#!/usr/bin/lua
--[[

	Part of AREDN -- Used for creating Amateur Radio Emergency Data Networks
	Copyright (C) 2016 Darryl Quinn
	See Contributors file for additional contributors

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation version 3 of the License.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.

	Additional Terms:

	Additional use restrictions exist on the AREDN(TM) trademark and logo.
		See AREDNLicense.txt for more info.

	Attributions to the AREDN Project must be retained in the source code.
	If importing this code into a new or existing project attribution
	to the AREDN project must be added to the source code.

	You must not misrepresent the origin of the material contained within.

	Modified versions must be modified to attribute to the original source
	and be marked in reasonable ways as differentiate it from the original
	version

--]]

require("aredn.utils")
require("aredn.info")
require("uci")
require("aredn.uci")
local nxo=require("nixio")
require("iwinfo")
require("luci.sys")


-- setup extensions
os.capture=capture
string.print=print_r


-- delay just after rssi_monitor has a chance to run noise floor calibration
local MAXLINES=2880 -- 2 days worth
local AGETIME=43200
local INACTIVETIMEOUT=10000
local tmpdir="/tmp/snrlog"
local lastdat="/tmp/snr.dat"
local lasttime={}
local lines={}
local arpcache={}
local nscache={}
local defnoise=-95
local tmpdirlist={}
local neighbors={}
local stations={}
local wifiiface=""
local bandwidth=""
local nulledout={}
local pidfile="/tmp/snrlog.pid"
local rssifile="/tmp/rssi_monitor.pid"

-- Neighbor Class
Neighbor={}
Neighbor.__index=Neighbor
function Neighbor.create(macaddress)
  local n={}
  setmetatable(n,Neighbor)
  n.mac=macaddress:lower()
  n.hostname=nil
  n.sigfile=nil
  n.datafile=nil
  n.ip=nil
  n.lastseen=nil
  n.level=nil

  n.ip=n:findIp()
  n.hostname=n:findHostname()
  n.signal=n:findSignal()
  n.noise=n:findNoise()
  n.tx_mcs=n:findTxMcs()
  n.tx_rate=n:findTxRate()
  n.rx_mcs=n:findRxMcs()
  n.rx_rate=n:findRxRate()
  n.lastseen=n:findLastTime()
  n.datafile=n:generateDataFileName()
  return n
end

function Neighbor:hasIP()
  return not (self.ip==nil)
end

function Neighbor:hasHostName()
  return not (self.hostname==nil)
end

function Neighbor:getExistingDataFileName()
  local efn=nil
  for fn in nxo.fs.glob(tmpdir.."/"..self.mac.."-*") do
    efn=nxo.fs.basename(fn)
  end
  return efn
end

function Neighbor:generateDataFileName()
  local tmpfn=nil
  local efn=self:getExistingDataFileName()
  if efn~=nil then
    -- existing file found, improve or use
    tmpfn=self.mac.."-"
    m,x=string.match(efn,"^([%x2:]*)%-(.*)")
    if x==nil or x=="" then	-- "00:11:22:33:44:55-"
      if self:hasHostName() then
        tmpfn=tmpfn..self.hostname
        nxo.fs.rename(tmpdir.."/"..efn,tmpdir.."/"..tmpfn)
      elseif self:hasIP() then
        tmpfn=tmpfn..self.ip
        nxo.fs.rename(tmpdir.."/"..efn,tmpdir.."/"..tmpfn)
      end
    elseif get_ip_type(x)==1 then -- "00:11:22:33:44:55-10.11.22.33"
      if self:hasHostName() then
        tmpfn=tmpfn..self.hostname
        nxo.fs.rename(tmpdir.."/"..efn,tmpdir.."/"..tmpfn)
      else
        tmpfn=efn
      end
    else 	-- "00:11:22:33:44:55-MAYBE-GOOD-HOST"
      if x==self.hostname then	-- "00:11:22:33:44:55-SAME-HOST"
        tmpfn=efn
      else	-- "00:11:22:33:44:55-NEW-HOST-NAME"
        if self.hostname~=nil then
          tmpfn=tmpfn..self.hostname
          nxo.fs.rename(tmpdir.."/"..efn,tmpdir.."/"..tmpfn)
        else
          tmpfn=efn
        end
      end
    end
  else
    -- no prior file, let's generate one
    tmpfn=self.mac.."-"
    if self:hasHostName() then
      tmpfn=tmpfn..self.hostname
    elseif self:hasIP() then
      tmpfn=tmpfn..self.ip
    end
  end
  return tmpfn
end

function Neighbor:findLastTime()
  self.lastseen=lasttime[mac]
  return self.lastseen
end

function Neighbor:findHostname()
  if self:hasIP() then
    self.hostname=nslookup(self.ip)
  end
  return self.hostname
end

function Neighbor:findIp()
  -- lookup IP from arpcache
  local myarp=arpcache[self.mac]
  if myarp~=nil then
    self.ip=myarp["IP address"]
  end
  return self.ip
end

function Neighbor:findSignal()
  -- lookup from iwinfo
  self.signal=stations[self.mac:upper()].signal
  return self.signal
end

function Neighbor:findNoise()
  -- lookup from iwinfo
  self.noise=stations[self.mac:upper()].noise
  return self.noise
end

function Neighbor:findTxMcs()
  self.tx_mcs=stations[self.mac:upper()].tx_mcs or -1
  return self.tx_mcs
end

function Neighbor:findTxRate()
  local r=(stations[self.mac:upper()].tx_rate)/1000
  self.tx_rate=adjust_rate(r,bandwidth)
  return self.tx_rate
end

function Neighbor:findRxMcs()
  self.rx_mcs=stations[self.mac:upper()].rx_mcs or -1
  return self.rx_mcs
end

function Neighbor:findRxRate()
  local r=(stations[self.mac:upper()].rx_rate)/1000
  self.rx_rate=adjust_rate(r,bandwidth)
  return self.rx_rate
end

function Neighbor:log()
  local oktolog=true
  if self.lastseen ~= nil then
    if stations[self.mac:upper()].inactive >= INACTIVETIMEOUT then
      -- beacons expired
      self.signal="null"
      if nulledout[self.mac] == "true" then
        -- No need to double log inactive null's
        oktolog=false
      end
    end
  end

  if self.signal==0 then
    oktolog=false
    if nulledout[self.mac] == nil then
      -- First time we have seen this show up
      -- but it is at 0 wont be logged but will
      -- end up in snrcache
      nulledout[self.mac]="true"
    end
  end

  if oktolog then
    nulledout[self.mac]="false"
    -- log neighbor data to datafile
    local f, err=assert(io.open(tmpdir.."/"..self.datafile, "a"),"Cannot open file ("..tmpdir.."/"..self.datafile..") for appending!")
    if f~=nil then
      local now=os.date("%m/%d/%Y %H:%M:%S",os.time())
      local outline=string.format("%s,%s,%s,%s,%s,%s,%s\n",now,self.signal,self.noise,self.tx_mcs,self.tx_rate,self.rx_mcs,self.rx_rate)
      f:write(outline)
      f:close()
      if self.signal == "null" then
        nulledout[self.mac]="true"
      end
    else
      print(err)
    end
  end
  return oktolog
end
-- Neighbor Class END

-- MAIN() -------------------------------------------------------------------------------------
-- check to make sure a prior instance is not still running
local f = io.open(pidfile,"r")
if (f) then
  local oldpid = f:read("*number")
  f:close()
  if (oldpid ~= nill and dir_exists("/proc/" .. oldpid)) then
    return
  end
end

--- create pid file to communicate I'm running
f, err=assert(io.open(pidfile, "w"),"Cannot open file (pidfile) to write!")
if (f) then
  local mypid = posix.unistd.getpid()
  f:write(mypid)
  f:close()
end

--- Do not run if prior period rssi_monitor is still running
local f = io.open(rssifile,"r")
if (f) then
  local oldpid = f:read("*number")
  f:close()
  if (oldpid ~= nill and dir_exists("/proc/" .. oldpid)) then
    os.remove(pidfile)
    return
  end
end

-- get wifi interface name
wifiiface=get_ifname("wifi")

-- load the lasttime table
if file_exists(lastdat) then
  local f,err=io.open(lastdat,"r")
  if f~=nil then
    for line in f:lines() do
      mac,last,nulled=string.match(line, "(.*)|(.*)|(.*)")
      lasttime[mac]=last
      nulledout[mac]=nulled
    end
  end
  f:close()
end

-- get radio noise floor
local nf=iwinfo["nl80211"].noise(wifiiface)
if (nf < -101 or nf > -50) then
  nf=defnoise
end

-- create tmp dir if needed
if not dir_exists(tmpdir) then
  nxo.fs.mkdir(tmpdir)
end

-- get system uptime
--now=os.time()
now=luci.sys.uptime()

-- get all stations
stations=iwinfo["nl80211"].assoclist(wifiiface)


-- load up arpcache
arptable(
function(a)
  arpcache[a["HW address"]:lower()]=a
end
)

-- get the current bandwidth setting
local radio=getMeshRadioDevice()
bandwidth=getChannelBW(radio)

-- iterate over all the stations
for mstation in pairs(stations) do
  local n=Neighbor.create(mstation)
  table.insert(neighbors,n)
end

-- get all the existing files in tmpdir
local tmpdirlist={}
for maclist in nxo.fs.dir(tmpdir) do
  maclistbase=nxo.fs.basename(maclist)
  table.insert(tmpdirlist,maclistbase)
end

-- neighbors loop START
for _,n in pairs(neighbors) do
  -- trim datafile
  file_trim(tmpdir.."/"..n.datafile,MAXLINES)
  if n:log()==true then
    lasttime[n.mac]=now
  end
end
-- neighbors loop END

-- update snr.dat
local snrdatcache={}
if not file_exists(lastdat) then
  -- create file
  local f,err=assert(io.open(lastdat,"w+"),"Cannot create "..lastdat)
  f:close()
end
for line in io.lines(lastdat) do
  local mac,lastt,nulledoutprev=string.match(line,"(.*)|(.*)|(.*)")
  if ((now-lastt) < AGETIME) then
    -- keep it
    snrdatcache[mac]=lastt

    -- check if in neighbors table
    local foundneighbor=false
    for _,n in pairs(neighbors) do
      if n.mac == mac then
        foundneighbor=true
      end
    end

    -- If wasn't previously nulled out and we don't have it in the neigbors table write a null
    if nulledoutprev[mac] == "false" and foundneigbor == false then

      -- find the log file name
      for maclist in nxo.fs.glob(tmpdir.."/"..mac.."*") do
        logdatafile=macclist
      end

      -- Write a null to the log file
      local f, err=assert(io.open(logdatafile, "a"),"Cannot open file ("..logdatafile..") for appending!")
      if f~=nil then
        local now=os.date("%m/%d %H:%M:%S",os.time())
        local outline=string.format("%s,%s,%s,%s,%s,%s,%s\n",now,'null',nf,'0','0','0','0')
        f:write(outline)
        f:close()
        nulledout[mac]="true"
      else
        -- Don't log the null into SNRLog cause we were not successful
        -- Though the assert() above should cause this too.
        nulledout[mac]="false"
      end

    end

  else
    -- find the file and purge it
    for maclist in nxo.fs.glob(tmpdir.."/"..mac.."*") do
      nxo.fs.remove(maclist)
    end
  end
end

for _,n in pairs(neighbors) do
  snrdatcache[n.mac]=now
end

-- re-write snr.dat file
local f,err=assert(io.open(lastdat,"w+"),"Cannot overwrite "..lastdat)
for k,v in pairs(snrdatcache) do
  f:write(string.format("%s|%s|%s\n",k,v,nulledout[k]))
end
f:close()

os.remove(pidfile)

-- END MAIN