"""
alembic/env.py
──────────────
Alembic runtime environment for PMDI.

· Reads DATABASE_URL from the environment (same source as the FastAPI app)
· Imports all ORM models so Alembic can perform autogenerate comparisons
· Supports both offline (--sql) and online migration execution
"""
from __future__ import annotations

import os
from logging.config import fileConfig

from alembic import context
from sqlalchemy import engine_from_config, pool

# Import the shared declarative Base AND all models so Alembic sees every table
from app.database import Base  # noqa: F401
from app.models import (      # noqa: F401
    AdminUser, Client, EmailTemplate, Invoice, NotificationLog,
)

# ── Alembic config object ──────────────────────────────────────────────────
config = context.config

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

# Override sqlalchemy.url from the environment so credentials are never
# stored in alembic.ini or any config file.
database_url = os.environ.get("DATABASE_URL")
if database_url:
    config.set_main_option("sqlalchemy.url", database_url)

target_metadata = Base.metadata


# ── Offline mode ───────────────────────────────────────────────────────────
def run_migrations_offline() -> None:
    """Generate SQL script without a live database connection."""
    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()


# ── Online mode ────────────────────────────────────────────────────────────
def run_migrations_online() -> None:
    """Run migrations against a live database connection."""
    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,
            compare_server_default=True,
        )
        with context.begin_transaction():
            context.run_migrations()


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