lots of work towards flattening the records. stalled at ezic_rule:next_event/4

src/ezic_flatten.erl

@@ -0,0 +1,145 @@
+-module(ezic_flatten).
+-include("include/ezic.hrl").
+
+-define(FLAT(W,S,U), #flatzone{wall_from=W, std_from=S, utc_from=U}).
+-define(ENDFLAT(F,W,S,U), F#flatzone{wall_to=W, std_to=S, utc_to=U}).
+-define(MINFLAT, ?FLAT(minimum,minimum,minimum)).
+
+
+
+
+-export([flatten/0]).
+
+
+
+
+flatten() ->
+    AllZones= ezic_db:get_all(zone),
+    flatten_zones(AllZones),
+    not_done.
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% PRIVATE
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+make_next_flat(#flatzone{wall_to=W, std_to=S, utc_to=U, offset=O}) ->
+    make_next_flat({W,S,U}, O);
+make_next_flat(EndTimes) ->
+    make_next_flat(EndTimes, undefined).
+
+
+make_next_flat({W,S,U}, O) ->
+    FW= ezic_date:add_seconds(W,1),
+    FS= ezic_date:add_seconds(S,1),
+    FU= ezic_date:add_seconds(U,1),
+    Flat= ?FLAT(FW, FS, FU),
+    Flat#flatzone{offset=O}.
+
+    
+    
+end_flat(Flat=#flatzone{}, {W,S,U}) ->
+    ?ENDFLAT(Flat,W,S,U).
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% INTERNAL
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+
+% recursively processes sets of similar zones until they're all done, passing zone sets to flatten_zone_set/1
+flatten_zones(Zones) ->
+    flatten_zones(Zones, []).
+
+flatten_zones([], Flats) ->
+    Flats;
+flatten_zones([Z1|_]= AllZones, Flats) ->
+    {CurrentZones, RestZones}= ezic_zone:split_by_name(Z1, AllZones),
+
+    SortedZones= lists:sort(fun ezic_zone:sort_ascending/2, CurrentZones),
+    NewFlats= lists:merge(Flats, flatten_zone_set(SortedZones)),
+
+    flatten_zones(RestZones, NewFlats).
+
+
+
+
+
+
+
+
+
+
+
+
+% takes zones one-by-one, gathering relevant rules and create flat periods of the same gmt offset (#flatzone)
+flatten_zone_set(Zones) ->
+    flatten_zone_set(?MINFLAT, Zones, []).
+
+
+% flatten_zone_set(FromTime, Zones, Flats) -> [#flatzone{}]
+%    FromTime= #flatzone{*_from =/= undefined}
+%    Zones= [#zone{}]
+%    Flats= [#flatzone{}]
+%
+% assumes a new zone every time it is called
+flatten_zone_set(_, [], Flats) ->
+    Flats;
+flatten_zone_set(FromTimeStub, [Z1=#zone{rule=RuleName, until=UntilTime, gmtoff=Offset} | RestZones] = Zones, Flats) ->
+
+    %% we have a flatzone with start times, we populate the base offset
+    FromTime= FromTimeStub#flatzone{offset=Offset},
+    
+    
+
+    %% we gather all rules that _may_ apply (same year)
+    Rules= ezic_db:rules(RuleName),
+    RelevantRules= ezic_rule:filter(FromTime, UntilTime, Rules),
+    SortedRules= lists:sort(fun ezic_rule:sort_ascending/2, RelevantRules),
+
+    %% Then we plot points, bouncing from rule to rule, ending when the zone ends
+    {ok, NextFromTimeStub, NewFlats}= flatten_zone(FromTime, Z1, SortedRules),
+    
+    
+    not_done.
+
+
+
+
+
+
+
+
+
+
+% flattens a single zone into multiple flatzones.
+% FromTime has its *_from fields and offset field populated. (it should anyway)
+% @todo invalid input checking
+% Rules are sorted
+flatten_zone(BaseFlat, Zone, Rules) ->
+    flatten_zone(BaseFlat, Zone, Rules, []).
+    
+flatten_zone(BaseFlat, Zone=#zone{until=Until, gmtoff=Offset}, Rules, Flats) ->
+    case ezic_rule:next_event(BaseFlat, Until, Offset, Rules) of
+         % is this enough information to compare all times corectly?
+	{end_until, EndTimes} ->
+	    NewFlats= [end_flat(BaseFlat, EndTimes) | Flats],
+	    NewFrom= make_next_flat(EndTimes),
+	    {ok, NewFrom, NewFlats}; % base case
+	
+	{end_rule, EndTimes, NextOffset} ->
+	    NewFlats= [end_flat(BaseFlat, EndTimes) | Flats],
+	    NewFrom= make_next_flat(EndTimes, NextOffset),
+	    flatten_zone(NewFrom, Zone, Rules, NewFlats) % tail recursion
+
+	end.
+
+
+
+