"""Recording money received against a membership's fee.

Mirrors billing.services.dues.record_payment for a different kind of money: a
member's own club fee, not the club's platform subscription. amount_paid is kept in
step here, never recomputed by re-aggregating FeePayment on every read.
"""

from decimal import Decimal

from django.db.models import F
from django.utils import timezone

from club.models import ClubMembership, FeePayment


def remaining_balance(membership):
    return max(membership.fee_amount - membership.amount_paid, Decimal("0.00"))


def record_payment(membership, *, amount, method=FeePayment.Method.BANK_TRANSFER, reference="", note="", recorded_by=None):
    """Record money received against one membership's fee. Several payments may
    land on one membership -- a family paying in two installments must not read as
    unpaid. Updates amount_paid and re-syncs fee_status/status to match."""
    payment = FeePayment.objects.create(membership=membership, amount=amount, method=method, reference=reference, note=note, recorded_by=recorded_by)

    membership.amount_paid = F("amount_paid") + amount
    membership.save(update_fields=["amount_paid"])
    membership.refresh_from_db(fields=["amount_paid"])
    _sync_fee_status(membership)

    return payment


def mark_as_paid(membership, *, recorded_by=None):
    """The "settle this one" action behind both the per-row and bulk buttons. If
    there's a real remaining balance, records it as a payment (auditable, shows up
    in history); if fee_amount was never priced (remaining is 0), just flips the
    flags directly -- there's no real transaction to log."""
    remaining = remaining_balance(membership)
    if remaining > 0:
        record_payment(membership, amount=remaining, method=FeePayment.Method.OTHER, note="Marked as paid", recorded_by=recorded_by)
    else:
        _sync_fee_status(membership, force_paid=True)


def _sync_fee_status(membership, *, force_paid=False):
    if membership.fee_status == ClubMembership.FeeStatus.WAIVED:
        return  # manual, independent of payments -- this never overrides it

    if force_paid or (membership.fee_amount > 0 and membership.amount_paid >= membership.fee_amount):
        new_status = ClubMembership.FeeStatus.PAID
    elif membership.amount_paid > 0:
        new_status = ClubMembership.FeeStatus.PARTIALLY_PAID
    else:
        new_status = ClubMembership.FeeStatus.UNPAID

    membership.fee_status = new_status
    update_fields = ["fee_status"]

    # Same "become a full member" behavior the bulk action already had: settling
    # the fee in full also activates the membership, once, first time only.
    if new_status == ClubMembership.FeeStatus.PAID:
        membership.status = ClubMembership.StatusChoices.ACTIVE
        update_fields.append("status")
        if membership.activated_at is None:
            membership.activated_at = timezone.localdate()
            update_fields.append("activated_at")

    membership.save(update_fields=update_fields)