--
-- (C) 2024 - ntop.org
--
local dirs = ntop.getDirs()
package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path

require "ntop_utils"
require "check_redis_prefs"
require "lua_utils_generic"
local json = require "dkjson"

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

-- ##############      NOTES       ##############
-- The asset table is a table containing the
-- assets found by ntopng. Periodically uses a script
-- to drop these data from C to Lua into the DB
-- (Clickhouse or SQLite).
-- The table is a single table, containing two types of data:
--   - Hosts data: identified from the column, type = 'host'
--   - MACs data: identified from the column, type = 'mac'
-- Whenever a query is done, MUST be controlled if the data
-- requested is for hosts or for macs and add the specific
-- type filter.

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

local asset_utils = {}
local table_name = "assets"

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

local function build_where(ifid, filters)
    local where = ""
    -- Exception for the status filter, it's last_seen = 0 or last_seen != 0
    local status_filter = filters["status"]
    local os_filter = filters["os_type"]
    local server_filter = filters["server_type"]
    filters["server_type"] = nil
    filters["os_type"] = nil
    filters["status"] = nil

    for key, value in pairs(filters) do
        where = where .. "AND"
        if tonumber(value) then
            value = tonumber(value)
        else
            value = string.format("'%s'", value)
        end

        where = string.format("%s %s=%s ", where, key, value)
    end

    if status_filter then
        where = string.format("%s AND %s%s%s", where, "last_seen",
                              ternary(status_filter == "0", "=", "!="), "0")
    end

    if os_filter then
        if isEmptyString(os_filter) or tostring(os_filter) == "0" then
            where = string.format("%s AND %s", where,
                                  "NOT simpleJSONHas(json_info, 'os_type')")
        else
            where = string.format("%s AND %s'%d'", where,
                                  "JSONExtractString(json_info, 'os_type') == ",
                                  tostring(os_filter))
        end
    end

    if server_filter then
        local server_type = ''
        if tonumber(server_filter) == 0 then
            server_type = "dns_server"
        elseif tonumber(server_filter) == 1 then
            server_type = "dhcp_server"
        elseif tonumber(server_filter) == 2 then
            server_type = "smtp_server"
        elseif tonumber(server_filter) == 3 then
            server_type = "ntp_server"
        elseif tonumber(server_filter) == 4 then
            server_type = "imap_server"
        elseif tonumber(server_filter) == 5 then
            server_type = "pop_server"
        end
        where = string.format("%s AND %s", where,
                              "simpleJSONExtractString(json_info, '" ..
                                  server_type .. "') == 'true'")
    end
    filters["status"] = status_filter
    filters["os_type"] = os_filter
    filters["server_type"] = server_filter
    return where
end

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

-- This function partially format the data retrieved from the query
local function partiallyFormatInfo(res)
    local res_formatted = {}
    for _, res_unformatted in pairs(res or {}) do
        local tmp = res_unformatted
        local json_info = json.decode(res_unformatted.json_info or "") or {}

        if json_info["os_type"] then
            tmp["os_type"] = json_info["os_type"]
            json_info["os_type"] = nil
        end

        local resolved_names = {}
        if table.len(json_info) > 0 then
            resolved_names["mdns_name"] = json_info["mdns_name"]
            resolved_names["dhcp_name"] = json_info["dhcp_name"]
            resolved_names["mdns_txt_name"] = json_info["mdns_txt_name"]
            resolved_names["netbios_name"] = json_info["netbios_name"]
            resolved_names["tls_name"] = json_info["tls_name"]
            resolved_names["http_name"] = json_info["http_name"]
            resolved_names["dns_name"] = json_info["dns_name"]

            if resolved_names["mdns_name"] then
                json_info["mdns_name"] = nil
            end
            if resolved_names["dhcp_name"] then
                json_info["dhcp_name"] = nil
            end
            if resolved_names["mdns_txt_name"] then
                json_info["mdns_txt_name"] = nil
            end
            if resolved_names["netbios_name"] then
                json_info["netbios_name"] = nil
            end
            if resolved_names["tls_name"] then
                json_info["tls_name"] = nil
            end
            if resolved_names["http_name"] then
                json_info["http_name"] = nil
            end
            if resolved_names["dns_name"] then
                json_info["dns_name"] = nil
            end
            tmp["names"] = resolved_names
        end

        tmp.json_info = json_info

        res_formatted[#res_formatted + 1] = tmp
    end
    return res_formatted
end

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

-- This function retrieves the data of a specific asset given a unique key
local function getAssetInfo(ifid, key, asset_type)
    if isEmptyString(key) then return nil end
    local query = nil
    if hasClickHouseSupport() then
        query = string.format(
                    "SELECT * FROM (SELECT type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, toUnixTimestamp(last_seen) as last_seen , toUnixTimestamp(first_seen) as first_seen, gateway_mac, json_info, argMax(version, version) AS version FROM %s WHERE key='%s' AND ifid=%d AND type='%s' GROUP BY type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, first_seen, last_seen, gateway_mac, json_info) t ORDER BY version DESC LIMIT 1",
                    table_name, key, ifid, asset_type)

    else
        query = string.format(
                    "SELECT type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, last_seen , first_seen, gateway_mac, json_info FROM %s WHERE key='%s' AND ifid=%d AND type='%s'",
                    table_name, key, ifid, asset_type)

    end
    local res = interface.alert_store_query(query)
    res = partiallyFormatInfo(res)
    return res
end

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

-- This function, given a table, remove the characters that can bring errors to the DB
local function cleanValues(table_to_clean)
    for key, value in pairs(table_to_clean or {}) do
        if type(value) == 'string' then
            table_to_clean[key] = string.gsub(value, "'", "")
        end
    end
    return table_to_clean
end

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

-- This function is used to update entry and merge those info with in DB informations
-- e.g. in case an host was already into the DB just update those data
local function updateData(entry, ifid, type)
    local data = getAssetInfo(ifid, entry.key, type)
    local version = 1
    
    if data and table.len(data) > 0 then
        data = data[1]
        if data.version and tonumber(data.version) then
            version = tonumber(data.version) + 1
        end
        entry.first_seen = data.first_seen -- Keep the old first_seen
        -- Merge the json_info field, note, that in case of duplicates, the data from
        -- entry table are used.
        local unified_json = table.merge(data.json_info or {},
                                         entry.json_info or {})
        entry = cleanValues(entry)
        entry.json_info = json.encode(cleanValues(unified_json))
        entry.version = version
    end

    return version, entry
end

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

-- This function merges the json of old and new data,
-- in case of duplicates, the new data are saved and old data lost
local function updateJsonField(fields, new_fields)
    if fields then
        local json_info = json.decode(fields.json_info) or {}
        for field_name, field_value in pairs(new_fields or {}) do
            json_info[field_name] = field_value
        end
        fields.json_info = json.encode(json_info)
    end
    return fields
end

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

-- This function retrieves the data from the db
local function getAssetData(ifid, order, sort, start, length, filters,
                            asset_type, check_last_seen)
    if not ifid then ifid = interface.getId() end

    if sort == "ip" and hasClickHouseSupport() then sort = "toIPv6(ip)" end
    local where = build_where(ifid, filters)
    local sort_query = "ORDER BY key ASC" -- By default the sorting is done on the key
    local limit_query = ""

    if sort and order then
        -- Here the ORDER BY key is still mantained, this is because when switching pages,
        -- without an order, the same value could be found in the second page for example, ecc.
        if sort == "last_seen" then
            -- Set last seen = 0 at start or end
            sort_query = string.format("ORDER BY (%s = 0) %s, %s %s, key ASC", sort,
                                       order, sort, order)
        else
            sort_query = string.format("ORDER BY %s %s, key ASC", sort, order)
        end
    end

    if start and length then
        limit_query = string.format("LIMIT %s, %s", start, length)
    end

    local query = nil

    if hasClickHouseSupport() then
        query = string.format(
                    "SELECT a.type, a.key, a.ifid, a.ip, a.mac, a.vlan, a.network, a.name, a.device_type, a.manufacturer, %s, %s, a.gateway_mac, a.json_info, a.version" ..
                        " FROM %s a INNER JOIN (SELECT type, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key) AS latest" ..
                        " ON a.type = latest.type AND a.key = latest.key AND a.version = latest.max_version %s %s",
                    ternary(hasClickHouseSupport(),
                            "toUnixTimestamp(a.last_seen) as last_seen",
                            "a.last_seen"),
                    ternary(hasClickHouseSupport(),
                            "toUnixTimestamp(a.first_seen) as first_seen",
                            "a.first_seen"), table_name, table_name, asset_type, -- Only hosts here
                    tonumber(ifid), where, sort_query, limit_query)
    else
        query = string.format(
                    "SELECT type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, last_seen, first_seen, gateway_mac, json_info" ..
                        " FROM %s WHERE type='%s' AND ifid=%d %s %s %s",
                    table_name, asset_type, -- Only hosts here
            tonumber(ifid), where, sort_query, limit_query)
    end
    return interface.alert_store_query(query)
end

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

-- This function returns the number of assets
-- This is used for the details table page
local function getNumAssets(ifid, filters, asset_type, check_last_seen)
    if not ifid then ifid = interface.getId() end

    local where = build_where(ifid, filters)
    local query = nil
    if hasClickHouseSupport() then
        query = string.format(
                    "SELECT count(*) as count FROM %s a INNER JOIN (SELECT type, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key) AS latest" ..
                        " ON a.type = latest.type AND a.key = latest.key AND a.version = latest.max_version",
                    table_name, table_name, asset_type, -- Only hosts here
            tonumber(ifid), where)
    else
        query = string.format("SELECT COUNT(*) as count " ..
                                  "FROM %s WHERE type='%s' %s AND ifid=%d",
                              table_name, asset_type, where, ifid)
    end

    return interface.alert_store_query(query)
end

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

local function get_mac_serialization_key(mac, ifid)
    return tostring(ifid) .. "_" .. mac
end

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

-- Given a new host, adds the asset to the hosts asset
function asset_utils.insertHost(entry, ifid)
    local query = nil
    local version = 1
    version, entry = updateData(entry, ifid, "host")
    if not isIPv4(entry["ip"]) and not isIPv6(entry["ip"]) then
        traceError(TRACE_ERROR, TRACE_CONSOLE,
                   "Detected Asset without IP Address:\n")
        tprint(entry)
        return
    end
    
    -- if manufacturer is unknown push it to db
    local manufacturer = entry["manufacturer"]

    if isEmptyString(entry["manufacturer"]) then
        manufacturer = "unknown"
    end

    if hasClickHouseSupport() then
        query = string.format("INSERT INTO %s " ..
                                  "(type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, first_seen, last_seen, version, json_info) " ..
                                  "VALUES ('%s','%s', %u, '%s', '%s', %u, %u, %s, %u, %s, %u, %u, %u, '%s')",
                              table_name, entry["type"], entry["key"], ifid,
                              entry["ip"] or "", entry["mac"] or "",
                              entry["vlan"] or 0, entry["network"] or 0,
                              ternary(not isEmptyString(entry["name"]),
                                      string.format("'%s'", entry["name"]),
                                      "NULL"), entry["device_type"],
                              ternary(not isEmptyString(manufacturer),
                                      string.format("'%s'",
                                      manufacturer),
                                      "NULL"), entry["first_seen"],
                              entry["last_seen"] or 0, version,
                              entry["json_info"] or "")
    else
        query = string.format("INSERT INTO %s " ..
                                  "(type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, first_seen, last_seen, json_info) " ..
                                  "VALUES ('%s','%s', %u, '%s','%s', %u, %u, %s, %u, %s, %u, %u, '%s') " ..
                                  "ON CONFLICT(key) DO UPDATE SET last_seen = %u, first_seen = %u;",
                              table_name, entry["type"], entry["key"], ifid,
                              entry["ip"], entry["mac"] or "",
                              entry["vlan"] or 0, entry["network"] or 0,
                              ternary(not isEmptyString(entry["name"]),
                                      string.format("'%s'", entry["name"]),
                                      "NULL"), entry["device_type"],
                              ternary(not isEmptyString(manufacturer),
                                      string.format("'%s'",
                                      manufacturer),
                                      "NULL"), entry["first_seen"],
                              entry["last_seen"] or 0, entry["json_info"] or "",
                              entry["last_seen"] or 0, entry["first_seen"] or 0)
    end

    return interface.alert_store_query(query)
end


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

-- Given a new mac, adds the asset to the macs asset
function asset_utils.insertMac(entry, ifid)
    local query = nil
    local version = 1
    version, entry = updateData(entry, ifid, "mac")

    -- if manufacturer is unknown push it to db as string
    local manufacturer = entry["manufacturer"]

    if isEmptyString(entry["manufacturer"]) then
        manufacturer = "unknown"
    end

    if hasClickHouseSupport() then
        query = string.format("INSERT INTO %s " ..
                                  "(type, key, ifid, mac, manufacturer, vlan, device_type, first_seen, last_seen, version, json_info) " ..
                                  "SELECT '%s','%s', %u, '%s','%s', %u, %u, %u, %u, %u, '%s'",
                              table_name, entry["type"], entry["key"],
                              tonumber(ifid), entry["mac"],
                              manufacturer, 0, -- VLAN
        tonumber(entry["device_type"]), tonumber(entry["first_seen"]),
                              tonumber(entry["last_seen"] or 0),
                              tonumber(version), entry["json_info"] or "")
    else
        query = string.format("INSERT INTO %s " ..
                                  "(type, key, ifid, mac, manufacturer, device_type, first_seen, last_seen, json_info) " ..
                                  "VALUES ('%s','%s', %u, '%s','%s', %u, %u, %u, '%s') " ..
                                  "ON CONFLICT(key) DO UPDATE SET last_seen = %u, first_seen = %u;",
                              table_name, entry["type"], entry["key"],
                              tonumber(ifid), entry["mac"],
                              manufacturer,
                              tonumber(entry["device_type"] or 0),
                              tonumber(entry["first_seen"] or 0),
                              tonumber(entry["last_seen"] or 0),
                              entry["json_info"] or "",
                              tonumber(entry["last_seen"] or 0),
                              tonumber(entry["first_seen"]))
    end

    return interface.alert_store_query(query)
end

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

function asset_utils.getDevicesAssets(ifid, order, sort, start, length, filters)
    return
        getAssetData(ifid, order, sort, start, length, filters, "mac" --[[ Asset Type ]] ,
                     false)
end

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

-- Return the lists of inactive hosts from the DB
function asset_utils.getHostsAssets(ifid, order, sort, start, length, filters)
    return
        getAssetData(ifid, order, sort, start, length, filters, "host" --[[ Asset Type ]] ,
                     true)
end

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

-- Return the lists of inactive hosts from the DB
function asset_utils.getNumDevices(ifid, filters)
    return getNumAssets(ifid, filters, "mac", false)
end

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

-- Return the lists of inactive hosts from the DB
function asset_utils.getNumAssets(ifid, filters)
    return getNumAssets(ifid, filters, "host", true)
end

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

-- Return the lists of inactive hosts from the DB
function asset_utils.getFilters(ifid)
    if not ifid then ifid = interface.getId() end

    local query = string.format(
                      "SELECT 'manufacturer' AS filter, manufacturer AS value, COUNT(*) AS count " ..
                          "FROM %s where type='host' AND ifid=%d GROUP BY manufacturer UNION ALL " ..
                          "SELECT 'device_type' AS filter, %s AS value, COUNT(*) AS count " ..
                          "FROM %s where type='host' AND ifid=%d GROUP BY device_type UNION ALL " ..
                          "SELECT 'vlan' AS filter, %s AS value, COUNT(*) AS count " ..
                          "FROM %s where type='host' AND ifid=%d GROUP BY vlan UNION ALL " ..
                          "%s " ..
                          "FROM %s where type='host' AND ifid=%d %s GROUP BY value UNION ALL " ..
                          "SELECT 'network' AS filter, %s AS value, COUNT(*) AS count " ..
                          "FROM %s where type='host' AND ifid=%d GROUP BY network",
                      table_name, ifid,
                      ternary(hasClickHouseSupport(),
                              "CAST(device_type, 'String')",
                              "CAST(device_type AS CHAR)"), table_name, ifid,
                      ternary(hasClickHouseSupport(), "CAST(vlan, 'String')",
                              "CAST(vlan AS CHAR)"), table_name, ifid,
                      ternary(hasClickHouseSupport(),
                              "SELECT 'os_type' AS filter, JSONExtractString(json_info, 'os_type') AS value, COUNT(*) AS count",
                              "SELECT 'os_type' AS filter, json_extract(json_info, '$.os_type') AS value, COUNT(*) AS count"),
                      table_name, ifid, ternary(hasClickHouseSupport(), "",
                                                "AND json_info IS NOT NULL AND json_info <> ''"),
                      ternary(hasClickHouseSupport(), "CAST(network, 'String')",
                              "CAST(network AS CHAR)"), table_name, ifid)
    local res = interface.alert_store_query(query)
    return res
end

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

function asset_utils.getInactiveHostInfo(ifid, key)
    return getAssetInfo(ifid, key, "host")
end

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

function asset_utils.getMacInfo(ifid, key) return getAssetInfo(ifid, key, "mac") end

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

-- Edit a list of macs with the specified trigger_alert value

function asset_utils.editMacList(device_list, trigger_alert, ifid)
    for _, device in pairs(device_list) do
        asset_utils.editMac(device, trigger_alert, "allowed", ifid)
    end
end

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

function asset_utils.editMac(device, trigger_alert, mac_status, ifid)
    if isMacAddress(device) then
        local key = get_mac_serialization_key(device, ifid)
        local fields = asset_utils.getMacInfo(ifid, key)
        if fields and table.len(fields) > 0 then
            fields = fields[1]
            fields = updateJsonField(fields, {
                device_status = mac_status,
                trigger_alert = trigger_alert
            })
            if hasClickHouseSupport() then
                asset_utils.insertMac(fields, tonumber(ifid))
            else
                local update_query = string.format(
                                         "UPDATE %s SET `json_info`='%s' WHERE type='mac' AND ifid=%d AND key='%s'",
                                         table_name, fields.json_info,
                                         fields.ifid, fields.key)
                interface.alert_store_query(update_query)
            end
        end
    end
end

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

function asset_utils.deleteAll(ifid, type)
    local query = ""
    if hasClickHouseSupport() then
        query = string.format(
                    "ALTER TABLE %s DELETE WHERE type='%s' and ifid=%d",
                    table_name, type, tonumber(ifid))
    else
        query = string.format("DELETE FROM %s WHERE type='%s' and ifid=%d",
                              table_name, type, tonumber(ifid))
    end
    interface.alert_store_query(query)
end

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

function asset_utils.deleteMac(device, ifid)
    local key = get_mac_serialization_key(device, ifid)
    local query = ""

    if hasClickHouseSupport() then
        query = string.format(
                    "ALTER TABLE %s DELETE WHERE key='%s' and type='mac'",
                    table_name, key)
    else
        query = string.format("DELETE FROM %s WHERE key='%s' and type='mac'",
                              table_name, key)
    end

    interface.alert_store_query(query)
end

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

function asset_utils.deleteHost(ifid, serial_key)
    local query = ""

    if hasClickHouseSupport() then
        query = string.format(
                    "ALTER TABLE %s DELETE WHERE key='%s' AND type='host' AND ifid=%s",
                    table_name, serial_key, ifid)
    else
        query = string.format(
                    "DELETE FROM %s WHERE key='%s' and type='host' AND ifid=%s",
                    table_name, serial_key, ifid)
    end

    interface.alert_store_query(query)
end

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

function asset_utils.deleteAllEntriesSince(ifid, type, last_seen)
    local query = ""

    if hasClickHouseSupport() then
        query = string.format(
                    "ALTER TABLE %s DELETE WHERE type='%s' AND ifid=%s AND last_seen<%s AND last_seen != 0",
                    table_name, type, ifid, last_seen)
    else
        query = string.format(
                    "DELETE FROM %s WHERE type='%s' AND ifid=%s AND last_seen<%s AND last_seen != 0",
                    table_name, type, ifid, last_seen)
    end

    interface.alert_store_query(query)
end

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

function asset_utils.updateLastSeen()
    local query = nil

    if hasClickHouseSupport() then
        query = string.format(
                    "INSERT INTO %s SELECT type, key, ifid, ip, mac, vlan, network, name, device_type, manufacturer, first_seen, now() AS last_seen, gateway_mac, json_info, version + 1 AS version FROM %s WHERE last_seen != 0",
                    table_name, table_name)
    else
        query = string.format(
                    "UPDATE %s SET last_seen = DATETIME('now') WHERE last_seen != 0",
                    table_name)
    end
    interface.alert_store_query(query)
end

-- ####### SECTION DEDICATED TO THE ASSETS DASHBOARD #######
-- #########################################################

-- Return the lists of assets from the DB
function asset_utils.getAllAssetsOverview(ifid, filters)
    if not ifid then ifid = interface.getId() end
    local asset_type = "host"
    local where = build_where(ifid, filters)

    local query = nil
    if hasClickHouseSupport() then
        query = string.format("SELECT count(*) as assets, " ..
                                  "SUM(JSONHas(json_info, 'dns_server')) AS dns_server, " ..
                                  "SUM(JSONHas(json_info, 'dhcp_server')) AS dhcp_server, " ..
                                  "SUM(JSONHas(json_info, 'smtp_server')) AS smtp_server, " ..
                                  "SUM(JSONHas(json_info, 'imap_server')) AS imap_server, " ..
                                  "SUM(JSONHas(json_info, 'pop_server')) AS pop_server, " ..
                                  "SUM(JSONHas(json_info, 'ntp_server')) AS ntp_server, " ..
                                  "SUM(last_seen != 0) AS offline_asset, " ..
                                  "SUM(last_seen == 0) AS online_asset " ..
                                  "FROM (SELECT type, json_info, last_seen, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key, json_info, last_seen) AS latest",
                              table_name, asset_type, -- Only hosts here
        tonumber(ifid), where)
    end

    return interface.alert_store_query(query)
end

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

-- Return the lists of manufacturers from the DB
function asset_utils.getManufacturers(ifid, filters)
    if not ifid then ifid = interface.getId() end
    local asset_type = "host"
    local where = build_where(ifid, filters)

    local query = nil
    if hasClickHouseSupport() then
        query = string.format(
                    "SELECT count(*) as count, " .. "manufacturer " ..
                        "FROM (SELECT type, manufacturer, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key, manufacturer) " ..
                        "GROUP BY manufacturer ORDER BY count DESC, manufacturer ASC",
                    table_name, asset_type, -- Only hosts here
            tonumber(ifid), where)
    end

    return interface.alert_store_query(query)
end

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

-- Return the lists of devices from the DB
function asset_utils.getDeviceTypes(ifid, filters)
    if not ifid then ifid = interface.getId() end
    local asset_type = "host"
    local where = build_where(ifid, filters)

    local query = nil
    if hasClickHouseSupport() then
        query = string.format("SELECT count(*) as count, " .. "device_type " ..
                                  "FROM (SELECT type, device_type, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key, device_type) " ..
                                  "GROUP BY device_type ORDER BY count DESC, device_type ASC",
                              table_name, asset_type, -- Only hosts here
        tonumber(ifid), where)
    end

    return interface.alert_store_query(query)
end

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

-- Return the lists of OSes from the DB
function asset_utils.getOSes(ifid, filters)
    if not ifid then ifid = interface.getId() end
    local asset_type = "host"
    local where = build_where(ifid, filters)

    local query = nil
    if hasClickHouseSupport() then
        query = string.format(
                    "SELECT simpleJSONExtractInt(json_info, 'os_type') AS os_type, " ..
                        "COUNT(*) as count " ..
                        "FROM (SELECT type, json_info, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key, json_info) " ..
                        "GROUP BY os_type ORDER BY count DESC, os_type ASC",
                    table_name, asset_type, -- Only hosts here
            tonumber(ifid), where)
    end

    return interface.alert_store_query(query)
end

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

-- Return the number of online/offline servers from the DB
function asset_utils.getServersOverview(ifid, filters)
    if not ifid then ifid = interface.getId() end
    local asset_type = "host"
    local where = build_where(ifid, filters)
    local query = nil
    if hasClickHouseSupport() then
        query = string.format(
                    "SELECT SUM(JSONHas(json_info, 'dns_server') AND last_seen != 0) AS dns_servers_offline, " ..
                        "SUM(JSONHas(json_info, 'dns_server') AND last_seen == 0) AS dns_servers_online, " ..
                        "SUM(JSONHas(json_info, 'smtp_server') AND last_seen != 0) AS smtp_servers_offline, " ..
                        "SUM(JSONHas(json_info, 'smtp_server') AND last_seen == 0) AS smtp_servers_online, " ..
                        "SUM(JSONHas(json_info, 'imap_server') AND last_seen != 0) AS imap_servers_offline, " ..
                        "SUM(JSONHas(json_info, 'imap_server') AND last_seen == 0) AS imap_servers_online, " ..
                        "SUM(JSONHas(json_info, 'pop_server') AND last_seen != 0) AS pop_servers_offline, " ..
                        "SUM(JSONHas(json_info, 'pop_server') AND last_seen == 0) AS pop_servers_online, " ..
                        "SUM(JSONHas(json_info, 'ntp_server') AND last_seen != 0) AS ntp_servers_offline, " ..
                        "SUM(JSONHas(json_info, 'ntp_server') AND last_seen == 0) AS ntp_servers_online, " ..
                        "SUM(JSONHas(json_info, 'dhcp_server') AND last_seen != 0) AS dhcp_servers_offline, " ..
                        "SUM(JSONHas(json_info, 'dhcp_server') AND last_seen == 0) AS dhcp_servers_online " ..
                        "FROM (SELECT type, json_info, last_seen, key, MAX(version) AS max_version FROM %s WHERE type='%s' AND ifid=%d %s GROUP BY type, key, json_info, last_seen) AS latest",
                    table_name, asset_type, -- Only hosts here
            tonumber(ifid), where)
    end

    return interface.alert_store_query(query)
end

return asset_utils