-module(file_logger_handler).
-include("include/types_rabbit.hrl").
-include_lib("kernel/include/logger.hrl").

-export([adding_handler/1, removing_handler/1, log/2]).
-export([init/1, handle_call/3, handle_cast/2, terminate/2]).



adding_handler(Config) ->
    MyConfig = maps:get(config,Config),
    {ok, Pid} = gen_server:start(?MODULE, MyConfig, []),
    {ok, Config#{config => MyConfig#{pid => Pid}}}.

init(#{logFolder := LogFolder}) ->
{ok,#{fileD => [], logFolder => LogFolder}}.

removing_handler(#{config := #{pid := Pid}}) ->
    gen_server:stop(Pid).

terminate(_Reason, #{fileD := FileDescriptors}) ->
    _ = closeFD(FileDescriptors),
    ok.

log(LogEvent,#{config := #{pid := Pid}} = Config) ->
    gen_server:cast(Pid, {log, LogEvent, Config}).

handle_cast({log, LogEvent = #{meta := #{mfa := {MODULE, _FUNCTION_NAME, _FUNCTION_ARITY}}}, Config}, #{logFolder := LogFolder, fileD := FileDescriptors} = State) ->
    FilePath = string:join([LogFolder,MODULE],"/"),
    case find_fd(FileDescriptors,FilePath) of
        none -> NewFD = open_new_fd(FilePath),
        NewFDL = lists:append(FileDescriptors,[{FilePath,NewFD}]),
        do_log(NewFD,LogEvent,Config),
        {noreply, State#{fileD => NewFDL}};
        Fd -> 
            do_log(Fd,LogEvent,Config),
            {noreply, State}
    end.

handle_call(_, _, State) ->
    {reply, {error, bad_request}, State}.

find_fd([], _Name) -> none;
find_fd([{Name,Fd}|_FileDescriptors], Name) ->
    Fd;
find_fd([_|FileDescriptors], Name) ->
find_fd(FileDescriptors,Name).


open_new_fd(File) ->
    {ok, Fd} = file:open(File, [append, {encoding, utf8}]),
    Fd.


do_log(Fd, LogEvent, #{formatter := {FModule, FConfig}}) ->
    String = FModule:format(LogEvent, FConfig),
    io:put_chars(Fd, String).

closeFD([]) -> ok;
closeFD([{_Name,Fd}|FileDescriptors]) ->
    file:close(Fd),
    closeFD(FileDescriptors).