"""Alembic environment for the Work Package Suite.

We reuse the application's own database configuration (server/db.py) so a
migration always targets the same database the app would connect to — Postgres
in production (from POSTGRES_* / DATABASE_URL) or the SQLite dev file otherwise.
No connection string is stored in alembic.ini.
"""
import os
import sys
from logging.config import fileConfig

from alembic import context

# Make the `server` package importable no matter where alembic is invoked from
# (repo root, /app in the container, etc.). env.py lives at server/alembic/env.py,
# so the repo root is two directories up.
_HERE = os.path.dirname(os.path.abspath(__file__))
_REPO = os.path.dirname(os.path.dirname(_HERE))
if _REPO not in sys.path:
    sys.path.insert(0, _REPO)

from server.db import Base, DATABASE_URL, engine  # noqa: E402
from server import models  # noqa: E402,F401  (imported for its side effect: registers all tables on Base.metadata)

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

# The app resolves its URL from the environment; feed the same value to Alembic.
config.set_main_option("sqlalchemy.url", str(DATABASE_URL))

target_metadata = Base.metadata


def run_migrations_offline() -> None:
    """Emit SQL to stdout (`alembic upgrade --sql`) without a live connection."""
    context.configure(
        url=str(DATABASE_URL),
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """Run migrations against a live connection, reusing the app's engine."""
    with engine.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            compare_type=True,
            # Each migration commits on its own. One transaction for the WHOLE
            # run meant a crash at step N rolled back steps 1..N-1 while their
            # "Running upgrade" lines stayed on screen claiming they ran - the
            # 2026-08-21 outage's stamp-to-head repair trusted those lines and
            # left production missing two tables (found 2026-08-23 when the
            # locations import 500'd on a table that "had been created").
            transaction_per_migration=True,
        )
        with context.begin_transaction():
            context.run_migrations()


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