import uuid

from django.db import models
from django.utils import timezone


class ShortLink(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    code = models.CharField(max_length=8, unique=True, db_index=True)
    target_url = models.URLField(max_length=2048)
    title = models.CharField(max_length=200, blank=True)
    created_by_token = models.CharField(max_length=64)
    external_ref = models.CharField(max_length=64, blank=True, db_index=True)
    is_active = models.BooleanField(default=True)
    expires_at = models.DateTimeField(null=True, blank=True)
    click_count = models.PositiveIntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]

    def __str__(self) -> str:
        return self.code

    def is_available(self) -> bool:
        if not self.is_active:
            return False
        if self.expires_at is not None and timezone.now() >= self.expires_at:
            return False
        return True

    @property
    def public_short_url(self) -> str:
        from django.conf import settings

        origin = (getattr(settings, "PUBLIC_SHORT_URL", "") or "").rstrip("/")
        return f"{origin}/{self.code}"


class Click(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    link = models.ForeignKey(ShortLink, on_delete=models.CASCADE, related_name="clicks")
    occurred_at = models.DateTimeField(auto_now_add=True)
    ip_hash = models.CharField(max_length=64, blank=True)
    user_agent = models.CharField(max_length=512, blank=True)
    referrer = models.CharField(max_length=1024, blank=True)

    class Meta:
        ordering = ["-occurred_at"]

    def __str__(self) -> str:
        return f"{self.link.code} @ {self.occurred_at}"