feat(backend): add apply_payment, apply_reversal, split_unmatched pure fns

backend/tests/test_reconcile.py

@@ -8,11 +8,14 @@ from __future__ import annotations
 
 from dataclasses import dataclass
 from datetime import date
+from decimal import Decimal
 from typing import Optional
 
 import pytest
 
 from cyclone import reconcile
+from cyclone.db import ClaimState
+from cyclone.reconcile import Match
 
 
 # --- Stand-in types -----------------------------------------------------------
@@ -112,3 +115,88 @@ def test_match_reversal_flag_propagates():
     remits = [FakeRemit("CLP-1", "PCN-A", date(2026, 6, 1), is_reversal=True)]
     matches = reconcile.match(claims, remits)
     assert matches[0].is_reversal is True
+
+
+# ApplyIntent + apply_payment / apply_reversal / split_unmatched ----------------
+
+
+def test_apply_payment_full_amount_returns_paid():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.SUBMITTED.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None)
+    intent = reconcile.apply_payment(claim, remit, charge=Decimal("100"), paid=Decimal("100"))
+    assert intent.new_state == ClaimState.PAID
+    assert intent.activity_kind == "reconcile"
+    assert intent.skipped is False
+
+
+def test_apply_payment_partial_amount_returns_partial():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.SUBMITTED.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None)
+    intent = reconcile.apply_payment(claim, remit, charge=Decimal("100"), paid=Decimal("60"))
+    assert intent.new_state == ClaimState.PARTIAL
+
+
+def test_apply_payment_zero_paid_returns_received():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.SUBMITTED.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None)
+    intent = reconcile.apply_payment(claim, remit, charge=Decimal("100"), paid=Decimal("0"))
+    assert intent.new_state == ClaimState.RECEIVED
+
+
+def test_apply_payment_status_4_returns_denied():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.SUBMITTED.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None)
+    intent = reconcile.apply_payment(claim, remit, charge=Decimal("100"), paid=Decimal("0"),
+                                       status_code="4")
+    assert intent.new_state == ClaimState.DENIED
+
+
+def test_apply_payment_already_paid_is_noop():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.PAID.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None)
+    intent = reconcile.apply_payment(claim, remit, charge=Decimal("100"), paid=Decimal("100"))
+    assert intent.skipped is True
+    assert intent.activity_kind == "invalid_state"
+    assert intent.new_state is None
+
+
+def test_apply_reversal_of_paid_returns_reversed_with_prior_state():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.PAID.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None, is_reversal=True)
+    intent = reconcile.apply_reversal(claim, remit)
+    assert intent.new_state == ClaimState.REVERSED
+    assert intent.prior_claim_state == ClaimState.PAID
+    assert intent.activity_kind == "reversal"
+    assert intent.skipped is False
+
+
+def test_apply_reversal_of_partial_works_same_way():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.PARTIAL.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None, is_reversal=True)
+    intent = reconcile.apply_reversal(claim, remit)
+    assert intent.new_state == ClaimState.REVERSED
+    assert intent.prior_claim_state == ClaimState.PARTIAL
+
+
+def test_apply_reversal_of_denied_is_noop():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.DENIED.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None, is_reversal=True)
+    intent = reconcile.apply_reversal(claim, remit)
+    assert intent.skipped is True
+    assert intent.activity_kind == "reversal_skipped"
+
+
+def test_apply_reversal_of_already_reversed_is_noop():
+    claim = FakeClaim("CLM-1", "PCN-A", None, state=ClaimState.REVERSED.value)
+    remit = FakeRemit("CLP-1", "PCN-A", None, is_reversal=True)
+    intent = reconcile.apply_reversal(claim, remit)
+    assert intent.skipped is True
+
+
+def test_split_unmatched_partitions_by_match_set():
+    claims = [FakeClaim("CLM-1", "A", None), FakeClaim("CLM-2", "B", None)]
+    remits = [FakeRemit("CLP-1", "A", None), FakeRemit("CLP-2", "C", None)]
+    matches = [Match(claim=claims[0], remittance=remits[0], strategy="auto", is_reversal=False)]
+    unmatched_claims, unmatched_remits = reconcile.split_unmatched(claims, remits, matches)
+    assert [c.id for c in unmatched_claims] == ["CLM-2"]
+    assert [r.id for r in unmatched_remits] == ["CLP-2"]