Need some pointers on using extenders

[jerryr]

I'm trying to wrap my mind around using extenders. Here's what I want to do:

My system consists of a cable box, receiver/amp, DVD player, Replay, VCR, and TV. I have 7 different modes in which I want to use the system:
- watch HD tv
- watch raw non-digital cable
- watch TV through the Replay
- watch a DVD
- listen to a CD
- listen to radio
- watch a tape

I want shift-[device key] to put me in one of the above modes, with each of the seven device keys corresponding to one of these modes (I'm using a RS 15-1994, btw).

shift-[device key] should make sure the required components for the mode are turned on, set the inputs on the amp and tv appropriately, and then set up the keypad appropriately for what keys are needed for that mode.

I want shift-power, in any mode, to check if the TV (or receiver/amp for radio or CD mode) is on, and if so, turn off everything. If it's not on, it should turn on the devices for the last mode it was in before it was turned off.

For example, shift-tv should set up "watch HD TV mode". Here is what I imagine the logic should be:

shift-TV:
if not in tv mode:
make sure RCVR, TV are on
Set TV to DVI input
Set RCVR to Cable input (TV)
else:
make sure RCVR, TV are on

set cbl/sat mode (i.e. remote will control cable box)

So I figure I need to use three ToadTog bits to keep track of mode, and two to keep track of the on/off state of the TV and DVD (which don't have discrete power controls), and one for the receiver (to keep track of whether devices are turned on).

What I need help on at this stage is what devices the keymoves and macros are going to go on, and combining these with device specific macros, if I indeed need to do that. I think I need one set of toadtogs for setting ons and offs, and another set for checking on/off states, and similarly for setting and checking the mode, and various macros. But I start to get confused when I try to figure out how to set up the above logic with all the keymoves and macros within IR. Can someone give me a rough outline of what I'd need to do to implement the above shift-tv logic in IR? That should give me a good idea of how to extrapolate for everything else.