import psycopg
import pytest

from app.platform import db

_TABLES = {"account", "auth_code", "storefront", "storefront_membership"}


def _table_names(conn) -> set[str]:
    rows = conn.execute(
        "SELECT tablename FROM pg_tables WHERE schemaname = 'public'"
    ).fetchall()
    return {r[0] for r in rows}


def test_migrate_from_empty_applies_all(fresh_db_url):
    with psycopg.connect(fresh_db_url) as conn:
        applied = db.migrate(conn)
    assert applied == ["0001_init.sql", "0002_products.sql"]
    with psycopg.connect(fresh_db_url) as conn:
        assert _TABLES.issubset(_table_names(conn))


def test_migrate_is_idempotent(fresh_db_url):
    with psycopg.connect(fresh_db_url) as conn:
        db.migrate(conn)
    with psycopg.connect(fresh_db_url) as conn:
        applied_again = db.migrate(conn)
    assert applied_again == []


def test_membership_has_no_unique_account_constraint(fresh_db_url):
    # INV-4: the schema must keep many-storefronts-per-account open — no UNIQUE on
    # storefront_membership.account_id anywhere.
    with psycopg.connect(fresh_db_url) as conn:
        db.migrate(conn)
        rows = conn.execute(
            """
            SELECT indexdef FROM pg_indexes
            WHERE schemaname = 'public' AND tablename = 'storefront_membership'
            """
        ).fetchall()
    defs = " ".join(r[0] for r in rows).lower()
    assert "unique" not in defs.replace("primary key", "") or "(account_id)" not in defs


def test_0002_products_tables_exist(fresh_db_url):
    with psycopg.connect(fresh_db_url) as conn:
        db.migrate(conn)
        for table in ("product", "variant", "product_image", "import_draft", "import_run", "import_run_error"):
            assert conn.execute("SELECT to_regclass(%s)", (f"public.{table}",)).fetchone()[0] == table


def test_0002_variant_option_combo_unique_treats_nulls_as_equal(fresh_db_url):
    # INV-13: the no-option product's single variant has NULL option values; a second
    # all-NULL combo must collide (NULLS NOT DISTINCT).
    with psycopg.connect(fresh_db_url) as conn:
        db.migrate(conn)
        sf = conn.execute("INSERT INTO storefront (name) VALUES ('s') RETURNING id").fetchone()[0]
        pid = conn.execute(
            "INSERT INTO product (storefront_id, handle, title) VALUES (%s,'h','T') RETURNING id", (sf,)
        ).fetchone()[0]
        conn.execute("INSERT INTO variant (product_id, position) VALUES (%s, 1)", (pid,))
        with pytest.raises(psycopg.errors.UniqueViolation):
            conn.execute("INSERT INTO variant (product_id, position) VALUES (%s, 2)", (pid,))