NoRemoveScen:

	; Remove from registry...
	!insertmacro MUI_STARTMENU_GETFOLDER "OpenTTD" $SHORTCUTS
	ReadRegStr $SHORTCUTS HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Shortcut Folder"

	DeleteRegKey HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD"

	; Delete self
	Delete "$INSTDIR\uninstall.exe"

	; Delete Shortcuts
	Delete "$DESKTOP\OpenTTD.lnk"
	Delete "$SMPROGRAMS\$SHORTCUTS\OpenTTD.lnk"
	Delete "$SMPROGRAMS\$SHORTCUTS\Uninstall.lnk"
	Delete "$SMPROGRAMS\$SHORTCUTS\Readme.lnk"
	Delete "$SMPROGRAMS\$SHORTCUTS\Changelog.lnk"
	Delete "$SMPROGRAMS\$SHORTCUTS\Known-bugs.lnk"

	; Clean up OpenTTD dir
	Delete "$INSTDIR\changelog.txt"
	Delete "$INSTDIR\readme.txt"
	Delete "$INSTDIR\known-bugs.txt"
	Delete "$INSTDIR\openttd.exe"
	Delete "$INSTDIR\COPYING"
	Delete "$INSTDIR\INSTALL.LOG"
	Delete "$INSTDIR\crash.log"
	Delete "$INSTDIR\crash.dmp"
	Delete "$INSTDIR\openttd.cfg"
	Delete "$INSTDIR\hs.dat"
	Delete "$INSTDIR\cached_sprites.*"
	Delete "$INSTDIR\save\autosave\network*.tmp" ; temporary network file

	; Data files
	Delete "$INSTDIR\data\opntitle.dat"

	Delete "$INSTDIR\data\2ccmap.grf"
	Delete "$INSTDIR\data\airports.grf"
	Delete "$INSTDIR\data\autorail.grf"
	Delete "$INSTDIR\data\canalsw.grf"
	Delete "$INSTDIR\data\dosdummy.grf"
	Delete "$INSTDIR\data\elrailsw.grf"
	Delete "$INSTDIR\data\nsignalsw.grf"
	Delete "$INSTDIR\data\openttd.grf"
	Delete "$INSTDIR\data\roadstops.grf"
	Delete "$INSTDIR\data\trkfoundw.grf"
	Delete "$INSTDIR\data\openttdd.grf"
	Delete "$INSTDIR\data\openttdw.grf"
	Delete "$INSTDIR\data\orig_win.obg"
	Delete "$INSTDIR\data\orig_dos.obg"
	Delete "$INSTDIR\data\orig_dos_de.obg"
	Delete "$INSTDIR\data\orig_win.obs"
	Delete "$INSTDIR\data\orig_dos.obs"

	Delete "$INSTDIR\data\sample.cat"
	; Windows Data files
	Delete "$INSTDIR\data\trg1r.grf"
	Delete "$INSTDIR\data\trghr.grf"
	Delete "$INSTDIR\data\trgtr.grf"
	Delete "$INSTDIR\data\trgcr.grf"
	Delete "$INSTDIR\data\trgir.grf"
	; Dos Data files
	Delete "$INSTDIR\data\trg1.grf"
	Delete "$INSTDIR\data\trgh.grf"
	Delete "$INSTDIR\data\trgt.grf"
	Delete "$INSTDIR\data\trgc.grf"
	Delete "$INSTDIR\data\trgi.grf"

	; Music
	Delete "$INSTDIR\gm\*.gm"

	; Language files
	Delete "$INSTDIR\lang\*.lng"

	; Scripts
	Delete "$INSTDIR\scripts\*.*"

	; Remove remaining directories
	RMDir "$SMPROGRAMS\$SHORTCUTS\Extras\"
	RMDir "$SMPROGRAMS\$SHORTCUTS"
	RMDir "$INSTDIR\gm"
	RMDir "$INSTDIR\lang"
	RMDir "$INSTDIR\data"
	RMDir "$INSTDIR"

SectionEnd

;------------------------------------------------------------
; Custom page function to find the TTDLX CD/install location
Function SelectCDEnter
	SectionGetFlags ${Section2} $0
	IntOp $1 $0 & 0x80 ; bit 7 set by upgrade, no need to copy files
	IntCmp $1 1 DoneCD ; Upgrade doesn't need copy files

	IntOp $0 $0 & 1
	IntCmp $0 1 NoAbort
	Abort
NoAbort:

	GetTempFileName $R0
	!insertmacro MUI_HEADER_TEXT "Locate TTD" "Setup needs the location of Transport Tycoon Deluxe in order to continue."
	!insertmacro MUI_INSTALLOPTIONS_EXTRACT_AS "CDFinder.ini" "CDFinder"

	ClearErrors
	; Now, let's populate $CDDRIVE
	ReadRegStr $R0 HKLM "SOFTWARE\Fish Technology Group\Transport Tycoon Deluxe" "HDPath"
	IfErrors NoTTD
	StrCmp $CDDRIVE "" 0 Populated
	StrCpy $CDDRIVE $R0
Populated:
	StrCpy $AddWinPrePopulate "Setup has detected your TTD folder. Don't change the folder. Simply press Next."
	Goto TruFinish
NoTTD:
	StrCpy $AddWinPrePopulate "Setup couldn't find TTD. Please enter the path where the graphics files from TTD are stored and press Next to continue."
TruFinish:
	ClearErrors
	!insertmacro MUI_INSTALLOPTIONS_WRITE "CDFinder" "Field 2" "State" $CDDRIVE          ; TTDLX path
	!insertmacro MUI_INSTALLOPTIONS_WRITE "CDFinder" "Field 3" "Text" $AddWinPrePopulate ; Caption
DoneCD:
	; Initialize the dialog *AFTER* we've changed the text otherwise we won't see the changes
	!insertmacro MUI_INSTALLOPTIONS_INITDIALOG "CDFinder"
	!insertmacro MUI_INSTALLOPTIONS_SHOW
FunctionEnd

;----------------------------------------------------------------
; Custom page function when 'next' is selected for the TTDLX path
Function SelectCDExit
	!insertmacro MUI_INSTALLOPTIONS_READ $CDDRIVE "CDFinder" "Field 2" "State"
	; If trg1r.grf does not exist at the path, retry with DOS version
	IfFileExists $CDDRIVE\trg1r.grf "" DosCD
	IfFileExists $CDDRIVE\trgir.grf "" NoCD
	IfFileExists $CDDRIVE\sample.cat hasCD NoCD
DosCD:
	IfFileExists $CDDRIVE\TRG1.GRF "" NoCD
	IfFileExists $CDDRIVE\TRGI.GRF "" NoCD
	IfFileExists $CDDRIVE\SAMPLE.CAT hasCD NoCD
NoCD:
	MessageBox MB_OK "Setup cannot continue without the Transport Tycoon Deluxe Location!"
	Abort
hasCD:
FunctionEnd

;----------------------------------------------------------------------------------
; Disable the "Back" button on finish page if the installer is run on Win9x systems
Function DisableBack
	Call GetWindowsVersion
	Pop $R0
	StrCmp $R0 "win9x" 0 WinNT
	!insertmacro MUI_INSTALLOPTIONS_WRITE "ioSpecial.ini" "Settings" "BackEnabled" "0"
WinNT:
	ClearErrors
FunctionEnd

;----------------------------------------------------------------------------------
; Custom page function to show notices for running OpenTTD (only for win32 systems)
; We have extracted this custom page as Notice in the .onInit function
Function ShowWarningsPage
	Call GetWindowsVersion
	Pop $R0
	; Don't show the UNICODE notice if the installer is run on Win9x systems
	StrCmp $R0 "win9x" 0 WinNT
	Abort
WinNT:
	!insertmacro MUI_HEADER_TEXT "Installation Complete" "Important notices for OpenTTD usage."
	!insertmacro MUI_INSTALLOPTIONS_EXTRACT_AS "notice.ini" "Notice"
	!insertmacro MUI_INSTALLOPTIONS_INITDIALOG "Notice"
	ClearErrors
	!insertmacro MUI_INSTALLOPTIONS_SHOW
FunctionEnd

;-------------------------------------------------------------------------------
; Determine windows version, returns "win9x" if Win9x/Me or "winnt" on the stack
Function GetWindowsVersion
	ClearErrors
	StrCpy $R0 "winnt"

	GetVersion::WindowsPlatformId
	Pop $R0
	IntCmp $R0 2 WinNT 0
	StrCpy $R0 "win9x"
WinNT:
	ClearErrors
	Push $R0
FunctionEnd

;-------------------------------------------------------------------------------
; Check whether we're not running an installer for 64 bits on 32 bits and vice versa
Function CheckProcessorArchitecture
	GetVersion::WindowsPlatformArchitecture
	Pop $R0
	IntCmp $R0 64 Win64 0
	ClearErrors
	IntCmp ${APPBITS} 64 0 Done
	MessageBox MB_OKCANCEL|MB_ICONSTOP "You want to install the 64 bits OpenTTD on a 32 bits Operating System. This is not going to work. Please download the correct version. Do you really want to continue?" IDOK Done IDCANCEL Abort
	GoTo Done
Win64:
	ClearErrors
	IntCmp ${APPBITS} 64 Done 0
	MessageBox MB_OKCANCEL|MB_ICONINFORMATION "You want to install the 32 bits OpenTTD on a 64 bits Operating System. This is not adviced, but will work with reduced capabilities. We suggest that you download the correct version. Do you really want to continue?" IDOK Done IDCANCEL Abort
	GoTo Done
Abort:
	Quit
Done:
FunctionEnd


;-------------------------------------------------------------------------------
; Check whether we're not running an installer for NT on 9x and vice versa
Function CheckWindowsVersion
	Call GetWindowsVersion
	Pop $R0
	StrCmp $R0 "win9x" 0 WinNT
	ClearErrors
	StrCmp ${APPARCH} "win9x" Done 0
	MessageBox MB_OKCANCEL|MB_ICONSTOP "You want to install the Windows 2000, XP and Vista version on Windows 95, 98 or ME. This is will not work. Please download the correct version. Do you really want to continue?" IDOK Done IDCANCEL Abort
	GoTo Done
WinNT:
	ClearErrors
	StrCmp ${APPARCH} "win9x" 0 Done
	MessageBox MB_OKCANCEL|MB_ICONEXCLAMATION "You want to install the Windows 95, 98 and ME version on Windows 2000, XP or Vista. This is not adviced, but will work with reduced capabilities. We suggest that you download the correct version. Do you really want to continue?" IDOK Done IDCANCEL Abort
Abort:
	Quit
Done:
FunctionEnd

Var OLDVERSION
Var UninstallString

;-----------------------------------------------------------------------------------
; NSIS Initialize function, determin if we are going to install/upgrade or uninstall
Function .onInit
	StrCpy $SHORTCUTS "OpenTTD"

	SectionSetFlags 0 17

	; Starts Setup - let's look for an older version of OpenTTD
	ReadRegDWORD $R8 HKLM "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Version"

	IfErrors ShowWelcomeMessage ShowUpgradeMessage
ShowWelcomeMessage:
	ReadRegStr $R8 HKLM "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "Version"
	; In the event someone still has OpenTTD 0.1, this will detect that (that installer used a string instead of dword entry)
	IfErrors FinishCallback

ShowUpgradeMessage:
	IntCmp ${INSTALLERVERSION} $R8 VersionsAreEqual InstallerIsOlder  WelcomeToSetup
WelcomeToSetup:
	; An older version was found.  Let's let the user know there's an upgrade that will take place.
	ReadRegStr $OLDVERSION HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "DisplayVersion"
	; Gets the older version then displays it in a message box
	MessageBox MB_OK|MB_ICONINFORMATION \
		"Welcome to ${APPNAMEANDVERSION} Setup.$\n \
		This will allow you to upgrade from version $OLDVERSION."
	SectionSetFlags ${Section2} 0x80 ; set bit 7
	Goto FinishCallback

VersionsAreEqual:
	ReadRegStr $UninstallString HKEY_LOCAL_MACHINE "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OpenTTD" "UninstallString"
	IfFileExists "$UninstallString" "" FinishCallback
	MessageBox MB_YESNO|MB_ICONQUESTION \
		"Setup detected ${APPNAMEANDVERSION} on your system. That's the version this program will install.$\n \
		Are you trying to uninstall it?" \
		IDYES DoUninstall IDNO FinishCallback
DoUninstall: ; You have the same version as this installer.  This allows you to uninstall.
	Exec "$UninstallString"
	Quit

InstallerIsOlder:
	MessageBox MB_OK|MB_ICONSTOP \
		"You have a newer version of ${APPNAME}.$\n \
		Setup will now exit."
	Quit

FinishCallback:
	ClearErrors
	Call CheckProcessorArchitecture
	Call CheckWindowsVersion
FunctionEnd
; eof