Reactor Remote Monitor Program

--
-- Remote monitor component for reactor control program
--
-- Author: VirtualDXS
-- Based heavily on original reactor control program by kla_sch
--
-- History:
--     v0.1, 2020-01-26
--         First version
--
--
-- Constant values (configuration)
--

-- Port to receive telemetry on (requires wireless modem)
receivePort=39124

-- Energy thresholds - make sure these match the reactor
critEnergy=3000000
lowEnergy=7000000
highEnergy=9000000

--
-- Write text with colors, if possible (advance monitor)
--
-- Parameters:
--     mon   - handle of monitor
--     color - text color
--     text  - text to write
--
function writeColor(mon, color, text)
   if (mon.isColor()) then
      mon.setTextColor(color)
   end
   mon.write(text)
   if (mon.isColor()) then
      mon.setTextColor(colors.white)
   end
end


--
-- Display reactor status to a monitor.
--
-- Parameters:
--     mon        - handle of monitor.
--     state      - state of reactor (table, see main loop for structure)
--
function displayStatusToMonitor(mon, state)
   mon.clear()

   -- First get the monitor size and try to scale, if the feature ist
   -- available.
   if mon.setTextScale ~= nil then
      -- reset text scale
      mon.setTextScale(1)
   end

   local width, height = mon.getSize()
   if width < 15 or height < 5 then
      -- too small: try to scale down.
      if mon.setTextScale ~= nil then
         mon.setTextScale(0.5)
      else
         return -- too small and no text scale available
      end

      width, height = mon.getSize()
      if width < 15 or height < 5 then
         return -- still too small
      end
   else
      -- Huge monitors? Try to scale up, if possible (max scale=5).
      local scale = math.min(width / 16, height / 5, 5)
      scale = math.floor(scale * 2) / 2 -- multiple of 0.5

      if scale > 1 and mon.setTextScale ~= nil then
         mon.setTextScale(scale)
         width, height = mon.getSize()
      end
   end


   --
   -- Output the data
   --

   mon.setCursorPos(1,1)
   mon.write("Reactor")

   mon.setCursorPos(1,3)
   mon.write("Status: ")

   if state.power then
      writeColor(mon, colors.green, "ACTIVE")
   else
      writeColor(mon, colors.red, "INACTIVE")
   end

   mon.setCursorPos(1,4)
   mon.write("Rod Level: " .. state.rodLevel .. "%")

   mon.setCursorPos(1,5)
   if width < 16 then
      mon.write("Cell: ") -- One block monitor (15x5 with scale 0.5)
   else
      mon.write("Energy Buffer: ")
   end

   local c
   if state.cellEnergy < critEnergy then
      c = colors.red -- Red: We use too much energy
   elseif state.cellEnergy > lowEnergy then
      c = colors.green -- Green: More energy then low water mark
   else
      c = colors.orange -- Orange: Less energy the low water mark, but OK
   end
   writeColor(mon, c, string.format("%d", math.floor(state.cellEnergy/1000 + 0.5)))
   mon.write(" kRF")
end


--
-- Display reactor status to any connected monitor and also to console.
--
-- Parameters:
--     state      - state of reactor (table, see main loop for structure)
--
function displayStatus(state)
   displayStatusToMonitor(term, state) -- console
   term.setCursorPos(1,7)
   term.write("* Hold Ctrl-T to terminate program")
   term.setCursorPos(1,8)

   local pList = peripheral.getNames()
   local i, name
   for i, name in pairs(pList) do
      if peripheral.getType(name) == "monitor" then
         -- found monitor as peripheral
         displayStatusToMonitor(peripheral.wrap(name), state)
      end
   end
end

--
-- Receive and unserialize telemetry from a reactor.
-- After perfoming some sanity checks, sets the global variable `state` to
-- the received table.
--
function receiveTelemetry()
    _,_,_,_,message = os.pullEvent("modem_message")
    print("Message received: " .. message)
    local rxState = textutils.unserialize(message)

    if type(rxState.power) == "boolean"
        and type(rxState.rodLevel) == "number"
        and type(rxState.cellEnergy) == "number" then
        print("pass")
        state = rxState
    end
end


--
-- Find the first connected wireless modem and return the wrapped handle.
--
-- If no wireless modem is found this function terminates the program.
--
-- Return:
--     Handle of first connected wireless modem found.
--
function getModemHandle()
   local pList = peripheral.getNames()
   local i, name
   for i, name in pairs(pList) do
      if peripheral.getType(name) == "modem" then
         if peripheral.call(name,"isWireless") then
            return peripheral.wrap(name)
         end
      end
   end

   error("No wireless modem connected: Exit program")
   exit()
end

modem = getModemHandle()
modem.open(receivePort)

--
-- Endless loop: Receive telemetry, display reactor state,
-- and wait for 5 seconds.
--
while true do
    state = nil

    local success,err = pcall(receiveTelemetry)
    if not success then print(err) end

    if state then
        displayStatus(state)
    end
end