nitrogen_core

% vim: sw=4 ts=4 et ft=erlang
% Nitrogen Web Framework for Erlang
% Copyright (c) 2008-2010 Rusty Klophaus
% Copyright (c) 2013-2014 Jesse Gumm
% See MIT-LICENSE for licensing information.

-module(nitrogen).
-behaviour(simple_bridge_handler).
-export([
        init_request/2,
        init_request/1,
        handler/2,
        handler/3,
        run/0
]).

%% Grid system setting
-export([
    default_grid_system/0,
    default_grid_system_module/0,
    default_grid_system/1,
    grid_system_module/2,
    grid_system_module/1
]).

%% Simple Bridge Callout functions
-export([
        run/1,
        ws_init/1,
        ws_message/3,
        ws_info/3,
        ws_terminate/3
    ]).

-deprecated([
        {run,0},
        {init_request,2}
    ]).

call_main_handler_ws_init() ->
    case erlang:function_exported(nitrogen_main_handler, ws_init, 0) of
        true -> nitrogen_main_handler:ws_init();
        false -> ok
    end.

%% init_request/2 kept for backwards compatibility, but is no longer needed
init_request(Bridge, _) ->
    init_request(Bridge).

init_request(Bridge) ->
    wf_context:init_context(Bridge).

handler(Module, Config) ->
    wf_handler:set_handler(Module, Config).

handler(Name, Module, Config) ->
    wf_handler:set_handler(Name, Module, Config).

default_grid_system() ->
    wf_grid_system:default_grid_system().

-spec default_grid_system(atom() | {atom(), atom()}) -> ok.
default_grid_system(GridSystem) ->
    wf_grid_system:default_grid_system(GridSystem).

default_grid_system_module() ->
    wf_grid_system:default_grid_system_module().

grid_system_module(Name, Module) ->
    wf_grid_system:grid_system_module(Name, Module).

grid_system_module(Name) ->
    wf_grid_system:grid_system_module(Name).

run(Bridge) ->
    init_request(Bridge),
    nitrogen_main_handler:run().

ws_init(Bridge) ->
    init_request(Bridge),
    call_main_handler_ws_init(),
    ok.

ws_message({text, <<"ping">>}, _Bridge, _State) ->
    {reply, {text, <<"pong">>}};
ws_message({text, _Text}=Msg, Bridge, _State) ->
    %% Nitrogen doesn't sent text messages from the client, so this should be
    %% handed off to the websocket handler
    dispatch_to_handler(Msg, Bridge);
ws_message({binary, Bin}=Msg, Bridge, _State) ->
    try binary_to_term(Bin, [safe]) of
        Decoded ->
            try
                ws_message_catched(Decoded, Bridge)
            catch
                Class:Error:Stacktrace ->
                    CrashReturn = wf_core:run_websocket_crash(Class, Error, Stacktrace),
                    {reply, {text, [<<"nitrogen_event:">>,CrashReturn]}}
                    end
    catch _:_ ->
        %% This is not a decodable term, which means it's intended to be a
        %% direct pass-thru message so we need to process this directly
        dispatch_to_handler(Msg, Bridge)
    end.

dispatch_to_handler(Msg, Bridge) ->
    {ok, Reply} = websocket_handler:ws_message(Msg, Bridge),
    Reply.

ws_message_catched({nitrogen_postback,Msg}, _Bridge) ->
    Return = wf_core:run_websocket(Msg),
    {reply, {text, [<<"nitrogen_event:">>,Return]}};
ws_message_catched(flush_switchover_comet_actions, _Bridge) ->
    %% If there are any actions that weren't
    ReconnectionRecovery = <<"Nitrogen.$reconnect_system();">>,
    Reply = case action_comet:get_actions_and_register_new_websocket_pid(self()) of
        [] ->
            [<<"nitrogen_system_event:">>, ReconnectionRecovery];
        Actions ->
            wf:wire(page, page, Actions),
            Return = wf_core:run_websocket_comet(),
            [<<"nitrogen_system_event:">>, [ReconnectionRecovery, Return]]
    end,
    {reply, {text, Reply}};
ws_message_catched({page_context, PageContext}, _Bridge) ->
    wf_core:init_websocket(PageContext),
    Reply = [
        %% init_websocket has changed the async mode to websocket, so
        %% let's tell the browser about our updated async_mode
        <<"nitrogen_event:">>,
        wf_core:serialize_context(),
        <<"Nitrogen.$enable_websockets();">>
    ],
    {reply, {text, Reply}};
ws_message_catched(Msg, Bridge) ->
    %% This message was not one of the standard Nitrogen decoded messages, so
    %% we'll pass the decoded value to the module.
    dispatch_to_handler({decoded, Msg}, Bridge).

ws_info({comet_actions, Actions} , _Bridge, _State) ->
    wf:wire(page, page, Actions),
    Return = wf_core:run_websocket_comet(),
    {reply, {text, [<<"nitrogen_system_event:">>, Return]}};
ws_info({'EXIT', _Pid, normal}, _Bridge, _State) ->
    noreply;
ws_info(Msg, _Bridge, _State) ->
    logger:warning("Unhandled message(~p) to websocket process (~p)~n", [Msg, self()]),
    noreply.

ws_terminate(_Reason, _Bridge, _State) ->
    ok.


%% Deprecated, kept for backwards compatibility. Use
%% nitrogen_main_handler:run/0 (defined in your own project's src directory)
run() ->
    wf_core:run().