import os
import pytest
from unittest.mock import patch
from sqlalchemy.orm import Session
from app.utils.database import get_db_credentials, get_db
from tests.utils.db_mocks import (
    session_mock,
    mock_get_db,
    mock_env,
    mock_ssm
)

def test_get_db_credentials_env(mock_env):
    """Test getting DB credentials from environment variables"""
    conn_str = get_db_credentials()
    assert conn_str == "postgresql://testuser:testpass@localhost/testdb"

def test_get_db_credentials_ssm(mock_ssm):
    """Test getting DB credentials from SSM"""
    os.environ.pop("MOCK_AUTH", None)
    conn_str = get_db_credentials()
    assert "postgresql://mocked_value:mocked_value@mocked_value/mocked_value" in conn_str
    mock_ssm.get_parameter.assert_called()

def test_get_db_credentials_ssm_exception(mock_ssm):
    """Test SSM credential fetching failure raises RuntimeError"""
    os.environ.pop("MOCK_AUTH", None)
    mock_ssm.get_parameter.side_effect = Exception("SSM timeout")
    
    with pytest.raises(RuntimeError) as excinfo:
        get_db_credentials()
    
    assert "Failed to fetch DB credentials from SSM: SSM timeout" in str(excinfo.value)

def test_session_creation():
    """Test database session creation"""
    session = session_mock()
    assert isinstance(session, Session)
    session.close()

def test_get_db_generator():
    """Test get_db dependency generator"""
    db_gen = get_db()
    db = next(db_gen)
    assert isinstance(db, Session)
    try:
        next(db_gen)  # Should raise StopIteration
    except StopIteration:
        pass

def test_init_db(mocker, mock_env):
    """Test database initialization creates tables"""
    mock_create_all = mocker.patch('app.models.Base.metadata.create_all')
    
    # Mock get_db_credentials to return SQLite test connection
    mocker.patch(
        'app.utils.database.get_db_credentials',
        return_value="sqlite:///:memory:"
    )
    
    from app.utils.database import init_db, engine
    init_db()
    
    # Verify create_all was called with the engine
    mock_create_all.assert_called_once_with(bind=engine)