Remote Door Lock for gknova61

-- Written by Grim Reaper of ComputerCraft Forums.

-- This solution is written that the door will close at 18:00 Minecraft time,
-- and open at 6.
rednet.open("top")
print("G&K Industries Day/Night Handler")

local doorComputerID = 379                                      -- The ID of the computer that is handling the door opening/closing.
local doorCommands = {open = "Door-Open", close = "Door-Close"} -- The commands we can send to the door.

local isDoorOpen     = true    -- Whether or not the door is currently open. Assuming that the door will begin open.
local isNight        = false   -- Whether or not the time is currently night or day. Assuming that the time is currently day.
local nightStartTime = 18 -- When, in hours, the time is considered night. This is when the door should be closed.
local dayStartTime   = 6  -- When, in hours, the time is considered day. This is when the door should be open.

-- Checks if the time is correct to open/close the door. Sets 'isNight' to the appropriate values.
-- Params : dayTime - The time the day starts, nightTime - The time the night starts.
-- Returns: true - If the time has changed
function checkTime(dayTime, nightTime)
      -- Get the time in 24 hour format and compare it to the times
      -- given for the start of night and the start of day.
      local time = textutils.formatTime(os.time(), true)
      local colonPosition = time:find(':')
      time = tonumber(time:sub(1, colonPos - 1)) -- The current time in decimal hours.

      local tempIsNight = isNight
      if time > dayTime and time < nightTime then
            isNight = false
      else
            isNight = true
      end
end

-- Sends the proper commands to close/open the door depending on whether or not the time is night.
-- Params : isNight - Whether or not it is currently night time.
-- Returns: nil
function updateDoor(isNight)
      if not isNight and not isDoorOpen then
            openDoor()
            isDoorOpen = true
      elseif isNight and isDoorOpen then
            closeDoor()
            isDoorOpen = false
      end
end

-- Sends the open door command.
-- Params : nil
-- Returns: nil
function openDoor()
      rednet.send(doorComputerID, doorCommands.open)
end

-- Sends the close door command.
-- Params : nil
-- Returns: nil
function closeDoor()
      rednet.send(doorComputerID, doorCommands.close)
end

while true do
      checkTime(dayStartTime, nightStartTime)
      updateDoor(isNight)
      sleep(1) -- Make sure there is some delay so the computer does not cause Java to throw an exception due to stack overflow.
end