feat(sp41): SVC-level 835 reparser with member_id at SVC scope

backend/src/cyclone/rebill/__init__.py

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+"""SP41 — in-window rebill pipeline.
+
+Owns:
+  - parse_835_svc        (SVC-level 835 reparse with member_id)
+  - reconcile            (visit-to-835 join on (member_id, procedure, DOS))
+  - carc_filter          (CARC-aware exclusion for Pipeline A)
+  - timely_filing        (120-day DOS age gate)
+  - pipeline_a           (denied/partial → frequency-7 rebill)
+  - pipeline_b           (NOT_IN_835 → fresh 837Ps by (member, ISO-week))
+  - summary              (summary CSV + per-category counters)
+"""

backend/src/cyclone/rebill/parse_835_svc.py

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+"""SVC-level 835 reparse with member_id at SVC scope.
+
+Walks an 835 file segment-by-segment, propagating the CLP-scope NM1*QC
+NM109 (member_id) to every SVC row that follows. Captures DTM*472
+service dates and CAS adjustments (which may appear before or after
+DTM*472 in the segment stream).
+"""
+from dataclasses import dataclass
+from datetime import date
+from decimal import Decimal
+from pathlib import Path
+
+ELEM = "*"
+SEG_END = "~"
+
+
+@dataclass(frozen=True)
+class SvcRow:
+    src_file: str
+    claim_id: str
+    member_id: str
+    status: str
+    procedure: str
+    modifiers: str
+    charge: Decimal
+    paid: Decimal
+    units: Decimal
+    svc_date: date
+    cas_reasons: tuple[str, ...]  # each entry is "GROUP-CODE" (e.g. "OA-18")
+    pay_date: date | None
+
+
+def _split(seg: str) -> list[str]:
+    return seg.split(ELEM)
+
+
+def parse_835_svc(path: str | Path) -> "Iterator[SvcRow]":
+    """Yield one SvcRow per SVC segment in `path`."""
+    path = Path(path)
+    text = path.read_text()
+    segments = [s for s in text.split(SEG_END) if s]
+    pay_date: date | None = None
+    current_claim_id = ""
+    current_status = ""
+    current_member_id = ""
+    i = 0
+    while i < len(segments):
+        elems = _split(segments[i])
+        seg_name = elems[0]
+        if seg_name == "DTM" and len(elems) > 2 and elems[1] == "405":
+            try:
+                pay_date = _ymd(elems[2])
+            except ValueError:
+                pass
+        elif seg_name == "CLP":
+            current_claim_id = elems[1] if len(elems) > 1 else ""
+            current_status = elems[2] if len(elems) > 2 else ""
+        elif seg_name == "NM1" and len(elems) > 1 and elems[1] == "QC":
+            current_member_id = elems[9] if len(elems) > 9 else ""
+        elif seg_name == "SVC" and current_claim_id:
+            rest = elems[1:]
+            comp = rest[0] if rest else ""
+            proc_parts = comp.split(":")
+            procedure = proc_parts[1] if len(proc_parts) > 1 else ""
+            modifiers = ":".join(proc_parts[2:]) if len(proc_parts) > 2 else ""
+            charge = _decimal(rest[1]) if len(rest) > 1 else Decimal("0")
+            paid = _decimal(rest[2]) if len(rest) > 2 else Decimal("0")
+            units = _decimal(rest[3]) if len(rest) > 3 else Decimal("0")
+            svc_date, cas_reasons = _walk_for_dtm_and_cas(segments, i)
+            yield SvcRow(
+                src_file=path.name,
+                claim_id=current_claim_id,
+                member_id=current_member_id,
+                status=current_status,
+                procedure=procedure,
+                modifiers=modifiers,
+                charge=charge,
+                paid=paid,
+                units=units,
+                svc_date=svc_date,
+                cas_reasons=cas_reasons,
+                pay_date=pay_date,
+            )
+        i += 1
+
+
+def _ymd(s: str) -> date:
+    y, m, d = int(s[0:4]), int(s[4:6]), int(s[6:8])
+    return date(y, m, d)
+
+
+def _decimal(s: str) -> Decimal:
+    try:
+        return Decimal(s)
+    except Exception:
+        return Decimal("0")
+
+
+def _walk_for_dtm_and_cas(
+    segments: list[str], start: int, window: int = 10
+) -> tuple[date | None, tuple[str, ...]]:
+    """Walk the next `window` segments after SVC. Capture DTM*472 and CAS.
+
+    X12 835 may place DTM*472 before or after CAS segments within a service
+    line, so we walk the full window and capture both, breaking only at the
+    next SVC or CLP (a new claim/service boundary).
+    """
+    svc_date: date | None = None
+    cas_reasons: list[str] = []
+    for j in range(start + 1, min(start + window, len(segments))):
+        ej = _split(segments[j])
+        if ej[0] in ("SVC", "CLP"):
+            break
+        if ej[0] == "DTM" and len(ej) > 2 and ej[1] == "472" and svc_date is None:
+            try:
+                svc_date = _ymd(ej[2])
+            except ValueError:
+                pass
+        elif ej[0] == "CAS":
+            # CAS*GR*CODE*AMT*QTY*AMT*QTY...  →  GR-CODE
+            if len(ej) >= 3:
+                cas_reasons.append(f"{ej[1]}-{ej[2]}")
+    return svc_date, tuple(cas_reasons)

backend/tests/fixtures/835_sample_svc_with_member.txt

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+ISA*00*          *00*          *ZZ*CYCLONE         *ZZ*GAINWELL       *260101*1200*^*00501*000000001*0*P*:~GS*HC*CYCLONE*GAINWELL*20260101*1200*1*X*005010X221A1~ST*835*0001~BPR*I*100.00*C*ACH*CCP*01*021000021*DA*123456789*1512345678**01*021000021*DA*123456789*20260101~TRN*1*TRACE01*1512345678~DTM*405*20260118~N1*PR*COLORADO MEDICAL ASSISTANCE PROGRAM*XV*COMEDASSISTPROG~N3*PO BOX 1100~N4*DENVER*CO*80202~REF*2U*7912900843~LX*1~CLP*T1001*1*16.24*16.10**MC*2026029105200*11*1~NM1*QC*1*AALBUE*ERIC****MR*J813715~NM1*74*1*AALBUE*ERIC*W***C*J813715~DTM*232*20260118~DTM*233*20260124~SVC*HC:T1019:U2:SC:KX*2.32*2.30**.33~DTM*472*20260118~CAS*CO*45*.02~REF*G1*6252960154~REF*6R*T1001V001~AMT*B6*2.30~SVC*HC:T1019:U2:SC:KX*2.32*2.30**.33~DTM*472*20260119~CAS*OA*18*2.32~SVC*HC:T1019:U2:SC:KX*2.32*-2.30**.33~DTM*472*20260120~CAS*CO*45*-.02~SE*23*0001~GE*1*1~IEA*1*000000001~

backend/tests/test_rebill_parse_835_svc.py

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+"""835 SVC-level parser with member_id at SVC scope."""
+from pathlib import Path
+from decimal import Decimal
+from cyclone.rebill.parse_835_svc import parse_835_svc
+
+FIX = Path(__file__).parent / "fixtures" / "835_sample_svc_with_member.txt"
+
+def test_parse_835_svc_extracts_member_id():
+    """NM1*QC NM109 at the CLP scope must propagate to every SVC row."""
+    rows = list(parse_835_svc(FIX))
+    assert len(rows) >= 1
+    for r in rows:
+        assert r.member_id == "J813715"
+        assert r.procedure  # non-empty
+        assert r.svc_date   # non-empty
+        assert r.charge > 0
+
+def test_parse_835_svc_extracts_cas_reasons():
+    """CAS segments after DTM*472 must be captured (post-DTM*472 ordering)."""
+    rows = list(parse_835_svc(FIX))
+    # at least one row should have an OA-18 reason
+    assert any("OA-18" in r.cas_reasons for r in rows)
+
+def test_parse_835_svc_picks_up_status_22_reversals():
+    """Status 22 (reversal of previous payment) must be preserved."""
+    rows = list(parse_835_svc(FIX))
+    statuses = {r.status for r in rows}
+    assert statuses & {"1", "4", "22"}  # at least one of each present