xqerl

%% -------------------------------------------------------------------
%%
%% xqerl - XQuery processor
%%
%% Copyright (c) 2019-2020 Zachary N. Dean  All Rights Reserved.
%%
%% This file is provided to you under the Apache License,
%% Version 2.0 (the "License"); you may not use this file
%% except in compliance with the License.  You may obtain
%% a copy of the License at
%%
%%   http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing,
%% software distributed under the License is distributed on an
%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%% KIND, either express or implied.  See the License for the
%% specific language governing permissions and limitations
%% under the License.
%%
%% -------------------------------------------------------------------
-module(xqerl_main_mod_server).

-behaviour(gen_server).

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

%% ====================================================================
%% API functions
%% ====================================================================
-export([start_link/0]).

start_link() ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).

%% ====================================================================
%% Behavioural functions
%% ====================================================================

init([]) ->
    State = load(),
    {ok, State}.

handle_call({available, Args}, _From, #{available := Available} = State) ->
    Reply = xqerl:run(Available, Args),
    {reply, Reply, State};
handle_call({create, Args}, _From, #{create := Create} = State) ->
    Reply = xqerl:run(Create, Args),
    {reply, Reply, State};
handle_call({retrieve, Args}, _From, #{retrieve := Retrieve} = State) ->
    Reply = xqerl:run(Retrieve, Args),
    {reply, Reply, State};
handle_call({delete, Args}, _From, #{delete := Delete} = State) ->
    Reply = xqerl:run(Delete, Args),
    {reply, Reply, State};
handle_call({update, Args}, _From, #{update := Update} = State) ->
    Reply = xqerl:run(Update, Args),
    {reply, Reply, State};
handle_call(greeter, _From, #{greeter := Greeter} = State) ->
    Reply = xqerl:run(Greeter),
    {reply, Reply, State}.

handle_cast(_Msg, State) -> {noreply, State}.

handle_info(_Info, State) -> {noreply, State}.

terminate(_Reason, _State) -> ok.

code_change(_OldVsn, State, _Extra) -> {ok, State}.

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

load() ->
    PrivDir = code:priv_dir(xqerl),
    MainDir = filename:join([PrivDir, "modules"]),
    Greeter = xqerl:compile(filename:join([MainDir, "greeter.xq"])),
    Available = xqerl:compile(filename:join([MainDir, "db_available.xq"])),
    Create = xqerl:compile(filename:join([MainDir, "db_create.xq"])),
    Retrieve = xqerl:compile(filename:join([MainDir, "db_retrieve.xq"])),
    Delete = xqerl:compile(filename:join([MainDir, "db_delete.xq"])),
    Update = xqerl:compile(filename:join([MainDir, "db_update.xq"])),
    #{
        available => Available,
        create => Create,
        retrieve => Retrieve,
        delete => Delete,
        update => Update,
        greeter => Greeter
    }.