Outdoor lamp with Motion Sensor


I’m trying to gain access to this whole new universe but I don’t really know where to start.
Plz let me explain what I would like to do.

There is an outdoor lamp which has no intelligence whatsoever, just two wires to get power from. I would like to make it kind of smart.

There shall be a motion sensor so when somebody passes by, the lamp switches on.
I only want this to happen, when the luminance levels are low enough. So in bright daylight, the lamp should of course stay off.

My idea was to get a Z-wave Stick and plug it into a spare Pi to make it a gateway/bridge.
Then put some multi-sensor onto the lamp and start integrating. What kind of switch do I need? The power wires coming out of the wall are connected to a regular switch inside of my house. I would need some kind of z-wave relay? Is there such a thing?

Yet those multi-sensors are battery, powered. I don’t want that. I also don’t want to have special bulbs.
Is z-wave the right direction or would you suggest to head into a different direction.

Sorry if I’m being noob.

These exist as stand-alone items from any hardware store for maybe €10-€50. That’s the simplest option.

Example: https://www.amazon.de/Motion-Outdoor-Waterproof-Adjustable-Pathway/dp/B07PQ6PTDQ/

Is there anything extra you want this device to do?

I really want to keep my existing lamp, I do not want to buy a different one.

It just should turn on and off like I explained, maybe it would be nice if I can override via OpenHAB so it stays switched on for a given time.

Your requirements are getting more complex as we go along. At first, we just wanted an existing outdoor light to come on when a motion sensor is triggered, but only if it is dark outside. T suggested a low cost solution that would do the job but that doesn’t work because we want to use the light we have. Perhaps it is the type of fixture that the bulb itself can’t be easily swapped for a bulb with sensors. We require a motion sensor, but we don’t want a battery powered one. There are mains powered light switches with motion sensors and light sensors built in. Obviously if the switch is indoors, that may not work, we want it to trigger from motion and light outside. Where is the light mounted? What area would the motion sensor need to monitor? How far is the light from where motion needs to be monitored? Could they be in the same area? Is there mains power where the motion sensor needs mounted?
Now we also want to possibly over-ride the motion sensor with a manual switch, possibly with a timer to turn the light back off if triggered manually. Where is this switch we wish to manually trigger the light mounted?
This is the type of scenario where something like openHAB becomes needed. You can see how something that seems initially pretty simple begins to turn more complex as we go along considering our requirements.
Ask yourself some of these questions and consider that if this is the only thing we ever want to automate, we can still probably figure out an off the shelf solution that does not require a controller. If however, we may want a few other things automated, our requirements might change at some time in the future or we want even greater control, then well… welcome to the wonderful addiction that is home automation.
Read the docs, read some tutorials in this forum, buy some crack… I mean… ah… home automation stuff…