# migrations/env.py
import os
from logging.config import fileConfig
from dotenv import load_dotenv
from alembic import context
from sqlalchemy import create_engine, pool

# 1) Берём Base из session.py
from app.db.session import Base

load_dotenv()

# 2) Импортируем сборщик моделей, чтобы metadata увидело всё
import app.db.base  # noqa: F401

config = context.config

if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata


def build_sync_url() -> str:
    """
    Возвращает sync-URL для Alembic.
    Приоритет:
    1) DATABASE_URL_SYNC (полная строка)
    2) Конструктор из DB_HOST/DB_PORT/DB_NAME/DB_USER/DB_PASSWORD
    """
    env_url = os.getenv("DATABASE_URL_SYNC")
    if env_url and "://" in env_url:
        return env_url

    host = os.getenv("DB_HOST")
    port = os.getenv("DB_PORT", "3306")
    name = os.getenv("DB_NAME")
    user = os.getenv("DB_USER")
    pwd = os.getenv("DB_PASSWORD")

    if host and name and user is not None and pwd is not None:
        # ВАЖНО: для Alembic нужна sync-строка с PyMySQL
        return f"mariadb+pymysql://{user}:{pwd}@{host}:{port}/{name}"

    raise RuntimeError(
        "No valid sync DB URL. Set DATABASE_URL_SYNC or DB_HOST/DB_PORT/DB_NAME/DB_USER/DB_PASSWORD."
    )


def run_migrations_offline() -> None:
    url = build_sync_url()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "pyformat"},
        compare_type=True,
        compare_server_default=True,
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    url = build_sync_url()

    connectable = create_engine(
        url,
        future=True,
        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()