%%%-------------------------------------------------------------------
%%% @private
%%% @doc
%%% Prefix tree server - This server provides a shared subject tree
%%% between members of the same ranch socket listener pool. 
%%% @end
%%%-------------------------------------------------------------------
-module(denrei_tree_server).

-behaviour(gen_server).

%% API
-export([start/0, start_link/0, stop/1]).
-export([insert/3, delete/3, match/2]).

%% gen_server callbacks
-export([init/1,
    handle_call/3,
    handle_cast/2,
    handle_info/2,
    terminate/2,
    code_change/3]).

-define(SERVER, ?MODULE).

%%%===================================================================
%%% API
%%%===================================================================
-spec insert(pid(), any(), denrei_tree:keys()) -> ok.
insert(Pid, Value, Keys) ->
    gen_server:call(Pid, {insert, Value, Keys}).

-spec delete(pid(), any(), denrei_tree:keys() | all) -> ok.
delete(Pid, Value, Keys) ->
    gen_server:call(Pid, {delete, Value, Keys}).

-spec match(pid(), denrei_tree:keys()) -> {ok, denrei_tree:values()}.
match(Pid, Keys) ->
    gen_server:call(Pid, {match, Keys}).

%%--------------------------------------------------------------------
%% @doc
%% Starts the server
%%
%% @end
%%--------------------------------------------------------------------
-spec(start() ->
    {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
start() ->
    gen_server:start(?MODULE, [], []).

-spec(start_link() ->
    {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
start_link() ->
    gen_server:start_link(?MODULE, [], []).

-spec(stop(Pid :: pid()) ->
    ok).
stop(Pid) ->
    gen_server:cast(Pid, stop).
%%%===================================================================
%%% gen_server callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Initializes the server
%%
%% @spec init(Args) -> {ok, Tree} |
%%                     {ok, Tree, Timeout} |
%%                     ignore |
%%                     {stop, Reason}
%% @end
%%--------------------------------------------------------------------
-spec(init(Args :: term()) ->
    {ok, Tree :: denrei_tree:tree()} | {ok, Tree :: denrei_tree:tree(), timeout() | hibernate} |
    {stop, Reason :: term()} | ignore).
init([]) ->
    {ok, denrei_tree:new()}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling call messages
%%
%% @end
%%--------------------------------------------------------------------
-spec(handle_call(Request :: term(), From :: {pid(), Tag :: term()},
        Tree :: denrei_tree:tree()) ->
    {reply, Reply :: term(), NewTree :: denrei_tree:tree()} |
    {reply, Reply :: term(), NewTree :: denrei_tree:tree(), timeout() | hibernate} |
    {noreply, NewTree :: denrei_tree:tree()} |
    {noreply, NewTree :: denrei_tree:tree(), timeout() | hibernate} |
    {stop, Reason :: term(), Reply :: term(), NewTree :: denrei_tree:tree()} |
    {stop, Reason :: term(), NewTree :: denrei_tree:tree()}).
handle_call({insert, Value, Keys}, _From, Tree) ->
    {reply, ok, denrei_tree:insert(Value, Keys, Tree)};

handle_call({delete, Value, Keys}, _From, Tree) ->
    {reply, ok, denrei_tree:delete(Value, Keys, Tree)};

handle_call({match, Keys}, _From, Tree) ->
    {reply, {ok, denrei_tree:match(Keys, Tree)}, Tree};

handle_call(_Request, _From, Tree) ->
    {reply, ok, Tree}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling cast messages
%%
%% @end
%%--------------------------------------------------------------------
-spec(handle_cast(Request :: term(), Tree :: denrei_tree:tree()) ->
    {noreply, NewTree :: denrei_tree:tree()} |
    {noreply, NewTree :: denrei_tree:tree(), timeout() | hibernate} |
    {stop, Reason :: term(), NewTree :: denrei_tree:tree()}).
handle_cast(_Request, Tree) ->
    {noreply, Tree}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling all non call/cast messages
%%
%% @spec handle_info(Info, Tree) -> {noreply, Tree} |
%%                                   {noreply, Tree, Timeout} |
%%                                   {stop, Reason, Tree}
%% @end
%%--------------------------------------------------------------------
-spec(handle_info(Info :: timeout() | term(), Tree :: denrei_tree:tree()) ->
    {noreply, NewTree :: denrei_tree:tree()} |
    {noreply, NewTree :: denrei_tree:tree(), timeout() | hibernate} |
    {stop, Reason :: term(), NewTree :: denrei_tree:tree()}).
handle_info(_Info, Tree) ->
    {noreply, Tree}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
%%
%% @spec terminate(Reason, Tree) -> void()
%% @end
%%--------------------------------------------------------------------
-spec(terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
        Tree :: denrei_tree:tree()) -> term()).
terminate(_Reason, _Tree) ->
    ok.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, Tree, Extra) -> {ok, NewTree}
%% @end
%%--------------------------------------------------------------------
-spec(code_change(OldVsn :: term() | {down, term()}, Tree :: denrei_tree:tree(),
        Extra :: term()) ->
    {ok, NewTree :: denrei_tree:tree()} | {error, Reason :: term()}).
code_change(_OldVsn, Tree, _Extra) ->
    {ok, Tree}.

%%%===================================================================
%%% Internal functions
%%%===================================================================