Measuring 230V AC current with low sample rate
A rudimentary pretense of safety could be achieved with a current transformer. This plus the appropriate burden resistor will reasonably accurately give you a signal that is pretty closely related to current drawn.

Then I'd consider using an op-amp configured as a precision rectifier: -



This one is a full-wave rectifier and here is a half wave rectifier circuit: -



The output will follow the rectified value of the input. You can add a capacitor on the output and a parallel resistor to give you a peak value of the current - this will be a slow moving DC signal that follows the envelope of the AC current. RMS will be peak value divided by \$\sqrt2\$ for resistive loads as mentioned in the question.