import os
import sys
from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context

# Add the project root directory to the Python path so we can import app
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

# Import Base from the app
from app.db.base import Base  # noqa

# This is the Alembic Config object
config = context.config

# Interpret the config file for Python logging
fileConfig(config.config_file_name)

# Import all models for Alembic to detect
target_metadata = Base.metadata

def run_migrations_offline():
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    """
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    connectable = engine_from_config(
        config.get_section(config.config_ini_section),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        is_sqlite = connection.dialect.name == 'sqlite'
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            render_as_batch=is_sqlite,  # Required for SQLite to handle ALTER TABLE operations properly
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()