-- ===================================================================

-- See "LICENSE" for license information
-- See "history.txt" for history

-- ===================================================================

minetest.register_privilege ("travelnet_attach",
    { description = "allows to attach travelnet boxes to travelnets of other players", give_to_singleplayer = false});

minetest.register_privilege ("travelnet_remove",
    { description = "allows to dig travelnet boxes which belog to nets of other players", give_to_singleplayer = false});

-- ===================================================================

local modname   = minetest.get_current_modname()
local modpath   = minetest.get_modpath (modname)
local worldpath = minetest.get_worldpath()
local datapath  = worldpath .. "/mod_travelnet.data"

-- ===================================================================

travelnet = {}
travelnet.modname   = modname
travelnet.modpath   = modpath
travelnet.worldpath = worldpath
travelnet.datapath  = datapath
travelnet.targets   = {}

-- ===================================================================

dofile (modpath .. "/config.lua")

-- ===================================================================

travelnet.save_data = function()
    local data    = minetest.serialize (travelnet.targets)
    local path    = travelnet.datapath
    local success = false

    if minetest.safe_file_write then
        success = minetest.safe_file_write (path, data)
    else
        local file = io.open (path, "w")
        if   (file) then
            file:write (data);
            file:close();
            success = true
        end
    end

    if not success then
        print "[travelnet] Error: Savefile '%s' could not be written"
    end
end

-- ===================================================================

travelnet.restore_data = function()
    local path = travelnet.datapath
    local file = io.open (path, "r")

    if    file then
        local data = file:read ("*all")
        travelnet.targets = minetest.deserialize (data)
        file:close();
    else
        print ("[Mod travelnet] Error: Savefile '" ..
            tostring (path) .. "' not found.")
    end
end

-- ===================================================================

travelnet.update_formspec = function (pos, puncher_name)

    local meta        = minetest.get_meta (pos)
    local this_node   = minetest.get_node (pos)
    local is_elevator = false

    if  this_node      ~= nil                  and
        this_node.name == 'travelnet:elevator' then
        is_elevator = true
    end

    if not meta then return end

    if not (travelnet.targets) then
            travelnet.targets = {}
    end

    local owner_name      = meta:get_string ("owner")
    local station_name    = meta:get_string ("station_name")
    local station_network = meta:get_string ("station_network")

    if  not (owner_name   )   or
        not (station_name )   or
        station_network == '' or
        not (station_network) then

        if is_elevator == true then
            travelnet.add_target (nil, nil, pos,
puncher_name, meta, owner_name)
            return
        end

        meta:set_string ("infotext"        ,
"Travelnet-box (unconfigured)");

        meta:set_string ("station_name"    , "");
        meta:set_string ("station_network" , "");
        meta:set_string ("owner"           , "");

        -- Prompt for initial data
        meta:set_string ("formspec",
"size[12,10]"..
"field[0.3,5.6;6,0.7;station_name;Name of this station:;]" ..
"field[0.3,6.6;6,0.7;station_network;Assign to Network:;]" ..
"field[0.3,7.6;6,0.7;owner_name;(optional) owned by:;]"    ..
"button_exit[6.3,5.4;1.7,0.7;station_dig;Remove]"          ..
"button_exit[6.3,6.4;1.7,0.7;station_set;Store]")

        minetest.chat_send_player (puncher_name,
"Error: Update failed! Resetting this box on the travelnet.")
        return
    end

    -- if the station got lost from the network for some reason (savefile corrupted?) then add it again
    if  not (travelnet.targets [owner_name])                  or
        not (travelnet.targets [owner_name][station_network]) or
        not (travelnet.targets [owner_name][station_network][station_name]) then

        -- first one by this player?
        if not (travelnet.targets [owner_name]) then
                travelnet.targets [owner_name] = {}
        end

        -- first station on this network?
        if not (travelnet.targets [owner_name][station_network]) then
                travelnet.targets [owner_name][station_network] = {}
        end

        local zeit = meta:get_int ("timestamp")

        if not (zeit) or type (zeit) ~= "number" or zeit < 100000 then
            zeit = os.time()
        end

        -- add this station
        travelnet.targets [owner_name][station_network][station_name] = { pos=pos, timestamp=zeit }
        minetest.chat_send_player (owner_name, "Station '" ..
station_name ..
"' has been reattached to the network '" ..
station_network .. "'.")
    end

    -- add name of station + network + owner + update-button
    local zusatzstr = ""
    local trheight  = "10"

    if  this_node and
        this_node.name == "locked_travelnet:travelnet" then
        zusatzstr = "field[0.3,11;6,0.7;locks_sent_lock_command;Locked travelnet. Type /help for help:;]"
        trheight  = "11.5"
    end

    local formspec = "size[12,"..trheight.."]"          ..
"label[3.3,0.0;Travelnet:]"                             ..
"label[0.3,0.4;Name of this station:]"                  ..
"label[3.3,0.4;" .. (station_name    or "?") .. "]"     ..
"label[0.3,0.8;Assigned to Network:]"                   ..
"label[3.3,0.8;" .. (station_network or "?") .. "]"     ..
"label[0.3,1.2;Owned by:]"                              ..
"label[3.3,1.2;" .. (owner_name      or "?") .. "]"     ..

"label[6.3,0.0;Punch box to update]"                    ..
"label[6.3,0.4;Click on target to travel there]"        ..
"button_exit[6.3,1.2;3,0.7;station_dig;Remove station]" ..
zusatzstr

-- "button_exit[5.3,0.3;8,0.8;do_update;Punch box to update destination list. Click on target to travel there.]"..

    local x = 0
    local y = 0
    local i = 0

    -- collect all station names in a table
    local stations = {}

    for k,v in pairs (travelnet.targets [owner_name][station_network]) do
        table.insert (stations, k)
    end

    -- minetest.chat_send_player(puncher_name, "stations: "..minetest.serialize( stations ));

    local ground_level = 1

    if is_elevator then
        table.sort (stations, function (a, b)
return travelnet.targets [owner_name][station_network][a].pos.y >
       travelnet.targets [owner_name][station_network][b].pos.y
end)
        -- find ground level
        local vgl_timestamp = 999999999999

        for index,k in ipairs (stations) do
            if not (travelnet.targets [owner_name][station_network][k].timestamp) then
                    travelnet.targets [owner_name][station_network][k].timestamp = os.time()
            end

            if  travelnet.targets [owner_name][station_network][k].timestamp < vgl_timestamp then
                vgl_timestamp = travelnet.targets [owner_name][station_network][k].timestamp
                ground_level  = index
            end
        end

        for index,k in ipairs (stations) do
            if index == ground_level then
                travelnet.targets [owner_name][station_network][k].nr = 'G'
            else
                travelnet.targets [owner_name][station_network][k].nr = tostring (ground_level - index)
            end
        end
    else
        if travelnet.enable_legacy_sort then
            table.sort (stations,
                function (a,b) return
travelnet.targets [owner_name] [station_network] [a].timestamp <
travelnet.targets [owner_name] [station_network] [b].timestamp
            end)
        else
            table.sort (stations, function (a,b) return a < b end)
        end
   end

    -- if there are only 8 stations (plus this one),
    -- center them in the formspec
    if #stations < 10 then x = 4 end

    for index,k in ipairs (stations) do

    -- check if there is an elevator door in front that needs to be opened
        local open_door_cmd = false

        if k == station_name then
            open_door_cmd = true
        end

        if  k ~= station_name or open_door_cmd then
            i = i+1

            -- new column
            if  y == 8 then
                x = x+4
                y = 0
            end

            if( open_door_cmd ) then
                formspec = formspec .."button_exit["..(x)..","..(y+2.5)..";1,0.5;open_door;<>]"..
                                  "label["..(x+0.9)..","..(y+2.35)..";"..tostring( k ).."]";
            elseif is_elevator then
                formspec = formspec .."button_exit["..(x)..","..(y+2.5)..";1,0.5;target;"..tostring( travelnet.targets[ owner_name ][ station_network ][ k ].nr ).."]"..
                                  "label["..(x+0.9)..","..(y+2.35)..";"..tostring( k ).."]";
            else
                formspec = formspec .."button_exit["..(x)..","..(y+2.5)..";4,0.5;target;"..k.."]";
            end

--          if is_elevator then
--              formspec = formspec ..' ('..tostring( travelnet.targets[ owner_name ][ station_network ][ k ].pos.y )..'m)';
--          end
--          formspec = formspec .. ']';

            y = y+1
            -- x = x+4
        end
    end

    meta:set_string( "formspec", formspec );
    meta:set_string( "infotext", "Station '"..tostring( station_name ).."' on travelnet '"..tostring( station_network )..
        "' (owned by "..tostring( owner_name )..") ready for usage. Right-click to travel, punch to update.");

    minetest.chat_send_player (puncher_name,
"The target list of this box on the travelnet has been updated.")
end

local function get_far_node (pos)
    local node = minetest.get_node (pos)
    if node.name == "ignore" then
        minetest.get_voxel_manip():read_from_map(pos, pos)
        node = minetest.get_node (pos)
    end

    return node
end

-- add a new target; meta is optional
travelnet.add_target = function (station_name,
network_name, pos, player_name, meta, owner_name)

    -- if it is an elevator, determine the network name through x and z coordinates
    local this_node   = minetest.get_node( pos )
    local is_elevator = false

    if( this_node.name == 'travelnet:elevator' ) then
--      owner_name   = '*'; -- the owner name is not relevant here
        is_elevator  = true
        network_name = tostring( pos.x )..','..tostring( pos.z )
        if( not( station_name ) or station_name == '' ) then
            station_name = 'at '..tostring( pos.y )..'m';
        end
    end

    if station_name == "" or not (station_name) then
        minetest.chat_send_player(player_name, "Please provide a name for this station.");
        return
    end

    if( network_name == "" or not( network_name )) then
        minetest.chat_send_player(player_name, "Please provide the name of the network this station ought to be connected to.");
        return
    end

    if (owner_name == nil or owner_name == '' or owner_name == player_name) then
        owner_name = player_name

   elseif( is_elevator ) then -- elevator networks
      owner_name = player_name

   elseif( not( minetest.check_player_privs(player_name, {interact=true}))) then

      minetest.chat_send_player(player_name, "There is no player with interact privilege named '"..tostring( player_name ).."'. Aborting.");
      return

   elseif( not( minetest.check_player_privs(player_name, {travelnet_attach=true}))
        and not( travelnet.allow_attach( player_name, owner_name, network_name ))) then

        minetest.chat_send_player(player_name, "You do not have the travelnet_attach priv which is required to attach your box to the network of someone else. Aborting.");
        return
   end

    if not (travelnet.targets) then
            travelnet.targets = {}
    end

    -- first one by this player?
    if not (travelnet.targets [owner_name]) then
            travelnet.targets [owner_name] = {}
    end

    -- first station on this network?
    if not (travelnet.targets [owner_name][network_name]) then
            travelnet.targets [owner_name][network_name] = {}
    end

    for k,v in pairs (travelnet.targets [owner_name][network_name]) do
        if k == station_name then
            local oldpos = v.pos

            if oldpos ~= nil then
                local oldname = nil
                local oldnode = get_far_node (oldpos)
                if    oldnode ~= nil then oldname = oldnode.name end

                if oldname ~= "travelnet:travelnet"         and
                   oldname ~= "travelnet:pad"               and
                   oldname ~= "travelnet:palantiri"         and
                   oldname ~= "travelnet:elevator"          and
                   oldname ~= "locked_travelnet:travelnet"  and
                   oldname ~= "travelnet:travelnet_private" then

                    local mmeta = minetest.get_meta (oldpos)
                    travelnet.remove_box (oldpos, nil,
                        mmeta:to_table(), nil)
                    break
                end
            end
        end
    end

    local anz = 0
    for k,v in pairs (travelnet.targets [owner_name][network_name]) do
        if k == station_name then
            minetest.chat_send_player (player_name,
"Error: A station named '" ..
station_name ..
"' already exists on this network. Please choose a different name.");
            return
        end
        anz = anz + 1
    end

    -- we don't want too many stations in the same network
    -- because that would get confusing when displaying the targets

   if( anz+1 > travelnet.MAX_STATIONS_PER_NETWORK ) then
      minetest.chat_send_player(player_name, "Error: Network '"..network_name.."' already contains the maximum number (="
              ..(travelnet.MAX_STATIONS_PER_NETWORK)..") of allowed stations per network. Please choose a diffrent/new network name.");
      return
   end

    -- add this station
    travelnet.targets [owner_name][network_name][station_name] =
        { pos=pos, timestamp=os.time()}

    -- do we have a new node to set up? (and are not just reading
    -- from a safefile?)

    if (meta) then

      minetest.chat_send_player(player_name, "Station '"..station_name.."' has been added to the network '"
..network_name.."', which now consists of "..( anz+1 ).." station(s).");

      meta:set_string( "station_name",    station_name );
      meta:set_string( "station_network", network_name );
      meta:set_string( "owner",           owner_name );
      meta:set_int( "timestamp",       travelnet.targets[ owner_name ][ network_name ][ station_name ].timestamp);

      meta:set_string("formspec",
                     "size[12,10]"..
                     "field[0.3,0.6;6,0.7;station_name;Station:;"..   meta:get_string("station_name").."]"..
                     "field[0.3,3.6;6,0.7;station_network;Network:;"..meta:get_string("station_network").."]" );

      -- display a list of all stations that can be reached from here
      travelnet.update_formspec (pos, player_name)

      -- save the updated network data in a savefile over server restart
      travelnet.save_data()
   end
end

-- allow doors to open
travelnet.open_close_door = function (pos, player, mode)

   local this_node = minetest.get_node (pos)
   local pos2 = {x=pos.x,y=pos.y,z=pos.z}

   if(     this_node.param2 == 0 ) then pos2 = {x=pos.x,y=pos.y,z=(pos.z-1)};
   elseif( this_node.param2 == 1 ) then pos2 = {x=(pos.x-1),y=pos.y,z=pos.z};
   elseif( this_node.param2 == 2 ) then pos2 = {x=pos.x,y=pos.y,z=(pos.z+1)};
   elseif( this_node.param2 == 3 ) then pos2 = {x=(pos.x+1),y=pos.y,z=pos.z};
   end

   local door_node = minetest.get_node( pos2 );
   if( door_node ~= nil and door_node.name ~= 'ignore' and door_node.name ~= 'air' and minetest.registered_nodes[ door_node.name ] ~= nil and minetest.registered_nodes[ door_node.name ].on_rightclick ~= nil) then

      -- at least for homedecor, same facedir would mean "door closed"

      -- do not close the elevator door if it is already closed
      if( mode==1 and ( door_node.name == 'travelnet:elevator_door_glass_closed'
                     or door_node.name == 'travelnet:elevator_door_steel_closed'
                     -- handle doors that change their facedir
                     or ( door_node.param2 == this_node.param2
                      and door_node.name ~= 'travelnet:elevator_door_glass_open'
                      and door_node.name ~= 'travelnet:elevator_door_steel_open'))) then
         return;
      end
      -- do not open the doors if they are already open (works only on elevator-doors; not on doors in general)
      if( mode==2 and ( door_node.name == 'travelnet:elevator_door_glass_open'
                     or door_node.name == 'travelnet:elevator_door_steel_open'
                     -- handle doors that change their facedir
                     or ( door_node.param2 ~= this_node.param2
                      and door_node.name ~= 'travelnet:elevator_door_glass_closed'
                      and door_node.name ~= 'travelnet:elevator_door_steel_closed'))) then
         return;
      end

      if( mode==2 ) then
         minetest.after( 1, minetest.registered_nodes[ door_node.name ].on_rightclick, pos2, door_node, player );
      else
         minetest.registered_nodes[ door_node.name ].on_rightclick(pos2, door_node, player);
      end
   end
end

travelnet.on_receive_fields = function (pos, formname, fields, player)
   local meta  = minetest.get_meta (pos)
   local pname = player:get_player_name()

   -- The player wants to remove the station
   if fields.station_dig then
        local owner = meta:get_string ("owner")
        local node  = minetest.get_node (pos)
        local nname = "?"
        if node and node.name then nname = node.name end
        local description = "station"

        if nname     == "travelnet:travelnet" then
            description = "travelnet box"
        elseif nname == "travelnet:elevator"  then
            description = "elevator"
        elseif nname == "travelnet:palantiri" then
            description = "palantiri"
        elseif nname == "travelnet:pad"       then
            description = "pad"
        else
            minetest.chat_send_player (pname, "Error: Unknown node")
            return
        end

      -- Players with travelnet_remove priv can dig the station
      if not minetest.check_player_privs (pname,
          { travelnet_remove=true })
          and owner ~= pname and owner ~= nil and owner ~= "" then

          local msg = "This " .. description ..
" belongs to " .. owner .. ". You can't remove it."
          minetest.chat_send_player (pname, msg)
          return
      end

      local pinv = player:get_inventory()
      if(not(pinv:room_for_item("main", node.name))) then
         minetest.chat_send_player (pname, "You do not have enough room in your inventory.")
         return
      end

      -- give the player the box
      pinv:add_item("main", node.name)
      -- remove the box from the data structure
      travelnet.remove_box( pos, nil, meta:to_table(), player );
      -- remove the node as such
      minetest.remove_node(pos)
      return;
   end

   -- if the box has not been configured yet
   if( meta:get_string("station_network")=="" ) then
      travelnet.add_target( fields.station_name, fields.station_network, pos, pname, meta, fields.owner_name );
      return;
   end

   if( fields.open_door ) then
      travelnet.open_close_door( pos, player, 0 );
      return;
   end

   if( not( fields.target )) then
      minetest.chat_send_player (pname, "Please click on the target you want to travel to.");
      return;
   end

   -- if there is something wrong with the data
   local owner_name      = meta:get_string( "owner" )
   local station_name    = meta:get_string( "station_name" )
   local station_network = meta:get_string( "station_network" )

   if(  not( owner_name  )
     or not( station_name )
     or not( station_network )
     or not( travelnet.targets[ owner_name ] )
     or not( travelnet.targets[ owner_name ][ station_network ] )) then

      if(     owner_name
          and station_name
          and station_network ) then
            travelnet.add_target( station_name, station_network, pos, owner_name, meta, owner_name );
      else
         minetest.chat_send_player(pname, "Error: There is something wrong with the configuration of this station. "..
" DEBUG DATA: owner: "..(  owner_name or "?")..
" station_name: "..(station_name or "?")..
" station_network: "..(station_network or "?")..".");
         return
      end
   end

   if(  not( owner_name )
     or not( station_network )
     or not( travelnet.targets )
     or not( travelnet.targets[ owner_name ] )
     or not( travelnet.targets[ owner_name ][ station_network ] )) then
      minetest.chat_send_player(pname, "Error: This travelnet is lacking data and/or improperly configured.");
      print( "ERROR: The travelnet at "..minetest.pos_to_string( pos ).." has a problem: "..
" DATA: owner: "..(  owner_name or "?")..
" station_name: "..(station_name or "?")..
" station_network: "..(station_network or "?")..".");
      return;
   end

   local this_node = minetest.get_node( pos );
   if( this_node ~= nil and this_node.name == 'travelnet:elevator' ) then
      for k,v in pairs( travelnet.targets[ owner_name ][ station_network ] ) do
         if( travelnet.targets[ owner_name ][ station_network ][ k ].nr  --..' ('..tostring( travelnet.targets[ owner_name ][ station_network ][ k ].pos.y )..'m)'
               == fields.target) then
            fields.target = k;
         end
      end
   end

   -- if the target station is gone
   if( not( travelnet.targets[ owner_name ][ station_network ][ fields.target ] )) then

      minetest.chat_send_player (pname, "Station '"..( fields.target or "?").." does not exist (anymore?) on this network.");
      travelnet.update_formspec( pos, pname );
      return;
   end

   if( not( travelnet.allow_travel( pname, owner_name, station_network, station_name, fields.target ))) then
      return;
   end

    minetest.chat_send_player (pname, "Initiating transfer to station '"..( fields.target or "?").."'.'");
    local sndfile = nil

    if not travelnet.disable_sound then
        if this_node.name == "travelnet:elevator" then
            sndfile = "travelnet_bell"
        else
            sndfile = travelnet.sound
        end
        minetest.sound_play (sndfile,
            { pos = pos, gain = 0.75, max_hear_distance = 25 })
    end

    -- close the doors at the sending station
    travelnet.open_close_door (pos, player, 1)

    -- transport the player to the target location
    local target_pos = travelnet.targets[ owner_name ][ station_network ][ fields.target ].pos;

    local player_model_bottom = tonumber(minetest.settings:get("player_model_bottom")) or -.5;  -- may be 0.0 for some versions of MT 5 player model
    local player_model_vec = vector.new(0, player_model_bottom, 0)
    local target_pos = travelnet.targets[ owner_name ][ station_network ][ fields.target ].pos
    player:move_to( vector.add(target_pos, player_model_vec), false)

    -- check if the box has at the other end has been removed
    local node2 = minetest.get_node_or_nil (target_pos)

    local oldmeta = {
        owner   = owner_name      ,
        name    = fields.target   ,
        network = station_network ,
        pname   = pname           ,
    }

    travelnet.rotate_player (target_pos, player, 0, sndfile, oldmeta)
end

-- ===================================================================

travelnet.rotate_player = function (target_pos, player, tries,
sndfile, oldmeta)

    -- play sound at the target position as well
    --
    if sndfile ~= nil then
        minetest.sound_play (sndfile,
            { pos = target_pos, gain = 0.75, max_hear_distance = 25 })
    end

    -- Wait until box is loaded
    local node2 = minetest.get_node_or_nil (target_pos)
    if    node2 == nil then
        if tries < 30  then
            minetest.after (0, travelnet.rotate_player,
                target_pos, player, tries+1, sndfile, oldmeta)
        end
        return
    end

    if node2.name ~= 'ignore'                      and
       node2.name ~= 'travelnet:travelnet'         and
       node2.name ~= 'travelnet:pad'               and
       node2.name ~= 'travelnet:palantiri'         and
       node2.name ~= 'travelnet:elevator'          and
       node2.name ~= "locked_travelnet:travelnet"  and
       node2.name ~= "travelnet:travelnet_private" then

        local t      = target_pos
        local t_str  = t.x .. "," .. t.y .. "," .. t.z
        local upnode = minetest.get_node ({ x = t.x,
           y = t.y + 1, z = t.z})

        if node2.name == "air" and upnode.name == "air" then
            minetest.set_node (t,
                { name = "travelnet:palantiri" })

            local meta = minetest.get_meta (t)
            meta:set_string ("infotext"        , "Travelnet"     )
            meta:set_string ("station_name"    , oldmeta.name    )
            meta:set_string ("station_network" , oldmeta.network )
            meta:set_string ("owner"           , oldmeta.owner   )
            travelnet.update_formspec (t, oldmeta.pname)

            minetest.log ("action",
"travelnet missing at " .. t_str .. "; replaced it")
        else
            minetest.log ("action",
"travelnet missing at " .. t_str .. "; couldn't replace it: " ..
node2.name .. " " .. upnode.name)
        end
    end

    local  yaw    = 0
    local  param2 = node2.param2

    if     param2 == 0 then yaw = 180
    elseif param2 == 1 then yaw =  90
    elseif param2 == 2 then yaw =   0
    elseif param2 == 3 then yaw = 270
    end

-- Rotate the player so that  he/she can walk straight out of the box.
-- Do this only on servers where the function(s) needed to do this ex-
-- ist.

    if  player.set_look_horizontal then
        player:set_look_horizontal (math.rad (yaw))
        player:set_look_vertical   (math.rad (0))
    elseif player.set_look_yaw then
        player:set_look_yaw        (math.rad (yaw))
        player:set_look_pitch      (math.rad (0))
    end

    travelnet.open_close_door (target_pos, player, 2)
end

travelnet.remove_box = function (pos, oldnode, oldmetadata, digger)

   if  not (oldmetadata) or oldmetadata == "nil" or
       not (oldmetadata.fields) then
      if digger ~= nil then
          minetest.chat_send_player (digger:get_player_name(),
"Error: Could not find information about the station that is to be removed.");
      end
      return
   end

   local owner_name      = oldmetadata.fields[ "owner" ];
   local station_name    = oldmetadata.fields[ "station_name" ];
   local station_network = oldmetadata.fields[ "station_network" ];

   -- station is not known? then just remove it
   if(  not( owner_name )
     or not( station_name )
     or not( station_network )
     or not( travelnet.targets[ owner_name ] )
     or not( travelnet.targets[ owner_name ][ station_network ] )) then

      if digger ~= nil then
          minetest.chat_send_player( digger:get_player_name(), "Error: Could not find the station that is to be removed.");
      end
      return
   end

   travelnet.targets[ owner_name ][ station_network ][ station_name ] = nil;

   -- inform the owner
   minetest.chat_send_player( owner_name, "Station '"..station_name.."' has been REMOVED from the network '"..station_network.."'.");
   if( digger ~= nil and owner_name ~= digger:get_player_name() ) then
      minetest.chat_send_player( digger:get_player_name(), "Station '"..station_name.."' has been REMOVED from the network '"..station_network.."'.");
   end

   -- save the updated network data in a savefile over server restart
   travelnet.save_data();
end

travelnet.can_dig = function( pos, player, description )
   -- forbid digging of the travelnet
   return false;
end

-- obsolete function
travelnet.can_dig_old = function( pos, player, description )
   if( not( player )) then
      return false;
   end
   local name          = player:get_player_name();

   -- players with that priv can dig regardless of owner
   if( minetest.check_player_privs(name, {travelnet_remove=true})
       or travelnet.allow_dig( player_name, owner_name, network_name )) then
      return true;
   end

   local meta          = minetest.get_meta( pos );
   local owner         = meta:get_string('owner');

   if( not( meta ) or not( owner) or owner=='') then
      minetest.chat_send_player(name, "This "..description.." has not been configured yet. Please set it up first to claim it. Afterwards you can remove it because you are then the owner.");
      return false;

   elseif( owner ~= name ) then
      minetest.chat_send_player(name, "This "..description.." belongs to "..tostring( meta:get_string('owner'))..". You can't remove it.");
      return false;
   end
   return true
end

if not travelnet.disable then
minetest.log ("action", "travelnet enabled")
   dofile(modpath.."/travelnet.lua")
   -- the travelnet node definition
end

if not travelnet.disable_travelpad then
   dofile(modpath.."/travelpad.lua")
end

if not travelnet.disable_elevator then
   dofile(modpath.."/elevator.lua")
   -- allows up/down transfers only
end

if not travelnet.disable_doors then
    dofile (modpath .. "/doors.lua")
    -- doors that open and close automatically
    -- when the travelnet or elevator is used
end

if not travelnet.disable_abm then
    -- restore travelnet data when players pass by broken networks
    dofile (modpath .. "/restorenet.lua")
end

-- upon server start, read the savefile
travelnet.restore_data()

minetest.log ("action", "travelnet loaded")