#!/usr/bin/lua

local socket = require "socket"
local lfs = require "lfs"
local uci = require "uci"
local posix = require "posix"

function startswith(String,Start)
   if String then
     return string.sub(String,1,string.len(Start))==Start
   else
     return False
   end    
end

function trim(s)
   return (s:gsub("^%s*(.-)%s*$", "%1"))
end

function url_decode(str)
  if not str then return nil end
  str = string.gsub (str, "+", " ")
  str = string.gsub (str, "%%(%x%x)", function(h) return
    string.char(tonumber(h,16)) end)
  str = string.gsub (str, "\r\n", "\n")
  return str
end

function url_encode(str)
  if (str) then
    str = string.gsub (str, "\n", "\r\n")
    str = string.gsub (str, "([^%w %-%_%.%~])",
        function (c) return string.format ("%%%02X", string.byte(c)) end)
    str = string.gsub (str, " ", "+")
  end
  return str	
end

function capture(cmd, raw)
  local f = assert(io.popen(cmd, 'r'))
  local s = assert(f:read('*a'))
  f:close()
  if raw then return s end
  s = string.gsub(s, '^%s+', '')
  s = string.gsub(s, '%s+$', '')
  s = string.gsub(s, '[\n\r]+', ' ')
  return s
end

function mqtt_encode(str)
  if (str) then
    str = string.gsub (str, "\n", "")
    str = string.gsub (str, "/", "-")
  end
  return str	
end

function touch(name)
  local file = io.open(name, 'a')
  file:close()
end

function write_file(name,data)
  pcall(function ()
    local f = io.open(name,"w")
    io.output(f)
    io.write(data)
    io.close(f)
  end)
end

function file_exists(name)
   local f=io.open(name,"r")
   if f~=nil then io.close(f) return true else return false end
end

function get_file_content(name)
  local f = io.open(name,"r")
  if f ~= nil then 
    local content = trim(f:read("*all"))
    io.close(f) 
    return content
  else 
    return false 
  end
end

function sleep(sec)
  socket.sleep(sec)
end

function split(s, delimiter)
    local result = {};
    for match in (s..delimiter):gmatch("(.-)"..delimiter) do
        result[#result+1] = match
    end
    return result;
end

function list_dir(name)
    local result = {}
    for name in lfs.dir(name) do
        if not startswith(name,".") then
          result[#result+1] = name
        end  
    end
    return result
end

function get_devid(config)

  local web_devid = uci.get(config,"web","devid")
  
  if web_devid then
    return web_devid
  end  
    
  web_iface = uci.get(config,"web","iface")
  
  if not web_iface then
    web_iface = list_dir('/sys/class/net/')[1]
  end
 
  io.input("/sys/class/net/"..web_iface.."/address")

  local web_devid = io.read("*line")
  return web_devid:gsub(":",""):upper()

end

function get_children()

  local pid = posix.getpid()
  local pidlist = list_dir('/proc')
  local pids = {}

  for k,v in pairs(pidlist) do

    pcall( function ()
      local stats = get_file_content('/proc/'..v..'/stat')
      local ppid = tonumber(split(stats,' ')[4])
      if pid == ppid then
        pids[#pids+1] = tonumber(v)
      end 
    end)

  end

  return pids

end