"""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

DB_PATH = Path(__file__).parent.parent.parent / "data" / "web.db"
DB_PATH.parent.mkdir(parents=True, exist_ok=True)

engine = create_engine(
    f"sqlite:///{DB_PATH}",
    connect_args={"check_same_thread": False},
    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():
    """建表 + 写入初始数据。"""
    Base.metadata.create_all(bind=engine)
    _migrate()
    _seed()


def _migrate():
    """数据库迁移：为已有表添加新列。"""
    from sqlalchemy import text
    with engine.connect() as conn:
        # 检查 accounts.tag 列是否存在
        result = conn.execute(text("PRAGMA table_info(accounts)"))
        columns = [row[1] for row in result]
        if 'tag' not in columns:
            conn.execute(text("ALTER TABLE accounts ADD COLUMN tag VARCHAR(64) DEFAULT ''"))
            conn.commit()

        # 检查 users.custom_permissions 列是否存在
        result = conn.execute(text("PRAGMA table_info(users)"))
        columns = [row[1] for row in result]
        if 'custom_permissions' not in columns:
            conn.execute(text("ALTER TABLE users ADD COLUMN custom_permissions JSON DEFAULT NULL"))
            conn.commit()

        # 检查 accounts.email_imap_ssl 列是否存在
        result = conn.execute(text("PRAGMA table_info(accounts)"))
        columns = [row[1] for row in result]
        if 'email_imap_ssl' not in columns:
            # 旧数据端口993的默认True（SSL），其他端口默认False
            conn.execute(text("ALTER TABLE accounts ADD COLUMN email_imap_ssl BOOLEAN DEFAULT 1"))
            conn.commit()
            # 修正旧数据中使用 111.229.206.54 的账号：端口改为143，SSL改为False
            conn.execute(text(
                "UPDATE accounts SET email_imap_port = 143, email_imap_ssl = 0 "
                "WHERE email_imap_server = '111.229.206.54'"
            ))
            conn.commit()
            # 修正旧数据中使用 mail.bdhg.xyz 的账号：993端口不通，改用143非SSL
            conn.execute(text(
                "UPDATE accounts SET email_imap_port = 143, email_imap_ssl = 0 "
                "WHERE email_imap_server = 'mail.bdhg.xyz'"
            ))
            conn.commit()


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()