from finance.models import Account, Transaction, Transfer
from .base import DomainError, identity, lock, money, save, write
from .posting import record


def match(outgoing_id, incoming_id):
    ids = [identity(outgoing_id), identity(incoming_id)]
    if ids[0] == ids[1]:
        raise DomainError("invalid_transfer_legs")
    rows = {obj.pk: obj for obj in Transaction.objects.select_for_update().filter(pk__in=ids).order_by("pk")}
    if len(rows) != 2:
        raise DomainError("not_found")
    outgoing, incoming = rows[ids[0]], rows[ids[1]]
    if outgoing.kind != "TRANSFER" or incoming.kind != "TRANSFER" or outgoing.amount >= 0 or incoming.amount <= 0 or outgoing.amount != incoming.amount.copy_negate():
        raise DomainError("invalid_transfer_legs")
    if outgoing.account_id == incoming.account_id or outgoing.account.currency != incoming.account.currency:
        raise DomainError("transfer_account_or_currency_mismatch")
    if Transfer.objects.filter(outgoing=outgoing).exists() or Transfer.objects.filter(incoming=incoming).exists():
        raise DomainError("already_paired")
    return save(Transfer(outgoing=outgoing, incoming=incoming))


@write("match_transfer")
def match_transfer(*, outgoing_id, incoming_id):
    return match(outgoing_id, incoming_id), ["outgoing", "incoming"]


@write("create_transfer")
def create_transfer(*, outgoing_account_id, incoming_account_id, amount, outgoing_date, incoming_date):
    amount = money(amount)
    if amount <= 0:
        raise DomainError("transfer_amount_must_be_positive")
    ids = [identity(outgoing_account_id), identity(incoming_account_id)]
    if ids[0] == ids[1]:
        raise DomainError("transfer_account_or_currency_mismatch")
    accounts = {obj.pk: obj for obj in Account.objects.select_for_update().filter(pk__in=ids).order_by("pk")}
    if len(accounts) != 2:
        raise DomainError("not_found")
    if any(obj.archived for obj in accounts.values()):
        raise DomainError("archived_reference")
    if accounts[ids[0]].currency != accounts[ids[1]].currency:
        raise DomainError("transfer_account_or_currency_mismatch")
    outgoing = record(account_id=ids[0], amount=amount.copy_negate(), posting_date=outgoing_date, kind="TRANSFER")
    incoming = record(account_id=ids[1], amount=amount, posting_date=incoming_date, kind="TRANSFER")
    return match(outgoing.pk, incoming.pk), ["outgoing", "incoming"]