local serial = require "serialization"
local minitel = require "minitel"
local event = require "event"
local rpc = {}
_G.rpcf = {}
rpc.port = 111

local function rpcexec(_, from, port, data)
 if port == rpc.port then
  local rpcrq = serial.unserialize(data)
  local rpcn, rpcid = table.remove(rpcrq,1), table.remove(rpcrq,1)
  if rpcf[rpcn] then
   local rt = {pcall(rpcf[rpcn],table.unpack(rpcrq))}
   if rt[1] == true then
    table.remove(rt,1)
   end
   minitel.send(from,port,serial.serialize({rpcid,table.unpack(rt)}))
  else
  end
 end
end
function rpcf.list()
 local rt = {}
 for k,v in pairs(rpcf) do
  rt[#rt+1] = k
 end
 return rt
end

function rpc.call(hostname,fn,...) -- string string -- boolean -- Calls exported function *fn* on host *hostname*, with parameters *...*, returning whatever the function returns, or false.
 if hostname == "localhost" then
  return rpcf[fn](...)
 end
 local rv = minitel.genPacketID()
 minitel.rsend(hostname,rpc.port,serial.serialize({fn,rv,...}),true)
 local st = computer.uptime()
 local rt = {}
 repeat
  local _, from, port, data = event.pull(30, "net_msg", hostname, rpc.port)
  rt = serial.unserialize(tostring(data)) or {}
 until (type(rt) == "table" and rt[1] == rv) or computer.uptime() > st + 30
 if table.remove(rt,1) == rv then
  return table.unpack(rt)
 end
 return false
end
function rpc.proxy(hostname,filter) -- string string -- table -- Returns a component.proxy()-like table from the functions on *hostname* with names matching *filter*.
 filter=(filter or "").."(.+)"
 local fnames = rpc.call(hostname,"list")
 if not fnames then return false end
 local rt = {}
 for k,v in pairs(fnames) do
  fv = v:match(filter)
  if fv then
   rt[fv] = function(...)
    return rpc.call(hostname,v,...)
   end
  end
 end
 return rt
end
function rpc.register(name,fn) -- string function -- -- Registers a function to be exported by the RPC library.
 local rpcrunning = false
 for k,v in pairs(os.tasks()) do
  if os.taskInfo(v).name == "rpc daemon" then
   rpcrunning = true
  end
 end
 if not rpcrunning then
  os.spawn(function()
   while true do
    rpcexec(event.pull("net_msg"))
   end
  end,"rpc daemon")
 end
 rpcf[name] = fn
end

return rpc