"""Unit tests: SQLAlchemy models register the pgvector schema on the metadata.

Importing :mod:`app.models` is what Alembic's ``env.py`` and the runtime rely
on; these tests lock the table/column contract (PLAN §5) without a live DB.
"""
from __future__ import annotations

from pgvector.sqlalchemy import Vector
from sqlalchemy import UniqueConstraint

import app.models  # noqa: F401  (import registers all tables on Base.metadata)
from app.db import Base


def test_all_tables_registered() -> None:
    tables = Base.metadata.tables
    assert "documents" in tables
    assert "chunks" in tables
    assert "query_log" in tables


def test_chunks_embedding_is_vector_768() -> None:
    chunks = Base.metadata.tables["chunks"]
    col = chunks.c["embedding"]
    assert isinstance(col.type, Vector)
    assert col.type.dim == 768
    # Embeddings are two-phase: inserted first, embedded later.
    assert col.nullable is True


def test_chunks_reference_documents_cascade() -> None:
    chunks = Base.metadata.tables["chunks"]
    fkc = list(chunks.foreign_key_constraints)[0]
    assert fkc.elements[0].column.table.name == "documents"
    assert fkc.ondelete == "CASCADE"


def test_documents_unique_source_path() -> None:
    documents = Base.metadata.tables["documents"]
    uq = [
        c
        for c in documents.constraints
        if isinstance(c, UniqueConstraint)
        and {col.name for col in c.columns} == {"source", "path"}
    ]
    assert uq, "documents must be unique on (source, path) — the upsert key"