#!/usr/bin/lua
local fs = require('nixio.fs')
local uci = require('luci.model.uci').cursor()
local site = require 'gluon.site_config'
local iwinfo = require 'iwinfo'
local configname = 'autoupdater-wifi-fallback'
local util = require 'luci.util'
local settings = uci:get_all(configname, 'settings')
local ut = require('autoupdater-wifi-fallback.util')
local debug = true

-- parse arguments
local force = false
local i = 1
while arg[i] do
  if arg[i] == '-f' then
    print("I will do what you want")
    force = true
  end
  i = i+1
end

-- preflight checks

if not force then
  if settings.enabled ~= '1' or uci:get('autoupdater','settings','enabled') ~= '1' then
    if debug then io.stderr:write('connectivity checks or autoupdater are disabled.\n') end
    os.exit(0)
  end
  
  if fs.stat("/tmp/run/fastd.mesh_vpn.socket", "type") == "socket" then
    if debug then io.stderr:write('we have a valid socket for fastd. no fallback required.\n') end
    os.exit(0)
  end
  
  if tonumber(fs.readfile('/proc/uptime'):match('^([^ ]+) ')) < tonumber(settings.min_uptime_secs) then
    if debug then io.stderr:write('we just booted. check skipped.\n') end
    os.exit(0)
  end
end

local function check_connectivity()
  local f = io.open("/sys/kernel/debug/batman_adv/bat0/gateways","r")
  if f ~= nil then
    f:close()
    local wifi = get_wifi_neighbours()
    if wifi ~= nil then
      for key, interface in ipairs(wifi) do                                          
        if os.execute(string.format("batctl ping -t5 -c1 %s > /dev/null 2>&1", interface)) == 0 then
              return true
        end
      end
    end 
    
    local list = io.lines("/sys/kernel/debug/batman_adv/bat0/gateways")
    for line in list do
      local gateway_mac = line:match("^=?>? +([0-9a-f:]+)")
      if gateway_mac ~= nil then
        if os.execute(string.format("batctl ping -t5 -c1 %s > /dev/null 2>&1", gateway_mac)) == 0 then
          return true
        end
      end
    end
  end

  
  -- connectivity check against updateserver
  local updateHosts = get_update_hosts()
  while #updateHosts > 0 do
    host = table.remove(updateHosts)
    if os.execute("ping -w2 -c1 " .. host .. " > /dev/null 2>&1") == 0 then
      return true
    end
  end

  return false
end

local function run_autoupdater()
  -- TODO:should be called with -f !
  os.execute("/usr/sbin/autoupdater -f")
end

local function switch_to_fallback_mode(wifiNetwork)
  print("I will connect to: " .. wifiNetwork)
  local disabled_radios = {'fallback'}
  uci:foreach('wireless', 'wifi-iface',
        function(s)
          uci:set('wireless', s['.name'], 'disabled', '1')
        end
  )
  
  uci:set('wireless', 'fallback', 'ssid', wifiNetwork) 
  uci:set('wireless', 'fallback', 'disabled', 0)
  uci:save('wireless')

  io.popen("wifi")
  os.execute("sleep 5")
  os.execute("iw dev fallback connect -w " .. wifiNetwork)
  os.execute("echo \"2\" > /proc/sys/net/ipv6/conf/fallback/accept_ra")
  os.execute("sleep 20")
end

local function revert_to_standard_mode(restart_network)
  print("Going back to standard config")
  uci:revert('wireless')
  uci:save('wireless')
  if restart_network then
    os.execute("/etc/init.d/network restart")
    os.execute("sleep 30")
  end
end

if is_in_fallback_mode() then
    revert_to_standard_mode(false)
    run_autoupdater()
    -- if there really is a firmware update, we should not reach this point
    os.execute("/etc/init.d/network restart")
    os.exit(0)
end

if not check_connectivity() then
  local offset = 2 * 3600
  if fs.stat("/tmp/run/fastd.mesh_vpn.socket", "type") == "socket" then offset = 4 * 3600 end
  local unreachable_since = settings.unreachable_since
  if unreachable_since == nil then 
    uci:set(configname, 'settings', 'unreachable_since', os.time())
    unreachable_since = os.time()
  else
    uci:set(configname, 'settings', 'last_run', os.time())
  end
  uci:save(configname)
  
  if tonumber(unreachable_since) + offset < os.time() or force then
    wifiNetwork = get_available_wifi_networks()
    if wifiNetwork then
      switch_to_fallback_mode(wifiNetwork)

      run_autoupdater()
      
      -- this is only reached if no updated happened
      revert_to_standard_mode(true)
    end
  end
else
  uci:delete(configname, 'settings','unreachable_since')
  uci:delete(configname, 'settings','last_run')
  uci:save(configname)
end