"""Minimal Postgres example using sqlmodel-pg-kit.

Prerequisites:
    1. Start the dockerized Postgres instance: ``docker compose -f docker/docker-compose.yml up -d``.
    2. Export env vars so the kit can discover the database::

           export SQL_HOST=localhost
           export SQL_PORT=5432
           export SQL_USER=appuser
           export SQL_PASSWORD=changeme
           export SQL_DATABASE=appdb
           export SQL_SSLMODE=disable

    3. Install dependencies (``pip install sqlmodel-pg-kit[async]`` or ``uv pip install .``).

Run:
    ``python examples/07_postgres_minimal.py``
"""

from typing import Optional, List

from sqlalchemy import func
from sqlmodel import Field, SQLModel, select

from sqlmodel_pg_kit import Repository, create_all, get_session


class Widget(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str
    in_stock: bool = True


if __name__ == "__main__":
    create_all()

    repo = Repository(Widget)

    with get_session() as session:
        # In web apps it's common to start each request by ensuring you have a clean view of data.
        session.execute(Widget.__table__.delete())
        session.commit()

        # Create: typical POST handler persisting a single payload.
        widget = repo.create(session, {"name": "rocket"})
        print("Created:", widget)

        # Bulk insert: useful for admin imports or seeding catalogs.
        repo.bulk_insert(
            session,
            [
                {"name": "satellite", "in_stock": True},
                {"name": "capsule", "in_stock": False},
                {"name": "probe", "in_stock": True},
            ],
        )

        # Read by id: GET /widgets/{id}
        same = repo.get(session, widget.id)
        print("Fetched by primary key:", same)

        # Query a paginated listing ordered by newest first, backing a GET /widgets endpoint.
        page: List[Widget] = repo.list(
            session,
            where=Widget.in_stock.is_(True),
            order_by=[Widget.id.desc()],
            page=1,
            size=2,
        )
        print("First page of in-stock widgets:", [(w.id, w.name) for w in page])

        # Free-form filtering with SQLModel/SQLAlchemy expressions for search endpoints.
        search_term = "ro"
        search_stmt = (
            select(Widget)
            .where(Widget.name.ilike(f"%{search_term}%"))
            .order_by(Widget.name.asc())
        )
        matches = session.exec(search_stmt).all()
        print(f"Search '{search_term}' ->", [(w.id, w.name) for w in matches])

        # Aggregate counts to power dashboards or pagination metadata.
        count_stmt = select(func.count(Widget.id)).where(Widget.in_stock.is_(True))
        # scalar() keeps compatibility across SQLAlchemy versions
        inventory_count = session.exec(count_stmt).scalar() or 0
        print("In-stock count:", inventory_count)

        # Update: PATCH /widgets/{id}
        updated = repo.update(session, widget.id, in_stock=False)
        print("Updated:", updated)

        # Delete: DELETE /widgets/{id}
        removed = repo.delete(session, widget.id)
        print("Deleted:", removed)