"""Space metadata — content bodies live in Forgejo (markdown), not here."""

from __future__ import annotations

import re
import uuid

from django.core.exceptions import ValidationError
from django.db import models
from django.utils.text import slugify


_SLUG_RE = re.compile(r"^[a-z0-9]+(?:-[a-z0-9]+)*$")


def validate_space_slug(value: str) -> None:
    if not _SLUG_RE.match(value or ""):
        raise ValidationError(
            "Slug must be lowercase alphanumeric with single hyphens (e.g. my-space)."
        )


class Space(models.Model):
    """Tenant-scoped co-creation space.

    Postgres holds metadata and Forgejo binding pointers only. Long-form pages
    are markdown in the bound repository (ADR-0002).
    """

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    tenant_id = models.CharField(max_length=64, db_index=True)
    slug = models.SlugField(max_length=80, validators=[validate_space_slug])
    title = models.CharField(max_length=255)
    description = models.TextField(blank=True)
    created_by = models.ForeignKey(
        "members.Member",
        on_delete=models.PROTECT,
        related_name="spaces_created",
        null=True,
        blank=True,
    )
    # Optional content binding (Forgejo) — empty until T04 wires the read path
    forgejo_owner = models.CharField(
        max_length=128,
        blank=True,
        help_text="Forgejo org or user owning the repo (e.g. coulomb).",
    )
    forgejo_repo = models.CharField(
        max_length=128,
        blank=True,
        help_text="Repository name (e.g. space-my-space).",
    )
    default_branch = models.CharField(max_length=128, blank=True, default="main")
    content_root = models.CharField(
        max_length=255,
        blank=True,
        default="pages",
        help_text="Path prefix inside the repo for markdown pages.",
    )
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["tenant_id", "slug"],
                name="spaces_space_tenant_slug_uniq",
            ),
        ]
        indexes = [
            models.Index(fields=["tenant_id", "is_active"]),
        ]
        ordering = ["title", "slug"]

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

    @property
    def has_content_binding(self) -> bool:
        return bool(self.forgejo_owner and self.forgejo_repo)

    @classmethod
    def suggest_slug(cls, title: str) -> str:
        return slugify(title)[:80] or "space"


class SpaceMembership(models.Model):
    """Optional explicit membership; v1 list also allows tenant-wide visibility."""

    class Role(models.TextChoices):
        OWNER = "owner", "Owner"
        MEMBER = "member", "Member"
        VIEWER = "viewer", "Viewer"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    space = models.ForeignKey(Space, on_delete=models.CASCADE, related_name="memberships")
    member = models.ForeignKey(
        "members.Member",
        on_delete=models.CASCADE,
        related_name="space_memberships",
    )
    role = models.CharField(max_length=16, choices=Role.choices, default=Role.MEMBER)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["space", "member"],
                name="spaces_membership_space_member_uniq",
            ),
        ]

    def __str__(self) -> str:
        return f"{self.member_id}@{self.space.slug}:{self.role}"