#!/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")
local nxo=require("nixio")
require("iwinfo")
require("luci.sys")
require("uci")

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


-- delay just after rssi_monitor has a chance to run noise floor calibration
sleep(5)
local MAXLINES=2880 -- 2 days worth
local AGETIME=25000
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=""


-- 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.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:log()
	local oktolog=false
	if self.lastseen ~= nil then
		if stations[self.mac:upper()].inactive < INACTIVETIMEOUT then
			oktolog=true
		end
	else
		oktolog=true
	end

	if self.signal==0 then
		oktolog=false
	end

	if oktolog then
		-- 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 %H:%M:%S",os.time())
			local outline=string.format("%s,%s,%s\n",now,self.signal,self.noise)
			f:write(outline)
			f:close()
		else
			print(err)
		end
	end
	return oktolog
end
-- Neighbor Class END

-- MAIN() -------------------------------------------------------------------------------------
-- 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=string.match(line, "(.*)|(.*)")
			lasttime[mac]=last
		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
luci.sys.net.arptable(
	function(a)
		arpcache[a["HW address"]:lower()]=a
	end
)

-- 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=string.match(line,"(.*)|(.*)")
	if ((now-lastt) < AGETIME) then
		-- keep it
		snrdatcache[mac]=lastt
	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\n",k,v))
end
f:close()

-- END MAIN