"""
依赖注入
"""
from fastapi import Depends, HTTPException, status, Request
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session
from typing import Optional
from app.database import get_db
from app.core.security import verify_token
from app.models.admin import Admin
from app.models.user import User
from app.models.session import Session
from app.services.session_service import SessionService

security = HTTPBearer()

def get_current_admin(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: Session = Depends(get_db)
) -> Admin:
    """获取当前管理员"""
    token = credentials.credentials
    payload = verify_token(token)
    if not payload:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="无效的令牌"
        )
    
    username = payload.get("sub")
    admin = db.query(Admin).filter(Admin.username == username).first()
    if not admin or admin.status != 1:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="管理员不存在或已被禁用"
        )
    
    return admin

def get_current_user_session(
    request: Request,
    db: Session = Depends(get_db),
    allow_expired_extend: bool = False
) -> tuple[User, Session]:
    """
    获取当前用户会话

    从请求头或查询参数中获取session_id，验证并返回用户和会话信息

    Args:
        allow_expired_extend: 是否允许延长已过期的活跃Session（用于心跳场景）

    Returns:
        tuple: (User对象, Session对象)
    """
    # 从请求头获取session_id
    session_id = request.headers.get("X-Session-ID")

    # 如果请求头中没有，从查询参数获取
    if not session_id:
        session_id = request.query_params.get("session_id")

    # 如果都没有，从请求体中获取（针对加密请求）
    if not session_id:
        # 对于加密请求，session_id会在解密后的数据中
        # 这里先设置为空，后续在接口中处理
        pass

    if not session_id:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="缺少会话ID"
        )

    # 验证会话（根据是否为心跳请求决定是否允许延长过期Session）
    is_valid, session, error_msg = SessionService.validate_session(db, session_id, allow_expired_extend=allow_expired_extend)
    if not is_valid:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail=f"会话验证失败: {error_msg}"
        )

    # 获取用户信息
    user = db.query(User).filter(User.id == session.user_id).first()
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="用户不存在"
        )

    # 验证header中的user_id和user_name是否与session匹配（组合校验）
    header_user_id = request.headers.get("x-user-id") or request.headers.get("X-User-Id")
    header_user_name = request.headers.get("x-user-name") or request.headers.get("X-User-Name")

    if header_user_id and header_user_name:
        try:
            header_user_id = int(header_user_id)
            if header_user_id != user.id or header_user_name != user.username:
                raise HTTPException(
                    status_code=status.HTTP_401_UNAUTHORIZED,
                    detail="用户信息校验失败"
                )
        except ValueError:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="用户信息格式错误"
            )
    else:
        # 如果没有提供header用户信息，认为是认证失败
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="缺少用户信息"
        )

    return user, session


def get_current_user_session_for_heartbeat(
    request: Request,
    db: Session = Depends(get_db)
) -> tuple[User, Session]:
    """
    获取当前用户会话（心跳专用）

    允许延长已过期的活跃Session，保持用户在线体验
    """
    return get_current_user_session(request, db, allow_expired_extend=True)

def get_optional_user_session(
    request: Request,
    db: Session = Depends(get_db)
) -> Optional[tuple[User, Session]]:
    """
    获取可选的用户会话（用于不需要强制登录的接口）

    Returns:
        Optional[tuple[User, Session]]: 用户和会话信息，如果没有则返回None
    """
    try:
        return get_current_user_session(request, db)
    except HTTPException:
        return None