set default install dir to whatever install dir was used last

prune old non-present installations by checking each for a Programs directory

stepmania/src/smpackage/SMPackageInstallDlg.cpp

@@ -259,6 +259,14 @@ void CSMPackageInstallDlg::OnOK()
 	CString sInstallDir;
 	m_comboDir.GetWindowText( sInstallDir );
 	
+	int iSelectedInstallDirIndex = m_comboDir.GetCurSel();
+	if( iSelectedInstallDirIndex == -1 )
+	{
+		MessageBox( "No Installations", "Error", MB_OK|MB_ICONEXCLAMATION );
+		return;
+	}
+
+	SetDefaultInstallDir( iSelectedInstallDirIndex );
 
 	// Show comment (if any)
 	CString sComment = m_zip.GetGlobalComment();

stepmania/src/smpackage/SMPackageUtil.cpp

@@ -42,6 +42,10 @@ void GetStepManiaInstallDirs( CStringArray& asInstallDirsOut )
 		if( sPath == "" )	// read failed
 			continue;	// skip
 
+		CString sProgramDir = sPath+"\\Program";
+		if( !DoesFileExist(sProgramDir) )
+			continue;	// skip
+
 		asInstallDirsOut.push_back( sPath );
 	} 
 
@@ -70,6 +74,17 @@ void AddStepManiaInstallDir( CString sNewInstallDir )
 	WriteStepManiaInstallDirs( asInstallDirs );
 }
 
+void SetDefaultInstallDir( int iInstallDirIndex )
+{
+	// move the specified index to the top of the list
+	CStringArray asInstallDirs;
+	GetStepManiaInstallDirs( asInstallDirs );
+	ASSERT( iInstallDirIndex > 0  &&  iInstallDirIndex < asInstallDirs.size() );
+	CString sDefaultInstallDir = asInstallDirs[iInstallDirIndex];
+	asInstallDirs.erase( asInstallDirs.begin()+iInstallDirIndex );
+	asInstallDirs.insert( asInstallDirs.begin(), sDefaultInstallDir );
+	WriteStepManiaInstallDirs( asInstallDirs );
+}
 
 bool GetPref( CString name, bool &val )
 {

stepmania/src/smpackage/smpackageUtil.h

@@ -6,6 +6,7 @@
 void WriteStepManiaInstallDirs( const CStringArray& asInstallDirsToWrite );
 void GetStepManiaInstallDirs( CStringArray& asInstallDirsOut );
 void AddStepManiaInstallDir( CString sNewInstallDir );
+void SetDefaultInstallDir( int iInstallDirIndex );
 
 bool GetPref( CString name, bool &val );
 bool SetPref( CString name, bool val );