unit

local component = require("component")
local event = require("event")
local m = component.modem
local ttf = require("ttf")
local fs = require("filesystem")

lookup = {}
mac_me = ""
for k,v in component.list("modem") do
  mac_me = k
end

function split(inputstr, sep)
  if sep == nil then
    sep = "%s"
  end
  local t={}
  for str in string.gmatch(inputstr, "([^"..sep.."]+)") do
    table.insert(t, str)
  end
  return t
end

function getIPPart(a, t)
  local ip = split(a, ".")
  local len = 0
  for k,v in pairs(ip) do
    len = len + 1
  end
  if (t == "last") then
    return ip[len]
  else
    return ip[len - (tonumber(t) - 1)]
  end
end

function getNodeCount(a)
  local ip = split(a, ".")
  local len = 0
  for k,v in pairs(ip) do
    len = len + 1
  end
  return len
end

function getUnitParentIP(a)
  local ip = split(a, ".")
  local ret = ""
  for k,v in pairs(ip) do
    if (v == getIPPart(a, "last")) then
      break
    end
    if (v == getIPPart(a, "2")) then
      ret = ret .. v
    else
      ret = ret .. v .. "."
    end
  end
  return ret
end

function stop()
  event.ignore("touch", stop)
  event.ignore("modem_message", listen)
  print("(:) Stopping...")
end

function start()
  m.open(1110)
  print("(:) Start...")
  if (fs.exists("/home/QuarksRouter/lookup.table")) then
    lookup = ttf.load("/home/QuarksRouter/lookup.table")
    print("(:) Lookups loaded")
  else
    print("(X) No lookups and parent ID!")
    lookup[-1] = "ffad-ffad-ffad-ffad"
    lookup[0] = "1.1"
  end
  print("(:) Booted up!")
  print("(:) MAC: " .. mac_me .. " IP: " .. lookup[0])
  event.listen("touch", stop)
  event.listen("modem_message", listen)
end

function import()
  local f = fs.open("/home/qclient.conf")
  local fc = f:read(fs.size("/home/qclient.conf"))
  local s = split(fc, ";")
  lookup[-1] = s[1]
  lookup[0] = s[2]
  print("(:) Successfully imported settings from QClient! " .. fc)
end

function listen(_, _, from, _, _, msg)
  packet = split(msg, ";")
  print("(:) Received packet! Resolving packet type... [" .. msg .."]")
  if (packet[3] == "DATA") then
    print("(:)       TYPE: DATA")
    handleData(from, packet, msg)
  elseif (packet[3] == "DNSLOOKUP") then
    print("(:)       TYPE: DNSLOOKUP")
    handleLookup(from, packet, msg)
  elseif (packet[3] == "DNSANSWER") then
    print("(:)       TYPE: DNSANSWER")
    handleAnswer(from, packet, msg)
  elseif (packet[3] == "DNSREG") then
    print("(:)       TYPE: DNSREG")
    handleReg(from, packet, msg)
  elseif (packet[3] == "FINDPARENT") then
    print("(:)       TYPE: FINDPARENT")
    handleFind(from, packet)
  else
    print("(X) Unknown packet type (" .. packet[3] .. ")")
  end
end

function handleData(from, p, mm)
  if (getUnitParentIP(p[2]) == lookup[0]) then
    print("(:) Rerouting packet to client in my subnet... [".. mm .."]")
    m.send(lookup[tonumber(getIPPart(p[2], "last"))], 1110, mm)
  elseif (lookup[0] == p[2]:sub( 0, lookup[0]:len() )) then
    local subip = p[2]:sub(lookup[0]:len() + 2)
    local node = split(subip, ".")[1]
    local mac = lookup[tonumber(node)]
    print("(:) Rerouting packet to child router in my subnet... (ID#" ..
    node .. " MAC:" .. mac .. " [".. mm .."]")
    m.send(mac, 1110, mm)
  else
    print("(:) Rerouting packet to parent router... [".. mm .."]")
    m.send(lookup[-1], 1110, mm)
  end
end

function handleLookup(from, p, mm)
  print("(:) Handled! ["..mm.."]")
  m.send(lookup[-1], 1110, mm)
end

function handleAnswer(from, p, mm)
  handleData(from, p, mm)
  print("(:) Handled! ["..mm.."]")
end

function handleReg(from, p, mm)
  print("(:) Handled! ["..mm.."]")
  m.send(lookup[-1], 1110, mm)
end

function handleFind(from, p)
  if (p[4] == "find") then
    m.send(from, 1110, "FINDROUTER:ME")
  elseif (p[4] == mac_me) then
    print("(:) Registering new client... (" .. from .. ")")
    local id = 0
    for k,v in pairs(lookup) do
      id = id + 1
    end
    local userip = lookup[0] .. "." .. tostring(id - 1)
    lookup[id - 1] = from
    print("(:) Allocated IP " .. userip .. " for MAC " .. from)
    m.send(from, 1110, userip)
  end
  print("(:) Handled FINDPARENT:[" .. p .. "]")
end



-- MAIN
start()
import()
event.pull("touch")
print("(:) Saving lookups...")
ttf.save(lookup, "/home/QuarksRouter/lookup.table")
print("(:) Stopped!")