"""Tenancy models (``TENANCY.md`` §2, §6)."""

from __future__ import annotations

import uuid

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

from .managers import AllObjectsManager, TenantManager

__all__ = ["Tenant", "TenantMembership", "TenantInvitation", "PlatformStaff"]


class Tenant(models.Model):
    """One customer company. UUID PK so ids are safe to expose and embed."""

    class Status(models.TextChoices):
        TRIALING = "trialing", "Trialing"
        ACTIVE = "active", "Active"
        SUSPENDED = "suspended", "Suspended"
        ARCHIVED = "archived", "Archived"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    slug = models.SlugField(max_length=100, unique=True)
    name = models.CharField(max_length=200)
    status = models.CharField(max_length=20, choices=Status.choices, default=Status.ACTIVE)
    locale = models.CharField(max_length=10, default="es")
    timezone = models.CharField(max_length=64, default="UTC")
    metadata = models.JSONField(default=dict, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    suspended_at = models.DateTimeField(null=True, blank=True)
    archived_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        db_table = "tenancy_tenant"

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


class TenantMembership(models.Model):
    """A user's membership in a tenant. The only correct user↔tenant link."""

    tenant = models.ForeignKey(Tenant, on_delete=models.CASCADE, related_name="memberships")
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="tenant_memberships",
    )
    role = models.CharField(max_length=50, default="member")
    is_owner = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    joined_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "tenancy_membership"
        unique_together = [("tenant", "user")]
        indexes = [models.Index(fields=["user", "is_active"])]

    def __str__(self) -> str:
        return f"{self.user}@{self.tenant.slug}"


class TenantInvitation(models.Model):
    """A pending invite to join a tenant. Tenant-owned and expiring."""

    tenant = models.ForeignKey(Tenant, on_delete=models.CASCADE, related_name="invitations")
    email = models.EmailField()
    role = models.CharField(max_length=50, default="member")
    token = models.CharField(max_length=64, unique=True)
    invited_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    expires_at = models.DateTimeField()
    accepted_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    objects = TenantManager()
    all_objects = AllObjectsManager()

    class Meta:
        db_table = "tenancy_invitation"
        indexes = [
            models.Index(fields=["tenant", "email"]),
            models.Index(fields=["tenant", "token"]),
        ]

    def is_expired(self) -> bool:
        return self.expires_at < timezone.now()

    def __str__(self) -> str:
        return f"invite:{self.email}@{self.tenant.slug}"


class PlatformStaff(models.Model):
    """Marks an InfraSynth team member allowed explicit, audited cross-tenant access.

    ``User`` is external (``AUTH_USER_MODEL``), so this cannot be a field on it.
    """

    user = models.OneToOneField(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="platform_staff",
    )
    reason = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "tenancy_platform_staff"

    def __str__(self) -> str:
        return f"platform-staff:{self.user_id}"