#!/usr/bin/lua

-- socket and related libraries for network communication
local socket = require("socket")
local http   = require("socket.http")
local ltn12  = require("ltn12")

-- SSDP multicast address and port
local SSDP_ADDR = '239.255.255.250'
local SSDP_PORT = 1900

-- M-SEARCH request
local msearch_request = table.concat({
  'M-SEARCH * HTTP/1.1',
  'HOST: ' .. SSDP_ADDR .. ':' .. SSDP_PORT,
  'MAN: "ssdp:discover"',
  'ST: urn:schemas-upnp-org:service:WANIPConnection:1',
  'MX: 3',
  '',
  ''
}, '\r\n')

-- LOCATION ヘッダからbase URL を抽出する
local function extract_base_url(response_text)
    local _, _, location_url = string.find(response_text, "LOCATION:%s*(.+)/gatedesc.xml")
    return location_url
end

-- UPnP データを取り出す
local function get_upnp_data(base_url, req_info)
    -- データ取得のためのURLを生成
    local url = base_url .. "/upnp/control/WANCommonIFC1"

    local soap_data = string.format([[<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
  <s:Body>
    <u:%s xmlns:u="urn:schemas-upnp-org:service:WANCommonInterfaceConfig:1">
    </u:%s>
  </s:Body>
</s:Envelope>]], req_info.action, req_info.action)

    local headers = {
        ["Content-Type"] = "text/xml; charset=\"utf-8\"",
        ["SOAPAction"] = '"urn:schemas-upnp-org:service:WANCommonInterfaceConfig:1#' .. req_info.action .. '"'
    }

    -- print("----------------------------------------")
    -- print(req_info.label .. "データを取得中...")

    local response_body = {}
    local res, status_code = http.request{
        url = url,
        method = "POST",
        headers = headers,
        source = ltn12.source.string(soap_data),
        sink = ltn12.sink.table(response_body),
        timeout = 10
    }

    if status_code and (status_code == 200 or status_code == "200 OK") then
        local response_text = table.concat(response_body)
        local start_tag = req_info.tag
        local end_tag = string.gsub(start_tag, "<", "</")
        
        local _, _, bytes_string = string.find(response_text, start_tag .. "(.*)" .. end_tag)

        if bytes_string then
            local total_bytes = tonumber(bytes_string)
            local megabytes = total_bytes / 1024 / 1024
            print(string.format("合計%sバイト数: %d", req_info.label, total_bytes))
            -- print(string.format("合計%sメガバイト数: %.2f MB", req_info.label, megabytes))
        else
            print(req_info.label .. "データが見つかりませんでした。")
            print("応答内容:\n" .. response_text)
        end
    else
        print(req_info.label .. "データの取得に失敗しました。")
        print("ステータスコード: " .. (status_code or "不明"))
        print("応答内容:\n" .. table.concat(response_body))
    end
end

-- Main logic
local base_url = nil

-- Create a UDP socket for M-SEARCH
local udp = socket.udp()
udp:setoption('broadcast', true)
udp:setoption('ip-multicast-loop', true)
udp:settimeout(5)

-- print("M-SEARCHリクエストを送信中...")

-- Send the request and wait for a response
local ok, err = udp:sendto(msearch_request, SSDP_ADDR, SSDP_PORT)
if ok then
  -- print("応答を待機中...")
  while true do
    local data, ip, port = udp:receivefrom()
    if data then
      local response_text = data
      -- print(data)
      base_url = extract_base_url(response_text)
      if base_url then
        -- print("デバイスを発見しました！")
        -- print("ベースURL:", base_url)
        break -- Exit loop after finding the URL
      end
    else
      if ip == "timeout" then
        print("M-SEARCH timeout")
      else
        print("M-SEARCH error:", ip)
      end
      break
    end
  end
else
  print("M-SEARCH request error:", err)
end

-- Close the M-SEARCH socket
udp:close()

-- If a base URL was found, proceed with data acquisition
if base_url then
    local requests = {
        { action = "GetTotalBytesReceived", tag = "<NewTotalBytesReceived>", label = "受信" },
        { action = "GetTotalBytesSent", tag = "<NewTotalBytesSent>", label = "送信" }
    }

    for _, req_info in ipairs(requests) do
        get_upnp_data(base_url, req_info)
    end
else
    print("SSDP no base url")
end