#!/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("uci")
require("aredn.uci")
require("aredn.utils")
require("aredn.http")
require("nixio")
require("iwinfo")
local ipc = require("luci.ip")
local json = require ("luci.jsonc")

-- Function extensions
os.capture = capture


-- ==== MAIN =====
ctx = uci.cursor()
if not ctx then
    error("Failed to get uci cursor")
end

local defnoise=-95
local ol={}
local dpa={}  -- datapoint table/array
local dirname="/tmp/snrlog"
local values={}
local counter=0
local datepattern="(%d+)/(%d+)/(%d+)%s(%d+):(%d+):(%d+)"

local parms={}
parms=parsecgi(nixio.getenv("QUERY_STRING") or "")

-- make sure snrlog dir is created
if dir_exists(dirname) then
  nixio.fs.mkdir(dirname)
end

-- get wifi ifname
local wifiiface=get_ifname("wifi")

-- get bandwidth
local bandwidth=get_bandwidth()

if parms.realtime then
  -- REALTIME
  local d=os.date("%H:%M:%S")
  local n   -- noise
  local m   -- margin
  local s   -- signal
  local dp={} -- datapoint
  local yinfo={}

  if (parms.device=="strongest" or parms.device=="" or (not parms.device)) then
    -- REALTIME/STRONGEST SIGNAL
    -- get radio noise floor
    n=iwinfo["nl80211"].noise(wifiiface)
    if (n < -101 or n > -50) then
      n=defnoise
    end
    -- get strongest signal
    s=iwinfo["nl80211"].signal(wifiiface)
    m=tonumber(n)-tonumber(s)
    if s==0 then
      s="null"
    end
    tx_rate="N/A"
    rx_rate="N/A"
    tx_mcs="N/A"
    rx_mcs="N/A"
    dp.tx_rate=tx_rate
    dp.rx_rate=rx_rate
    dp.tx_mcs=tx_mcs
    dp.rx_mcs=rx_mcs
  else
    -- REALTIME/SPECIFIC SIGNAL
    -- split out device to mac-host
    local mac,host=string.match(parms.device,"([^-]*)-(.*)")
    local macinfo=iwinfo["nl80211"].assoclist(wifiiface)[mac:upper()]
    n=macinfo.noise
    s=macinfo.signal
    n=tonumber(n)
    s=tonumber(s)
    m=s-n
    tx_rate=macinfo.tx_rate/1000
    tx_rate=adjust_rate(tx_rate,bandwidth)
    rx_rate=macinfo.rx_rate/1000
    rx_rate=adjust_rate(rx_rate,bandwidth)
    tx_mcs=macinfo.tx_mcs
    rx_mcs=macinfo.rx_mcs
    m=tonumber(s)-tonumber(n)
  end

  if s==0 then
    s="null"
  end

  table.insert(yinfo,s)
  table.insert(yinfo,n)
  dp.label=d
  dp.y=yinfo
  dp.m=m
  dp.tx_rate=tx_rate
  dp.rx_rate=rx_rate
  dp.tx_mcs=tx_mcs
  dp.rx_mcs=rx_mcs
  table.insert(dpa,dp)
  table.insert(ol,dpa)
else
  -- ARCHIVE
  local filename
  if not parms.device or parms.device=="" then
    -- get the first file from dirlist
    for maclist in nixio.fs.glob(dirname.."/".."*") do
      filename=maclist
      parms.device=maclist
      break
    end
  else
    filename=dirname.."/"..parms.device
  end

  if filename then
    for line in io.lines(filename) do
      local yinfo={}
      local dp={}
      local dt,s,n,tm,tr,rm,rr=line:match("(.*)%,(.*)%,(.*),(.*),(.*),(.*),(.*)")
      local dtm,dtd,dty,dth,dtmin,dts=dt:match(datepattern)
      local dtseconds=os.time({month=dtm,day=dtd,year=dty,hour=dth,min=dtmin,sec=dts})
      dtseconds=dtseconds*1000
      dtseconds=math.floor(dtseconds)
      n=tonumber(n)

      if s~="null" then
        s=tonumber(s)
        m=s-n
      else
        m="N/A"
      end
      table.insert(yinfo,s)
      table.insert(yinfo,n)
      dp.label=dt
      dp.x=dtseconds
      dp.y=yinfo
      dp.m=m
      dp.tx_rate=tr
      dp.rx_rate=rr
      dp.tx_mcs=tm
      dp.rx_mcs=rm
      table.insert(dpa,dp)
    end
    table.insert(ol,dpa)
  end
end

-- Output the HTTP header for JSON
json_header()

-- Output the info table as json
print(json.stringify(ol,false))
-- END MAIN