"""Alembic environment configuration for async SQLAlchemy."""

import asyncio
from logging.config import fileConfig

from alembic import context
from sqlalchemy import pool, text
from sqlalchemy.engine import Connection
from sqlalchemy.ext.asyncio import async_engine_from_config

# Import your models' Base to enable autogenerate
from alpine_bits_python.config_loader import load_config
from alpine_bits_python.db import Base, get_database_schema, get_database_url

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Load application config to get database URL and schema
try:
    app_config = load_config()
except (FileNotFoundError, KeyError, ValueError):
    # Fallback if config can't be loaded (e.g., during initial setup)
    app_config = {}

# Get database URL from application config
db_url = get_database_url(app_config)
if db_url:
    config.set_main_option("sqlalchemy.url", db_url)

# Get schema name from application config
SCHEMA = get_database_schema(app_config)

# add your model's MetaData object here for 'autogenerate' support
target_metadata = Base.metadata

# Configure metadata to resolve unqualified table names in the schema
# This is needed so ForeignKey("customers.id") can find "alpinebits.customers"
if SCHEMA:
    target_metadata.schema = SCHEMA


def run_migrations_offline() -> None:
    """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.

    Calls to context.execute() here emit the given string to the
    script output.
    """
    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():
        # Set search path for offline mode if schema is configured
        if SCHEMA:
            print(f"Setting search_path to {SCHEMA}, public")
            context.execute(f"SET search_path TO {SCHEMA}, public")
        context.run_migrations()


def do_run_migrations(connection: Connection) -> None:
    """Run migrations with the given connection."""
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
    )

    with context.begin_transaction():
        # Create schema if it doesn't exist
        if SCHEMA:
            connection.execute(text(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}"))
            # Set search path to our schema
            print(f"setting search path to schema {SCHEMA}, ")
            connection.execute(text(f"SET search_path TO {SCHEMA}"))
        context.run_migrations()


async def run_async_migrations() -> None:
    """In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    connectable = async_engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    async with connectable.connect() as connection:
        if connection.dialect.name == "postgresql":
            # set search path on the connection, which ensures that
            # PostgreSQL will emit all CREATE / ALTER / DROP statements
            # in terms of this schema by default

            connection.execute(text(f"SET search_path TO {SCHEMA}"))
            # in SQLAlchemy v2+ the search path change needs to be committed
            connection.commit()
        await connection.run_sync(do_run_migrations)

    await connectable.dispose()


def run_migrations_online() -> None:
    """Run migrations in 'online' mode - entry point."""
    asyncio.run(run_async_migrations())


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