fix(shadbala): Ayana hemisphere after wrap, civil-weekday hora lord, continuous mean motion, short-arc Chesta midpoint (upstream 0afa2780)

Ported from yinduzhanxing 0afa2780 (algorithm hunks and its four regression
tests; the PyJHora / profile-metadata hunks do not apply to our file). The
archived-PyJHora Kala test follows upstream's rewrite. The V.P. Jain
benchmark expectations still need the three-column update (follow-up in this
branch). TASK-upstream-sync4-20261002 T3.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4f2nya58RoRu4yEmJgRGE

scripts/shadbala.py

@@ -24,6 +24,7 @@ import swisseph as swe
 import sys
 import os
 import json
+from datetime import date
 from typing import Dict, Tuple
 
 # v6.1.10: 导入实际Varga计算器（支持脚本和包两种调用方式）
@@ -351,7 +352,7 @@ def _lagrange_interpolate(xs: tuple[float, ...], ys: tuple[float, ...], value: f
 def _ayana_bala(pname: str, longitude: float, ayanamsa: float) -> tuple[float, float]:
     raw_tropical = longitude + ayanamsa
     tropical = raw_tropical % 360.0
-    north = raw_tropical < 180.0
+    north = tropical < 180.0
     folded = tropical
     if 90.0 < tropical < 180.0:
         folded = 180.0 - tropical
@@ -397,12 +398,14 @@ def _calendar_lords(context: Dict) -> Dict[str, str]:
         vaara_ahargana -= 1
     vaara = _ABDA_WEEKDAY_PLANETS[int(vaara_ahargana) % 7]
 
-    civil_weekday = int(math.ceil(local_jd + 1.0) % 7)
+    # Civil weekday must not change at astronomical Julian noon. Sunday=0.
+    civil_weekday = (date(year, month, day).weekday() + 1) % 7
     local_hour = context["local_hour"]
     if local_hour < context["sunrise_hour"]:
         civil_weekday = (civil_weekday - 1) % 7
         local_hour += 24.0
-    hora_index = (int(local_hour - context["sunrise_hour"]) + civil_weekday + 1) % 7
+    weekday_lord = ("Sun", "Moon", "Mars", "Mercury", "Jupiter", "Venus", "Saturn")[civil_weekday]
+    hora_index = (int(local_hour - context["sunrise_hour"]) + _HORA_ORDER.index(weekday_lord)) % 7
     return {"abda": abda, "masa": masa, "vaara": vaara, "hora": _HORA_ORDER[hora_index]}
 
 
@@ -452,15 +455,38 @@ def calc_kala_bala_precise(pname: str, all_planets: Dict, context: Dict) -> Dict
 
 
 def _surya_mean_longitude(pname: str, context: Dict) -> float:
-    """Surya Siddhanta mean motion with desantara correction from Ujjain."""
+    """Surya Siddhanta mean motion at the Ujjain mean-time meridian.
-    local_jd = context["jd_local"]
+
-    kali_days = int(local_jd - 588_465.0)
+    Civil clock time is not local mean solar time. Convert through UTC so
-    weekday = int(math.ceil(local_jd + 1.0) % 7)
+    changing a time-zone representation cannot change a geocentric mean.
-    kali_days += weekday - 5 - kali_days % 7
+    """
+    if "jd_ut" in context:
+        jd_ut = float(context["jd_ut"])
+    else:
+        # Legacy callers must explicitly identify their civil-clock offset.
+        jd_ut = float(context["jd_local"]) - float(context["timezone"]) / 24.0
+    ujjain_jd = jd_ut + _UJJAIN_LONGITUDE / 360.0
+    # Mean motion is continuous elapsed time. Re-aligning this count to a
+    # weekday introduced seven-day jumps; integer truncation lost sub-day
+    # motion. Preserve the existing epoch/rates rather than tune to an oracle.
+    kali_days = ujjain_jd - 588_465.0
     daily_motion = round(_SURYA_REVOLUTIONS[pname] / _SURYA_CIVIL_DAYS * 360.0, 7)
     mean_longitude = (kali_days * daily_motion) % 360.0
-    desantara = (_UJJAIN_LONGITUDE - context["lon"]) / 360.0 * daily_motion
+    return mean_longitude
-    return (mean_longitude + desantara) % 360.0
+
+
+def chesta_from_longitudes(mean: float, true: float, apogee: float) -> float:
+    """Bounded Chesta with a coordinate-invariant short-arc midpoint.
+
+    Short-arc continuation across zero is geometric, not an additional rule
+    explicitly supplied by Raman's non-crossing published example.
+    """
+    separation = (true - mean + 180.0) % 360.0 - 180.0
+    if abs(separation) == 180.0:
+        raise ValueError("Antipodal mean/true longitudes have no unique short-arc midpoint")
+    midpoint = (mean + separation / 2.0) % 360.0
+    angle = (apogee - midpoint + 180.0) % 360.0 - 180.0
+    return round(abs(angle) / 3.0, 2)
 
 
 def calc_chesta_bala_precise(pname: str, all_planets: Dict, kala: Dict, context: Dict) -> float:
@@ -479,11 +505,7 @@ def calc_chesta_bala_precise(pname: str, all_planets: Dict, kala: Dict, context:
         seeghrochcha, mean_longitude = planet_mean, sun_mean
     else:
         seeghrochcha, mean_longitude = sun_mean, planet_mean
-    average_longitude = (_planet_longitude(pname, all_planets) + mean_longitude) / 2.0
+    return chesta_from_longitudes(mean_longitude, _planet_longitude(pname, all_planets), seeghrochcha)
-    chesta_kendra = abs(seeghrochcha - average_longitude)
-    if chesta_kendra > 180.0:
-        chesta_kendra = 360.0 - chesta_kendra
-    return round(max(0.0, chesta_kendra) / 3.0, 2)
 
 
 def calc_shadbala(planets: Dict, asc_sign: str, birth_hour: float,

tests/test_chesta_circular_midpoint.py

@@ -0,0 +1,31 @@
+import pytest
+
+from scripts.shadbala import chesta_from_longitudes as circular_chesta
+
+
+@pytest.mark.parametrize("rotation", range(0, 360, 15))
+def test_strength_does_not_depend_on_choice_of_zodiac_origin(rotation):
+    # Mean350/true10 must average to0, not180. Apogee180 gives full strength.
+    angles = [(angle + rotation) % 360 for angle in (350, 10, 180)]
+    assert circular_chesta(*angles) == 60
+
+
+def test_midpoint_is_continuous_across_zero_and_full_turns():
+    assert circular_chesta(359.9999, 10, 180) == circular_chesta(.0001, 10, 180)
+    assert circular_chesta(-10, 370, 540) == circular_chesta(350, 10, 180)
+
+
+def test_does_not_guess_an_antipodal_branch():
+    with pytest.raises(ValueError, match="Antipodal"):
+        circular_chesta(0, 180, 90)
+
+
+@pytest.mark.parametrize("mean,true,apogee,expected", [
+    (266.34, 229.50, 181.23, 22.23),
+    (181.23, 181.52, 174.49, 2.29),
+    (66.91, 84.01, 181.23, 35.26),
+    (181.23, 171.16, 158.35, 5.95),
+    (111.23, 124.39, 181.23, 21.14),
+])
+def test_published_non_crossing_inputs_keep_their_arithmetic(mean, true, apogee, expected):
+    assert circular_chesta(mean, true, apogee) == expected

tests/test_shadbala_ayana_wrap.py

@@ -0,0 +1,13 @@
+import pytest
+from scripts.shadbala import _ayana_bala
+
+
+@pytest.mark.parametrize("planet", ["Sun", "Moon", "Mars", "Mercury", "Jupiter", "Venus", "Saturn"])
+def test_ayana_uses_wrapped_tropical_hemisphere(planet):
+    assert _ayana_bala(planet, 350.0, 22.0) == _ayana_bala(planet, -10.0, 22.0)
+
+
+def test_venus_just_after_tropical_aries_uses_north_addition():
+    bala, declination = _ayana_bala("Venus", 350.0, 22.0)
+    assert declination > 0
+    assert bala > 30

tests/test_shadbala_hora_civil_weekday.py

@@ -0,0 +1,30 @@
+from datetime import date, timedelta
+import swisseph as swe
+import pytest
+from scripts.shadbala import _calendar_lords
+
+
+def context(day, hour):
+    return {"year": day.year, "month": day.month, "day": day.day,
+            "jd_local": swe.julday(day.year, day.month, day.day, hour),
+            "local_hour": hour, "sunrise_hour": 6.0}
+
+
+@pytest.mark.parametrize("offset,lord", enumerate(
+    ("Sun", "Moon", "Mars", "Mercury", "Jupiter", "Venus", "Saturn")))
+def test_first_hora_is_weekday_lord(offset, lord):
+    assert _calendar_lords(context(date(2026, 9, 27) + timedelta(days=offset), 6.1))["hora"] == lord
+
+
+def test_no_artificial_weekday_switch_at_julian_noon():
+    # Saturday: seventh hour is Moon, eighth Saturn, ninth Jupiter.
+    day = date(1993, 4, 17)
+    assert _calendar_lords(context(day, 12.0))["hora"] == "Moon"
+    assert _calendar_lords(context(day, 12.01))["hora"] == "Moon"
+    assert _calendar_lords(context(day, 13.01))["hora"] == "Saturn"
+    assert _calendar_lords(context(day, 14.01))["hora"] == "Jupiter"
+
+
+def test_before_sunrise_uses_previous_weekday():
+    # Sunday 05:30 remains Saturday's 24th hora (Mars).
+    assert _calendar_lords(context(date(2026, 9, 27), 5.5))["hora"] == "Mars"

tests/test_shadbala_mean_motion_continuity.py

@@ -0,0 +1,30 @@
+import pytest
+
+from scripts.shadbala import _surya_mean_longitude, _SURYA_REVOLUTIONS, _SURYA_CIVIL_DAYS
+
+
+@pytest.mark.parametrize("planet", list(_SURYA_REVOLUTIONS))
+@pytest.mark.parametrize("start", [2451544.49999, 2451544.99999, 2451545.1, 2451546.1,
+                                   2451547.1, 2451548.1, 2451549.1, 2451550.1, 2451551.1])
+def test_mean_motion_has_no_noon_midnight_or_weekday_jumps(planet, start):
+    rate = round(_SURYA_REVOLUTIONS[planet] / _SURYA_CIVIL_DAYS * 360, 7)
+    for interval in (1 / 86400, 1.0, 7.0):
+        a = _surya_mean_longitude(planet, {"jd_ut": start})
+        b = _surya_mean_longitude(planet, {"jd_ut": start + interval})
+        delta = (b - a + 180) % 360 - 180
+        assert delta == pytest.approx(rate * interval, abs=1e-8)
+
+
+@pytest.mark.parametrize("planet", list(_SURYA_REVOLUTIONS))
+def test_same_instant_has_one_mean_independent_of_clock_and_location(planet):
+    instant = 2451545.0
+    expected = _surya_mean_longitude(planet, {"jd_ut": instant})
+    for timezone, longitude in [(0, 0), (5.5, 77.5), (8, 120), (-8, -122.4)]:
+        context = {"jd_local": instant + timezone / 24,
+                   "timezone": timezone, "lon": longitude}
+        assert _surya_mean_longitude(planet, context) == pytest.approx(expected, abs=1e-8)
+
+
+def test_ambiguous_civil_clock_without_offset_is_rejected():
+    with pytest.raises(KeyError, match="timezone"):
+        _surya_mean_longitude("Mercury", {"jd_local": 2451545.0, "lon": 120})

tests/test_shadbala_precise_context.py

@@ -59,13 +59,18 @@ def test_precise_sthana_bala_matches_pyjhora_same_chart() -> None:
         assert calc_sthana_bala_precise(planet, planets, houses[planet])["total"] == expected
 
 
-def test_precise_kala_bala_matches_pyjhora_same_chart() -> None:
+def test_precise_kala_preserves_archived_comparison_with_corrected_hora() -> None:
+    # 原值: 每颗星 Kala 总分 == 存档 PyJHora 值（test_precise_kala_bala_matches_pyjhora_same_chart）
+    # 新值: 月亮 +52.18、金星 −60.0，其余仍等于存档值（同上游 yinduzhanxing 0afa2780 的改法）
+    # 原因: TASK-upstream-sync4-20261002 T3：时主按民用星期查 _HORA_ORDER（周四此时为月亮时），
+    #       Ayana 南北按取模后的回归黄经判断；存档 PyJHora 值只作对照，不作本地公式的标准答案
     planets = _planets()
     context = build_shadbala_context(2435163.6354166665, 37.7749, -122.4194, "lahiri", -8.0)
     assert abs(context["sunrise_hour"] - 6.886306) < 0.00001
     assert abs(context["sunset_hour"] - 17.890427) < 0.00001
     for planet, expected in PYJHORA_KALA.items():
-        assert calc_kala_bala_precise(planet, planets, context)["total"] == expected
+        delta = 52.18 if planet == "Moon" else -60.0 if planet == "Venus" else 0.0
+        assert abs(calc_kala_bala_precise(planet, planets, context)["total"] - expected - delta) < 0.001
 
 
 def test_precise_chesta_uses_classical_bounded_variant() -> None: