local socket = require "socket"
local imt = require "interminitel"
local pcap = require "pcap"

local tArgs = {...}

local port, timeout, pf = tonumber(tArgs[1]) or 4096, tonumber(tArgs[2]) or 60, tArgs[3]

local clients, coroutines, messages = {}, {}, {}

local clientcounter = 1

local function spawn(f)
 coroutines[#coroutines+1] = coroutine.create(function()
  pid = #coroutines
  while true do
   print(pid,pcall(f))
  end
 end)
end

function reprint(...)
 local tA = {...}
 for k,v in pairs(tA) do
  local s = ""
  v=tostring(v)
  for i = 1, v:len() do
   if string.byte(v:sub(i,i)) < 32 or string.byte(v:sub(i,i)) > 127 then
    s=s .. "\\" .. tostring(string.byte(v:sub(i,i)))
   else
    s=s..v:sub(i,i)
   end
  end
  print(s)
 end
end

local function hasValidPacket(s)
 local w, res = pcall(imt.decodePacket,s)
 if res then return true end
end
hasValidPacket("")

function socketLoop()
 local server = socket.bind("*", port)
 server:settimeout(0.01)
 print("vTunnel bridge server listening on port "..tostring(port))
 while true do
  local client,err = server:accept()
  if client then
   client:settimeout(0)
   clients[clientcounter+1] = {["conn"]=client,last=os.time(),buffer=""}
   clientcounter = clientcounter + 1
   local i,p = client:getsockname()
   print("Gained client #"..tostring(clientcounter)..": "..i..":"..tostring(p))
  end
  coroutine.yield()
 end
end

spawn(socketLoop)

function clientLoop()
 while true do
  for id,client in pairs(clients) do
   local s,b,c=client.conn:receive(1)
   if s then
    client.buffer = client.buffer .. s
    client.last=os.time()
   elseif b == "closed" then
    print("Client "..tostring(id).." disconnected")
    client.conn:close()
    clients[id] = nil
   end
   if client.buffer:sub(1,3) == "\0\1\0" then
    client.buffer=client.buffer:sub(4)
   end
   if client.buffer:len() > 16384 then
    print("Dropping client "..tostring(id).." for wasting resources")
    client.conn:close()
    clients[id] = nil
   end
   if client.last+timeout < os.time() then
    print("Dropping client "..tostring(id).." for inactivity")
    client.conn:close()
    clients[id] = nil
   end
  end
  coroutine.yield()
 end
end

spawn(clientLoop)

function pushLoop()
 while true do
  for id,msg in pairs(messages) do
   if msg[1]:len() > 3 then
    for k,client in pairs(clients) do
     if k ~= msg[2] then
      client.conn:send(msg[1])
      reprint("Message #"..tostring(id).." (Client #"..tostring(msg[2]).." -> Client #"..tostring(k)..") - "..msg[1])
     end
    end
    if pf then
     local f=io.open(pf,"ab")
     if f then
      f:write(pcap.packet(msg[1]))
      print(pcap.packet(msg[1]))
      f:close()
     end
    end
   end
   messages[id] = nil
  end
  coroutine.yield()
 end
end

spawn(pushLoop)

function bufferLoop()
 while true do
  for id,client in pairs(clients) do
   if client.buffer:len() > 0 then
    if imt.decodePacket(client.buffer) then
    messages[#messages+1] = {imt.encodePacket(imt.decodePacket(client.buffer)),id}
    client.buffer = imt.getRemainder(client.buffer) or ""
    end
   end
  end
  coroutine.yield()
 end
end

spawn(bufferLoop)

if pf then
 local f=io.open(pf,"wb")
 if f then
  f:write(pcap.header())
  f:close()
 else
  pf=nil
 end
end

while #coroutines > 0 do
 for k,v in pairs(coroutines) do
  coroutine.resume(v)
 end
end