#include <CtrlLib/CtrlLib.h>

using namespace Upp;

int count = 0x100000;
Vector<String> data;

template <String (GetData) (int index)>
struct NumberToText : public Convert {
	virtual Value Format(const Value& q) const {
		return GetData(int(q));
	}
};

String GetIndexData(int index)
{
	ASSERT(index >= 0 && index < data.GetCount());
	return data[index];
}

String GetReverseData(int index)
{
	ASSERT(index >= 0 && index < data.GetCount());
	return data[count - index - 1];
}

String FormatData(int index)
{
	return NFormat("Data #%d", index + 1);
}

class App : public TopWindow {
public:
	typedef App CLASSNAME;
	App();

	// Ctrls
	ArrayCtrl list;
	Button btnAdd, btnRemove;
	// Events
	void OnAdd();
	void OnRemove();
};

const int addition = count / 2;

void App::OnAdd()
{
	const int prevCount = count;
	count += addition;
	data.SetCount(count);

	for (int i = prevCount; i < count; ++i)
		data[i] = FormatData(i);

	list.SetVirtualCount(count);
}

void App::OnRemove()
{
	count -= addition;
	if (count < 0)
		count = 0;

	data.SetCount(count);
	list.SetVirtualCount(count);
}

App::App()
{
	Title("Virtual ArrayCtrl");
	Sizeable().Zoomable();
	const Size sz(640, 480);
	SetRect(sz); SetMinSize(sz);

	btnAdd.SetLabel("Add") <<= THISBACK(OnAdd);
	btnRemove.SetLabel("Remove") <<= THISBACK(OnRemove);

	HeaderCtrl::Column& hc = list.AddRowNumColumn("Index").HeaderTab();
	const int textWidth = GetTextSize(AsString(count), Draw::GetStdFont()).cx,
		columnWidth = textWidth + hc.GetMargin() * 2 + 1;
	hc.Fixed(columnWidth);

	list.AddRowNumColumn("Data", 50).SetConvert(Single<NumberToText<GetIndexData> >());
	list.AddRowNumColumn("Reverse Data", 50).SetConvert(Single<NumberToText<GetReverseData> >());
	list.SetVirtualCount(count);

	const int offset = 75;
	Add(btnAdd.TopPosZ(4, 20).LeftPosZ(4, offset));
	Add(btnRemove.TopPosZ(4, 20).LeftPosZ(offset + 8, offset));
	Add(list.HSizePosZ(4, 4).VSizePosZ(28, 4));
}

GUI_APP_MAIN
{
	Ctrl::GlobalBackPaint();

	data.SetCount(count);
	{
		Progress p;
		p.SetText("Preparing the data..");
		for (int i = 0; i < count; ++i) {
			data[i] = FormatData(i);
			p.Set(i, count);
		}
	}

	App app;
	app.Run();
}