local vcomponent = require "vcomponent"
local serial = require "serialization"
local rpc = require "rpc"
local wgd = {}
wgd.rescanTime = 60*5
wgd.allowTypes = {filesystem=true}
wgd.hosts = {}
wgd.components = {}
wgd.ignore = {computer.tmpAddress()}
local cImported = {}
local hostStat = {}

local function loadConfig()
 local f = io.open("/boot/cfg/workgroup.cfg")
 if not f then return false end
 local cfg = serial.unserialize(f:read("*a"))
 f:close()
 for k,v in pairs(cfg) do
  wgd[k] = v
 end
end
local function saveConfig()
 local wt = {
  allowTypes=wgd.allowTypes,
  hosts=wgd.hosts,
  ignore=wgd.ignore,
  rescanTime=wgd.rescanTime,
 }
 local f = io.open("/boot/cfg/workgroup.cfg","wb")
 if not f then return false end
 f:write(serial.serialize(wt))
 f:close()
end

local function getComponents()
 return wgd.components
end

local function exportComponent(a,norescan)
 local p = component.proxy(a)
 if p and wgd.allowTypes[p.type] and not cImported[a] and not wgd.ignore[a] then
  for k,v in pairs(p) do
   --[[
   if type(v) == "function" or (type(v) == "table" and v.address == a and v.name == k) then
    rpc.register(string.format("wg_%s_%s",a,k),v)
   end
   ]]
   rpc.register(string.format("wg_%s_%s",a,k),v)
   wgd.components[a] = p.type
  end
  if norescan then return true end
  for k,v in ipairs(wgd.hosts) do
   rpc.call(v, "wg_rescan", os.getenv("HOSTNAME"))
  end
 end
end
local function unexportComponent(a)
 if wgd.components[a] then
  wgd.components[a] = nil
  for k,v in ipairs(rpcf) do
   if k:match("^wg_"..a:gsub("%-","%%-").."_") then
    rpcf[k] = nil
   end
  end
  for k,v in ipairs(hosts) do
   rpc.call(v, "wg_rescan", os.getenv("HOSTNAME"))
  end
 end
end

local function hostUp(name,clist)
 syslog("Host "..name.." is up, scanning components.")
 for a,t in pairs(clist) do
  syslog("Found "..a:sub(1,8).." ("..t..") on host "..name)
  local px = rpc.proxy(name, "wg_"..a:gsub("%-","%%-").."_")
  if type(px) == "table" then
   if t == "filesystem" then
    px.fstype = wg_mtfs
    local olabel = px.getLabel
    function px.getLabel()
     local rl = olabel() or a:sub(1,3)
     return string.format("/net/%s/%s",name,rl)
    end
   end
   cImported[a] = name
   vcomponent.register(a, t, px)
   syslog("Attached "..a:sub(1,8).." ("..t..") on host "..name)
   service.fsmanager.mount(a)
  end
 end
end
local function hostDown(name)
 for ca,ha in pairs(cImported) do
  if ha == name then
   vcomponent.unregister(ca)
   cImported[ca] = nil
  end
 end
end

function wgd.addHost(name)
 wgd.removeHost(name)
 wgd.hosts[#wgd.hosts+1] = name
 saveConfig()
 wgd.rescan(name)
end
function wgd.removeHost(name)
 for i = #wgd.hosts, 1, -1 do
  if wgd.hosts[i] == name then
   print(table.remove(wgd.hosts, i))
  end
 end
 saveConfig()
 hostDown(name)
end

function wgd.rescan(name)
 local targets = {name}
 targets = #targets > 0 and targets or wgd.hosts
 for _,n in ipairs(targets) do
  os.spawn(function()
   local clist = rpc.call(n, "wg_components")
   if clist then
    hostUp(n,clist)
   else
    hostDown(n)
   end
  end,"wgd worker: "..n)
  coroutine.yield()
 end
end

local run
function wgd.start()
 if run then return end
 run = true
 return os.spawn(function()
  loadConfig()
  rpc.register("wg_components",getComponents)
  rpc.register("wg_rescan",wgd.rescan)
  local rst = computer.uptime() + 5
  for a,t in component.list() do
   exportComponent(a,true)
  end

  for k,v in ipairs(wgd.hosts) do
   rpc.call(v, "wg_rescan", os.getenv("HOSTNAME"))
  end

  while run do
   local tE = {coroutine.yield()}
   if tE[1] == "component_added" then
    exportComponent(tE[2])
   elseif tE[1] == "component_removed" then
    unexportComponent(tE[2])
   end
   if computer.uptime() > rst then
    wgd.rescan()
    rst = computer.uptime() + wgd.rescanTime
   end
  end
 end, "workgroupd")
end
function wgd.stop()
 run = false
end

return wgd