"""
Alembic Environment Configuration fuer Classroom Engine.

Laedt die DB-Konfiguration und Models fuer Migrationen.
"""
import os
from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context

# Alembic Config
config = context.config

# Logging Setup
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Import unserer Models fuer autogenerate
from classroom_engine.database import Base
from classroom_engine.db_models import (
    LessonSessionDB,
    PhaseHistoryDB,
    TeacherSettingsDB,
)

# Alerts Agent Models (nutzt gleiche Base)
from alerts_agent.db.models import (
    AlertTopicDB,
    AlertItemDB,
    AlertRuleDB,
    AlertProfileDB,
)

# Test Registry Models
try:
    from api.tests.db_models import (
        TestRunDB,
        TestResultDB,
        FailedTestBacklogDB,
        TestFixHistoryDB,
        TestServiceStatsDB,
    )
except ImportError:
    # Models noch nicht vorhanden - wird bei Migration erstellt
    pass

target_metadata = Base.metadata

# Database URL aus Umgebungsvariable oder Config
_raw_url = os.getenv(
    "DATABASE_URL",
    config.get_main_option("sqlalchemy.url")
)
# SQLAlchemy 2.0 erfordert "postgresql://" statt "postgres://"
DATABASE_URL = _raw_url.replace("postgres://", "postgresql://", 1) if _raw_url and _raw_url.startswith("postgres://") else _raw_url


def run_migrations_offline() -> None:
    """
    Run migrations in 'offline' mode.

    Generiert SQL-Skripte ohne DB-Verbindung.
    """
    url = DATABASE_URL
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

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


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

    Fuehrt Migrationen direkt auf der DB aus.
    """
    configuration = config.get_section(config.config_ini_section)
    configuration["sqlalchemy.url"] = DATABASE_URL

    connectable = engine_from_config(
        configuration,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

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

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


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