%% -*- erlang -*-
%% -------------------------------------------------------------------
%%
%% nodetool: Helper Script for interacting with live nodes
%%
%% -------------------------------------------------------------------

main(Args) ->
    %% Extract the args
    {RestArgs, TargetNode} = process_args(Args, [], undefined),

    %% See if the node is currently running  -- if it's not, we'll bail
    case net_adm:ping(TargetNode) of
        pong -> 
            ok;
        pang -> 
            io:format("Node ~p not responding to pings.\n", [TargetNode]),
            halt(1)
    end,

    case RestArgs of
        ["ping"] ->
            %% If we got this far, the node already responsed to a ping, so just dump
            %% a "pong"
            io:format("pong\n");
        ["stop"] ->
            io:format("~p\n", [rpc:call(TargetNode, init, stop, [], 60000)]);
        ["restart"] ->
            io:format("~p\n", [rpc:call(TargetNode, init, restart, [], 60000)]);
        ["reboot"] ->
            io:format("~p\n", [rpc:call(TargetNode, init, reboot, [], 60000)]);
        ["rpc", Module, Function | RpcArgs] ->
            case rpc:call(TargetNode, list_to_atom(Module), list_to_atom(Function), [RpcArgs], 60000) of
                ok ->
                    ok;
                {badrpc, Reason} ->
                    io:format("RPC to ~p failed: ~p\n", [TargetNode, Reason]),
                    halt(1);
                _ ->
                    halt(1)
            end;
        Other ->
            io:format("Other: ~p\n", [Other]),
            io:format("Usage: nodetool {ping|stop|restart|reboot}\n")
    end,
    net_kernel:stop().
    
process_args([], Acc, TargetNode) ->
    {lists:reverse(Acc), TargetNode};
process_args(["-setcookie", Cookie | Rest], Acc, TargetNode) ->
    erlang:set_cookie(node(), list_to_atom(Cookie)),
    process_args(Rest, Acc, TargetNode);
process_args(["-name", TargetName | Rest], Acc, _) ->
    ThisNode = append_node_suffix(TargetName, "_maint_"),
    {ok, _} = net_kernel:start([ThisNode, longnames]),
    process_args(Rest, Acc, nodename(TargetName));
process_args(["-sname", TargetName | Rest], Acc, _) ->
    ThisNode = append_node_suffix(TargetName, "_maint_"),
    {ok, _} = net_kernel:start([ThisNode, shortnames]),
    process_args(Rest, Acc, nodename(TargetName));
process_args([Arg | Rest], Acc, Opts) ->
    process_args(Rest, [Arg | Acc], Opts).


nodename(Name) ->
    case string:tokens(Name, "@") of
        [_Node, _Host] ->
            list_to_atom(Name);
        [Node] ->
            [_, Host] = string:tokens(atom_to_list(node()), "@"),
            list_to_atom(lists:concat([Node, "@", Host]))
    end.

append_node_suffix(Name, Suffix) ->
    case string:tokens(Name, "@") of
        [Node, Host] ->
            list_to_atom(lists:concat([Node, Suffix, os:getpid(), "@", Host]));
        [Node] ->
            list_to_atom(lists:concat([Node, Suffix, os:getpid()]))
    end.
