from django.conf import settings
from django.db import models

from apps.core.models import Audience, TimeStampedModel
from apps.library.models import LibraryItem


class MomentQuerySet(models.QuerySet):
    def visible_to(self, user):
        """FAMILY and CUSTOM audiences intentionally fall back to
        owner-only visibility until circles/custom-audience membership
        (V1.5) exists — better to under-share than leak content."""
        from apps.accounts.models import Follow

        following_ids = Follow.objects.filter(
            follower=user, status=Follow.Status.ACCEPTED
        ).values_list("following_id", flat=True)
        follower_ids = set(
            Follow.objects.filter(
                following=user, status=Follow.Status.ACCEPTED
            ).values_list("follower_id", flat=True)
        )
        friend_ids = follower_ids & set(following_ids)

        return self.filter(
            models.Q(owner=user)
            | models.Q(audience=Audience.PUBLIC)
            | models.Q(audience=Audience.FOLLOWERS, owner_id__in=following_ids)
            | models.Q(audience=Audience.FRIENDS, owner_id__in=friend_ids)
        ).distinct()


class Moment(TimeStampedModel):
    """The social-media object: one or more LibraryItems shared with an
    explicit audience. Sharing a Moment never moves or copies the original
    file — it just makes the existing library item visible to others."""

    owner = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="moments", on_delete=models.CASCADE)
    caption = models.TextField(max_length=2200, blank=True)
    location = models.CharField(max_length=255, blank=True)
    audience = models.CharField(max_length=10, choices=Audience.choices, default=Audience.PUBLIC)

    objects = MomentQuerySet.as_manager()

    class Meta:
        ordering = ["-created_at"]

    def __str__(self):
        return f"Moment({self.id}) by {self.owner}"


class MomentItem(models.Model):
    moment = models.ForeignKey(Moment, related_name="items", on_delete=models.CASCADE)
    library_item = models.ForeignKey(LibraryItem, related_name="moment_items", on_delete=models.CASCADE)
    order = models.PositiveIntegerField(default=0)

    class Meta:
        ordering = ["order"]
        unique_together = ("moment", "library_item")


class Comment(TimeStampedModel):
    moment = models.ForeignKey(Moment, related_name="comments", on_delete=models.CASCADE)
    author = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="comments", on_delete=models.CASCADE)
    parent = models.ForeignKey("self", related_name="replies", on_delete=models.CASCADE, null=True, blank=True)
    body = models.TextField(max_length=1000)

    class Meta:
        ordering = ["created_at"]

    def __str__(self):
        return f"{self.author}: {self.body[:40]}"


class Reaction(models.Model):
    class ReactionType(models.TextChoices):
        LIKE = "like", "Like"

    moment = models.ForeignKey(Moment, related_name="reactions", on_delete=models.CASCADE)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="reactions", on_delete=models.CASCADE)
    reaction_type = models.CharField(max_length=10, choices=ReactionType.choices, default=ReactionType.LIKE)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ("moment", "user")