"""Offline PostgreSQL DDL test for the study tools migration; no database access."""
import io
import os
import subprocess
import sys
from pathlib import Path
import unittest
from unittest.mock import patch

os.environ['DATABASE_URL'] = 'sqlite:///:memory:'
from app.database import Base
from alembic import command
from alembic.config import Config
from alembic.script import ScriptDirectory


class StudyToolsMigrationTests(unittest.TestCase):
    def test_alembic_model_imports_register_lab_table_in_fresh_process(self):
        result = subprocess.run([sys.executable, '-c',
            "import app.models; from app.database import Base; assert 'lab_reference_values' in Base.metadata.tables"],
            capture_output=True, text=True, env={**os.environ, 'DATABASE_URL': 'sqlite:///:memory:'})
        self.assertEqual(result.returncode, 0, result.stderr)

    def test_explicit_offline_upgrade_and_downgrade(self):
        output = io.StringIO()
        config = Config(output_buffer=output)
        config.set_main_option('script_location', str(Path(__file__).resolve().parents[1] / 'alembic'))
        scripts = ScriptDirectory.from_config(config)
        self.assertEqual(len(scripts.get_heads()), 1)
        self.assertEqual(scripts.get_revision('d94a26b8f302').down_revision, 'c82d19e4a601')
        with patch.dict(os.environ, {'DATABASE_URL': 'postgresql://unused@127.0.0.1/offline_only'}):
            command.upgrade(config, 'c82d19e4a601:d94a26b8f302', sql=True)
            sql = output.getvalue()
            self.assertIn('ADD COLUMN IF NOT EXISTS mode VARCHAR(10)', sql)
            self.assertIn('CREATE TABLE IF NOT EXISTS lab_reference_values', sql)
            self.assertIn('is_published BOOLEAN NOT NULL DEFAULT FALSE', sql)
            self.assertIn('source VARCHAR(500) NOT NULL', sql)
            self.assertNotIn('UPDATE quiz_attempts', sql)
            output.seek(0)
            output.truncate()
            command.downgrade(config, 'd94a26b8f302:c82d19e4a601', sql=True)
            self.assertIn('DROP TABLE IF EXISTS lab_reference_values', output.getvalue())
            self.assertIn('DROP COLUMN IF EXISTS mode', output.getvalue())


if __name__ == '__main__':
    unittest.main()