Biolisten 1.0

rednet.open("left")
maxx, maxy = term.getSize()
xscale=0
yscale=0
xbounds = {}
ybounds = {}
entities = {}

function termwrite(message)
  cx, cy = term.getCursorPos()
  mx, my = term.getSize()

  if(cy == my) then
    term.scroll(1)
    term.setCursorPos(1, cy)
  else
    term.setCursorPos(1, cy + 1)
  end

  term.write(message)
end

function parsedraw(message)
  separated=textutils.unserialize(message)
  id=separated[1]
  category=separated[2]
  position=textutils.unserialize(separated[3])
  updatebounds(position)
  updateentity(id, category, position)
  turtledraw()
end

function updateentity(id, category, position)
  local s=category
  if s == "T" then
    if    (position[4]==0) then s="v"
    elseif(position[4]==1) then s="<"
    elseif(position[4]==2) then s="^"
    elseif(position[4]==3) then s=">" end
  end

  local coords={position[1],position[2],s}
  entities[id] = coords
end

function updatebounds(position)
  if(xbounds[1] == null) or (xbounds[1] > position[1]) then
    xbounds[1] = position[1]
  end
  if(xbounds[2] == null) or (xbounds[2] < position[1]) then
    xbounds[2] = position[1]
  end
  if(ybounds[1] == null) or (ybounds[1] > position[2]) then
    ybounds[1] = position[2]
  end
  if(ybounds[2] == null) or (ybounds[2] < position[2]) then
    ybounds[2] = position[2]
  end
  xscale=xbounds[2]-xbounds[1]
  yscale=ybounds[2]-ybounds[1]
end

function calccp(x, y)
  xcp = math.ceil(((x-xbounds[1])/xscale)*(maxx-1))+1
  ycp = math.ceil(((y-ybounds[1])/yscale)*(maxy-1))+1
  return xcp, ycp
end

function turtledraw()
  term.clear()
  for id, position in pairs(entities) do
    x,y = calccp(position[1],position[2])
    term.setCursorPos(x,y)
    term.write(position[3])
  end
end

term.clear()
term.setCursorPos(1,0)
termwrite("Listening...")

while true do
  id, msg = rednet.receive()
  if id ~= null then
    parsedraw(msg)
  end
end