import os
from pathlib import Path
from uuid import uuid4

import pytest
from alembic import command
from alembic.config import Config
from sqlalchemy import create_engine
from sqlalchemy.engine import make_url
from sqlalchemy.orm import sessionmaker

from wisegrade.config import get_settings
from wisegrade.db import engine_for
from wisegrade.seed import seed_initial


@pytest.fixture(scope="session")
def test_database_url():
    value = os.environ.get("TEST_DATABASE_URL")
    if not value:
        pytest.fail("Set TEST_DATABASE_URL to a dedicated PostgreSQL database named wisegrade_tests")
    url = make_url(value)
    if url.drivername != "postgresql+psycopg" or url.database != "wisegrade_tests":
        pytest.fail("TEST_DATABASE_URL must use postgresql+psycopg and the wisegrade_tests database")
    return url


@pytest.fixture
def environment(tmp_path, monkeypatch):
    inbox = tmp_path / "inbox"
    inbox.mkdir()
    monkeypatch.setenv("INBOX_PATH", str(inbox))
    monkeypatch.setenv("PROCESSED_PATH", str(tmp_path / "processed"))
    monkeypatch.setenv("EXPORTS_PATH", str(tmp_path / "exports"))
    monkeypatch.setenv("WISEGRADE_SECRET_KEY", "test-only-secret-key-of-at-least-32-characters")
    get_settings.cache_clear()
    yield tmp_path
    get_settings.cache_clear()


@pytest.fixture
def session_factory(environment, monkeypatch, test_database_url):
    admin_engine = create_engine(test_database_url, isolation_level="AUTOCOMMIT")
    name = f"wisegrade_test_{uuid4().hex}"
    engine = None
    created = False
    try:
        with admin_engine.connect() as connection:
            connection.exec_driver_sql(f'CREATE DATABASE "{name}"')
        created = True
        url = test_database_url.set(database=name).render_as_string(hide_password=False)
        monkeypatch.setenv("DATABASE_URL", url)
        get_settings.cache_clear()
        backend_root = Path(__file__).resolve().parents[1]
        migration_config = Config(str(backend_root / "alembic.ini"))
        migration_config.set_main_option("script_location", str(backend_root / "migrations"))
        command.upgrade(migration_config, "head")
        engine = engine_for(url)
        factory = sessionmaker(bind=engine, expire_on_commit=False)
        with factory() as db:
            seed_initial(db)
        yield factory
    finally:
        if engine is not None:
            engine.dispose()
        get_settings.cache_clear()
        if created:
            with admin_engine.connect() as connection:
                connection.exec_driver_sql(f'DROP DATABASE "{name}" WITH (FORCE)')
        admin_engine.dispose()


@pytest.fixture
def db(session_factory):
    with session_factory() as session:
        yield session