--
-- (C) 2017-20 - ntop.org
--
dirs = ntop.getDirs()

package.path = dirs.installdir .. "/scripts/lua/modules/?/init.lua;" .. package.path

local ntop_info = ntop.getInfo()

local os_utils = require "os_utils"

local host_pools_nedge = {}
host_pools_nedge.DEFAULT_POOL_ID = "0"
host_pools_nedge.DEFAULT_ROUTING_POLICY_ID = "1"
host_pools_nedge.FIRST_AVAILABLE_POOL_ID = "1"
host_pools_nedge.DEFAULT_POOL_NAME = "Not Assigned"
host_pools_nedge.MAX_NUM_POOLS = 128 -- Note: keep in sync with C

--
-- BEGIN NEDGE specific code
--
function host_pools_nedge.usernameToPoolId(username)
  local res = ntop.getPref("ntopng.user."..string.lower(username)..".host_pool_id")
  return ternary(not isEmptyString(res), res, nil)
end

function host_pools_nedge.poolIdToUsername(pool_id)
  local ifid = getInterfaceId(ifname) -- in nEdge this always takes one interface
  return host_pools_nedge.getPoolName(pool_id)
end

function host_pools_nedge.getUserUrl(pool_id)
  return ntop.getHttpPrefix() .."/lua/pro/nedge/admin/nf_edit_user.lua?username=" ..
    ternary(tostring(pool_id) == host_pools_nedge.DEFAULT_POOL_ID, "", host_pools_nedge.poolIdToUsername(pool_id))
end
--
-- END NEDGE specific code
--

host_pools_nedge.LIMITED_NUMBER_POOL_MEMBERS = ntop_info["constants.max_num_pool_members"]
-- this takes into account the special pools
host_pools_nedge.LIMITED_NUMBER_TOTAL_HOST_POOLS = ntop_info["constants.max_num_host_pools"]
-- this does not take into account the special pools
host_pools_nedge.LIMITED_NUMBER_USER_HOST_POOLS = host_pools_nedge.LIMITED_NUMBER_TOTAL_HOST_POOLS - 1

local function get_pool_members_key(pool_id)
  return "ntopng.prefs.host_pools.members." .. pool_id
end

local function get_pool_ids_key()
  return "ntopng.prefs.host_pools.pool_ids"
end

local function get_pool_details_key(pool_id)
  return "ntopng.prefs.host_pools.details." .. pool_id
end

local function get_pools_serialized_key(ifid)
  return "ntopng.serialized_host_pools.ifid_" .. ifid
end

-- It is safe to call this multiple times
local function initInterfacePools()
  host_pools_nedge.createPool(host_pools_nedge.DEFAULT_POOL_ID, host_pools_nedge.DEFAULT_POOL_NAME)
end

function host_pools_nedge.getPoolDetail(pool_id, detail)
  local details_key = get_pool_details_key(pool_id)

  return ntop.getHashCache(details_key, detail)
end

function host_pools_nedge.setPoolDetail(pool_id, detail, value)
  local details_key = get_pool_details_key(pool_id)

  return ntop.setHashCache(details_key, detail, tostring(value))
end

local function traceHostPoolEvent(severity, event)
    if ntop.getPref("ntopng.prefs.enable_host_pools_log") ~= "1" then
       return
    end

    local f_name = debug.getinfo(2, "n").name
    if f_name ~= nil then
       f_name = string.format("[%s] ", f_name)
    end

    traceError(severity, TRACE_CONSOLE, string.format("%s%s", f_name or '', event))
end

local function addMemberToRedisPool(pool_id, member_key)
  if pool_id == host_pools_nedge.DEFAULT_POOL_ID then
    -- avoid adding default pool members explicitly
    traceHostPoolEvent(TRACE_NORMAL,
		       string.format("Setting DEFAULT_POOL_ID (aka 'Not Assigned'). [pool_id: %d][member: %s]",
				     host_pools_nedge.DEFAULT_POOL_ID, member_key))
    return true
  end

  local members_key = get_pool_members_key(pool_id)
  local n = table.len(ntop.getMembersCache(members_key) or {})

  if n >= host_pools_nedge.LIMITED_NUMBER_POOL_MEMBERS then
    traceHostPoolEvent(TRACE_ERROR, string.format("Unable to set host pool, maximum number of pool members hit. [max num pool members: %d][member: %s] [members_key: %s]", host_pools_nedge.LIMITED_NUMBER_POOL_MEMBERS, member_key, members_key))
    return false
  end

  ntop.setMembersCache(members_key, member_key)
  traceHostPoolEvent(TRACE_NORMAL, string.format("Member added to pool. [member: %s] [members_key: %s]", member_key, members_key))
  return true
end

--------------------------------------------------------------------------------

function host_pools_nedge.getPoolMembersRaw(pool_id)
  local members_key = get_pool_members_key(pool_id)
  return ntop.getMembersCache(members_key) or {}
end

-- Export host pools
function host_pools_nedge.export()
  local pools = {}

  for _,pool in pairs(host_pools_nedge.getPoolsList()) do
    pool.members = host_pools_nedge.getPoolMembersRaw(pool.id)
    pools[pool.id] = pool
  end

  return pools
end

-- Import host pools, in case of conflict (same name) the pool is replaced
function host_pools_nedge.import(pools)
  local existing_pools = host_pools_nedge.getPoolsList()
  local retval = true

  -- Import pools
  for _,pool in pairs(pools) do

    for k,existing_pool in pairs(existing_pools) do
      if pool.name == existing_pool.name then
        -- Same name, delete the old pool and reuse the id
        pool.id = existing_pool.id
        host_pools_nedge.emptyPool(existing_pool.id) 
        host_pools_nedge.deletePool(existing_pool.id)
      end
    end

    -- Add pool
    host_pools_nedge.createPool(pool.id, pool.name, pool.children_safe,
      pool.enforce_quotas_per_pool_member, pool. enforce_shapers_per_pool_member,
      true)

    -- Add members
    for _,member in ipairs(pool.members) do
      local success = addMemberToRedisPool(pool.id, member)
      if not success then
        retval = false
      end
    end
  end

  return retval
end

--------------------------------------------------------------------------------

function host_pools_nedge.createPool(pool_id, pool_name, children_safe,
				     enforce_quotas_per_pool_member, enforce_shapers_per_pool_member, ignore_exist)
  local details_key = get_pool_details_key(pool_id)
  local ids_key = get_pool_ids_key()
  local members = ntop.getMembersCache(ids_key) or {}

  local n = table.len(members)

  if n >= host_pools_nedge.LIMITED_NUMBER_TOTAL_HOST_POOLS then
    return false
  end

  if not ignore_exist then
    for _, m in pairs(members) do
      if m == pool_id then
        return true
      end
    end
  end

  ntop.setMembersCache(ids_key, pool_id)
  ntop.setHashCache(details_key, "name", pool_name)
  ntop.setHashCache(details_key, "children_safe", tostring(children_safe or false))
  ntop.setHashCache(details_key, "enforce_quotas_per_pool_member",  tostring(enforce_quotas_per_pool_member  or false))
  ntop.setHashCache(details_key, "enforce_shapers_per_pool_member", tostring(enforce_shapers_per_pool_member or false))
  ntop.setHashCache(details_key, "forge_global_dns", "true")
  return true
end

function host_pools_nedge.deletePool(pool_id)
  local ts_utils = require "ts_utils"
  local ids_key = get_pool_ids_key()
  local details_key = get_pool_details_key(pool_id)
  local members_key = get_pool_members_key(pool_id)

  host_pools_nedge.emptyPool(pool_id)
  ntop.delMembersCache(ids_key, pool_id)
  ntop.delCache(details_key)
  ntop.delCache(members_key)

  -- Delete serialized values and timeseries across all interfaces
  for ifid, ifname in pairs(interface.getIfNames()) do
     local serialized_key = get_pools_serialized_key(ifid)
     ntop.delHashCache(serialized_key, pool_id)
     ts_utils.delete("host_pool", {ifid = tonumber(ifid), pool = pool_id})
  end
end

function getMembershipInfo(member_and_vlan)
  -- Check if the member is already in another pool
  local hostinfo = hostkey2hostinfo(member_and_vlan)
  local addr, mask = splitNetworkPrefix(hostinfo["host"])
  local vlan = hostinfo["vlan"]
  local is_mac = isMacAddress(addr)

  if not is_mac then
    addr = ntop.networkPrefix(addr, mask)
  end

  local find_info = interface.findMemberPool(addr, vlan, is_mac)

  -- This is the normalized key, which should always be used to refer to the member
  local key
  if not is_mac then
    key = host2member(addr, vlan, mask)
  else
    key = addr
  end

  local info = {key=key}
  local exists = false

  if find_info ~= nil then
    -- The host has been found
    if is_mac or ((not is_mac)
                  and (find_info.matched_prefix == addr)
                  and (find_info.matched_bitmask == mask)) then
      info["existing_member_pool"] = find_info.pool_id
      exists = true
    end
  end

  return exists, info
end

--
-- Note:
--
-- When strict_host_mode is not set, hosts which have a MAC address will have the
-- MAC address changed instead of the IP address when their MAC address is already bound to
-- a pool.
--
function host_pools_nedge.changeMemberPool(member_and_vlan, new_pool, info --[[optional]], strict_host_mode --[[optional]])
  traceHostPoolEvent(TRACE_NORMAL,
		     string.format("Pool change requested. [member: %s][new_pool: %s][strict_host_mode: %s]",
				   member_and_vlan, new_pool, tostring(strict_host_mode)))

  if not strict_host_mode then
    local hostkey, is_network = host_pools_nedge.getMemberKey(member_and_vlan)

    if (not is_network) and (not isMacAddress(member_and_vlan)) then
      -- this is a single host, try to get the MAC address
      if info == nil then
        local hostinfo = hostkey2hostinfo(hostkey)
        info = interface.getHostInfo(hostinfo["host"], hostinfo["vlan"])
      end

      if not isEmptyString(info["mac"]) and (info["mac"] ~= "00:00:00:00:00:00") then
        local mac_has_pool, mac_pool_info = getMembershipInfo(info["mac"])

        -- Two cases:
        --  1. if we are moving to a well defined pool, we must set the mac pool
        --  2. if we are moving to the default pool, we must set the mac pool only
        --     if the mac already has a pool, otherwise we set the ip pool
        if (new_pool ~= host_pools_nedge.DEFAULT_POOL_ID) or mac_has_pool then
          -- we must change the MAC address in order to change the host pool
          member_and_vlan = info["mac"]
        end
      end
    end
  end

  local member_exists, info = getMembershipInfo(member_and_vlan)
  local prev_pool

  if member_exists then
    -- use the normalized key
    member_and_vlan = info.key
    prev_pool = info.existing_member_pool
  else
    prev_pool = host_pools_nedge.DEFAULT_POOL_ID
  end

  if prev_pool == new_pool then
     traceHostPoolEvent(TRACE_ERROR,
		     string.format("Pool did't change. Exiting. [member: %s][prev_pool: %s][new_pool: %s]",
				   member_and_vlan, prev_pool, new_pool))
    return false
  end

  traceHostPoolEvent(TRACE_NORMAL,
		     string.format("Pool change prepared. [member: %s][info.key: %s][prev_pool: %s][new_pool: %s]",
				   member_and_vlan, tostring(info.key), prev_pool, new_pool))

  host_pools_nedge.deletePoolMember(prev_pool, info.key)
  addMemberToRedisPool(new_pool, info.key)
  return true
end

function host_pools_nedge.addPoolMember(pool_id, member_and_vlan)
  traceHostPoolEvent(TRACE_NORMAL,
		     string.format("Pool member addition requested. [member: %s][pool_id: %s]",
				   member_and_vlan, pool_id))

  local member_exists, info = getMembershipInfo(member_and_vlan)

  if member_exists then
     traceHostPoolEvent(TRACE_NORMAL, string.format("Member already in pool. [pool_id: %d] [member: %s]", pool_id, member_and_vlan))
    return false, info
  else
    local rv = addMemberToRedisPool(pool_id, info.key)
    return rv, info
  end
end

function host_pools_nedge.deletePoolMember(pool_id, member_and_vlan)
  traceHostPoolEvent(TRACE_NORMAL,
		     string.format("Pool member deletion requested. [member: %s][pool_id: %s]",
				   member_and_vlan, pool_id))

  local members_key = get_pool_members_key(pool_id)

  -- Possible delete volatile member
  if ntop.isPro() then
    interface.removeVolatileMemberFromPool(member_and_vlan, tonumber(pool_id))
  end

  -- Possible delete non-volatile member
  ntop.delMembersCache(members_key, member_and_vlan)
end

function host_pools_nedge.getPoolsList(without_info)
  local ids_key = get_pool_ids_key()
  local ids = ntop.getMembersCache(ids_key)

  if not ids then ids = {} end
  for i, id in pairs(ids) do
     ids[i] = tonumber(id)
  end

  local pools = {}

  initInterfacePools()

  for _, pool_id in pairsByValues(ids, asc) do
    pool_id = tostring(pool_id)
    local pool

    if without_info then
      pool = {id=pool_id}
    else
      pool = {
        id = pool_id,
        name = host_pools_nedge.getPoolName(pool_id),
        children_safe = host_pools_nedge.getChildrenSafe(pool_id),
	enforce_quotas_per_pool_member  = host_pools_nedge.getEnforceQuotasPerPoolMember(pool_id),
	enforce_shapers_per_pool_member = host_pools_nedge.getEnforceShapersPerPoolMember(pool_id),
      }
    end

    pools[#pools + 1] = pool
  end

  return pools
end

function host_pools_nedge.getPoolMembers(pool_id)
  local members_key = get_pool_members_key(pool_id)
  local members = {}

  local all_members = ntop.getMembersCache(members_key) or {}
  local volatile = {}

  if ntop.isPro() then
    for _,v in pairs(interface.getHostPoolsVolatileMembers()[tonumber(pool_id)] or {}) do
      if not v.expired then
        all_members[#all_members + 1] = v["member"]
        volatile[v["member"]] = v["residual_lifetime"]
      end
    end
  end

  for _,v in pairsByValues(all_members, asc) do
    local hostinfo = hostkey2hostinfo(v)
    local residual_lifetime = NULL
    if volatile[v] ~= nil then
      residual_lifetime = volatile[v];
    end

    members[#members + 1] = {address=hostinfo["host"], vlan=hostinfo["vlan"], key=v, residual=residual_lifetime}
  end

  return members
end

function host_pools_nedge.getMemberKey(member)
  -- handle vlan
  local is_network
  local host_key
  local address = hostkey2hostinfo(member)["host"]

  if isMacAddress(address) then
    host_key = address
    is_network = false
  else
    local network, prefix = splitNetworkPrefix(address)

    if(((isIPv4(network)) and (prefix ~= 32)) or
      ((isIPv6(network)) and (prefix ~= 128))) then
      -- this is a network
      host_key = address
      is_network = true
    else
      -- this is an host
      host_key = network
      is_network = false
    end
  end

  return host_key, is_network
end

function host_pools_nedge.getPoolName(pool_id)
  return host_pools_nedge.getPoolDetail(pool_id, "name")
end

function host_pools_nedge.getChildrenSafe(pool_id)
  return toboolean(host_pools_nedge.getPoolDetail(pool_id, "children_safe"))
end

function host_pools_nedge.setChildrenSafe(pool_id, value)
  host_pools_nedge.setPoolDetail(pool_id, "children_safe", ternary(value, "true", "false"))
end

function host_pools_nedge.getRoutingPolicyId(pool_id)
  local routing_policy_id = host_pools_nedge.getPoolDetail(pool_id, "routing_policy_id")
  if isEmptyString(routing_policy_id) then routing_policy_id = host_pools_nedge.DEFAULT_ROUTING_POLICY_ID end
  return routing_policy_id
end

function host_pools_nedge.setRoutingPolicyId(pool_id, routing_policy_id)
  return host_pools_nedge.setPoolDetail(pool_id, "routing_policy_id", routing_policy_id)
end

function host_pools_nedge.getEnforceQuotasPerPoolMember(pool_id)
  return toboolean(host_pools_nedge.getPoolDetail(pool_id, "enforce_quotas_per_pool_member"))
end

function host_pools_nedge.getEnforceShapersPerPoolMember(pool_id)
  return toboolean(host_pools_nedge.getPoolDetail(pool_id, "enforce_shapers_per_pool_member"))
end

function host_pools_nedge.emptyPool(pool_id)
  local members_key = get_pool_members_key(pool_id)

  if ntop.isPro() then
    -- Remove volatile members
    for _,v in pairs(interface.getHostPoolsVolatileMembers()[tonumber(pool_id)] or {}) do
      interface.removeVolatileMemberFromPool(v.member, tonumber(pool_id))
    end
  end

  -- Remove non-volatile members
  ntop.delCache(members_key)
end

function host_pools_nedge.emptyPools()
  for _, ifname in pairs(interface.getIfNames()) do
    local ifid = getInterfaceId(ifname)
    local ifstats = interface.getStats()

    local pools_list = host_pools_nedge.getPoolsList()
    for _, pool in pairs(pools_list) do
       host_pools_nedge.emptyPool(pool["id"])
    end
  end
end

function host_pools_nedge.initPools()
  for _, ifname in pairs(interface.getIfNames()) do
    local ifid = getInterfaceId(ifname)
    local ifstats = interface.getStats()

    -- Note: possible shapers are initialized in shaper_utils::initShapers
    initInterfacePools()
  end
end

function host_pools_nedge.getMacPool(mac_address)
  local exists, info = getMembershipInfo(mac_address)
  if exists then
    return tostring(info.existing_member_pool)
  else
    return host_pools_nedge.DEFAULT_POOL_ID
  end
end

function host_pools_nedge.getUndeletablePools()
  local pools = {}

  for user_key,_ in pairs(ntop.getKeysCache("ntopng.user.*.host_pool_id") or {}) do
    local pool_id = ntop.getCache(user_key)

    if tonumber(pool_id) ~= nil then
      local username = string.split(user_key, "%.")[3]
      local allowed_ifname = ntop.getCache("ntopng.user."..username..".allowed_ifname")

      -- verify if the Captive Portal User is actually active for the interface
      if getInterfaceName(ifid) == allowed_ifname then
        pools[pool_id] = true
      end
    end
  end

  return pools
end

function host_pools_nedge.updateRRDs(ifid, dump_ndpi, verbose)
  local ts_utils = require "ts_utils"
  require "ts_5min"

  -- NOTE: requires graph_utils
  for pool_id, pool_stats in pairs(interface.getHostPoolsStats() or {}) do
    ts_utils.append("host_pool:traffic", {ifid=ifid, pool=pool_id,
              bytes_sent=pool_stats["bytes.sent"], bytes_rcvd=pool_stats["bytes.rcvd"]}, when)

    if pool_id ~= tonumber(host_pools_nedge.DEFAULT_POOL_ID) then
       local flows_dropped = pool_stats["flows.dropped"] or 0

       ts_utils.append("host_pool:blocked_flows", {ifid=ifid, pool=pool_id,
              num_flows=flows_dropped}, when)
    end

    -- nDPI stats
    if dump_ndpi then
      for proto,v in pairs(pool_stats["ndpi"] or {}) do
        ts_utils.append("host_pool:ndpi", {ifid=ifid, pool=pool_id, protocol=proto,
              bytes_sent=v["bytes.sent"], bytes_rcvd=v["bytes.rcvd"]}, when)
      end
    end
  end

  -- Also write info on the number of members per pool, both in terms of hosts and l2 devices
  local pools = interface.getHostPoolsInfo() or {}
  for pool, info in pairs(pools.num_members_per_pool or {}) do
     ts_utils.append("host_pool:hosts", {ifid = ifid, pool = pool, num_hosts = info["num_hosts"]}, when)
     ts_utils.append("host_pool:devices", {ifid = ifid, pool = pool, num_devices = info["num_l2_devices"]}, when)
  end
end

function host_pools_nedge.hostpool2record(ifid, pool_id, pool)
   local record = {}
   record["key"] = tostring(pool_id)

   local pool_name = host_pools_nedge.getPoolName(pool_id)
   local pool_link = "<A HREF='"..ntop.getHttpPrefix()..'/lua/hosts_stats.lua?pool='..pool_id.."' title='"..pool_name.."'>"..pool_name..'</A>'
   record["column_id"] = pool_link

   record["column_hosts"] = pool["num_hosts"]..""
   record["column_since"] = secondsToTime(os.time() - pool["seen.first"] + 1)
   record["column_num_dropped_flows"] = (pool["flows.dropped"] or 0)..""

   local sent2rcvd = round((pool["bytes.sent"] * 100) / (pool["bytes.sent"] + pool["bytes.rcvd"]), 0)
   record["column_breakdown"] = "<div class='progress'><div class='progress-bar bg-warning' style='width: "
      .. sent2rcvd .."%;'>Sent</div><div class='progress-bar bg-info' style='width: " .. (100-sent2rcvd) .. "%;'>Rcvd</div></div>"

   if(throughput_type == "pps") then
      record["column_thpt"] = pktsToSize(pool["throughput_pps"])
   else
      record["column_thpt"] = bitsToSize(8*pool["throughput_bps"])
   end

   record["column_traffic"] = bytesToSize(pool["bytes.sent"] + pool["bytes.rcvd"])

   record["column_chart"] = ""

   if areHostPoolsTimeseriesEnabled(ifid) then
      record["column_chart"] = '<A HREF="'..ntop.getHttpPrefix()..'/lua/pool_details.lua?pool='..pool_id..'&page=historical"><i class=\'fas fa-chart-area fa-lg\'></i></A>'
   end

   return record
end

function host_pools_nedge.printQuotas(pool_id, host, page_params)
  local pools_stats = interface.getHostPoolsStats()
  local pool_stats = pools_stats and pools_stats[tonumber(pool_id)]

  local ndpi_stats = pool_stats.ndpi
  local category_stats = pool_stats.ndpi_categories
  -- ifId is a global variable here
  local quota_and_protos = shaper_utils.getPoolProtoShapers(ifId, pool_id)
  local cross_traffic_quota, cross_time_quota = shaper_utils.getCrossApplicationQuotas(ifId, pool_id)

  -- Empty check
  local empty = (cross_traffic_quota == shaper_utils.NO_QUOTA) and (cross_time_quota == shaper_utils.NO_QUOTA)

  if empty then
    for _, proto in pairs(quota_and_protos) do
      if ((tonumber(proto.traffic_quota) > 0) or (tonumber(proto.time_quota) > 0)) then
        -- at least a quota is set
        empty = false
        break
      end
    end
  end

  if empty then
    local url = "/lua/pro/nedge/admin/nf_edit_user.lua?page=protocols&username=" .. host_pools_nedge.poolIdToUsername(pool_id)

    print("<div class=\"alert alert alert-danger\"><img src=".. ntop.getHttpPrefix() .. "/img/warning.png>"..i18n("shaping.no_quota_data")..
      ". " .. i18n("host_pools.create_new_quotas_here", {url=ntop.getHttpPrefix()..url}) .. "</div>")
  else
    print[[
    <table class="table table-bordered table-striped">
    <thead>
      <tr>
        <th>]] print(i18n("application")) print[[</th>
        <th class="text-center">]] print(i18n("shaping.daily_traffic")) print[[</th>
        <th class="text-center">]] print(i18n("shaping.daily_time")) print[[</th>
      </tr>
    </thead>
    <tbody id="pool_quotas_ndpi_tbody">
    </tbody>
    </table>

    <script>
      function update_ndpi_table() {
        $.ajax({
          type: 'GET',
          url: ']]
    print(getPageUrl(ntop.getHttpPrefix().."/lua/pro/pool_details_ndpi.lua").."', data: ")
    print(tableToJsObject(page_params))
    print[[,
          success: function(content) {
            if(content)
              $('#pool_quotas_ndpi_tbody').html(content);
            else
              $('#pool_quotas_ndpi_tbody').html('<tr><td colspan="3"><i>]] print(i18n("shaping.no_quota_traffic")) print[[</i></td></tr>');
          }
        });
      }

      setInterval(update_ndpi_table, 5000);
      update_ndpi_table();
     </script>]]
  end

end

function host_pools_nedge.getFirstAvailablePoolId()
  local ids_key = get_pool_ids_key()
  local ids = ntop.getMembersCache(ids_key) or {}

  for i, id in pairs(ids) do
    ids[i] = tonumber(id)
  end

  local host_pool_id = tonumber(host_pools_nedge.FIRST_AVAILABLE_POOL_ID)

  for _, pool_id in pairsByValues(ids, asc) do
    if pool_id > host_pool_id then
      break
    end

    host_pool_id = math.max(pool_id + 1, host_pool_id)
  end

  return tostring(host_pool_id)
end

-- @brief Perform migration from the old host pools which were configured per-interface
--        to global host pools which are now system-wide
function host_pools_nedge.migrateHostPools()
   -- Migration is only performed when host pools are configured for 1 and only 1 interface (this always cover the case of nEdge)
   -- https://github.com/ntop/ntopng/issues/4086
   if ntop.getKeysCache(get_pool_ids_key()) then
      -- Already migrated
      return
   end

   local host_pools_migration = require "host_pools_migration"
   local delete_data_utils = require "delete_data_utils"
   local json = require "dkjson"
   local migration_ifid

   -- The migration is only done when there's 1 active interface
   if table.len(interface.getIfNames()) == 1 then
      -- Avoid calling interface.getId() as this migration function
      -- can be executed too early
      for ifid, ifname in pairs(interface.getIfNames()) do
	 migration_ifid = ifid
	 break
      end
   end

   -- Do the actual migration
   -- table.len >= 1 used to check whether pools different from the default one were present
   if migration_ifid and table.len(host_pools_migration.export(migration_ifid)) >= 1 then
      -- Call the `new` import with the `old` export which takes ifid as argument
      host_pools_nedge.import(host_pools_migration.export(migration_ifid))

      traceError(TRACE_WARNING, TRACE_CONSOLE, "Host pools configuration migrated.")
   end

   for ifid, ifname in pairs(delete_data_utils.list_all_interfaces()) do
      if ifid == migration_ifid then
	 -- Don't delete migrated elements
	 goto continue
      end

      local if_pools = host_pools_migration.getPoolsList(ifid)

      if table.len(if_pools) <= 1 then
	 -- Nothing to migrate, only the default pool is present
	 goto continue
      end

      -- Copy the pool configuration
      local base_dir = os_utils.fixPath(dirs.workingdir .. "/" .. ifid .. "/migration/host_pools/")
      ntop.mkdir(base_dir)
      local config_filename = os_utils.fixPath(base_dir.."/".."pools_configuration.json")
      local config_file = assert(io.open(config_filename, "w"))
      config_file:write(json.encode(host_pools_migration.export(ifid)))
      config_file:close()

      -- Delete data
      for _, pool in ipairs(if_pools) do
	 host_pools_migration.deletePool(ifid, pool.id)
      end

      -- Print out a message
      traceError(TRACE_WARNING, TRACE_CONSOLE, string.format("[%s] host pools configuration backed up to file %s due to major changes. It is possible to take the file and re-import it manually.", ifname, config_filename))

      ::continue::
   end


   -- Cleanup old host-pool related keys
   local old_keys_pattern = string.format("ntopng.prefs.*.host_pools.*")
   local old_keys = ntop.getKeysCache(old_keys_pattern)

   for old_key in pairs(old_keys) do
      ntop.delCache(old_key)
   end

   ntop.reloadHostPools()
end

function host_pools_nedge.resetPoolsQuotas(pool_filter)
  local serialized_key = get_pools_serialized_key(tostring(interface.getId()))
  local keys_to_del

  if pool_filter ~= nil then
    keys_to_del = {[pool_filter]=1, }
  else
    keys_to_del = ntop.getHashKeysCache(serialized_key) or {}
  end

  -- Delete the redis serialization
  for key in pairs(keys_to_del) do
    ntop.delHashCache(serialized_key, tostring(key))
  end

  -- Delete the in-memory stats
  interface.resetPoolsQuotas(pool_filter)
end

host_pools_nedge.traceHostPoolEvent = traceHostPoolEvent

return host_pools_nedge
