lighting

Daemon to automate control of lights
Uses mqtt for both control and state

Note that all messages are to be sent as persistent
Messages that are really commands will be deleted by the controller
as a way of acknowledging processing that command

mqtt hierarchy

lighting/<region>/#
  region is a set of lights that turn on and off at the same time.
  Examples might be "indoor" or "outdoor"

Messages that should be set by an outside configuration utility or
UI:
    lighting/<region>/window-start
      value is either "light", which means turn on at dusk or hh:mm.
      Time is on a 24 hour clock.  Default is "light"

    lighting/<region>/window-end
      value is hh:mm.

    lighting/<region>/devices
     payload is a comma separated list of devices in this region.
     Completely overwrites the previous list of devices.  Any devices
     that are in another region are moved to this one  Any devices
     that were in this region but not listed here are dropped.

    lighting/<region>/command
     These are commands that might be generated by an UI
     Payload is one of "on", "off", "toggle"
     The command will be erased to acknowledge it
     Any other ocmmand will be silently erased.

    lighting/<region>/drop
     all the devices in the region

    lighting/<region>/season/start
      value is mm/dd.  Default is year round

    lighting/<region>/season/end
      value is mm/dd.  Default is year round

    lighting/enable
      value is true or false

Messages that are internal state and should NOT be messed with

    lighting/<region>/control
      Values are "auto", "manual-o", "manual-i"
      When "auto" lights are off outside the window, and on inside the window.
      More on window below.
      When "manual-*" lights are the oposite of the auto setting.
      If the state is "manual-o" and we are inside the window, or if
      the state is "manual-i" and we are outside the window, set the
      state to auto.

      There are various ways to set the "manual-*" state, including
      by button press on the plug devices.  If the button is set
      and we are in manual-*, set it to auto.  IF the button is set
      and we are in auto, set to manual-i if inside the window, and
      manual-o if we are outside the window.

    lighting/<region>/state
      values are "on" and "off".  Current state of the lights.