from __future__ import annotations

import os
import sys
from logging.config import fileConfig
from pathlib import Path

from alembic import context
from sqlalchemy import engine_from_config, pool


BACKEND_ROOT = Path(__file__).resolve().parents[1]
for import_root in (BACKEND_ROOT, BACKEND_ROOT.parents[1]):
    if (import_root / "src").exists():
        sys.path.insert(0, str(import_root))

config = context.config

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

target_metadata = None


def _database_url() -> str:
    configured = os.environ.get("DATABASE_URL") or os.environ.get("POSTGRES_DSN")
    if not configured:
        return config.get_main_option("sqlalchemy.url")

    if configured.startswith("postgresql://"):
        return "postgresql+psycopg://" + configured.removeprefix("postgresql://")
    if configured.startswith("postgres://"):
        return "postgresql+psycopg://" + configured.removeprefix("postgres://")
    return configured


def run_migrations_offline() -> None:
    context.configure(
        url=_database_url(),
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

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


def run_migrations_online() -> None:
    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()