#!/usr/bin/lua
local uci = require('simple-uci').cursor()
local autil = require 'autoupdater-wifi-fallback.util'
local util = require 'gluon.util'

local configname = 'autoupdater-wifi-fallback'
local force = false
local min_uptime_secs = 3600
local branch_name = uci:get('autoupdater', 'settings', 'branch')

local function parse_args()
local i = 1
  while arg[i] do
    if arg[i] == '-f' then
      force = true
    elseif arg[i] == '-b' then
      i=i+1

      if not arg[i] then
        io.stderr:write('Error parsing command line: expected branch name\n')
        os.exit(1)
      end

      branch_name = arg[i]
    else
      io.stderr:write("Error parsing command line: unexpected argument '" .. arg[i] .. "'\n")
      os.exit(1)
    end
    i = i+1
  end
end

local function preflight_check()
  if not uci:get_bool(configname, 'settings', 'enabled') then
    return false
  end
  if not uci:get_bool('autoupdater', 'settings', 'enabled') then
    return false
  end
  local f = io.open('/proc/uptime')
  local c = f.read "*a"
  f:close()
  if tonumber(c:match('^([^ ]+) ')) < min_uptime_secs then
    return false
  end

  return true
end

local function connectivity_check()
  local f = io.open('/sys/kernel/debug/batman_adv/bat0/gateways', 'r')
  if f then
    for line in f:lines() do
      local gateway_mac = line:match('^=?>? +([0-9a-f:]+)')
      if gateway_mac then
        if os.execute('batctl ping -t5 -c1 ' .. gateway_mac .. ' > /dev/null 2>&1') == 0 then
          return true
        end
      end
    end
    f:close()
  end

  -- connectivity check against updateserver
  for _, host in ipairs(get_update_hosts(branch_name)) do
    if os.execute('ping -w2 -c1 ' .. host .. ' > /dev/null 2>&1') == 0 then
      return true
    end
  end

  io.popen('logger -s -t autoupdater-wifi-fallback -p local0.info "connectivity check failed"')
  return false
end

local function run_autoupdater()
  io.popen('logger -s -t autoupdater-wifi-fallback -p local0.info "execute the autoupdater"')
  os.execute('/usr/sbin/autoupdater -f -b ' .. branch_name)
end

local function switch_to_fallback_mode(radio, ssid, bssid)
  io.popen('logger -s -t autoupdater-wifi-fallback -p local0.info "connect to '  .. radio .. ' ' .. ssid .. ' ' .. bssid .. '"')
  uci:delete_all('wireless', 'wifi-iface')
  uci:section('wireless', 'wifi-iface', 'fallback', {
    device = radio,
    network = 'fallback',
    mode = 'sta',
    disabled = false,
    macaddr = util.generate_mac(3, 10),
    bssid = bssid,
    ssid = ssid,
    ifname = 'fallback',
    encryption = 'none',
  })
  uci:set('wireless', radio, 'disabled', false)
  uci:save('wireless')

  os.execute('wifi')
  os.execute('sleep 5')
  uci:revert('wireless')
  os.execute('sleep 20')
end

local function revert_to_standard_mode()
  io.popen('logger -s -t autoupdater-wifi-fallback -p local0.info "going back to standard mode"')
  os.execute('/etc/init.d/network restart')
  os.execute('sleep 30')
end

parse_args()

if not uci:get('autoupdater', branch_name) then
  io.stderr:write("Can't find configuration for branch '" .. branch_name .. "'\n")
  os.exit(1)
end

if (force or preflight_check()) and not connectivity_check() then
  local offset = 2 * 3600
  local unreachable_since = os.time()
  if not uci:get('autoupdater-wifi-fallback', 'settings', 'unreachable_since') then
    uci:set(configname, 'settings', 'unreachable_since', unreachable_since)
  else
    uci:set(configname, 'settings', 'last_run', unreachable_since)
    unreachable_since = uci:get(configname, 'settings', 'unreachable_since')
  end
  uci:save(configname)

  if force or tonumber(unreachable_since) + offset < os.time() then
    io.popen('logger -s -t autoupdater-wifi-fallback -p local0.info "going to fallback mode"')
    for radio, netlist in pairs(get_available_wifi_networks()) do
      for _, net in ipairs(netlist) do
        switch_to_fallback_mode(radio, net.ssid, net.bssid)
        if run_autoupdater() == 0 then
          break
        end
      end
    end
    -- this is only reached if no updated happened
    revert_to_standard_mode()
  end
else
  uci:delete(configname, 'settings', 'unreachable_since')
  uci:delete(configname, 'settings', 'last_run')
  uci:save(configname)
end