Charging rule

[potato]

I understand the defense needs to establish legal defensive position before the offense come charging at them to get a charging call, however i would like to know how early does the defense need to establish the position?

Does he need to establish the legal position before the offense take off, ram in and whether the offensive usual shooting habit (i.e 1-2 step before layup/ pivoting before shot needs to be taken in consideration, so if A1 is going for the layup in 1 direction D1 needs to be there to take the charge before A1 does the 1-2 step, or before he make the jump)

And the even more confusing thing would be when it happens within the restriction zone since no charge can occur in the zone. Does it mean that any charge contact that occurs in the zone cannot be called for a charge or the shot/jump/ram has to start within the zone (an easy example would be some guy jumps from free throw line and rams into a Defense who has established LDP inside the zone.)

And if an offensive crash into a Defensive with LDP inside the zone, no charge will be called, would the D1 be called for any defensive foul or just play on?

Don't know about you guys but seems the Zone is created to give the offense opportunity to play real rough.