"""Alembic env — SQLModel + app.config.DATABASE_URL + защита autogenerate."""
import sys
from logging.config import fileConfig
from pathlib import Path

from alembic import context
from sqlalchemy import engine_from_config, pool
from sqlmodel import SQLModel

PROJECT_ROOT = Path(__file__).resolve().parent.parent
if str(PROJECT_ROOT) not in sys.path:
    sys.path.insert(0, str(PROJECT_ROOT))

from app import config as app_config  # noqa: E402
from app import models  # noqa: E402,F401

config = context.config
config.set_main_option("sqlalchemy.url", app_config.DATABASE_URL)

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

target_metadata = SQLModel.metadata


# ── Таблицы, существовавшие до Alembic ───────────────────────────────
_EXISTING_TABLES = {
    "event", "eventsubscriber", "globalstatus", "notification",
    "portalfile", "project", "projectmember", "projectpost",
    "projectpostattachment", "projectsubscription", "projecttask",
    "user", "usersession", "workshop", "workshopassistant",
    "workshopfeedback", "workshopmaterial", "workshoppost",
    "workshoppostattachment", "workshopregistration",
    "workshopsession", "workshopsubscription",
}


def include_object(obj, name, type_, reflected, compare_to):
    """
    FK/index/unique для существующих таблиц — игнорируются
    (модели vs БД расходятся в именах/ondelete, это косметика).
    Отражённое в БД, но отсутствующее в модели — не дропаем.
    Новые таблицы/колонки — разрешены.
    """
    if type_ in ("foreign_key_constraint", "index", "unique_constraint"):
        parent = getattr(obj, "table", None)
        parent_name = getattr(parent, "name", None)
        if parent_name in _EXISTING_TABLES:
            return False
        if reflected:
            return False
    if reflected and compare_to is None:
        return False
    return True


def render_item(type_, obj, autogen_context):
    """
    SQLModel использует свои типы (AutoString, UTCDateTime). В миграции их
    нельзя писать как `sqlmodel.sql.sqltypes.AutoString()` — не будет
    импортировано. Рендерим как нативные SQLAlchemy типы.

    Покрываемые типы:
      • AutoString   → sa.String()             (str-поля)
      • UTCDateTime  → sa.DateTime(timezone=True)  (datetime-поля)
      • Integer, Boolean, Float — нативные, не трогаем
    """
    if type_ != "type":
        return False
    try:
        import sqlmodel
    except ImportError:
        return False
    if isinstance(obj, sqlmodel.sql.sqltypes.UTCDateTime):
        return "sa.DateTime(timezone=True)"
    if isinstance(obj, sqlmodel.sql.sqltypes.AutoString):
        return "sa.String()"
    return False


def run_migrations_offline() -> None:
    context.configure(
        url=config.get_main_option("sqlalchemy.url"),
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
        include_object=include_object,
        render_item=render_item,
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    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,
            compare_type=True,
            include_object=include_object,
            render_item=render_item,
        )
        with context.begin_transaction():
            context.run_migrations()


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