"""Unit tests for database module."""

import pytest
from sqlalchemy.orm import Session

from app.database import get_db, init_db, SessionLocal, Base, engine


class TestDatabase:
    """Test database initialization and session management."""

    def test_init_db_creates_tables(self):
        """Test that init_db creates all model tables."""
        init_db()
        
        # Check that tables exist
        from app.models import User, Project, Task, LogEntry, ProjectMembership
        
        # Verify table names are in metadata
        assert "users" in Base.metadata.tables
        assert "projects" in Base.metadata.tables
        assert "tasks" in Base.metadata.tables
        assert "log_entries" in Base.metadata.tables
        assert "project_memberships" in Base.metadata.tables

    def test_session_local_returns_session(self):
        """Test SessionLocal creates a valid session."""
        session = SessionLocal()
        assert isinstance(session, Session)
        session.close()

    def test_get_db_yields_session(self):
        """Test get_db generator yields a session and closes it."""
        gen = get_db()
        db = next(gen)
        
        assert isinstance(db, Session)
        
        # Exhaust generator to trigger cleanup
        try:
            next(gen)
        except StopIteration:
            pass

    def test_get_db_closes_on_exception(self):
        """Test get_db closes session even on exception."""
        gen = get_db()
        db = next(gen)
        
        # Simulate exception by closing manually
        try:
            gen.throw(Exception("test error"))
        except Exception:
            pass
        
        # Session should be closed (no error means cleanup happened)


class TestDatabaseEngine:
    """Test database engine configuration."""

    def test_engine_is_sqlite(self):
        """Test engine is configured for SQLite."""
        assert "sqlite" in str(engine.url)

    def test_engine_allows_multithread(self):
        """Test SQLite is configured for multi-threaded access."""
        # check_same_thread=False is set in database.py
        assert engine.pool is not None