from django.core.validators import MaxValueValidator, MinValueValidator
from django.db import models
from django.utils.translation import gettext_lazy as _


class Currency(models.Model):
    code = models.CharField(max_length=10, unique=True, verbose_name=_("Currency Code"))
    name = models.CharField(max_length=50, verbose_name=_("Currency Name"), unique=True)
    decimal_places = models.PositiveIntegerField(
        default=2,
        validators=[MaxValueValidator(30), MinValueValidator(0)],
        verbose_name=_("Decimal Places"),
    )
    prefix = models.CharField(max_length=10, verbose_name=_("Prefix"), blank=True)
    suffix = models.CharField(max_length=10, verbose_name=_("Suffix"), blank=True)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = _("Currency")
        verbose_name_plural = _("Currencies")


class ExchangeRate(models.Model):
    from_currency = models.ForeignKey(
        Currency,
        on_delete=models.CASCADE,
        related_name="from_exchange_rates",
        verbose_name=_("From Currency"),
    )
    to_currency = models.ForeignKey(
        Currency,
        on_delete=models.CASCADE,
        related_name="to_exchange_rates",
        verbose_name=_("To Currency"),
    )
    rate = models.DecimalField(
        max_digits=42, decimal_places=30, verbose_name=_("Exchange Rate")
    )
    date = models.DateTimeField(verbose_name=_("Date and Time"))

    class Meta:
        verbose_name = _("Exchange Rate")
        verbose_name_plural = _("Exchange Rates")
        unique_together = ("from_currency", "to_currency", "date")

    def __str__(self):
        return f"{self.from_currency.code} to {self.to_currency.code} on {self.date}"