feat: report reconciliation status

finance/reconciliation.py

@@ -0,0 +1,88 @@
+"""Read models and shared calculations for reconciliation checkpoints."""
+
+from dataclasses import dataclass
+from datetime import date
+from decimal import Decimal
+from uuid import UUID
+
+from django.db.models import DecimalField, Sum, Value
+from django.db.models.functions import Coalesce
+
+from finance.models import ReconciliationCheckpoint, Transaction
+
+
+_MONEY_FIELD = DecimalField(max_digits=24, decimal_places=2)
+_ZERO = Decimal("0.00")
+
+
+@dataclass(frozen=True)
+class CheckpointStatus:
+    checkpoint_id: UUID
+    account_id: UUID
+    account_name: str
+    currency: str
+    as_of_date: date
+    institution_balance: Decimal
+    snapshot_ledger_balance: Decimal
+    snapshot_difference: Decimal
+    live_ledger_balance: Decimal
+    live_difference: Decimal
+    state: str
+
+
+def ledger_balance_through(account_id: UUID, as_of_date: date) -> Decimal:
+    from finance.services.base import money
+
+    total = Transaction.objects.filter(
+        account_id=account_id,
+        posting_date__lte=as_of_date,
+    ).aggregate(
+        total=Coalesce(
+            Sum("amount"),
+            Value(_ZERO),
+            output_field=_MONEY_FIELD,
+        )
+    )["total"]
+    return money(total, allow_zero=True)
+
+
+def checkpoint_status(checkpoint: ReconciliationCheckpoint) -> CheckpointStatus:
+    account = checkpoint.account
+    live_ledger_balance = ledger_balance_through(checkpoint.account_id, checkpoint.as_of_date)
+    live_difference = checkpoint.institution_balance - live_ledger_balance
+    if live_difference == _ZERO:
+        state = "reconciled"
+    elif checkpoint.difference_at_creation == _ZERO:
+        state = "changed_since_reconciliation"
+    else:
+        state = "difference"
+    return CheckpointStatus(
+        checkpoint_id=checkpoint.pk,
+        account_id=account.pk,
+        account_name=account.name,
+        currency=account.currency,
+        as_of_date=checkpoint.as_of_date,
+        institution_balance=checkpoint.institution_balance,
+        snapshot_ledger_balance=checkpoint.ledger_balance_at_creation,
+        snapshot_difference=checkpoint.difference_at_creation,
+        live_ledger_balance=live_ledger_balance,
+        live_difference=live_difference,
+        state=state,
+    )
+
+
+def checkpoint_history(account_id: UUID) -> list[CheckpointStatus]:
+    checkpoints = ReconciliationCheckpoint.objects.filter(
+        account_id=account_id,
+    ).select_related("account").order_by("-as_of_date", "-created_at", "-id")
+    return [checkpoint_status(checkpoint) for checkpoint in checkpoints]
+
+
+def latest_checkpoint_statuses(currency: str) -> list[CheckpointStatus]:
+    checkpoints = ReconciliationCheckpoint.objects.filter(
+        account__archived=False,
+        account__currency=currency,
+    ).select_related("account").order_by(
+        "account_id", "-as_of_date", "-created_at", "-id"
+    ).distinct("account_id")
+    return [checkpoint_status(checkpoint) for checkpoint in checkpoints]

finance/services/reconciliation.py

@@ -1,36 +1,14 @@
-from decimal import Decimal
-
-from django.db.models import DecimalField, Sum, Value
-from django.db.models.functions import Coalesce
-
-from finance.models import Account, ReconciliationCheckpoint, Transaction
+from finance.models import Account, ReconciliationCheckpoint
+from finance.reconciliation import ledger_balance_through
 
 from .base import lock, money, save, write
 
 
-_MONEY_FIELD = DecimalField(max_digits=24, decimal_places=2)
-_ZERO = Decimal("0.00")
-
-
-def _ledger_balance_through(account_id, as_of_date):
-    total = Transaction.objects.filter(
-        account_id=account_id,
-        posting_date__lte=as_of_date,
-    ).aggregate(
-        total=Coalesce(
-            Sum("amount"),
-            Value(_ZERO),
-            output_field=_MONEY_FIELD,
-        )
-    )["total"]
-    return money(total, allow_zero=True)
-
-
 @write("reconciliation_checkpoint.created")
 def create_reconciliation_checkpoint(*, account_id, as_of_date, institution_balance):
     account = lock(Account, account_id, active=True)
     institution_balance = money(institution_balance, allow_zero=True)
-    ledger_balance = _ledger_balance_through(account.pk, as_of_date)
+    ledger_balance = ledger_balance_through(account.pk, as_of_date)
     checkpoint = save(ReconciliationCheckpoint(
         account=account,
         as_of_date=as_of_date,

tests/finance/test_reconciliation.py

@@ -6,6 +6,11 @@ from decimal import Decimal
 import pytest
 
 from finance.models import AuditEvent, ReconciliationCheckpoint
+from finance.reconciliation import (
+    checkpoint_history,
+    latest_checkpoint_statuses,
+    ledger_balance_through,
+)
 from finance.services import (
     Actor,
     DomainError,
@@ -25,11 +30,11 @@ def account(name="Synthetic reconciliation account"):
     return create_account(name=name, kind="BANK", actor=ACTOR)
 
 
-def post(account, amount, posting_date):
+def post(account, amount, posting_date, kind="EXPENSE"):
     return record_transaction(
         account_id=account.pk,
         amount=Decimal(amount),
-        kind="EXPENSE",
+        kind=kind,
         posting_date=posting_date,
         actor=ACTOR,
     )
@@ -67,6 +72,18 @@ def test_checkpoint_snapshots_inclusive_ledger_balance_and_audit_metadata():
     ]
 
 
+def test_ledger_balance_through_returns_zero_and_includes_opening_entries():
+    bank = account()
+
+    assert ledger_balance_through(bank.pk, AS_OF_DATE) == Decimal("0.00")
+
+    post(bank, "100.00", date(2026, 8, 31), kind="OPENING")
+    post(bank, "-40.00", AS_OF_DATE)
+    post(bank, "-7.50", date(2026, 9, 2))
+
+    assert ledger_balance_through(bank.pk, AS_OF_DATE) == Decimal("60.00")
+
+
 def test_checkpoint_correction_retains_same_date_history():
     bank = account()
     post(bank, "-40.00", AS_OF_DATE)
@@ -113,3 +130,127 @@ def test_archived_account_rejects_checkpoint_without_creating_one():
     assert failed.operation == "reconciliation_checkpoint.created"
     assert failed.outcome == "FAILURE"
     assert failed.error_code == "archived_reference"
+
+
+@pytest.mark.parametrize(
+    (
+        "institution_balance",
+        "later_amount",
+        "expected_live_ledger_balance",
+        "expected_state",
+        "expected_live_difference",
+    ),
+    [
+        ("-40.00", None, Decimal("-40.00"), "reconciled", Decimal("0.00")),
+        ("-39.00", None, Decimal("-40.00"), "difference", Decimal("1.00")),
+        ("-40.00", "-2.00", Decimal("-42.00"), "changed_since_reconciliation", Decimal("2.00")),
+    ],
+)
+def test_checkpoint_history_reports_live_reconciliation_state(
+    institution_balance,
+    later_amount,
+    expected_live_ledger_balance,
+    expected_state,
+    expected_live_difference,
+):
+    bank = account(name=f"Synthetic status {expected_state}")
+    post(bank, "-40.00", AS_OF_DATE)
+    checkpoint = create_reconciliation_checkpoint(
+        account_id=bank.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal(institution_balance),
+        actor=ACTOR,
+    )
+    if later_amount is not None:
+        post(bank, later_amount, AS_OF_DATE)
+
+    [status] = checkpoint_history(bank.pk)
+
+    assert status.checkpoint_id == checkpoint.pk
+    assert status.snapshot_ledger_balance == Decimal("-40.00")
+    assert status.live_ledger_balance == expected_live_ledger_balance
+    assert status.live_difference == expected_live_difference
+    assert status.state == expected_state
+
+
+def test_checkpoint_history_retains_same_date_corrections_newest_first():
+    bank = account()
+    post(bank, "-40.00", AS_OF_DATE)
+    first = create_reconciliation_checkpoint(
+        account_id=bank.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-39.00"),
+        actor=ACTOR,
+    )
+    correction = create_reconciliation_checkpoint(
+        account_id=bank.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-40.00"),
+        actor=ACTOR,
+    )
+
+    history = checkpoint_history(bank.pk)
+
+    assert [status.checkpoint_id for status in history] == [correction.pk, first.pk]
+    assert history[0].snapshot_difference == Decimal("0.00")
+    assert history[1].snapshot_difference == Decimal("1.00")
+
+
+def test_latest_checkpoint_statuses_select_by_as_of_date_then_creation_for_active_currency():
+    by_date = account(name="Synthetic latest by date")
+    post(by_date, "-40.00", AS_OF_DATE)
+    newer_as_of_date = create_reconciliation_checkpoint(
+        account_id=by_date.pk,
+        as_of_date=date(2026, 9, 2),
+        institution_balance=Decimal("-40.00"),
+        actor=ACTOR,
+    )
+    create_reconciliation_checkpoint(
+        account_id=by_date.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-39.00"),
+        actor=ACTOR,
+    )
+
+    by_creation = account(name="Synthetic latest by creation")
+    post(by_creation, "-20.00", AS_OF_DATE)
+    create_reconciliation_checkpoint(
+        account_id=by_creation.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-19.00"),
+        actor=ACTOR,
+    )
+    correction = create_reconciliation_checkpoint(
+        account_id=by_creation.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-20.00"),
+        actor=ACTOR,
+    )
+
+    archived = account(name="Synthetic archived status")
+    post(archived, "-5.00", AS_OF_DATE)
+    create_reconciliation_checkpoint(
+        account_id=archived.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-5.00"),
+        actor=ACTOR,
+    )
+    archive(archived, actor=ACTOR)
+
+    usd = create_account(
+        name="Synthetic USD status", kind="BANK", currency="USD", actor=ACTOR
+    )
+    post(usd, "-7.00", AS_OF_DATE)
+    create_reconciliation_checkpoint(
+        account_id=usd.pk,
+        as_of_date=AS_OF_DATE,
+        institution_balance=Decimal("-7.00"),
+        actor=ACTOR,
+    )
+
+    statuses = latest_checkpoint_statuses("BRL")
+
+    assert {status.account_id: status.checkpoint_id for status in statuses} == {
+        by_date.pk: newer_as_of_date.pk,
+        by_creation.pk: correction.pk,
+    }