--
-- (C) 2013-17 - ntop.org
--

--[[
Top statistics are calculated by ntopng minute.lua callback
and keep track of minute-by-minute top hosts, asn, networks, and so on.

Since local hosts are dumped to redis, top statistics for such
hosts may be inaccurate when a local host:
1. goes idle and ntopng flushes its counters, say X and Y, to redis
2. becomes active again and ntopng restores its counters from redis

Without additional logic, top statistics would not know that
the local host has been pulled out from redis and would consider
X and Y as the last minute statistics while, in practice, they
are just counters of a past active period.

For this reason we have implemented a function that gives
hosts statistics without counting deserialized byte values:
interface.getLatestActivityHostsInfo()

For example, say 192.168.2.130 is a local host

latest = interface.getLatestActivityHostsInfo()
alltime = interface.getHostsInfo()
tprint(latest["en4"]["hosts"]["192.168.2.130"]["bytes.rcvd"])
tprint(alltime["en4"]["hosts"]["192.168.2.130"]["bytes.rcvd"])

Result in
 number 1581811117
 number 5664436991

and the correct number to consider when computing minute statistics
is the one obtained via getLatestActivityHostsInfo() as the other
includes deserialized data.

--]]

dirs = ntop.getDirs()
package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path

require "persistence"

other_stats_id = "Other"

-- #################################################

function getTop(stats, sort_field_key, max_num_entries, lastdump_dir, lastdump_key, use_threshold)
   local _filtered_stats, filtered_stats, counter, total, threshold, low_threshold

   if (use_threshold == nil) then use_threshold = true end

   -- stats is a hash of hashes organized as follows:
   -- { "id1" : { "key1": "value1", "key2": "value2", ...}, "id2 : { ... } }
   -- filter out the needed values
   _filtered_stats = {}

   for id,content in pairs(stats) do
      _filtered_stats[id] = content[sort_field_key]
   end
  local file_key = sort_field_key
  if (lastdump_key ~= nil) then
    file_key = file_key.."_"..lastdump_key
  end

   -- Read the lastdump; the name of the lastdump file has the following
   -- format: <lastdump_dir>/.<sort_field_key>_lastdump
   lastdump = lastdump_dir .. "/."..file_key.."_lastdump"
   last = nil
   if(ntop.exists(lastdump)) then
      last = persistence.load(lastdump)
   end
   if(last == nil) then last = {} end

   persistence.store(lastdump, _filtered_stats);

   local total = 0
   for key, value in pairs(_filtered_stats) do
      if(last[key] ~= nil) then
         v = _filtered_stats[key]-last[key]
         if(v < 0) then v = 0 end
         _filtered_stats[key] = v
	 total = total + v
      end
   end

   threshold = total / 10 -- 10 %
   low_threshold = total * 0.05  -- 5%

   -- build a new hashtable sorted by the required field
   top_stats = {}
   other_stats = 0
   counter = 0
   for _id, _value in pairsByValues(_filtered_stats, rev) do
      if (counter < max_num_entries) then
         if ((_value == 0) or (use_threshold == true and ((_value < low_threshold or
             _value < threshold) and (counter > max_num_entries / 2)))) then
            other_stats = other_stats + _value
            goto loop_more_top
         end
         top_stats[_value] = _id -- still keep it in order
         counter = counter + 1
      else
         other_stats = other_stats + _value
      end
   ::loop_more_top::
   end

   if (other_stats > 0) then
     top_stats[other_stats] = other_stats_id
   end

   return top_stats
end

function getLastDumpKey(unique_key, filter_col, filter_val)
   -- lastdump_key will be used to uniquely identify on disk the most recent dump of the statistics.
   local lastdump_key = ""
   if unique_key ~= nil then lastdump_key = unique_key end
   if filter_col ~= nil and filter_val ~= nil then
      -- using only the unique_key may not be enough as one can filter using different criteria
      -- (e.g., vlan 1 / vlan 2 / etc..) even for the same uniqueKey.
      lastdump_key = lastdump_key.."_"..tostring(filter_col).."_"..tostring(filter_val)
   end
   return lastdump_key
end

-- #################################################

function filterBy(stats, col, val)
  local filtered_by = {}

  if (col == "" or col == nil or val == nil) then
    return stats
  end

-- io.write(debug.traceback())
  for id,content in pairs(stats) do
    if (content[col] == val) then
      filtered_by[id] = content
    end
  end

  return filtered_by
end

-- #####################################################

function getCurrentTopTalkers(ifid, ifname, filter_col, filter_val, concat, mode, use_threshold, lastdump_key)
   local max_num_entries = 10
   local rsp = ""
   local num = 0
   local latest

   interface.select(ifname)
   hosts_stats = interface.getLatestActivityHostsInfo()
   hosts_stats = filterBy(hosts_stats, filter_col, filter_val)

   talkers_dir = fixPath(dirs.workingdir .. "/" .. ifid .. "/top_talkers")
   if(not(ntop.exists(talkers_dir))) then
      ntop.mkdir(talkers_dir)
   end

   if(concat == false and mode == nil) then
      rsp = rsp.."{\n"
   end
   rsp = rsp..'\t"hosts": [\n'

   if(mode == nil) then
      rsp = rsp .. "{\n"
      rsp = rsp .. '\t"senders": ['
   end

   --print("Hello\n")
   if((mode == nil) or (mode == "senders")) then
      top_talkers = getTop(hosts_stats, "bytes.sent", max_num_entries, talkers_dir, lastdump_key, use_threshold)
      num = 0
      other_stats = 0
      for value,id in pairsByKeys(top_talkers, rev) do
         if (id == other_stats_id) then
            other_stats = value
         else
	    if(num > 0) then rsp = rsp .. " }," end
	    rsp = rsp .. '\n\t\t { "address": "'..id.. '", "label": "'
	       ..(hosts_stats[id]["name"] or 'n.a.')

	    if((hosts_stats[id]["name"] ~= "") and (isIPv6Address(id) == true)) then
	       rsp = rsp .. " (IPv6)"
	       end

	       rsp = rsp ..'", "url": "'
                  ..ntop.getHttpPrefix()..
	       '/lua/host_details.lua?host='..id..'", "value": '..value..
	       ', "local": "'..tostring(hosts_stats[id]["localhost"])..'"'
	    num = num + 1
         end
      end
      if (other_stats > 0) then
         rsp = rsp .. '},\n\t\t { "address": "'..other_stats_id.. '", "label": "'
            ..other_stats_id..'", "url": "", "value": '..other_stats..
            ', "local": "false"'
      end
   end

   if(mode == nil) then
      if(num > 0) then rsp = rsp .. " }" end
      rsp = rsp .. "\n\t],\n"
      rsp = rsp .. '\t"receivers": ['
   end

   if((mode == nil) or (mode == "receivers")) then
      top_listeners = getTop(hosts_stats, "bytes.rcvd", max_num_entries, talkers_dir, lastdump_key, use_threshold)
      num = 0
      other_stats = 0
      for value,id in pairsByKeys(top_listeners, rev) do
         if (id == other_stats_id) then
            other_stats = value
         else
	    if(num > 0) then rsp = rsp .. " }," end
	    rsp = rsp .. '\n\t\t { "address": "'..id.. '", "label": "'
	       ..(hosts_stats[id]["name"] or 'n.a.')..'", "url": "'
                  ..ntop.getHttpPrefix()..
                  '/lua/host_details.lua?host='..id..'", "value": '..value..
                  ', "local": "'..tostring(hosts_stats[id]["localhost"])..'"'
	    num = num + 1
         end
      end
      if (other_stats > 0) then
         rsp = rsp .. '},\n\t\t { "address": "'..other_stats_id.. '", "label": "'
            ..other_stats_id..'", "url": "", "value": '..other_stats..
            ', "local": "false"'
      end    
   end

   if(mode == nil) then
      if(num > 0) then rsp = rsp .. " }" end
      rsp = rsp .. "\n\t]\n"
      rsp = rsp .. "\n}\n"
   else
      if(num > 0) then rsp = rsp .. " }\n" end
   end

   rsp = rsp.."]"
   if(concat == false and mode == nil) then
      rsp = rsp.."\n}"
   end

   --print(rsp.."\n")
   return(rsp)
end

-- #####################################################

function groupHostsStatsByColumn(ifid, ifname, col)
   if hosts_stats ~= nil then
      if hosts_stats.hosts ~= nil then
	 hosts_stats = hosts_stats.hosts
      end
   else
      hosts_stats = {}
   end
   local _group = {}
   local total = 0
   -- Group hosts info by the required column
   for _key, value in pairs(hosts_stats) do
      local key = hosts_stats[_key][col]

      if ((not key) or
          (col == "country" and key == "") or
          (col == "local_network_id" and key == -1) or
          (col == "os" and key == "")) then goto continue end
      if (_group[key] == nil) then
         _group[key] = {}
         old = 0
      else
         assert(_group[key][col.."_bytes.sent"] ~= nil)
         assert(_group[key][col.."_bytes.rcvd"] ~= nil)
         assert(_group[key][col.."_bytes"] ~= nil)
         old = _group[key][col.."_bytes"]
      end

      if (col == "asn") then
         if(key == 0) then
            _group[key]["name"] = "0 [Local/Unknown]"
         else
            _group[key]["name"] = key .." ["..hosts_stats[_key]["asname"].."]"
         end
      elseif (col == "vlan") then
         if (key == 0) then
           _group[key]["name"] = "No VLAN"
         else
           _group[key]["name"] = "VLAN"..hosts_stats[_key]["vlan"]
         end
      elseif (col == "country") then
         if (key == "") then
           _group[key]["name"] = "Unknown"
         else
           _group[key]["name"] = key
         end
      elseif (col == "local_network_id") then
         if (key == -1) then
           _group[key]["name"] = "[Unknown]"
         else
           _group[key]["name"] = hosts_stats[_key]["local_network_name"]
         end
      elseif (col == "os") then
         if (key == "") then
           _group[key]["name"] = "[Unknown]"
         else
           _group[key]["name"] = hosts_stats[_key]["os"]
         end
      end
      local val = hosts_stats[_key]["bytes.sent"] + hosts_stats[_key]["bytes.rcvd"]
      total = total + val
      _group[key][col.."_bytes"] = old + val
      _group[key][col.."_bytes"] = old + val
      _group[key][col.."_bytes.sent"] = ternary(_group[key][col.."_bytes.sent"] ~= nil,
                                                _group[key][col.."_bytes.sent"], 0)
                                        + hosts_stats[_key]["bytes.sent"]
      _group[key][col.."_bytes.rcvd"] = ternary(_group[key][col.."_bytes.rcvd"] ~= nil,
                                                _group[key][col.."_bytes.rcvd"], 0)
	 + hosts_stats[_key]["bytes.rcvd"]
     ::continue::
   end

  return _group, total
end

function getCurrentTopGroupsSeparated(ifid, ifname, max_num_entries, use_threshold,
                                      use_delta, filter_col, filter_val, col, key, loc, concat, mode, lastdump_key)
   max_num_entries = 10  -- TODO: check if max_num_entries can be forcefully set to 10
   rsp = ""

   interface.select(ifname)
   hosts_stats = interface.getLatestActivityHostsInfo()
   hosts_stats = filterBy(hosts_stats, filter_col, filter_val)
   if (loc ~= nil) then
     hosts_stats = filterBy(hosts_stats, "localhost", loc)
   end

   talkers_dir = fixPath(dirs.workingdir .. "/" .. ifid .. "/top_talkers")
   if(not(ntop.exists(talkers_dir))) then
      ntop.mkdir(talkers_dir)
   end

   _group, total = groupHostsStatsByColumn(ifid, ifname, col)

   if(concat == false and mode == nil) then
      rsp = rsp.."{\n"
   end
   rsp = rsp..'\t"'..key..'": [\n'

   if(mode == nil) then
      rsp = rsp .. "{\n"
      rsp = rsp .. '\t"senders": ['
   end

   if((mode == nil) or (mode == "senders")) then
      top_talkers = getTop(_group, col.."_bytes.sent", max_num_entries, talkers_dir, lastdump_key)
      num = 0
      other_stats = 0
      for value,id in pairsByKeys(top_talkers, rev) do
         if (id == other_stats_id) then
            other_stats = value
         else
	    if(num > 0) then rsp = rsp .. " }," end
	    rsp = rsp .. '\n\t\t { "label": "'.._group[id]["name"].. '", "url": "'
                  ..ntop.getHttpPrefix()..
                  '/lua/hosts_stats.lua?'..col..'='..id..'", "address": "'
                  ..id..'", "value": '..value
	    num = num + 1
         end
      end
      if (other_stats > 0) then
         rsp = rsp .. '},\n\t\t { "address": "'..other_stats_id.. '", "label": "'
            ..other_stats_id..'", "url": "", "value": '..other_stats..
            ', "local": "false"'
      end
   end

   if(mode == nil) then
      if(num > 0) then rsp = rsp .. " }" end
      rsp = rsp .. "\n\t],\n"
      rsp = rsp .. '\t"receivers": ['
   end

   if((mode == nil) or (mode == "receivers")) then
      top_listeners = getTop(_group, col.."_bytes.rcvd", max_num_entries, talkers_dir, lastdump_key)
      num = 0
      other_stats = 0
      for value,id in pairsByKeys(top_listeners, rev) do
         if (id == other_stats_id) then
            other_stats = value
         else
	    if(num > 0) then rsp = rsp .. " }," end
	    rsp = rsp .. '\n\t\t { "label": "'.._group[id]["name"].. '", "url": "'
                  ..ntop.getHttpPrefix()..
                  '/lua/hosts_stats.lua?'..col..'='..id..'", "address": "'
                  ..id..'", "value": '..value
	    num = num + 1
         end
      end
      if (other_stats > 0) then
         rsp = rsp .. '},\n\t\t { "address": "'..other_stats_id.. '", "label": "'
            ..other_stats_id..'", "url": "", "value": '..other_stats..
            ', "local": "false"'
      end
   end

   if(mode == nil) then
      if(num > 0) then rsp = rsp .. " }" end
      rsp = rsp .. "\n\t]\n"
      rsp = rsp .. "\n}\n"
   else
      if(num > 0) then rsp = rsp .. " }\n" end
   end

   rsp = rsp.."]"
   if(concat == false and mode == nil) then
      rsp = rsp.."\n}"
   end

   --print(rsp.."\n")
   return(rsp)
end

function getCurrentTopGroups(ifid, ifname, max_num_entries, use_threshold,
                             use_delta, filter_col, filter_val, col, key, concat, mode, lastdump_key)
   rsp = ""

   --if(ifname == nil) then ifname = "any" end

   interface.select(ifname)
   hosts_stats = interface.getLatestActivityHostsInfo()
   hosts_stats = filterBy(hosts_stats, filter_col, filter_val)

   talkers_dir = fixPath(dirs.workingdir .. "/" .. ifid .. "/top_talkers")
   if(not(ntop.exists(talkers_dir))) then
      ntop.mkdir(talkers_dir)
   end

   _group, total = groupHostsStatsByColumn(ifid, ifname, col)

   if(concat == true) then
      rsp = rsp..'"'..key..'": '
   end

   rsp = rsp .. "[\n"

   -- Get top groups
   top_groups = getTop(_group, col.."_bytes", max_num_entries, talkers_dir, lastdump_key, use_threshold)

   num = 0
   other_stats = 0
   for _value,_key in pairsByKeys(top_groups, rev) do
      if (key == other_stats_id) then
         other_stats = value
      else
         if(num > 0) then rsp = rsp .. " }," end
         rsp = rsp .. '\n\t\t { "label": "'.._key..'", "url": "'
               ..ntop.getHttpPrefix()..
	    '/lua/hosts_stats.lua?'..col..'='.._key..'", "name": "'

	 if((_group[_key] ~= nil) and (_group[_key]["name"] ~= nil)) then rsp = rsp .. _group[_key]["name"] end
	 rsp = rsp ..'", "value": '.._value
         num = num + 1
      end
   end
   if (other_stats > 0) then
      rsp = rsp .. '},\n\t\t { "address": "'..other_stats_id.. '", "label": "'
         ..other_stats_id..'", "url": "", "value": '..other_stats..
         ', "local": "false"'
   end

   if (num > 0) then
      rsp = rsp .. " }\n"
   end
   rsp = rsp .. "\n]"

   return(rsp)
end