-- ComputerCraft oil refinery controller
-- Alternates between two banks of combustion engines so the engines don't overheat and explode

function enableWire(color) -- Turn on a colored wire in the bundle without affecting the other colors
  local currentSet = rs.getBundledOutput("back")
  if not colors.test(currentSet, color) then
    currentSet = colors.combine(currentSet, color)
    rs.setBundledOutput("back", currentSet)
  end
end

function disableWire(color) -- Turn off a colored wire in the bundle without affecting the other colors
  local currentSet = rs.getBundledOutput("back")
  if colors.test(currentSet, color) then
    currentSet = colors.subtract(currentSet, color)
    rs.setBundledOutput("back", currentSet)
  end
end

function toggleWire(color) -- Toggle a colored wire in the bundle without affecting the other colors
  local currentSet = rs.getBundledOutput("back")
  if colors.test(currentSet, color) then
    disableWire(color)
  else
    enableWire(color)
  end
end

function outputOnOff(color) -- write "ON " or "OFF" depending on the state of a wire in the bundle
  local currentSet = rs.getBundledOutput("back")
  if colors.test(currentSet, color) then
    write("ON \n")
  else
    write("OFF\n")
  end
end

local onDuration = 240 -- Keep the engines on for 4 minutes
local offDuration = 180 -- Turn the engines off for 3 minutes to cool down
local bank1_start = os.startTimer(5) -- Start the first bank of engines after 5 seconds to allow the water and fuel to start circulating
local bank1_stop
local bank2_start = os.startTimer(195) -- Start the 2nd bank of engines after around 3 minutes so they will overlap for a minute
local bank2_stop
local update_display = os.startTimer(1) -- Draw the status display

enableWire(colors.green) -- Turn on the fuel pump

while true do
  local evt, arg = os.pullEvent()
  if evt == "key" then
    if arg == 45 then -- X key is pressed
      write("Shutting down!\n")
      rs.setBundledOutput("back", 0) -- Turn everything off
      break
    elseif arg == 17 then -- W key is pressed, toggle the water pump
      toggleWire(colors.blue)
    elseif arg == 24 then -- O key is pressed, toggle the oil pump
      toggleWire(colors.black)
    end
  elseif evt == "timer" then -- Timers to start and top the engine banks
    if arg == bank1_start then
      enableWire(colors.red)
      bank1_stop = os.startTimer(onDuration)
    elseif arg == bank1_stop then
      disableWire(colors.red)
      bank1_start = os.startTimer(offDuration)
    elseif arg == bank2_start then
      enableWire(colors.yellow)
      bank2_stop = os.startTimer(onDuration)
    elseif arg == bank2_stop then
      disableWire(colors.yellow)
      bank2_start = os.startTimer(offDuration)
    elseif arg == update_display then -- Draw the status display
      term.setCursorPos(1,1)
      write("=== OIL REFINERY STATUS ===\n")
      local currentSet = rs.getBundledOutput("back")
      write("Engine bank 1: ")
      outputOnOff(colors.red)
      write("Engine bank 2: ")
      outputOnOff(colors.yellow)
      write("Fuel pump: ")
      outputOnOff(colors.green)
      write("Water tank pump: ")
      outputOnOff(colors.blue)
      write("Oil tank pump: ")
      outputOnOff(colors.black)
      write("===========================\n")
      write("X: Shutdown\n")
      write("W: Toggle water tank pump\n")
      write("O: Toggle oil tank pump\n")
      update_display = os.startTimer(1)
    end
  end
end