Little help with planning circuit :)

I have new project - I'm building boombox with 12v battery like that:
http://www.zbattery.com/B-B-12V-20Ah-10-hr-rate-Sealed-Lead-Acid-Battery

Now, I want to build electronic circuit that when I'll push a switch, one of three LEDs will turn on:
If the battery is full charged, the green led turn on.
If the battery have anough energy, the yellow led turn on.
If there is low battery, the red led turn on.
If the battery is charging (connected to power supply), all three LEDs will turn on (or another blue led, if it's too hard).

Please help me plan the easiest schema, so I can build it just with buying the right parts, and put it together on electronic board...

Thanks!

This is a simple 3 led battery indicator circuit:

https://www.circuitstoday.com/3-led-battery-monitor-circuit