import uuid
from decimal import Decimal

from django.conf import settings
from django.core.validators import MinValueValidator, RegexValidator
from django.db import models


class PayrollOffCyclePayment(models.Model):
    """A cash fact; never a payroll input or a new employee statement."""

    employee = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="off_cycle_payments",
    )
    payee_name = models.CharField("Получатель", max_length=250)
    paid_on = models.DateField("Дата выдачи", db_index=True)
    amount = models.DecimalField(
        "Выдано",
        max_digits=19,
        decimal_places=2,
        validators=[MinValueValidator(Decimal("0.01"))],
    )
    currency = models.CharField(
        max_length=3,
        default="RUB",
        validators=[RegexValidator(r"^[A-Z]{3}$")],
    )
    source_period = models.ForeignKey(
        "finance.PayrollPeriod",
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="off_cycle_payments",
    )
    source_statement = models.ForeignKey(
        "finance.PayrollStatement",
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="off_cycle_payments",
    )
    note = models.CharField("Основание", max_length=1000)
    request_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.PROTECT,
        related_name="off_cycle_payments_created",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    voided_at = models.DateTimeField(null=True, blank=True)
    voided_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="off_cycle_payments_voided",
    )
    void_reason = models.CharField(max_length=1000, blank=True)

    class Meta:
        ordering = ["-paid_on", "-pk"]
        constraints = [
            models.CheckConstraint(
                condition=models.Q(amount__gt=0),
                name="off_cycle_payment_positive",
            ),
            models.CheckConstraint(
                condition=(
                    models.Q(
                        voided_at__isnull=True, voided_by__isnull=True, void_reason=""
                    )
                    | (
                        models.Q(voided_at__isnull=False, voided_by__isnull=False)
                        & ~models.Q(void_reason="")
                    )
                ),
                name="off_cycle_payment_void_consistent",
            ),
        ]
        verbose_name = "Выплата вне периода"
        verbose_name_plural = "Выплаты вне периода"