watertank

-- Valve, Monitor & Wireless Modem
local tank = peripheral.wrap("back")
local mon = peripheral.wrap("top")
local wmod = peripheral.wrap("bottom")

-- Make sure channel/frequency match main computer

local sendFreq = 2       -- Modem "Frequency"
local warning = 50       -- Warning level in %
local cap                -- Tank capacity
local amount             -- Amount liquid in tank
local percentfull        -- Percent liquid in tank
local lastpercent = 1000 -- Percent last loop
local sendmsg            -- Message to send
local sleeptime          -- How long to sleep

-- Set warning lamp to off
redstone.setOutput("right", false)

function getTank(tankPeriph)
    local tableInfo = tankPeriph.getTankInfo("unknown") -- Local to the getTank function.

    for k,v in pairs(tableInfo) do
        fluidRaw = v.rawName -- local to this for loop
        fluidName = v.name -- local to this for loop
        fluidAmount = v.amount -- local to this for loop
        fluidCapacity = v.capacity -- local to this for loop
    end

    return fluidRaw, fluidName, fluidAmount, fluidCapacity -- Returning the values of global variables (which are nil).
end

-- Main prog loop, never stop
while true do
  mon.clear()
  mon.setCursorPos(1,1)

  -- Fill table with data from tank valve
  local fluidRaw, fluidName, fluidAmount, fluidCapacity = getTank(tank)

  if fluidName then
    -- Get values for tank capacity and amount
    fluidName = string.gsub(fluidName, "^%l", string.upper)
    cap = fluidCapacity / 1000
    amount = fluidAmount

    -- If tank is empty, to avoid math issues with 0
    if amount == nil then
      amount = 0
      percentfull = 0
    else
      -- Use math.floor to convert to integers
      amount = math.floor(amount / 1000)
      percentfull = math.floor(100 * amount / cap)
    end

    -- Self explanatory :)
    mon.write(fluidName)
    mon.setCursorPos(1,2)
    mon.write("Amount: " ..amount .."/"..cap .." B.")
    mon.setCursorPos(1,3)
    mon.write("Amount: " ..percentfull .."%  ")

    -- Check for change since last loop
    if percentfull == lastpercent then
      print("Still " ..percentfull .. "%, nothing sent.")
    else
      -- If value changed, send to main!
      if percentfull < warning then
        sendmsg = ".red." ..fluidName ..": " ..percentfull .."%"
      else
        sendmsg = ".green." ..fluidName ..": " ..percentfull .."%"
      end
      wmod.transmit(sendFreq,0,sendmsg)
      print("Sent: " ..sendmsg)
    end

    -- Save for next loop
    lastpercent = percentfull

    -- Warning control, local lamp
    mon.setCursorPos(1,5)

    if percentfull < warning then
      redstone.setOutput("right", true)
      mon.write("Less than " ..warning .."% full")
      sleep(1)
      redstone.setOutput("right", false)
      sleeptime = 1
    else
      -- Above warning level, sleep longer
      mon.write("More than " ..warning .."% full")
      sleeptime = 10
    end
  else
    -- If no liquid is found in tank..
    mon.write("No liquid in tank")
    term.clear()
    term.setCursorPos(1,1)
    print("No liquid in tank")
    sleeptime = 10
  end

    -- Sleep either 1 or 10 seconds
  sleep(sleeptime)
end