datetime manipulation is now much clearer. tests were added, and expectations stated explicitly in many places. rules got lots of attention.

src/ezic_rule.erl

@@ -3,8 +3,7 @@
 
 
 -export([parse/1]).
--export([next_event/4]).
-
+-export([project_next/4]).
 
 
 parse([Name,FromS,ToS,_Type,InS,OnS,AtS,SaveS,Letters]) ->
@@ -25,37 +24,38 @@ parse([Name,FromS,ToS,_Type,InS,OnS,AtS,SaveS,Letters]) ->
 
 
 
-% determines the next zone or dst change event
-% returns the latest possible times the previous period is in effect (`Until -1sec` in most cases)
-% Rules are sorted
-next_event(_BaseFlat, ZoneEnd, Offset, []) ->
-    {end_until, make_times(ZoneEnd, Offset)};
-
-% BaseFlat has offset defined
-% @todo ensure offset defined on BaseFlat
-% Rules are sorted in ascending order (oldest first)
-next_event(_BaseFlat=#flatzone{utc_from=#tztime{time={{_Year,_,_},_}}}, 
-	   _ZoneEnd, _ZoneOffset, [_Rule|_RestRules]) ->
-
-    not_done.
-
-
-
+% returns the projected date of the next "rule event" in UTC time,
+%  after the given UTCDatetime, with the given the zone Offset and current DST offset.
+project_next(Rule=#rule{from=RFrom, to=RTo}, Offset, DSTOff, UTCAfter={{AY,_,_},_}) ->
+    AllYears= years(Rule),
+    GoodYears= years_after(AY, AllYears),
+    project_next2(Rule, Offset, UTCAfter, DSTOff, GoodYears).
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % PRIVATE
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-% create endtimes for a #flatzone, with no dst offset
-make_times(Until, Offset) ->
-    make_times(Until, Offset, 0).
-
-make_times(Until, Offset, DSTOffset) ->
-    ezic_date:all_times(Until, Offset, DSTOffset).
-
 
+% returns the sorted list of years a rule existed for.
+years(Rule=#rule{from=From, to=only}) ->
+    [From];
+years(Rule=#rule{from=From, to=To}) ->
+    try lists:seq(From, To)
+    catch error:function_clause ->
+	    erlang:error(bad_year_range)
+    end.
 
+% returns the years from the list that are greater than OR equal to Y
+years_after(Y, []) ->
+    [];
+years_after(Y, Years) ->
+    {GOOD, _}= lists:partition(
+      fun(X) when Y =< X -> true; 
+	 (_) -> false 
+      end, Years),
+    GOOD.
+			    
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % INTERNAL
@@ -63,4 +63,45 @@ make_times(Until, Offset, DSTOffset) ->
 
 
 
+project_next2(_,_,_,_,[]) ->
+    none;
+project_next2(Rule, Offset, UTCAfter, DSTOffset, [Year|RestYears]) ->
+    RuleDate= ezic_date:for_rule_utc(Rule, Offset, DSTOffset, Year),
+    case ezic_date:compare(UTCAfter, RuleDate) andalso (not ezic_date:equal(UTCAfter, RuleDate)) of
+	true -> RuleDate;
+	_ -> project_next2(Rule, Offset, UTCAfter, DSTOffset, RestYears)
+    end.
 
+
+
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Tests of Private Methods
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+
+years_test_() ->
+    [
+     ?_assertEqual([1952], years(#rule{from=1952,to=only}))
+     , ?_assertEqual([1952,1953], years(#rule{from=1952,to=1953}))
+     , ?_assertEqual([1952,1953,1954,1955], years(#rule{from=1952,to=1955}))
+     , ?_assertError(bad_year_range, years(#rule{from=1955,to=1952}))
+    ].
+
+
+% @todo type checking. lack of types worries me sometimes :(
+years_after_test_() ->
+    [
+     ?_assertEqual([2010], years_after(2010, [2010]))
+     , ?_assertEqual([2010,2011], years_after(2010, [2010,2011]))
+     , ?_assertEqual([2011], years_after(2011, [2010,2011]))
+     , ?_assertEqual([], years_after(2012, [2010,2011]))
+     , ?_assertEqual([], years_after(2012, []))
+    ].
+
+-endif.