X-Git-Url: https://git.xandkar.net/?a=blobdiff_plain;f=life%2F001%2Fsrc%2Flife_observer.erl;fp=life%2F001%2Fsrc%2Flife_observer.erl;h=f2d6baac0db32e9921b3da4c56f8c878b438d157;hb=8d06c463b83b79e046250fbe60e5429f182e3a7a;hp=0000000000000000000000000000000000000000;hpb=4eb3be32ce405e69f39573b5e38171764cd0d789;p=cellular-automata.git

diff --git a/life/001/src/life_observer.erl b/life/001/src/life_observer.erl
new file mode 100644
index 0000000..f2d6baa
--- /dev/null
+++ b/life/001/src/life_observer.erl
@@ -0,0 +1,132 @@
+-module(life_observer).
+-behaviour(gen_event).
+
+
+%% API
+-export([start_link/2
+        ,register_with_logger/0
+        ,add_handler/2
+        ,delete_handler/0
+        ,log_generation/4
+        ]).
+
+%% Callbacks
+-export([init/1
+        ,terminate/2
+        ,code_change/3
+        ,handle_event/2
+        ,handle_call/2
+        ,handle_info/2
+        ]).
+
+
+-define(EVENT_MGR_REF, ?MODULE).
+-define(HANDLER, ?MODULE).
+
+-define(PATH_DIR__DATA, "data").
+-define(CSV_DELIMITER, ",").
+
+
+-record(state, {log_file :: file:io_device()}).
+
+
+%% ============================================================================
+%% API
+%% ============================================================================
+
+start_link(X, Y) ->
+    EventMgrName = {local, ?EVENT_MGR_REF},
+    {ok, PID} = gen_event:start_link(EventMgrName),
+    ok = add_handler(X, Y),
+    {ok, PID}.
+
+
+register_with_logger() ->
+    error_logger:add_report_handler(?HANDLER).
+
+
+add_handler(X, Y) ->
+    Args = [X, Y],
+    gen_event:add_handler(?EVENT_MGR_REF, ?HANDLER, Args).
+
+
+delete_handler() ->
+    Args = [],
+    gen_event:delete_handler(?EVENT_MGR_REF, ?HANDLER, Args).
+
+
+log_generation(GenID, GenDuration, Dead, Alive) ->
+    Event = {generation, GenID, GenDuration, Dead, Alive},
+    gen_event:notify(?EVENT_MGR_REF, Event).
+
+
+%% ============================================================================
+%% Callbacks (unused)
+%% ============================================================================
+
+code_change(_Old, State, _Other) -> {ok, State}.
+handle_call(_Request, State)     -> Reply = ok, {ok, Reply, State}.
+handle_info(_Info, State)        -> {ok, State}.
+
+
+%% ============================================================================
+%% Callbacks
+%% ============================================================================
+
+init([X, Y]) ->
+    N = X * Y,
+    {{Year, Month, Day}, {Hour, Min, Sec}} = calendar:local_time(),
+    DateTime = lists:flatten(io_lib:format(
+        "~4.10.0B-~2.10.0B-~2.10.0B--~2.10.0B:~2.10.0B:~2.10.0B",
+        [Year, Month, Day, Hour, Min, Sec]
+    )),
+
+    FileNameComponents = [DateTime | [integer_to_list(I) || I <- [N, X, Y]]],
+    FileName = string:join(FileNameComponents, "--") ++ ".csv",
+    FilePath = filename:join(?PATH_DIR__DATA, FileName),
+
+    ok = validate_makedir(file:make_dir(?PATH_DIR__DATA)),
+    {ok, LogFile} = file:open(FilePath, write),
+
+    CSVHeaders = ["Generation", "Duration", "Dead", "Alive"],
+    ok = do_write(LogFile, list_to_csvline(CSVHeaders)),
+
+    {ok, #state{log_file=LogFile}}.
+
+
+terminate(_Reason, #state{log_file=LogFile}=State) ->
+    file:close(LogFile),
+    {ok, State}.
+
+
+handle_event({generation, GenID, GenDuration, Dead, Alive},
+    #state{log_file=LogFile}=State) ->
+
+    Values = [integer_to_list(GenID)
+             ,float_to_string(GenDuration)
+             ,integer_to_list(Dead)
+             ,integer_to_list(Alive)
+             ],
+    ok = do_write(LogFile, list_to_csvline(Values)),
+    {ok, State}.
+
+
+%% ============================================================================
+%% Internal
+%% ============================================================================
+
+validate_makedir(ok) -> ok;
+validate_makedir({error, eexist}) -> ok;
+validate_makedir(Other) -> Other.
+
+
+do_write(File, Line) ->
+    ok = io:format(File, "~s~n", [Line]).
+
+
+list_to_csvline(List) ->
+    string:join(List, ?CSV_DELIMITER).
+
+
+float_to_string(Float) ->
+    io_lib:format("~f", [Float]).