if(SERVER)
then

    local _Spawns = {};

    concommand.Add("zombie_addspawn", function(ply, cmd, args, argstr)

        if(!ply:IsAdmin())
        then

            return;

        end

        if(#args == 0)
        then

            ply:ChatPrint("usage: zombie_addspawn <identifier> <maxzombies>");
            return;

        end

        if(#args != 2)
        then

            ply:ChatPrint("failed");
            return;

        end

        _Spawns[args[1]] = {

            ["pos"] = ply:GetPos(),
            ["maxzombies"] = tonumber(args[2]);

        };

    end);

    concommand.Add("zombie_removespawn", function(ply, cmd, args, argstr)

        if(!ply:IsAdmin())
        then

            return;

        end

        if(#args == 0)
        then

            ply:ChatPrint("usage: zombie_removespawn <identifier>");
            return;

        end

        if(#args != 1)
        then

            ply:ChatPrint("failed");
            return;

        end

        if(_Spawns[args[1]] == nil)
        then

            ply:ChatPrint("no such spawner");
            return;

        end

        _Spawns[args[1]] = nil;
        ply:ChatPrint("successfully removed");

    end);

    concommand.Add("zombie_gotospawn", function(ply, cmd, args, argstr)

        if(!ply:IsAdmin())
        then

            return;

        end

        if(#args == 0)
        then

            ply:ChatPrint("usage: zombie_gotospawn <identifier>");
            return;

        end

        if(!_Spawns[args[1]])
        then

            return;

        end

        ply:SetPos(_Spawns[args[1]]["pos"]);

    end);

    concommand.Add("zombie_listspawns", function(ply, cmd, args, argstr)

        if(!ply:IsAdmin())
        then

            return;

        end

        for k,v in next, _Spawns do

            ply:ChatPrint(string.format("%s = %d (%f, %f, %f)", k, v["maxzombies"], v["pos"].x, v["pos"].y, v["pos"].z));

        end

    end);

    hook.Add("Think", "zombiem3n", function()

        for k,v in next, _Spawns do

            if(v["zombies"] == nil)
            then

                v["zombies"] = {};

            end

            if(v["curzombies"] == nil)
            then

                v["curzombies"] = 0;

            end

            if(v["curzombies"] > 0)
            then

                local idx = 1;
                while(true)
                do

                    if(idx > v["curzombies"])
                    then

                        break;

                    end

                    if(v["zombies"][idx] == nil)
                    then

                        print(idx);
                        break;

                    end

                    if(!v["zombies"][idx]:IsValid())
                    then

                        table.remove(v["zombies"], idx);
                        v["curzombies"] = v["curzombies"] - 1;

                    else

                        idx = idx + 1;

                    end

                end

            end

            while(v["curzombies"] < v["maxzombies"])
            do

                local newzombie = ents.Create("npc_zombie");
                newzombie:SetPos(v["pos"] + Vector(math.random(-200, 200), math.random(-200, 200), 0));
                newzombie:Spawn();
                v["zombies"][v["curzombies"] + 1] = newzombie;
                v["curzombies"] = v["curzombies"] + 1;

                print(v["curzombies"]);

            end

        end

    end);

end