%%%
%%% Copyright 2011, Boundary
%%%
%%% 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.
%%%


%%%-------------------------------------------------------------------
%%% File:      folsom_vm_metrics.erl
%%% @author    joe williams <j@boundary.com>
%%% @doc
%%% convert erlang system metrics to proplists
%%% @end
%%%-----------------------------------------------------------------

-module(folsom_vm_metrics).

-export([get_system_info/0,
         get_statistics/0,
         get_memory/0,
         get_process_info/0,
         get_port_info/0
        ]).

-include("folsom.hrl").


% api

get_memory() ->
    erlang:memory().

get_statistics() ->
    [{Key, convert_statistics({Key, erlang:statistics(Key)})} || Key <- ?STATISTICS].

get_system_info() ->
    [{Key, convert_system_info({Key, erlang:system_info(Key)})} || Key <- ?SYSTEM_INFO].

get_process_info() ->
    [{pid_to_list(Pid), get_process_info(Pid)} || Pid <- processes()].

get_port_info() ->
    [{erlang:port_to_list(Port), get_port_info(Port)} || Port <- erlang:ports()].


% internal functions

%% conversion functions for erlang:statistics(Key)

convert_statistics({context_switches, {ContextSwitches, 0}}) ->
    ContextSwitches;
convert_statistics({exact_reductions, {TotalExactReductions,
                                        ExactReductionsSinceLastCall}}) ->
    [{"total_exact_reductions", TotalExactReductions},
     {"exact_reductions_since_last_call", ExactReductionsSinceLastCall}];
convert_statistics({garbage_collection, {NumberofGCs, WordsReclaimed, 0}}) ->
    [{"number_of_gcs", NumberofGCs}, {"words_reclaimed", WordsReclaimed}];
convert_statistics({io, {Input, Output}}) ->
    [Input, Output];
convert_statistics({reductions, {TotalReductions, ReductionsSinceLastCall}}) ->
    [{"total_reductions", TotalReductions},
     {"reductions_since_last_call", ReductionsSinceLastCall}];
convert_statistics({runtime, {TotalRunTime, TimeSinceLastCall}}) ->
    [{"total_run_time", TotalRunTime}, {"time_since_last_call", TimeSinceLastCall}];
convert_statistics({wall_clock, {TotalWallclockTime, WallclockTimeSinceLastCall}}) ->
    [{"Total_Wall_Clock_time", TotalWallclockTime},
     {"wall_clock_time_since_last_call", WallclockTimeSinceLastCall}];
convert_statistics({_, Value}) ->
    Value.

%% conversion functions for erlang:system_info(Key)

convert_system_info({allocated_areas, List}) ->
    [convert_allocated_areas(Value) || Value <- List];
convert_system_info({allocator, {_,_,_,List}}) ->
    List;
convert_system_info({c_compiler_used, {Compiler, Version}}) ->
    [{compiler, Compiler}, {version, convert_c_compiler_version(Version)}];
convert_system_info({cpu_topology, [{processor, List}]}) ->
    [{processor, convert_cpu_topology(List, [])}];
convert_system_info({dist_ctrl, List}) ->
    lists:map(fun({Node, Socket}) ->
                      {ok, Stats} = inet:getstat(Socket),
                      {Node, Stats}
              end, List);
convert_system_info({driver_version, Value}) ->
    list_to_binary(Value);
convert_system_info({machine, Value}) ->
    list_to_binary(Value);
convert_system_info({otp_release, Value}) ->
    list_to_binary(Value);
convert_system_info({scheduler_bindings, Value}) ->
    tuple_to_list(Value);
convert_system_info({system_version, Value}) ->
    list_to_binary(Value);
convert_system_info({system_architecture, Value}) ->
    list_to_binary(Value);
convert_system_info({version, Value}) ->
    list_to_binary(Value);
convert_system_info({_, Value}) ->
    Value.

convert_allocated_areas({Key, Value1, Value2}) ->
    {Key, [Value1, Value2]};
convert_allocated_areas({Key, Value}) ->
    {Key, Value}.

convert_c_compiler_version({A, B, C}) ->
    list_to_binary(io_lib:format("~p.~p.~p", [A, B, C]));
convert_c_compiler_version({A, B}) ->
    list_to_binary(io_lib:format("~p.~p", [A, B])).

convert_cpu_topology([{core, Value}| Tail], Acc) when is_tuple(Value) ->
  convert_cpu_topology(Tail, lists:append(Acc, [{core, tuple_to_list(Value)}]));
convert_cpu_topology([{core, Value}| Tail], Acc) when is_list(Value) ->
  convert_cpu_topology(Tail, lists:append(Acc, [{core, convert_cpu_topology(Value, [])}]));
convert_cpu_topology([{thread, Value}| Tail], Acc) ->
  convert_cpu_topology(Tail, lists:append(Acc, [{thread, tuple_to_list(Value)}]));
convert_cpu_topology([], Acc) ->
  Acc.

get_process_info(Pid) ->
    [process_info(Pid, Key) || Key <- ?PROCESS_INFO].

get_port_info(Port) ->
    Stat = get_socket_getstat(Port),
    SockName = get_socket_sockname(Port),
    Opts = get_socket_opts(Port),
    Info = erlang:port_info(Port),
    Protocol = get_socket_protocol(Port),
    Status = get_socket_status(Port),
    Type = get_socket_type(Port),

    lists:flatten(lists:append([
                                Stat,
                                SockName,
                                Opts,
                                Info,
                                Protocol,
                                Status,
                                Type
                               ])).

get_socket_getstat(Socket) ->
    case catch inet:getstat(Socket) of
        {ok, Info} ->
            Info;
        _ ->
            []
    end.

get_socket_status(Socket) ->
    case catch prim_inet:getstatus(Socket) of
        {ok, Status} ->
            [{status, Status}];
        _ ->
         []
    end.

get_socket_type(Socket) ->
    case catch prim_inet:gettype(Socket) of
        {ok, Type} ->
            [{type, Type}];
        _ ->
         []
    end.

get_socket_opts(Socket) ->
    [get_socket_opts(Socket, Key) || Key <- ?SOCKET_OPTS].

get_socket_opts(Socket, Key) ->
    case catch inet:getopts(Socket, [Key]) of
        {ok, Opt} ->
            Opt;
        _ ->
            []
    end.

get_socket_protocol(Socket) ->
    case erlang:port_info(Socket, name) of
        {name, "tcp_inet"} ->
            [{protocol, tcp}];
        {name, "udp_inet"} ->
            [{protocol, udp}];
        {name,"sctp_inet"} ->
            [{protocol, sctp}];
        _ ->
            []
    end.

get_socket_sockname(Socket) ->
    case catch inet:sockname(Socket) of
        {ok, {Ip, Port}} ->
            [{ip, ip_to_list(Ip)}, {port, Port}];
        _ ->
            []
    end.

ip_to_list({A, B, C, D}) ->
    [A, B, C, D].