"""
Alembic migration environment.

Configured for async SQLAlchemy with PostgreSQL/SQLite.
"""

from __future__ import annotations

import os
import sys
from logging.config import fileConfig

from sqlalchemy import engine_from_config, pool

from alembic import context

# Add parent directory to path so 'bloxserver' package is importable
# bloxserver/ is at xml-pipeline/bloxserver/, so we need xml-pipeline/ on the path
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))))

# Import models to register them with Base.metadata
from bloxserver.api.models.database import Base
from bloxserver.api.models import tables  # noqa: F401 - imports register models

# Alembic Config object
config = context.config

# Setup logging from alembic.ini
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Target metadata for autogenerate
target_metadata = Base.metadata


def get_url() -> str:
    """
    Get database URL from environment.
    
    Converts async URLs (postgresql+asyncpg://) to sync (postgresql://)
    because Alembic runs migrations synchronously.
    """
    url = os.getenv(
        "DATABASE_URL",
        "sqlite:///./bloxserver.db",
    )
    
    # Convert async driver to sync for Alembic
    if url.startswith("postgresql+asyncpg://"):
        url = url.replace("postgresql+asyncpg://", "postgresql://", 1)
    elif url.startswith("sqlite+aiosqlite://"):
        url = url.replace("sqlite+aiosqlite://", "sqlite://", 1)
    
    return url


def run_migrations_offline() -> None:
    """
    Run migrations in 'offline' mode.
    
    Generates SQL script without connecting to database.
    Useful for reviewing migrations before applying.
    """
    url = get_url()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
        compare_server_default=True,
    )

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


def run_migrations_online() -> None:
    """
    Run migrations in 'online' mode.
    
    Connects to database and applies migrations directly.
    """
    configuration = config.get_section(config.config_ini_section, {})
    configuration["sqlalchemy.url"] = get_url()
    
    connectable = engine_from_config(
        configuration,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            compare_type=True,
            compare_server_default=True,
        )

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


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