%%% @hidden
%%% @doc Storage backend for mysql.
%%%
%%% Copyright 2012 Inaka <hello@inaka.net>
%%%
%%% Licensed 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.
%%% @end
%%% @copyright Inaka <hello@inaka.net>
%%%
-module(sumo_backend_mysql).
-author("Marcelo Gornstein <marcelog@gmail.com>").
-github("https://github.com/inaka").
-license("Apache License 2.0").

-behaviour(gen_server).
-behaviour(sumo_backend).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Exports.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%% Public API.
-export(
  [ get_pool/1
  ]).

%%% Exports for sumo_backend
-export(
  [ start_link/2
  ]).

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

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Types.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-record(state, {
  pool = undefined :: atom()
}).
-type state() :: #state{}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% External API.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-spec start_link(atom(), proplists:proplist()) -> {ok, pid()}|term().
start_link(Name, Options) ->
  gen_server:start_link({local, Name}, ?MODULE, Options, []).

-spec get_pool(atom() | pid()) -> atom().
get_pool(Name) ->
  gen_server:call(Name, get_pool).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% gen_server stuff.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

-spec init([term()]) -> {ok, state()}.
init(Options) ->
  PoolSize = proplists:get_value(poolsize, Options),
  Pool     = list_to_atom(erlang:ref_to_list(make_ref())),
  _ = emysql:add_pool(
    Pool,
    PoolSize,
    proplists:get_value(username, Options),
    proplists:get_value(password, Options),
    proplists:get_value(host,     Options, "localhost"),
    proplists:get_value(port,     Options, 3306),
    proplists:get_value(database, Options),
    proplists:get_value(encoding, Options, utf8)
  ),
  {ok, #state{pool=Pool}}.

-spec handle_call(term(), term(), state()) -> {reply, term(), state()}.
handle_call(get_pool, _From, State = #state{pool=Pool}) ->
  {reply, Pool, State}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Unused Callbacks
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

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

-spec handle_info(term(), state()) -> {noreply, state()}.
handle_info(_Msg, State) -> {noreply, State}.

-spec terminate(term(), state()) -> ok.
terminate(_Reason, _State) -> ok.

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