-module(prime_server).
-export([start/1]).

%% Run by calling: prime_server:start(Number of Digits)

start(Digits) ->
	io:format("Creating a ~w digit random number~n", [Digits]),
	StartNum	= lib_primes:make_random_int(Digits),
	Counter	= spawn(counter, start, [StartNum]),
	%% Spawn checkers for stuff already online
	spawn_current_nodes(Counter, nodes()),
	io:format("Waiting for nodes to come online~n"),
	monitor([], [], Counter).

spawn_current_nodes(Counter, Nodes) ->
	case Nodes of
		[] -> ok;
		[Node | T] ->
			io:format("~n~p is up.~n", [Node]),
			io:format("Nodes are now ~p~n", [nodes()]),
			spawn(checker, start, [Counter, Node]),
			spawn_current_nodes(Counter, T)
	end.

monitor(UpFun, DownFun, Counter) ->
	case net_kernel:monitor_nodes(true) of
		ok ->
			receive
				{nodeup, Node} ->
					flush_nodedown_messages(),
					flush_nodeup_messages(),
					io:format("~n~p is up.~n", [Node]),
					io:format("Nodes are now ~p~n", [nodes()]),
					spawn(checker, start, [Counter, Node]),
					%%io:format("Spawned checker to handle new node ~w~n", [Node]),
					monitor(UpFun, DownFun, Counter);
				{nodedown, Node} ->
					flush_nodedown_messages(),
					flush_nodeup_messages(),
					io:format("~n~p is down.~n",[Node]),
					io:format("Nodes are now ~p~n", [nodes()]),
					monitor(UpFun, DownFun, Counter);
				Any ->
					io:format("Unknown message received in node_mon: ~w~n", [Any]),
					monitor(UpFun, DownFun, Counter)
			end;
		Other ->
			io:format("Unable to start monitor - ~w~n", [Other]) 
	end.

flush_nodedown_messages() ->
    receive
		{nodedown,_Node} ->
			flush_nodedown_messages()
	after
		0 ->
			done
    end.

flush_nodeup_messages() ->
	receive
		{nodeup,_Node} ->
			flush_nodeup_messages()
	after
		0 ->
			done
	end.