local detail_level = 20
local spherebox = {}
local detail = detail_level
local sehne

for i = 1, detail-1 do
    sehne = math.sqrt (0.25 - (((i/detail)-0.5)^2))

    spherebox [i] = {
        -sehne                      ,
        (i/detail)-0.5              ,
        -sehne                      ,
         sehne                      ,
        (i/detail) + (1/detail)-0.5 ,
         sehne                      ,
    }
end

local param_palantiri = {
    description = "Palantiri",
    drawtype = "nodebox",
    sunlight_propagates = true,
    paramtype = 'light',
    paramtype2 = "facedir",

    selection_box = {
                type = "fixed",
                fixed = { -0.5, -0.5, -0.5, 0.5, 0.5, 0.5 }
    },
    node_box = {
        type = "fixed",
        fixed = spherebox,
    },
    tiles = {"default_obsidian.png"},
    groups = { cracky=1,choppy=1,snappy=1,travelnet=1 } ,
    light_source = 10,

    after_place_node  = function(pos, placer, itemstack)
        local meta = minetest.get_meta (pos)
        meta:set_string ("infotext", "Palantiri (unconfigured)")
        meta:set_string ("station_name",   "")
        meta:set_string ("station_network","")
        meta:set_string ("owner", placer:get_player_name())

        -- request 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]")
    end ,

    on_receive_fields = travelnet.on_receive_fields ,

    on_punch          = function (pos, node, puncher)
        travelnet.update_formspec (pos, puncher:get_player_name())
    end ,

    can_dig = function (pos, player)
        return travelnet.can_dig (pos, player, "travelnet box")
    end ,

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

    on_place = function (itemstack, placer, pointed_thing)
        local pos   = pointed_thing.above
        local anode

        anode = minetest.get_node ({x=pos.x, y=pos.y+1, z=pos.z})
        if anode.name ~= "air" and
           anode.name ~= "default:vacuum" then
            minetest.chat_send_player (placer:get_player_name(),
'Not enough vertical space to place the travelpad')
            return
        end

        anode = minetest.get_node ({x=pos.x, y=pos.y+2, z=pos.z})
        if anode.name ~= "air" and
           anode.name ~= "default:vacuum" then
            minetest.chat_send_player (placer:get_player_name(),
'Not enough vertical space to place the travelpad')
            return
        end
        return minetest.item_place(itemstack, placer, pointed_thing)
    end ,
}

minetest.register_node ("travelnet:palantiri", param_palantiri)

minetest.register_craft({
    output = "travelnet:palantiri" ,
    recipe = {
{'default:obsidian'     , 'default:diamondblock' , 'default:obsidian'     } ,
{'default:diamondblock' , 'default:mese'         , 'default:diamondblock' } ,
{'default:obsidian'     , 'default:diamondblock' , 'default:obsidian'     }
    }
})

local tiles_classic = {
    "travelnet_classic_front.png",   -- backward view
    "travelnet_classic_back.png",    -- front view
    "travelnet_classic_side.png",    -- sides
    "default_steel_block.png",       -- view from top
    "default_clay.png",              -- view from bottom
}

local tiles_oldcoder = {
    "travelnet_oldcoder_front.png",  -- backward view
    "travelnet_oldcoder_side.png",   -- front view
    "travelnet_oldcoder_side.png",   -- sides
    "default_steel_block.png",       -- view from top
    "default_clay.png",              -- view from bottom
}

local tiles_poikilos = {
    "travelnet_poikilos_front.png",  -- backward view
    "travelnet_poikilos_back.png",   -- front view
    "travelnet_poikilos_side.png",   -- sides
    "default_steel_block.png",       -- view from top
    "default_clay.png",              -- view from bottom
}

local sound           = minetest.setting_get ("travelnet_sound")
if    sound == nil then
      sound = "travelnet_sound_poikilos"
end
travelnet.sound       = sound

local theme           = minetest.setting_get ("travelnet_theme")
local tiles_travelnet = tiles_oldcoder
travelnet.theme       = theme

if theme == "classic"  then tiles_travelnet = tiles_classic  end
if theme == "legacy"   then tiles_travelnet = tiles_classic  end
if theme == "oldcoder" then tiles_travelnet = tiles_oldcoder end
if theme == "poikilos" then tiles_travelnet = tiles_poikilos end
if theme == "tardis"   then tiles_travelnet = tiles_oldcoder end

if theme == "palantiri" then
minetest.register_node ("travelnet:travelnet", param_palantiri)
else
minetest.register_node ("travelnet:travelnet", {

    description = "Travelnet box",
    drawtype = "mesh",
    mesh = "travelnet.obj",
    sunlight_propagates = true,
    paramtype = 'light',
    paramtype2 = "facedir",
    wield_scale = {x=0.6, y=0.6, z=0.6},
    selection_box = {
        type = "fixed",
        fixed = { -0.5, -0.5, -0.5, 0.5, 1.5, 0.5 }
    },

    collision_box = {
        type = "fixed",
        fixed = {

            { 0.45, -0.5,-0.5,  0.5,  1.45, 0.5},
            {-0.5 , -0.5, 0.45, 0.45, 1.45, 0.5},
            {-0.5,  -0.5,-0.5 ,-0.45, 1.45, 0.5},

            --groundplate to stand on
            { -0.5,-0.5,-0.5,0.5,-0.45, 0.5},
            --roof
            { -0.5, 1.45,-0.5,0.5, 1.5, 0.5},
        } ,
    } ,

    tiles           = tiles_travelnet     ,
    inventory_image = "travelnet_inv.png" ,

    groups = { cracky=1,choppy=1,snappy=1,travelnet=1 } ,
    light_source = 10 ,

    after_place_node  = function(pos, placer, itemstack)
        local meta = minetest.get_meta (pos)
        meta:set_string ("infotext", "Travelnet-box (unconfigured)")
        meta:set_string ("station_name", "")
        meta:set_string ("station_network", "")
        meta:set_string ("owner", placer:get_player_name())

        -- request 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]")
    end,

    on_receive_fields = travelnet.on_receive_fields ,

    on_punch          = function(pos, node, puncher)
        travelnet.update_formspec(pos, puncher:get_player_name())
    end,

    can_dig = function( pos, player )
        return travelnet.can_dig( pos, player, 'travelnet box' )
    end,

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

    on_place = function (itemstack, placer, pointed_thing)

       local pos = pointed_thing.above
       local anode

       anode = minetest.get_node ({x=pos.x, y=pos.y+1, z=pos.z})
       if anode.name ~= "air" and
          anode.name ~= "default:vacuum" then
          minetest.chat_send_player (placer:get_player_name(),
'Not enough vertical space to place the travelnet')
          return
       end

       return minetest.item_place(itemstack, placer, pointed_thing);
    end ,
})
end

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

minetest.register_alias ("palantiri" , "travelnet:palantiri" )
minetest.register_alias ("travelnet" , "travelnet:travelnet" )