from datetime import datetime

from sqlalchemy import JSON, DateTime, String, func
from sqlalchemy.dialects import postgresql
from sqlalchemy.orm import Mapped, mapped_column

# Portable JSON type (see CONVENTIONS C8): plain JSON on SQLite (tests),
# JSONB on PostgreSQL (production). Use this alias for every JSON column.
JSONB_V = JSON().with_variant(postgresql.JSONB(), "postgresql")


class TimestampMixin:
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
    )


class SourceMixin:
    """Provenance + dedupe columns for every imported/ingested row.

    source: "manual" | importer id ("foodvisor_csv") | ingest source ("android_bridge")
    external_id: stable id from the source system, if any
    content_hash: sha256 of canonical payload, used when no external_id exists
    """

    source: Mapped[str] = mapped_column(String(50), default="manual")
    external_id: Mapped[str | None] = mapped_column(String(255), default=None)
    content_hash: Mapped[str | None] = mapped_column(String(64), default=None)