from __future__ import annotations

import importlib
import os
import stat
from pathlib import Path
from typing import Any

import pytest
from alembic import command
from alembic.config import Config
from sqlalchemy import inspect, text

EXPECTED_TABLES = {
    "alembic_version",
    "api_tokens",
    "audit_events",
    "backups",
    "executions",
    "idempotency_records",
    "jobs",
    "notification_deliveries",
    "notification_subscriptions",
    "repositories",
    "restores",
    "schedules",
    "secrets",
    "sources",
    "users",
}


def settings_for(tmp_path: Path) -> Any:
    config_module = importlib.import_module("backup_tool.config")
    key = tmp_path / "master.key"
    key.write_bytes(os.urandom(32))
    key.chmod(stat.S_IRUSR | stat.S_IWUSR)
    roots = []
    for name in ("repositories", "sources", "restores"):
        root = tmp_path / name
        root.mkdir()
        roots.append(root)
    return config_module.Settings(
        database_url=f"sqlite+aiosqlite:///{(tmp_path / 'metadata.db').as_posix()}",
        data_dir=tmp_path,
        repository_roots=[roots[0]],
        local_source_roots=[roots[1]],
        restore_roots=[roots[2]],
        master_key_file=key,
    )


def alembic_config(database_url: str) -> Config:
    project_root = Path(__file__).resolve().parents[2]
    config = Config(project_root / "backend" / "alembic.ini")
    config.set_main_option("sqlalchemy.url", database_url)
    return config


@pytest.mark.asyncio
async def test_migration_round_trip_and_sqlite_pragmas(tmp_path: Path) -> None:
    db_module = importlib.import_module("backup_tool.db.engine")
    settings = settings_for(tmp_path)
    migration = alembic_config(settings.database_url)

    command.upgrade(migration, "head")
    engine = db_module.create_engine(settings)
    try:
        await db_module.assert_schema_current(engine, migration)
        async with engine.connect() as connection:
            tables = await connection.run_sync(
                lambda sync_connection: set(inspect(sync_connection).get_table_names())
            )
            foreign_keys = await connection.scalar(text("PRAGMA foreign_keys"))
            journal_mode = await connection.scalar(text("PRAGMA journal_mode"))
            busy_timeout = await connection.scalar(text("PRAGMA busy_timeout"))
        assert tables == EXPECTED_TABLES
        assert foreign_keys == 1
        assert str(journal_mode).lower() == "wal"
        assert busy_timeout == settings.sqlite_busy_timeout_ms
    finally:
        await engine.dispose()

    command.downgrade(migration, "base")
    command.upgrade(migration, "head")


@pytest.mark.asyncio
async def test_startup_rejects_unmigrated_database(tmp_path: Path) -> None:
    db_module = importlib.import_module("backup_tool.db.engine")
    settings = settings_for(tmp_path)
    migration = alembic_config(settings.database_url)
    engine = db_module.create_engine(settings)
    try:
        with pytest.raises(db_module.SchemaNotCurrentError):
            await db_module.assert_schema_current(engine, migration)
    finally:
        await engine.dispose()


def test_runtime_never_uses_create_all() -> None:
    offenders = []
    for root in (Path("backend/src"), Path("backend/alembic")):
        if not root.exists():
            continue
        for path in root.rglob("*.py"):
            if "create_all" in path.read_text(encoding="utf-8"):
                offenders.append(path.as_posix())
    assert offenders == []