from contextlib import contextmanager
from unittest.mock import MagicMock

import pytest

from core import postgres


def test_safe_identifier_quotes_names_and_rejects_sql_expressions():
    assert postgres._safe_id("scheduled_jobs") == '"scheduled_jobs"'

    for unsafe in ["jobs.id", "jobs; DROP TABLE jobs", "two words", "", 7, None]:
        with pytest.raises(ValueError, match="Invalid SQL identifier"):
            postgres._safe_id(unsafe)


def test_order_clause_allows_only_identifiers_and_directions():
    assert postgres._order_clause(
        ["created_at desc", ("id", "ASC")]
    ) == '"created_at" DESC, "id" ASC'

    unsafe_values = [
        "created_at DESC NULLS LAST",
        "created_at;drop DESC",
        [("created_at", "SIDEWAYS")],
        [("created_at", "ASC", "extra")],
    ]
    for value in unsafe_values:
        with pytest.raises(ValueError):
            postgres._order_clause(value)


def test_select_builds_parameterized_where_and_safe_order(monkeypatch):
    cursor = MagicMock()
    cursor.fetchall.return_value = [{"id": "job-1"}]

    @contextmanager
    def fake_cursor():
        yield cursor

    monkeypatch.setattr(postgres, "get_cursor", fake_cursor)

    rows = postgres.select(
        "scheduled_jobs",
        where={"user_uuid": "user-1", "status": ("IN", ["pending", "running"])},
        order_by=[("run_at", "ASC"), ("id", "DESC")],
        limit=10,
    )

    assert rows == [{"id": "job-1"}]
    query, params = cursor.execute.call_args.args
    assert 'FROM "scheduled_jobs"' in query
    assert '"user_uuid" = %(user_uuid_0)s' in query
    assert '"status" IN (%(status_1_0)s, %(status_1_1)s)' in query
    assert 'ORDER BY "run_at" ASC, "id" DESC' in query
    assert "LIMIT %(query_limit)s" in query
    assert params == {
        "user_uuid_0": "user-1",
        "status_1_0": "pending",
        "status_1_1": "running",
        "query_limit": 10,
    }


def test_empty_update_and_delete_conditions_fail_before_opening_cursor(monkeypatch):
    cursor_factory = MagicMock(
        side_effect=AssertionError("a database cursor must not be opened")
    )
    monkeypatch.setattr(postgres, "get_cursor", cursor_factory)

    with pytest.raises(ValueError, match="update data cannot be empty"):
        postgres.update("users", {}, {"id": "user-1"})
    with pytest.raises(ValueError, match="non-empty where"):
        postgres.update("users", {"timezone": "UTC"}, {})
    with pytest.raises(ValueError, match="non-empty where"):
        postgres.delete("users", {})

    cursor_factory.assert_not_called()