How to run a scheduled event at Solar Noon?

[sgraystar]

revised script

Code:

--[[
Warning: database functions are subject to change with firmware updates.
]]--

-- Update the start time for any solarNoon scheduler events.

local namePrefix = 'solarNoon%'
local maxOffsetHours = 8    -- avoid 24hr boundaries
local namePattern = "^solarNoon%s*([+-])%s*(0[0-"..maxOffsetHours.."])([0-5]%d)%D*"
local typeSpecificTime = ''

for _, evt in ipairs(db:getall('SELECT * FROM scheduler_events WHERE name LIKE ?', namePrefix)) do
  if evt then
    if (type(evt.start_hour) == "number") and (evt.start_hour % 1 == 0) and (type(evt.start_min) == "number") and (evt.start_min % 1 == 0) and (type(evt.type) == 'string') then
   
      local _, _, plusMinus, offsetHour, offsetMin = string.find(evt.name, namePattern)
      if plusMinus and offsetHour and offsetMin and (evt.type == typeSpecificTime) then
        local sunrise, sunset = rscalc(latitudeMel, longitudeMel)
        local solarNoon = math.floor(((sunset + sunrise) / 2) + 0.5) -- approximation

        local offsetMinutes = (offsetHour * 60) + offsetMin
        local eventMinutes
        if plusMinus == '+' then
          eventMinutes = solarNoon + offsetMinutes
        else
          eventMinutes = solarNoon - offsetMinutes
        end

        local eventStartHour = math.floor(eventMinutes / 60)
        local eventStartMin = math.floor(eventMinutes % 60)

        if (evt.start_hour ~= eventStartHour) or (evt.start_min ~= eventStartMin) then
          db:update('scheduler_events', {
            start_hour = eventStartHour,
            start_min = eventStartMin
          }, { id = evt.id })

          io.writefile('/tmp/lm-scheduler-clear', '')
        end
      else
        log("Error. '"..evt.name.."' event name must begin with 'solarNoon[+-]HHMM' where max HH = 0"..maxOffsetHours..", and event setting 'Run at:' must be 'Specific time'")
      end
     
    else
      log("Error. Firmware change, check evt.start_hour and evt.start_min are integers, and evt.type is a string.", evt)
    end
  end
end