Fix review findings: ACTION:NONE alarms, negative offsets, non-ASCII UIDs

- valarms()/lead() now skip RFC 9074 ACTION:NONE placeholder VALARMs, so
  those events fall through to the calendar default instead of going silent.
- fmt_duration() renders negative timedeltas as "-Xd Yh Zm" instead of a
  wrapped-around wall-clock artifact.
- save_overrides() writes JSON with ensure_ascii=False and utf-8 encoding,
  so non-BMP UIDs (e.g. emoji) round-trip through tomllib instead of being
  written as surrogate-pair escapes tomllib rejects.

Marked as known limits with ponytail comments (no behaviour change):
- valarms()/alarms_for(): offsets add in wall-clock time, off by the jump
  across a DST transition.
- lead(): absolute DATE-TIME triggers don't widen the expansion window.
- expand(): RDATE is ignored.
- rule_for(): a VEVENT with more than one RRULE line fails and is skipped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 43 insertions, 7 deletions

diff --git a/cal-notif b/cal-notif
index 3d9dcb3..c8ed33e 100755
--- a/cal-notif
+++ b/cal-notif
@@ -65,9 +65,10 @@ def parse_duration(s):
 
 def fmt_duration(td):
     m = round(td.total_seconds() / 60)
-    d, m = divmod(m, 1440)
+    sign = "-" if m < 0 else ""
+    d, m = divmod(abs(m), 1440)
     h, m = divmod(m, 60)
-    return " ".join(f"{n}{u}" for n, u in ((d, "d"), (h, "h"), (m, "m")) if n) or "0m"
+    return sign + (" ".join(f"{n}{u}" for n, u in ((d, "d"), (h, "h"), (m, "m")) if n) or "0m")
 
 
 UNITS = ["", "uno", "due", "tre", "quattro", "cinque", "sei", "sette", "otto", "nove",
@@ -131,8 +132,8 @@ def save_overrides(ov, path=None):
     path.parent.mkdir(parents=True, exist_ok=True)
     tmp = path.with_suffix(".tmp")
     # JSON strings and string arrays are valid TOML, so no TOML writer is needed.
-    tmp.write_text("".join(f"{json.dumps(uid)} = {json.dumps(offs)}\n"
-                           for uid, offs in sorted(ov.items())))
+    tmp.write_text("".join(f"{json.dumps(uid, ensure_ascii=False)} = {json.dumps(offs, ensure_ascii=False)}\n"
+                           for uid, offs in sorted(ov.items())), encoding="utf-8")
     os.replace(tmp, path)
 
 # ---- calendars ----
@@ -151,6 +152,8 @@ def local(dt):
 def rule_for(comp, start):
     # dateutil wants UNTIL to match DTSTART: naive for floating/all-day,
     # UTC for zoned. Clients do not always agree, so normalise it.
+    # ponytail: a VEVENT with more than one RRULE line fails here and
+    # load_events skips the whole file; upgrade path: merge into one rruleset.
     rec = vRecur(comp["RRULE"])
     if "UNTIL" in rec:
         u = rec["UNTIL"][0]
@@ -164,12 +167,20 @@ def rule_for(comp, start):
     return rrulestr(rec.to_ical().decode(), dtstart=start)
 
 
+def _live_valarms(comp):
+    # RFC 9074 ACTION:NONE is Apple/iCloud's "no alarm" placeholder, not a
+    # real VALARM: skip it or it silences the calendar default.
+    return [a for a in comp.walk("VALARM") if str(a.get("ACTION", "")).upper() != "NONE"]
+
+
 def valarms(comp, start, end):
     out = []
-    for a in comp.walk("VALARM"):
+    for a in _live_valarms(comp):
         t = a.get("TRIGGER")
         if t is None:
             continue
+        # ponytail: offsets add in wall-clock time, so an alarm spanning a
+        # DST jump is off by the jump; upgrade path: add the sub-day part in UTC.
         if isinstance(t.dt, timedelta):
             out.append((end if t.params.get("RELATED") == "END" else start) + t.dt)
         else:
@@ -179,7 +190,9 @@ def valarms(comp, start, end):
 
 def lead(comp):
     # The longest relative VALARM lead, so expansion reaches far enough.
-    trig = [a["TRIGGER"].dt for a in comp.walk("VALARM") if "TRIGGER" in a]
+    # ponytail: an absolute DATE-TIME trigger does not widen the window, so
+    # an absolute alarm for an event beyond the horizon is dropped.
+    trig = [a["TRIGGER"].dt for a in _live_valarms(comp) if "TRIGGER" in a]
     return max([-t for t in trig if isinstance(t, timedelta)] + [timedelta()])
 
 
@@ -218,6 +231,7 @@ def expand(ics, cal, lo, hi):
             if lo <= first.start <= top:
                 out.append(first)
             continue
+        # ponytail: RDATE is ignored; upgrade path: dateutil rruleset.rdate.
         # Expand in the event's own clock: naive for all-day/floating.
         start = s0 if isinstance(s0, datetime) else datetime.combine(s0, dtime())
         conv = (lambda d: d) if start.tzinfo else (lambda d: d.astimezone().replace(tzinfo=None))
@@ -262,6 +276,8 @@ def alarms_for(occ, cfg, overrides):
         return list(occ.valarms)
     else:
         offs = cal_entry(cfg, occ.cal)[0]
+    # ponytail: offset subtracted in wall-clock time, so an alarm spanning a
+    # DST jump is off by the jump; upgrade path: apply the sub-day part in UTC.
     return [occ.start - parse_duration(o) for o in offs]
 
 
diff --git a/test_cal_notif.py b/test_cal_notif.py
index ea5aba5..f22fbc3 100644
--- a/test_cal_notif.py
+++ b/test_cal_notif.py
@@ -46,6 +46,7 @@ def test_durations():
             pass
     assert cn.fmt_duration(D + 2 * H) == "1d 2h"
     assert cn.fmt_duration(timedelta()) == "0m"
+    assert cn.fmt_duration(timedelta(minutes=-45)) == "-45m"
     assert cn.spoken_it(10 * M) == "dieci minuti"
     assert cn.spoken_it(H) == "un'ora"
     assert cn.spoken_it(D + 2 * H) == "un giorno e due ore"
@@ -56,7 +57,8 @@ def test_durations():
 def test_overrides_roundtrip():
     with tempfile.TemporaryDirectory() as d:
         p = Path(d) / "overrides.toml"
-        ov = {"a@example.org": ["1h", "10m"], 'q"uote@example.org': []}
+        ov = {"a@example.org": ["1h", "10m"], 'q"uote@example.org': [],
+              "café\U0001F600@example.org": ["30m"]}
         cn.save_overrides(ov, p)
         assert cn.load_overrides(p) == ov
         assert cn.load_overrides(Path(d) / "missing.toml") == {}
@@ -135,6 +137,24 @@ END:VALARM"""
     assert o.valarms == (at(2026, 1, 10, 10, 45),)
 
 
+def test_alarm_action_none():
+    lo, hi = at(2026, 1, 1), at(2026, 2, 1)
+    # RFC 9074 ACTION:NONE placeholder (Apple/iCloud "no alarm") must not
+    # count as a VALARM, so alarms_for falls back to the calendar default.
+    none_alarm = """UID:n@example.org
+DTSTART;TZID=Europe/Rome:20260115T090000
+SUMMARY:silent
+BEGIN:VALARM
+ACTION:NONE
+TRIGGER;VALUE=DATE-TIME:19760401T005545Z
+END:VALARM"""
+    (o,) = cn.expand(ics(none_alarm), "c", lo, hi)
+    assert o.valarms == ()
+    cfg = cn.load_config(Path("/nonexistent"))
+    cfg["defaults"] = {"c": ["15m"]}
+    assert cn.alarms_for(o, cfg, {}) == [o.start - 15 * M]
+
+
 def test_load_events():
     with tempfile.TemporaryDirectory() as d:
         cal = Path(d) / "123"