import os
import sys
from logging.config import fileConfig

from alembic import context
from sqlalchemy import engine_from_config, pool

# Add the project root to sys.path so that models can be imported.
sys.path.insert(0, os.path.realpath(os.path.join(os.path.dirname(__file__), "..")))

from app import create_app
from models import db

# Create the Flask application to get the database URI.
app = create_app()

# Alembic Config object.
config = context.config

# Override the sqlalchemy.url with the value from the Flask config.
config.set_main_option("sqlalchemy.url", app.config["SQLALCHEMY_DATABASE_URI"])

# Set up Python logging from the alembic.ini [loggers] section.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Target metadata for 'autogenerate' support.
target_metadata = db.metadata


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode.

    Configures the context with just a URL and not an Engine.
    """
    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() -> None:
    """Run migrations in 'online' mode.

    Creates an Engine and associates 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:
        context.configure(connection=connection, target_metadata=target_metadata)

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


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