-module(client).
-export([register/3, login/3, list/0, handle/2, getVotes/0, vote/2, devote/2]).

contains([], _) ->
    false;
contains([H|_], H) ->
    true;
contains([_|T], Search) ->
    contains(T, Search).

checkLogin(Value) ->
    checkLogin(Value, contains(registered(), cli)).
checkLogin(Value, Value) ->
    true;
checkLogin(_, _) ->
    throw({error, login_state}).

buildNode(Server) ->
    list_to_atom("distributed_music_system_main_node@" ++ Server).

rpc(Server, Function, Params) ->
    rpc:call(buildNode(Server), client, Function, Params).

register(Server, Name, Password) ->
    rpc(Server, register, [self(), {Name, Password}]),
    receive
	{_, Msg} ->
	    Msg
    end.

login(Server, Name, Password) ->
    code:purge(server),
    code:load_abs("../common/server"),

    try checkLogin(false) of
	_ ->
	    rpc(Server, login, [self(), {node(), Name, Password}]),
	    receive
		{ok, {ok, {logged_in, Pid}}} ->
		    register(cli, Pid),
		    {ok, logged_in};
		{_, Msg} ->
		    Msg;
		Msg ->
		    Msg
	    end
    catch
	{error, login_state} ->
	    {error, logged_in}
    end.

list() ->
    try checkLogin(true) of
	_ ->
	    server:rpc(cli, list)
    catch
	{error, login_state} ->
	    {error, not_logged_in}
    end.

send_to_server(Cmd, Server) ->
    Server ! Cmd,
    receive
    	{ok, Msg} ->
    	    {Msg, Server};
    	Msg ->
    	    {Msg, Server}
    end.

handle(list, Server) ->
    send_to_server(list, Server);
handle(get_votes, Server) ->
    send_to_server(get_votes, Server);
handle({vote, Artist, Title}, Server) ->
    send_to_server({vote, Artist, Title}, Server);
handle({devote, Artist, Title}, Server) ->
    send_to_server({devote, Artist, Title}, Server);

handle({change_state, NewState}, _) ->
    {{ok}, NewState};

handle(Cmd, Server) ->
    {{error, {unknown_command, Cmd}}, Server}.

%queries the server for the current votes this client possesses
getVotes() ->
    try checkLogin(true) of
	_ ->
	    server:rpc(cli, get_votes)
    catch
	{error, login_state} ->
	    {error, not_logged_in}
    end.

%positive vote, increments the votes for {Artist, Title} by one
vote(Artist, Title) ->
    try checkLogin(true) of
	_ ->
	    server:rpc(cli, {vote, Artist, Title})
    catch
	{error, login_state} ->
	    {error, not_logged_in}
    end.

%negative vote, decrements the votes for {Artist, Title} by one
devote(Artist, Title) ->
    try checkLogin(true) of
	_ ->
	    server:rpc(cli, {devote, Artist, Title})
    catch
	{error, login_state} ->
	    {error, not_logged_in}
    end.