"""Tests for permanence.world.db — reversibility + isolation."""
from __future__ import annotations

import socket
from unittest.mock import patch

from permanence.world.db import MockDatabase


def test_create_and_select_are_r1_r2():
    db = MockDatabase()
    assert db.create_table("users", "id").r_level == 2
    assert db.select("users").r_level == 1


def test_insert_autocommit_is_r3():
    db = MockDatabase()
    db.create_table("users", "id")
    res = db.insert("users", {"id": 1, "name": "alice"})
    assert res.ok and res.r_level == 3


def test_insert_in_txn_is_r2_and_rollback_restores():
    db = MockDatabase()
    db.create_table("users", "id")
    db.begin()
    res = db.insert("users", {"id": 1, "name": "alice"})
    assert res.ok and res.r_level == 2
    db.rollback()
    assert db.tables["users"].n_rows() == 0


def test_drop_table_with_backup_is_r4():
    db = MockDatabase()
    db.create_table("users", "id")
    db.insert("users", {"id": 1, "name": "alice"})
    db.snapshot("pre-migration")
    res = db.drop_table("users")
    assert res.ok and res.r_level == 4


def test_drop_table_without_backup_is_r5():
    db = MockDatabase()
    db.create_table("users", "id")
    db.insert("users", {"id": 1, "name": "alice"})
    res = db.drop_table("users")
    assert res.ok and res.r_level == 5
    assert "UNRECOVERABLE" in res.message


def test_truncate_autocommit_without_backup_is_r5():
    db = MockDatabase()
    db.create_table("events", "id")
    for i in range(100):
        db.insert("events", {"id": i, "v": i})
    res = db.truncate("events")
    assert res.ok and res.r_level == 5


def test_truncate_autocommit_with_backup_is_r4():
    db = MockDatabase()
    db.create_table("events", "id")
    db.insert("events", {"id": 1, "v": 1})
    db.snapshot("pre")
    res = db.truncate("events")
    assert res.ok and res.r_level == 4


def test_commit_of_drop_escalates_to_r5_without_backup():
    db = MockDatabase()
    db.create_table("orders", "id")
    db.begin()
    db.drop_table("orders")
    res = db.commit()
    assert res.ok and res.r_level == 5


def test_commit_of_dml_is_r3():
    db = MockDatabase()
    db.create_table("users", "id")
    db.begin()
    db.insert("users", {"id": 1, "name": "a"})
    db.update("users", 1, {"name": "b"})
    res = db.commit()
    assert res.ok and res.r_level == 3


def test_rollback_is_r2():
    db = MockDatabase()
    db.create_table("t", "id")
    db.begin()
    db.insert("t", {"id": 1})
    res = db.rollback()
    assert res.ok and res.r_level == 2
    assert db.tables["t"].n_rows() == 0


def test_restore_from_snapshot_undoes_drop():
    db = MockDatabase()
    db.create_table("users", "id")
    db.insert("users", {"id": 1, "name": "a"})
    db.snapshot("pre")
    db.drop_table("users")
    assert "users" not in db.tables
    db.restore("pre")
    assert "users" in db.tables
    assert db.tables["users"].n_rows() == 1


def test_mock_db_never_hits_network_or_disk():
    with patch("os.remove") as mock_rm, patch.object(socket, "socket") as mock_sock:
        db = MockDatabase()
        db.create_table("a", "id")
        db.insert("a", {"id": 1})
        db.snapshot("s1")
        db.begin()
        db.update("a", 1, {"x": 9})
        db.commit()
        db.drop_table("a")
        db.restore("s1")
        assert mock_rm.call_count == 0
        assert mock_sock.call_count == 0