"""Permission template model — reusable permission presets for entity types.

Templates define default sharing rules that can be applied to entities.
When applied, they automatically create entity_permissions entries.
"""

from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy import (
    CheckConstraint,
    DateTime,
    String,
    func,
)
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.dialects.postgresql import UUID as PGUUID
from sqlalchemy.orm import Mapped, mapped_column

from app.core.db import Base, TenantMixin


class PermissionTemplate(Base, TenantMixin):
    """Reusable permission template for entity types.

    When applied to an entity, the template evaluates trigger_condition
    and auto_share_with to create entity_permissions entries.

    Fields:
    - name: Human-readable template name
    - entity_type: Which entity type this template applies to
    - trigger_condition: JSONB conditions that must be met for auto-apply
    - auto_share_with: JSONB list of {principal_type, principal_id, level} to share with
    - level: Default permission level for this template
    """

    __tablename__ = "permission_templates"
    __table_args__ = (
        CheckConstraint(
            "level IN ('read', 'write', 'admin', 'delete')",
            name="ck_pt_level",
        ),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    name: Mapped[str] = mapped_column(String(200), nullable=False)
    entity_type: Mapped[str] = mapped_column(String(50), nullable=False, index=True)
    trigger_condition: Mapped[dict | None] = mapped_column(JSONB, nullable=True, default=None)
    auto_share_with: Mapped[list | None] = mapped_column(JSONB, nullable=True, default=None)
    level: Mapped[str] = mapped_column(String(20), nullable=False, default="read")
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now(),
        onupdate=func.now(),
    )