Tekkit ccSensors ComputerCraft proximity door

-- [ (http://i.imgur.com/dDEV0) Image of my setup ] --

controller=sensors.getController() -- Constant, but may start out nil, so we prompt in setup
probe="Players" -- Constant

-- Direction Constants --
NEG_X=0
POS_X=1
NEG_Z=2
POS_Z=3
NO_DIR=4

function directionMatch(x1,y1,z1,x2,y2,z2,dir)
  x1,y1,z1=tonumber(x1),tonumber(y1),tonumber(z1)
  x2,y2,z2=tonumber(x2),tonumber(y2),tonumber(z2)
  dir=tonumber(dir)
  if(dir == NO_DIR) then
    return true
  elseif (dir == NEG_X) then
    return x1<x2
  elseif (dir == POS_X) then
    return x2>x2
  elseif (dir == NEG_Z) then
    return z1<z2
  elseif (dir == POS_Z) then
    return z1>z2
  else
    return true
  end
end

function getDirection(text)
  if(text == nil) then
    return NO_DIR
  end
  pn,d=string.match(text, "([%-%+])([a-z])")
  if (pn ~= nil) then
    if(pn == "+") then
      if(d ~= nil) then
        if(d == "x") then
          return POS_X
        elseif (d == "z") then
          return POS_Z
        else
          return NO_DIR
        end
      end
    elseif (pn == "-") then
      if(d ~= nil) then
        if(d == "x") then
          return NEG_X
        elseif (d == "z") then
          return NEG_Z
        else
          return NO_DIR
        end
      end
    else
      return NO_DIR
    end
  else
    return NO_DIR
  end
end

function show(text)
  term.clear()
  mon.clear()
  term.setCursorPos(1,3)
  write(" "..text)
  mon.setCursorPos(1,3)
  mon.write(" "..text)
end

function findPlayer(availTargets)
  for i,val in ipairs(availTargets) do
    what,x,y,z=string.match(val,"([a-z]+),(-?[0-9]+),(-?[0-9]+),(-?[0-9]+)")
    if(what=="vq") then
      return what,x,y,z
    end
  end
  return nil
end

function findClosestPlayer(availTargets)
  local what,x,y,z
  local closestDistance=math.huge
  for i,val in ipairs(availTargets) do
    local w,lx,ly,lz = string.match(val,"([a-z]+),(-?[0-9]+),(-?[0-9]+),(-?[0-9]+)")
    if(w == "vq") then
      lx,ly,lz=tonumber(lx),tonumber(ly),tonumber(lz)
      local dist=distance(lx,ly,lz,doorX,doorY,doorZ)
      if(dist <= closestDistance) then
        what,x,y,z=w,lx,ly,lz
      end
    end
  end
  return what,x,y,z
end

function inRange(x,y,z)
  x,y,z=tonumber(x),tonumber(y),tonumber(z)
  return distance(x,y,z,doorX,doorY,doorZ) <= radius
end

function distance(x1,y1,z1,x2,y2,z2)
  local dx=math.pow(x2-x1,2)
  local dy=math.pow(y2-y1,2)
  local dz=math.pow(z2-z1,2)
  return math.sqrt(dx+dy+dz)
end

function setup()
  promptSensorSetup()
  promptMonitor()
  promptRednet()
  promptRedstone()
  promptDoorLocation()
  promptDisplayDirection()
  term.clear()
  mon.clear()
  --term.redirect(mon)
  hasPlayerBeenDetected=false
end

function promptSensorSetup()
  if(controller == nil) then
    write("What side is the sensor controller on? ")
    controller=read()
    while controller ~= nil do
      controller=read()
      os.sleep(0.1)
    end
  else
    print("Sensor Controller found on "..controller.." side")
  end
  write("What is the name of the sensor? ")
  sensor=read()
  while sensor == nil do
    sensor=read()
    os.sleep(0.1)
  end
end

function promptDoorLocation()
  write("Where is the door? (x,y,z) ")
  local loc=read()
  if(loc == nil) then
    while loc == nil do
      loc=read()
      os.sleep(0.1)
    end
  end
  local x,y,z=getXYZ(loc)
  doorX,doorY,doorZ=tonumber(x),tonumber(y),tonumber(z)
  write("What distance (in blocks) triggers the door? ")
  local rad=read()
  while rad == nil do
    rad=read()
    os.sleep(0.1)
  end
  radius=tonumber(rad)
end

function getXYZ(text)
  return string.match(text, "(-?[0-9]+),(-?[0-9]+),(-?[0-9]+)")
end

function promptMonitor()
  write("What side is the monitor on? ")
  local monSide=read()
  while monSide == nil do
    monSide=read()
    os.sleep(0.1)
  end
  mon=peripheral.wrap(monSide)
end

function promptRednet()
  write("What side is the rednet modem on? ")
  local network=read()
  while network == nil do
    network=read()
    os.sleep(0.1)
  end
  if(network ~= "none") then
    rednet.open(network)
    usingRednet=true
  else
    usingRednet=false
  end
end

function promptRedstone()
  write("What side is the door's redstone controll on? ")
  doorRed=read()
  if(doorRed == nil) then
    while doorRed == nil do
      doorRed=read()
      os.sleep(0.1)
    end
  end
end

function promptDisplayDirection()
  write("what direction triggers the display? (-x,+x,-z,+z, or none) ")
  local dir=read()
  if(dir == nil) then
    while dir == nil do
      dir = read()
    end
  end
  displayDir=getDirection(dir)
end

function main()
 while true do
    local at=sensors.getAvailableTargetsforProbe(controller,sensor,probe)
    local what,x,y,z=findClosestPlayer(at)
    if(what ~= nil) then
      if(inRange(x,y,z)) then
        if(usingRednet and hasPlayerBeenDetected == false) then
          rednet.broadcast("Door accessed at "..os.time())
        end
        if(directionMatch(x,y,z,doorX,doorY,doorZ,displayDir)) then
          show("Player detected")
        end
        hasPlayerBeenDetected=true
        redstone.setOutput(doorRed, true)
      else
        show("")
        hasPlayerBeenDetected=false
        redstone.setOutput(doorRed, false)
      end
    end
    os.sleep(0.2)
  end
  term.restore()
end

setup()
main()