--
-- (C) 2020 - ntop.org
--

local dirs = ntop.getDirs()
package.path = dirs.installdir .. "/scripts/lua/modules/system_config/?.lua;" .. package.path
package.path = dirs.installdir .. "/pro/scripts/lua/modules/?.lua;" .. package.path
require "lua_utils" 
local system_config = require "system_config"
local json = require "dkjson"
local ipv4_utils = require "ipv4_utils"
local os_utils = require "os_utils"
local sys_utils = require "sys_utils"
local tz_utils = require "tz_utils"

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

-- Example 
-- package.path = dirs.installdir .. "/scripts/lua/modules/system_config/?.lua;" .. package.path
-- -- Editable
-- local appliance_config = require "appliance_config":create(true)
-- -- Readable
-- local appliance_config = require "appliance_config":create()

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

local appliance_config = {}

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

function appliance_config:create(editable)
   -- Instance of the base class
   local _system_config = system_config:create()

   -- Subclass using the base class instance
   self.key = "appliance"
   -- self is passed as argument so it will be set as base class metatable
   -- and this will actually make it possible to override functions
   local _appliance_config = _system_config:create(self)

   if editable then
      _appliance_config:editable()
   else
      _appliance_config:readable()
   end

   -- Return the instance
   return _appliance_config
end

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

function appliance_config:_get_config_skeleton()
   local config = {}
   local defaults = { }
   local default_global_dns = self:_get_default_global_dns_preset()

   local config = {
      ["defaults"] = defaults,
      ["disabled_wans"] = {},
      ["globals"] = {
         ["available_modes"] = {},
         ["dns"] =  {
            ["global_preset"] = default_global_dns.id,
            ["global"] =  default_global_dns.primary_dns,
            ["secondary"] =  default_global_dns.secondary_dns,
            ["forge_global"] = false
         },
         ["lan_recovery_ip"] =  {
            ["ip"] =  "192.168.160.10",
            ["netmask"] =  "255.255.255.0",
            ["comment"] =  "Static LAN IP address used to reach the box. In bridging mode it is set on the bridge interface, in routing mode on the first (in case of multiple interfaces) LAN interface"
         },
	 ["management_access"] = {
	    ["bind_to"] = "lan",
	 },
      },
      ["interfaces"] = {
         ["comment"]= "List of available network interfaces. Only those listed in globals.operating_mode are actually configured",
         ["configuration"] = {}
      },
      ["gateways"] = {
      },
      ["static_routes"] = {
      },
      ["date_time"] = {
	 ["ntp_sync"] = {
	    ["enabled"] = true,
	 },
	 ["timezone"] = "Europe/Rome",
      },
      ["dhcp_server"] = {
         ["enabled"] = false,
         ["options"] = {
            "ddns-update-style none",
            "log-facility local7",
            "authoritative"
         },
         ["subnet"] = {
            ["network"] = "192.168.1.0",
            ["netmask"] = "255.255.255.0",
            ["first_ip"] = "192.168.1.10",
            ["last_ip"] = "192.168.1.200",
            ["gateway"] = "192.168.1.1",
            ["broadcast"] = "192.168.1.255",
            ["options"] = {
               "option domain-name \"ntop.local\"",
               "default-lease-time 600",
               "max-lease-time 7200"
            }
         },
         ["leases"] = {}
      }
   }
   return config
end

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

function appliance_config:_guess_config()
   local config = self:_get_config_skeleton()
   local devs   = { }
   local wifi   = { }
   local bridge = { }
   local wired  = { }
   local dhcp_ifaces = {}
   local wired_default = nil
   local wifi_default = nil
   local ip_devs   = system_config._split_dev_names('ip addr | awk \'$1 == "inet" && $7 { split( $2, addr, "/" ); print $7, addr[1] }\'', " ")
   local devs      = system_config._split_dev_names('cat /proc/net/dev', ":")
   local wifi_devs = system_config._split_dev_names('cat /proc/net/wireless', ":")
   local lan_iface
   local wan_iface = nil

   -- set the timezone to the current system timezone

   if not isEmptyString(tz_utils.TimeZone()) then
      config["date_time"]["timezone"] = tz_utils.TimeZone()
   end

   -- Necessary for inactive wifi devices
   for dev in pairs(devs) do
      local rv = sys_utils.execShellCmd("iwconfig 2>/dev/null | grep \"" .. dev .. "\" | grep \"IEEE 802.11\"")
      if not isEmptyString(rv) then
         wifi_devs[dev] = 1
      end
   end

   -- Find DHCP interface
   local res = sys_utils.execShellCmd('ps aux | grep dhclient')
   if not isEmptyString(res) then
      for _, line in pairs(split(res, "\n")) do
         local name = line:gmatch(".([^.]+).leases")()

         if devs[name] ~= nil then
            dhcp_ifaces[name] = 1
         end
      end 
   end

   -- Find the wan interface
   local rv = sys_utils.execShellCmd("ip route show | grep \"default via\" | awk '{printf \"%s\", $5}'")
   if not isEmptyString(rv) and devs[rv] ~= nil then
      wan_iface = rv
   end

   local some_wired = nil
   local static_wired = nil

   -- Identify the type of the devices in the system
   -- NOTE: we use pairsByKeys to impose an order across multiple guesses
   for name, _ in pairsByKeys(devs) do
      local addr = ip_devs[name]
      -- print("==> "..tostring(name).."\n")

      -- Not TUN/dummy/lo interface
      if((name ~= "lo") and (not starts(name, "dummy")) and not(ntop.exists('/sys/class/net/'.. name ..'/tun_flags')) and not string.contains(name, ":")) then
         if(ntop.exists('/sys/class/net/'.. name ..'/bridge')) then
            local devs = system_config._split_dev_names('ls /sys/class/net/'.. name ..'/brif/', nil)

            bridge[name] = { ["ports"] = devs }
            if(addr ~= nil) then bridge[name]["ip"] = addr end
         elseif(wifi_devs[name] ~= nil) then
            wifi[name]   = { }
            if(addr ~= nil) then wifi[name]["ip"] = addr end
            if(wifi_default == nil) then wifi_default = name end
         else
            -- Add per-interface gateway
            config.gateways[name] = {interface=name, ping_address="8.8.8.8"}

            wired[name] = { }
            if(some_wired == nil) then some_wired = name end
	    if((name ~= wan_iface) and (dhcp_ifaces[name] == nil) and (static_wired == nil)) then static_wired = name end

            if(addr ~= nil) then
               wired[name]["ip"] = addr
            end

            -- print("[WIRED] ==> "..name.."\n")
         end
      end
   end

   wired_default = static_wired or some_wired

   -- TODO modify this after supporting the other modes:
   -- e.g. for bridge interface the lan should be br0
   lan_iface = wired_default

   -- ###################
   -- Bridge interfaces

   local bridging = {}
   local operating_mode = nil
   local bridging_defined = false
   local bridge_ifname = nil

   -- If we currently have a bridge interface, use its configuration
   if table.len(bridge) > 0 then
      local used_ifaces = {}

      for a,b in pairsByKeys(bridge) do
         if table.len(b.ports) > 1 then
            bridge_ifname = a
            bridging["name"] = a
            bridging["interfaces"] = {unused={}}
            bridging["comment"] = "Transparent bridge"

            bridging["interfaces"]["lan"] = {}
            bridging["interfaces"]["wan"] = {}

            for n,c in pairsByKeys(b.ports) do
               if(n == 1) then
                  table.insert(bridging["interfaces"]["lan"], c)
               else
                  table.insert(bridging["interfaces"]["wan"], c)
               end
               used_ifaces[c] = true
            end

            operating_mode = "bridging"
            bridging_defined = true
            break
         end
      end

      if bridging_defined then
         -- add other interfaces to the unused ones
         for iface,_ in pairsByKeys(wired) do
            if used_ifaces[iface] == nil then
               table.insert(bridging["interfaces"]["unused"], iface)
            end
         end
      end
   end

   -- If we do not have a bridge interface but have enough interfaces
   if((not bridging_defined) and(table.len(wired) > 1)) then
      local n = 0
      bridge_ifname = "br0"

      bridging["name"] = bridge_ifname
      bridging["interfaces"] = {unused={}}
      bridging["comment"] = "Transparent bridge"

      for a,b in pairsByKeys(wired) do
         if(n == 0) then
            bridging["interfaces"]["lan"] = { a }
         elseif(n == 1) then
            bridging["interfaces"]["wan"] = { a }
         else
            table.insert(bridging["interfaces"]["unused"], a)
         end

         n = n + 1
      end

      bridging_defined = true
   end

   if(bridging_defined) then
      config["globals"]["available_modes"]["bridging"] = bridging
   end

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

   -- TODO standard or bridging
   operating_mode = "bridging"

   if(operating_mode ~= nil) then
      config["globals"]["operating_mode"] = operating_mode
   end

   -- ###################
   -- Network configuration

   for a,b in pairs(wired) do
      local speed = (interface.getMaxIfSpeed(a) or 10) * 1000 -- Mbps to Kbps that are more tc-friendly :)

      config["interfaces"]["configuration"][a] = {
         ["family"] = "wired", ["masquerade"] = true, ["network"] = {  },
         ["speed"] = {["upload"] = speed, ["download"] = speed} }

      -- Note: we force static on the wired_default if not in bridging mode
      if dhcp_ifaces[a] and ((a ~= wired_default) or (operating_mode == "bridging")) then
         config["interfaces"]["configuration"][a]["network"]["mode"] = "dhcp"
         config["interfaces"]["configuration"][a]["network"]["ip"] = "192.168.10.1"
         config["interfaces"]["configuration"][a]["network"]["netmask"] = "255.255.255.0"
         config["interfaces"]["configuration"][a]["network"]["gateway"] = "0.0.0.0"
      else
         -- non DHCP interface / wired_default
         config["interfaces"]["configuration"][a]["network"]["mode"] = "static"

         local netmask

         if (ip_devs[a] == nil) then
            -- e.g. on the wired_default
            ip_devs[a] = "192.168.1.1"
            netmask = "255.255.255.0"
         else
            -- The device has an IP address
            local addresses = getAllInterfaceAddresses(a)
            for _, addr in pairs(addresses) do
               if addr.ip == ip_devs[a] then
                  netmask = addr.netmask
               end
            end

            if isEmptyString(netmask) then netmask = "255.255.255.0" end
         end

         local gateway = system_config._interface_get_default_gateway(a)
         config["interfaces"]["configuration"][a]["network"]["ip"] = ip_devs[a]
         config["interfaces"]["configuration"][a]["network"]["netmask"] = netmask

         if not isEmptyString(gateway) then
            config["interfaces"]["configuration"][a]["network"]["gateway"] = gateway
         end
      end
   end

   if(wired_default ~= nil) then
      -- Add the aliased interface to the configuration
       config["interfaces"]["configuration"][wired_default..":1"] = { ["family"] = "wired", ["network"]={},
          ["speed"] = {["upload"]= speed, ["download"] = speed}  }
      config["interfaces"]["configuration"][wired_default..":1"]["network"]["mode"] = "static"
      config["interfaces"]["configuration"][wired_default..":1"]["network"]["ip"] = "192.168.10.1"
      config["interfaces"]["configuration"][wired_default..":1"]["network"]["netmask"] = "255.255.255.0"
   end

   if(bridge_ifname ~= nil) then
      local speed = 100 * 1000 -- Kbps, not really important here

      -- Add the bridge interface to the configuration
      config["interfaces"]["configuration"][bridge_ifname] = { ["family"] = "bridge", ["network"]={},
          ["speed"] = {["upload"]= speed, ["download"] = speed}  }
      config["interfaces"]["configuration"][bridge_ifname]["network"]["mode"] = "dhcp"
      config["interfaces"]["configuration"][bridge_ifname]["network"]["ip"] = "192.168.20.1"
      config["interfaces"]["configuration"][bridge_ifname]["network"]["netmask"] = "255.255.255.0"
   end

   -- Not supported right now
   --for a,b in pairs(wifi) do
      --config["interfaces"]["configuration"][a] = { ["family"] = "wireless", ["network"] = { ["mode"] = "dhcp" } }
   --end

   -- Make sure we have a valid DHCP range
   self:_fix_dhcp_from_lan(config, lan_iface)

   -- Make sure to apply the mode specific settings
   self:_apply_operating_mode_settings(config)

   return config
end

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

return appliance_config