%%
%% Copyright (C) 2010-2014 by krasnop@bellsouth.net (Alexei Krasnopolski)
%%
%% 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. 
%%

%% @since 2010-10-08
%% @copyright 2010-2014 Alexei Krasnopolski
%% @author Alexei Krasnopolski <krasnop@bellsouth.net> [http://krasnopolski.org/]
%% @version {@version}
%% @doc Function handle_response of the module splits the binary data stream from socket to MySQL packets, 
%% separates metadata packets and row data packets and forms a response tuple.

-module(packet_response).

%%
%% Include files
%%

-include("client_records.hrl").

%%
%% Import modules
%%
-import(lists, [reverse/1]).
-import(conn, []).
-import(io_socket, []).
-import(packet_parser, []).

%%
%% Exported Functions
%%
-export([handle_response/2, handle_response/3]).

%%
%% API Functions
%%
-spec handle_response(Connection::#connection{}, Stmt::atom()) -> {#metadata{}, list()}.

%% @spec handle_response(Connection::#connection{}, Initial_metadata::#metadata{}, Stmt::atom()) -> {Metadata::#metadata{}, Result} | #mysql_error{}
%% Result = [#ok_packet{}] | [#ok_stmt_packet{}] |
%% list(integer() | float() | string() | binary() | #mysql_time{} | #mysql_decimal{})
%% @doc Waits for response from SQL server, retrieves packets from socket and parses its to list 
%%
handle_response(Connection, Initial_metadata, Stmt) -> 
%  Is_compress = Connection#connection.ds_def#datasource.flags#client_options.compress =:= 1,
%  case Packet_list = io_socket:receive_data(Connection#connection.socket, Is_compress) of
%    #mysql_error{} -> Packet_list;
%    _ -> handle_response(Connection, 0, reverse(Packet_list), Initial_metadata, [], Stmt, false, false)
%  end.
  handle_response(Connection, 0, [], Initial_metadata, [], Stmt, false, false).

%% @spec handle_response(Connection::#connection{}, Stmt::atom()) -> {Metadata::#metadata{}, Result} | #mysql_error{}
%% Result = [#ok_packet{}] | [#ok_stmt_packet{}] | [#error_packet{}] | [#rs_header{}] | [#eof_packet{}] |
%%          list(integer() | float() | string() | binary() | #mysql_time{} | #mysql_decimal{})
%% 
%% @doc
%% @see handle_response/3
%%
handle_response(Connection, Stmt) -> handle_response(Connection, #metadata{}, Stmt).

%%
%% Local Functions
%%
-spec handle_response(Connection::#connection{}, State::integer(), Packet_list::list(#packet{}), Metadata::#metadata{}, Result::list(), Stmt::atom(), ParMark::boolean(), Termination::boolean())
        -> {#metadata{}, list()} | #mysql_error{}.

% TODO:  each packet in separate processes
%% @spec handle_response(Connection::#connection{}, State::integer(), Packet_list::list(#packet{}), Metadata::#metadata{}, Result::list(), Stmt::atom(), ParMark::boolean(), Termination::boolean()) -> {#metadata{}, list()} | #mysql_error{}
%% 
%% @doc
%% Transforms list of binary mySQL packets to Metadata record and list of row record.
handle_response(_, _, [], Metadata, Result, _, _, true) -> 
%%   io:format("  --$-- EndOfResultSet~n", []),
  {Metadata, reverse(Result)};
handle_response(Connection, State, [], Metadata, Result, Stmt, ParMark, false) -> 
  Is_compress = Connection#connection.ds_def#datasource.flags#client_options.compress =:= 1,
  case Packet_list = io_socket:receive_data(Connection#connection.socket, Is_compress) of
    #mysql_error{} -> Packet_list;
    _ -> handle_response(Connection, State, reverse(Packet_list), Metadata, Result, Stmt, ParMark, false)
  end;
handle_response(Connection, State, [Packet | Packet_list], Metadata, Result, Stmt, ParMark, _Termination) -> 
  R = packet_parser:parse_server_response_packet(State, Packet#packet.body, Metadata, Stmt),
%%   case R of
%%     #ok_packet{} -> 
%%       io:format("  --$-- #ok_packet{}~n", []);
%%     #ok_stmt_packet{} -> 
%%       io:format("  --$-- #ok_stmt_packet{} [col#=~p par#=~p]~n", [R#ok_stmt_packet.columns_number, R#ok_stmt_packet.params_number]);
%%     #error_packet{} ->
%%       io:format("  --$-- #error_packet{}~n", []);
%%     #rs_header{} ->
%%       io:format("  --$-- #rs_header{} [~p;~p]~n", [R#rs_header.field_count, R#rs_header.extra]);
%%     #field_metadata{} when (State =:= 1) and (Stmt =:= prepare) -> 
%%       io:format("  --$-- #field_metadata{}~n", []);
%%     #field_metadata{} ->
%%       io:format("  --$-- #field_metadata{}~n", []);
%%     #eof_packet{} when (State =:= 1) ->
%%       io:format("  --$-- #eof_packet{} [state=~p, pr.stmnt=~p] ~n", [State, Stmt]);
%%     #eof_packet{} ->
%%       io:format("  --$-- #eof_packet{} [state=~p, pr.stmnt=~p] ~n", [State, Stmt]);
%%     #mysql_error{} ->
%%       io:format("  --$-- #mysql_error{}~n", []);
%%     [_|_] -> 
%%       io:format("  --$-- data packet~n", []);
%%     _ ->
%%       io:format("  --$-- something wrong~n", [])
%%   end,
  case R of
    #ok_packet{} -> 
      New_metadata = Metadata#metadata{server_status = R#ok_packet.server_status},
      handle_response(Connection, State, Packet_list, New_metadata, [R#ok_packet{server_status = undefined} | Result], Stmt, ParMark, true);
    #ok_stmt_packet{} -> 
      NCol = R#ok_stmt_packet.columns_number,
      NPar = R#ok_stmt_packet.params_number,
      New_metadata = Metadata#metadata{field_count = NCol, param_count = NPar},
      New_State = if
        (NCol > 0)   and (NPar > 0)   -> 1;
        true -> 2
      end,
      handle_response(Connection, New_State, Packet_list, New_metadata, [R | Result], Stmt, (NPar > 0), (New_State < 0));
    #error_packet{} ->
      handle_response(Connection, State, Packet_list, Metadata, [R | Result], Stmt, ParMark, true);
    #rs_header{} -> New_metadata = Metadata#metadata{field_count = R#rs_header.field_count}, 
      handle_response(Connection, State + 1, Packet_list, New_metadata, Result, Stmt, ParMark, false);
%    #field_metadata{} when (State =:= 2) and (Stmt =:= prepare) -> 
%      New_metadata = Metadata#metadata{field_metadata = [R|Metadata#metadata.field_metadata]},
%      handle_response(State, Packet_list, New_metadata, Result, Stmt);
    #field_metadata{} when ((State =:= 1) or (ParMark and (State =:= 2))) and (Stmt =:= prepare) -> 
      New_metadata = Metadata#metadata{param_metadata = [R | Metadata#metadata.param_metadata]},
      handle_response(Connection, State, Packet_list, New_metadata, Result, Stmt, ParMark, false);
    #field_metadata{} ->
      New_metadata = Metadata#metadata{field_metadata = [R | Metadata#metadata.field_metadata]},
      handle_response(Connection, State, Packet_list, New_metadata, Result, Stmt, ParMark, false);
    #eof_packet{} when (State =:= 1) ->
      New_metadata = Metadata#metadata{
        field_metadata = reverse(Metadata#metadata.field_metadata)
      },
      handle_response(Connection, State + 1, Packet_list, New_metadata, Result, Stmt, ParMark, (Stmt =:= cursor));
    #eof_packet{} ->
      New_metadata = Metadata#metadata{
        server_status = R#eof_packet.server_status
      },
      handle_response(Connection, State + 1, Packet_list, New_metadata, Result, Stmt, ParMark, true);
    #mysql_error{} -> R;
    [_|_] -> handle_response(Connection, State, Packet_list, Metadata, [R | Result], Stmt, ParMark, false);
    _ -> false
  end.