"""Alembic environment configuration for training service"""

import asyncio
import os
import sys
from logging.config import fileConfig
from sqlalchemy import pool
from sqlalchemy.engine import Connection
from sqlalchemy.ext.asyncio import async_engine_from_config
from alembic import context

# Add the service directory to the Python path
service_path = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
if service_path not in sys.path:
    sys.path.insert(0, service_path)

# Add shared modules to path
shared_path = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", "shared"))
if shared_path not in sys.path:
    sys.path.insert(0, shared_path)

try:
    from app.core.config import settings
    from shared.database.base import Base

    # Import all models to ensure they are registered with Base.metadata
    from app.models import *  # noqa: F401, F403

except ImportError as e:
    print(f"Import error in migrations env.py: {e}")
    print(f"Current Python path: {sys.path}")
    raise

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

# Determine service name from file path
service_name = os.path.basename(os.path.dirname(os.path.dirname(__file__)))
service_name_upper = service_name.upper().replace('-', '_')

# Set database URL from environment variables with multiple fallback strategies
database_url = (
    os.getenv(f'{service_name_upper}_DATABASE_URL') or  # Service-specific
    os.getenv('DATABASE_URL')  # Generic fallback
)

# If DATABASE_URL is not set, construct from individual components
if not database_url:
    # Try generic PostgreSQL environment variables first
    postgres_host = os.getenv('POSTGRES_HOST')
    postgres_port = os.getenv('POSTGRES_PORT', '5432')
    postgres_db = os.getenv('POSTGRES_DB')
    postgres_user = os.getenv('POSTGRES_USER')
    postgres_password = os.getenv('POSTGRES_PASSWORD')

    if all([postgres_host, postgres_db, postgres_user, postgres_password]):
        database_url = f"postgresql+asyncpg://{postgres_user}:{postgres_password}@{postgres_host}:{postgres_port}/{postgres_db}"
    else:
        # Try service-specific environment variables
        db_host = os.getenv(f'{service_name_upper}_DB_HOST', f'{service_name}-db-service')
        db_port = os.getenv(f'{service_name_upper}_DB_PORT', '5432')
        db_name = os.getenv(f'{service_name_upper}_DB_NAME', f'{service_name.replace("-", "_")}_db')
        db_user = os.getenv(f'{service_name_upper}_DB_USER', f'{service_name.replace("-", "_")}_user')
        db_password = os.getenv(f'{service_name_upper}_DB_PASSWORD')

        if db_password:
            database_url = f"postgresql+asyncpg://{db_user}:{db_password}@{db_host}:{db_port}/{db_name}"
        else:
            # Final fallback: try to get from settings object
            try:
                database_url = getattr(settings, 'DATABASE_URL', None)
            except Exception:
                pass

if not database_url:
    error_msg = f"ERROR: No database URL configured for {service_name} service"
    print(error_msg)
    raise Exception(error_msg)

config.set_main_option("sqlalchemy.url", database_url)

# Interpret the config file for Python logging
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Set target metadata
target_metadata = Base.metadata


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode."""
    url = config.get_main_option("sqlalchemy.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 do_run_migrations(connection: Connection) -> None:
    """Execute migrations with the given connection."""
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        compare_type=True,
        compare_server_default=True,
    )

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


async def run_async_migrations() -> None:
    """Run migrations in 'online' mode with async support."""
    connectable = async_engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)

    await connectable.dispose()


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


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