"""
app/tenancy/resolver.py
-----------------------
Resolve an incoming Host header to a tenant by querying the control plane.

The `control` package is imported lazily inside the function so that the data
plane carries no import-time dependency on the control plane when
multi-tenancy is disabled.

Resolution rules:
  * exact match on tenant_domains.domain (host, lowercased, port stripped)
  * tenant must be status='active'
  * custom domains must be verified; subdomains we issue are trusted
Returns a detached TenantContext or None.
"""

from app.tenancy.context import TenantContext


def resolve_tenant(host):
    if not host:
        return None

    # Lazy import — keeps control plane optional when MT is disabled.
    from control.base import control_session
    from control.models import TenantDomain

    with control_session() as s:
        domain = (
            s.query(TenantDomain)
            .filter(TenantDomain.domain == host)
            .first()
        )
        if domain is None:
            return None
        if domain.kind == 'custom' and not domain.verified:
            return None

        tenant = domain.tenant
        if tenant is None or tenant.status != 'active':
            return None

        # Materialise everything needed while the session is still open
        # (db_uri decrypts the stored credential).
        return TenantContext(
            id=tenant.id,
            slug=tenant.slug,
            name=tenant.name,
            plan_id=tenant.plan_id,
            db_uri=tenant.db_uri,
        )