#!/usr/bin/lua

local json = require("json")
local server = require("nginx.websocket.server")
local sqlite = require("lsqlite3")

local basepath = "/home/paul/git/micodus_server"
local dbfile = string.format("%s/data/tracker.db",basepath)
local query = [[
  SELECT time,latitude,longitude,height,speed,direction,serial
  FROM log
  ORDER BY time DESC
  LIMIT 1;
]]

--ngx.shared.geo:set("last_time","")

function getdata()
  local db = sqlite.open(dbfile,sqlite3.OPEN_READONLY)
  local res, vm = db:nrows(query)
  local data
  for row in res, vm do
    data = {
      ["time"]=row.time,
      ["latitude"]=row.latitude,
      ["longitude"]=row.longitude,
      ["height"]=row.height,
      ["speed"]=row.speed,
      ["direction"]=row.direction,
      ["serial"]=row.serial,
    }
  end
  db:close()
  return data
end

function geows()
  local locstr = nil
  local wb, err = server:new {
    timeout = 5000,
    max_payload_len = 65535
  }
  if not wb then
    ngx.log(ngx.ERR, "failed to new websocket: ", err)
    return ngx.exit(444)
  end
  local last_time = nil

  while true do
    local data = getdata()
    if data.time ~= last_time then
      local locstr = json.encode(data)
      local bytes, err = wb:send_text(locstr)
      if not bytes then
        ngx.log(ngx.ERR, "failed to send text: ", err)
        return ngx.exit(444)
      end
      last_time = data.time
    end
    ngx.sleep(1)
  end
  wb:send_close()
end

geows()