local unescape = function (s)
   s = string.gsub(s, "+", " ")
   s = string.gsub(s, "%%(%x%x)", function (h)
         return string.char(tonumber(h, 16))
      end)
   return s
end

function Sendfile(conn, filename)
   if file.open(filename, "r") then
      local function sendChunk()
	 local line = file.read(512)
	 if line then 
	    conn:send(line, sendChunk) 
	 else
	    file.close()
	    conn:close()
	    collectgarbage()
	 end
      end
      conn:send("HTTP/1.1 200 OK\r\n" ..
      --	 "Server: NodeMCU on ESP8266\r\n" ..
      	 "Content-Type: text/html; charset=UTF-8\r\n\r\n", sendChunk)
      -- conn:send("HTTP/1.1 200 OK\r\n", sendChunk)
   else
      conn:send("HTTP/1.0 404 Not Found\r\n\r\nPage not found")
      conn:close()
   end
end

srv=net.createServer(net.TCP)
srv:listen(80,function(conn)
   conn:on("receive", function(conn,request)
      local _, _, method, path, vars = string.find(request, "([A-Z]+) (.+)?(.+) HTTP")
      if(method == nil)then
	  _, _, method, path = string.find(request, "([A-Z]+) (.+) HTTP")
      end

      local _GET = {}
      if (vars ~= nil)then
	  for k, v in string.gmatch(vars, "(%w+)=([^%&]+)&*") do
	      _GET[k] = unescape(v)
	  end
      end

      if (_GET.psw ~= nil and _GET.ap ~= nil and string.len(_GET.psw)>=8 and _GET.stnname ~= nil and _GET.stnpsw ~= nil) then
	 conn:send("Saving configuration data...")
	 file.open("config.lua", "w")

	 file.writeline('stnname = "' .. _GET.stnname .. '"')
	 print(_GET.stnname)
	 file.writeline('stnpsw = "' .. _GET.stnpsw .. '"')
	 print(_GET.stnpsw)

	 file.writeline('ssid = "' .. _GET.ap .. '"')
	 print(_GET.ap)
	 file.writeline('password = "' .. _GET.psw .. '"')
	 print(_GET.psw)

	 if (_GET.ipaddr ~= nil and _GET.netmask ~= nil and _GET.gateway ~= nil and _GET.wsport ~= nil) then
	    file.writeline('ipaddr = "' .. _GET.ipaddr .. '"')
	    file.writeline('netmask = "' .. _GET.netmask .. '"')
	    file.writeline('gateway = "' .. _GET.gateway .. '"')
	    file.writeline('wsport = "' .. _GET.wsport .. '"')
	    print(_GET.ipaddr)
	    print(_GET.netmask)
	    print(_GET.gateway)
	    print(_GET.wsport)
	 else
	    file.writeline('wsport = 80')
	    print("Webserver IP address and netmask and gateway and port NOT provided -- DHCP will be used")
	 end

	 if (_GET.tschanid ~= nil and _GET.tsapikey ~= nil) then
	    file.writeline('tschanid = "' .. _GET.tschanid .. '"')
	    print(_GET.tschanid)
	    file.writeline('tsapikey = "' .. _GET.tsapikey .. '"')
	    print(_GET.tsapikey)
	 else
	    print("ThingSpeak API write key NOT provided")
	 end

	 if (_GET.wuapiid ~= nil and _GET.wuapikey ~= nil) then
	    file.writeline('wuapiid = "' .. _GET.wuapiid .. '"')
	    print(_GET.wuapiid)
	    file.writeline('wuapikey = "' .. _GET.wuapikey .. '"')
	    print(_GET.wuapikey)
	 else
	    print("Weather Underground station ID and key NOT provided")
	 end

	 if (_GET.ubitoken ~= nil and _GET.ubidevid ~= nil) then
	    file.writeline('ubitoken = "' .. _GET.ubitoken .. '"')
	    print(_GET.ubitoken)
	    file.writeline('ubidevid = "' .. _GET.ubidevid .. '"')
	    print(_GET.ubidevid)
	 else
	    print("Ubidots token and device ID NOT provided")
	 end

	 file.close()

	 file.open("config.lua", "r")
	 print(file.read())
	 file.close()

	 node.compile("config.lua")
	 file.remove("config.lua")
	 print("Rebooting with new SSID/PASSWORD...")
	 node.restart()
      else
         print("AP and Wifi Password and Station Name and Station Password NOT provided...")
      end

      Sendfile(conn, 'main_ap.html')
   end)
end)