"""Synthetic checks for immutable, audited reconciliation checkpoints."""

from datetime import date
from decimal import Decimal

import pytest

from finance.models import AuditEvent, ReconciliationCheckpoint
from finance.services import (
    Actor,
    DomainError,
    archive,
    create_account,
    create_reconciliation_checkpoint,
    record_transaction,
)


pytestmark = pytest.mark.django_db(transaction=True)
ACTOR = Actor(kind="HUMAN", identifier="synthetic-local-owner")
AS_OF_DATE = date(2026, 9, 1)


def account(name="Synthetic reconciliation account"):
    return create_account(name=name, kind="BANK", actor=ACTOR)


def post(account, amount, posting_date):
    return record_transaction(
        account_id=account.pk,
        amount=Decimal(amount),
        kind="EXPENSE",
        posting_date=posting_date,
        actor=ACTOR,
    )


def test_checkpoint_snapshots_inclusive_ledger_balance_and_audit_metadata():
    bank = account()
    post(bank, "-40.00", date(2026, 8, 31))
    post(bank, "-2.50", AS_OF_DATE)
    post(bank, "-7.50", date(2026, 9, 2))

    checkpoint = create_reconciliation_checkpoint(
        account_id=bank.pk,
        as_of_date=AS_OF_DATE,
        institution_balance=Decimal("0.00"),
        actor=ACTOR,
    )

    assert checkpoint.institution_balance == Decimal("0.00")
    assert checkpoint.ledger_balance_at_creation == Decimal("-42.50")
    assert checkpoint.difference_at_creation == Decimal("42.50")
    event = AuditEvent.objects.get(
        operation="reconciliation_checkpoint.created",
        target_id=checkpoint.pk,
    )
    assert event.outcome == "SUCCESS"
    assert event.actor_kind == "HUMAN"
    assert event.actor_identifier == "synthetic-local-owner"
    assert event.changed_fields == [
        "account",
        "as_of_date",
        "institution_balance",
        "ledger_balance_at_creation",
        "difference_at_creation",
    ]


def test_checkpoint_correction_retains_same_date_history():
    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,
    )

    assert first.pk != correction.pk
    assert ReconciliationCheckpoint.objects.filter(
        account=bank,
        as_of_date=AS_OF_DATE,
    ).count() == 2
    assert correction.ledger_balance_at_creation == Decimal("-40.00")
    assert correction.difference_at_creation == Decimal("0.00")


def test_archived_account_rejects_checkpoint_without_creating_one():
    bank = account()
    archive(bank, actor=ACTOR)
    checkpoint_count = ReconciliationCheckpoint.objects.count()
    audit_count = AuditEvent.objects.count()

    with pytest.raises(DomainError, match="archived_reference"):
        create_reconciliation_checkpoint(
            account_id=bank.pk,
            as_of_date=AS_OF_DATE,
            institution_balance=Decimal("0.00"),
            actor=ACTOR,
        )

    assert ReconciliationCheckpoint.objects.count() == checkpoint_count
    failed = AuditEvent.objects.exclude(operation="archive").latest("created_at")
    assert AuditEvent.objects.count() == audit_count + 1
    assert failed.operation == "reconciliation_checkpoint.created"
    assert failed.outcome == "FAILURE"
    assert failed.error_code == "archived_reference"