from typing import override

from django.db import models
from django.utils.translation import gettext_lazy as _

from apps.core.models import BaseModel


class ConflictPolicy(models.TextChoices):
    MUTUAL_EXCLUSION = "mutual_exclusion", _("Mutual exclusion")
    PRIORITY = "priority", _("Priority tiers")


class ConflictDomain(BaseModel):
    name = models.CharField(
        max_length=200,
        unique=True,
        verbose_name=_("name"),
    )
    description = models.TextField(
        blank=True,
        verbose_name=_("description"),
    )
    policy = models.CharField(
        max_length=30,
        choices=ConflictPolicy.choices,
        default=ConflictPolicy.MUTUAL_EXCLUSION,
        verbose_name=_("conflict policy"),
    )
    max_concurrent = models.PositiveIntegerField(
        default=1,
        verbose_name=_("max concurrent experiments"),
    )
    created_at = models.DateTimeField(
        auto_now_add=True,
        verbose_name=_("created at"),
    )
    updated_at = models.DateTimeField(
        auto_now=True,
        verbose_name=_("updated at"),
    )

    class Meta:
        verbose_name = _("conflict domain")
        verbose_name_plural = _("conflict domains")
        ordering = ["name"]

    @override
    def __str__(self) -> str:
        return f"{self.name} ({self.policy})"


class ExperimentConflictDomain(BaseModel):
    experiment = models.ForeignKey(
        "experiments.Experiment",
        on_delete=models.CASCADE,
        related_name="conflict_memberships",
        verbose_name=_("experiment"),
    )
    conflict_domain = models.ForeignKey(
        ConflictDomain,
        on_delete=models.CASCADE,
        related_name="experiment_memberships",
        verbose_name=_("conflict domain"),
    )
    priority = models.IntegerField(
        default=0,
        verbose_name=_("priority"),
        help_text=_("Higher value wins in priority-based resolution"),
    )
    created_at = models.DateTimeField(
        auto_now_add=True,
        verbose_name=_("created at"),
    )

    class Meta:
        verbose_name = _("experiment conflict domain")
        verbose_name_plural = _("experiment conflict domains")
        ordering = ["-priority"]
        constraints = [
            models.UniqueConstraint(
                fields=["experiment", "conflict_domain"],
                name="unique_experiment_conflict_domain",
            ),
        ]

    @override
    def __str__(self) -> str:
        return (
            f"{self.experiment.name} in {self.conflict_domain.name} "
            f"(priority={self.priority})"
        )