from __future__ import annotations

import tempfile
import unittest
from pathlib import Path

from alembic import command
from alembic.runtime.migration import MigrationContext
from sqlalchemy import create_engine, inspect

from app.db.base import Base
from app.db.migrations import (
    REVISION_AUTH_RBAC,
    REVISION_FILE_FOLDERS,
    alembic_config,
    migrate_database,
)


class DatabaseMigrationTests(unittest.TestCase):
    def test_repairs_create_all_schema_drift_and_upgrades_to_head(self) -> None:
        with tempfile.TemporaryDirectory(prefix="msm-migration-test-") as directory:
            database = Path(directory) / "legacy.db"
            url = f"sqlite:///{database}"

            # Reproduce the historical development database: Alembic was run
            # through auth/RBAC, then create_all() created later file tables
            # without advancing alembic_version and without altering the
            # already-existing campaign_versions table.
            command.upgrade(alembic_config(database_url=url), REVISION_AUTH_RBAC)
            engine = create_engine(url)
            try:
                Base.metadata.create_all(bind=engine)
                with engine.connect() as connection:
                    self.assertEqual(
                        MigrationContext.configure(connection).get_current_revision(),
                        REVISION_AUTH_RBAC,
                    )
                    self.assertIn("file_blobs", inspect(connection).get_table_names())
                    self.assertNotIn(
                        "user_lock_state",
                        {column["name"] for column in inspect(connection).get_columns("campaign_versions")},
                    )
            finally:
                engine.dispose()

            result = migrate_database(database_url=url)
            self.assertEqual(result.previous_revision, REVISION_AUTH_RBAC)
            self.assertEqual(result.reconciled_revision, REVISION_FILE_FOLDERS)

            engine = create_engine(url)
            try:
                with engine.connect() as connection:
                    current = MigrationContext.configure(connection).get_current_revision()
                    columns = {
                        column["name"]
                        for column in inspect(connection).get_columns("campaign_versions")
                    }
                self.assertEqual(current, result.current_revision)
                self.assertIn("user_lock_state", columns)
                self.assertIn("user_locked_at", columns)
                self.assertIn("user_locked_by_user_id", columns)
            finally:
                engine.dispose()