"""数据库引擎与会话管理"""

import os
from pathlib import Path
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base

PROJECT_ROOT = Path(__file__).resolve().parents[2]
DB_PATH = PROJECT_ROOT / "data" / "web.db"
DB_PATH.parent.mkdir(parents=True, exist_ok=True)
DATABASE_URL = os.getenv("DATABASE_URL", f"sqlite:///{DB_PATH}")

connect_args = {"check_same_thread": False} if DATABASE_URL.startswith("sqlite") else {}

engine = create_engine(
    DATABASE_URL,
    connect_args=connect_args,
    echo=False,
)

SessionLocal = sessionmaker(bind=engine, autocommit=False, autoflush=False)
Base = declarative_base()


def get_db():
    """FastAPI 依赖：提供数据库会话，请求结束自动关闭。"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    """执行数据库迁移 + 写入初始数据。"""
    run_migrations()
    _seed()


def run_migrations():
    """运行 Alembic 迁移到最新版本。"""
    from alembic import command
    from alembic.config import Config

    config = Config(str(PROJECT_ROOT / "alembic.ini"))
    config.set_main_option("script_location", str(PROJECT_ROOT / "web" / "backend" / "migrations"))
    config.set_main_option("sqlalchemy.url", DATABASE_URL)
    command.upgrade(config, "head")


def _seed():
    """写入默认超管账号和角色（账号密码通过环境变量配置）。"""
    from .models import User
    from .security import hash_password

    admin_username = os.getenv("ADMIN_USERNAME", "admin")
    admin_password = os.getenv("ADMIN_PASSWORD", "admin123")

    db = SessionLocal()
    try:
        if not db.query(User).first():
            admin = User(
                username=admin_username,
                password_hash=hash_password(admin_password),
                role="super_admin",
                is_active=True,
                remark="默认超级管理员",
            )
            db.add(admin)
            db.commit()
    finally:
        db.close()