from django.core.validators import RegexValidator
from django.db import models
from django.db.models import Q

from .base import TimestampedModel


class Account(TimestampedModel):
    class Kind(models.TextChoices):
        BANK = "BANK", "Bank"
        CREDIT_CARD = "CREDIT_CARD", "Credit card"

    name = models.CharField(max_length=255, unique=True)
    kind = models.CharField(max_length=16, choices=Kind.choices)
    currency = models.CharField(max_length=3, default="BRL", validators=[
        RegexValidator(r"\A[A-Z]{3}\Z", "Use three uppercase ASCII letters.")])
    archived = models.BooleanField(default=False)

    class Meta:
        constraints = [
            models.CheckConstraint(condition=Q(kind__in=["BANK", "CREDIT_CARD"]), name="account_valid_kind"),
            models.CheckConstraint(condition=Q(currency__regex=r"^[A-Z]{3}$"), name="account_valid_currency"),
            models.CheckConstraint(condition=Q(name__regex=r"\S"), name="account_nonblank_name"),
        ]


class Payee(TimestampedModel):
    name = models.CharField(max_length=255, unique=True)
    archived = models.BooleanField(default=False)

    class Meta:
        constraints = [models.CheckConstraint(condition=Q(name__regex=r"\S"), name="payee_nonblank_name")]


class CategoryGroup(TimestampedModel):
    name = models.CharField(max_length=255, unique=True)
    archived = models.BooleanField(default=False)

    class Meta:
        constraints = [models.CheckConstraint(condition=Q(name__regex=r"\S"), name="category_group_nonblank_name")]


class Category(TimestampedModel):
    class Kind(models.TextChoices):
        INCOME = "INCOME", "Income"
        EXPENSE = "EXPENSE", "Expense"

    name = models.CharField(max_length=255)
    kind = models.CharField(max_length=16, choices=Kind.choices)
    group = models.ForeignKey(CategoryGroup, on_delete=models.PROTECT, related_name="categories", null=True, blank=True)
    archived = models.BooleanField(default=False)

    class Meta:
        constraints = [
            models.CheckConstraint(condition=Q(kind__in=["INCOME", "EXPENSE"]), name="category_valid_kind"),
            models.CheckConstraint(condition=Q(name__regex=r"\S"), name="category_nonblank_name"),
            models.UniqueConstraint(fields=["group", "name"], name="category_group_name_unique"),
            models.UniqueConstraint(fields=["name"], condition=Q(group__isnull=True), name="category_ungrouped_name_unique"),
        ]


class Tag(TimestampedModel):
    name = models.CharField(max_length=255, unique=True)
    archived = models.BooleanField(default=False)

    class Meta:
        constraints = [models.CheckConstraint(condition=Q(name__regex=r"\S"), name="tag_nonblank_name")]