from fastapi import HTTPException, status, Request, Depends
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from typing import Optional
from app.services.jwt_service import jwt_service
from app.core.database import get_db_connection

security = HTTPBearer()

def get_current_user(credentials: HTTPAuthorizationCredentials = Depends(security)):
    """获取当前用户信息的依赖函数"""
    token = credentials.credentials
    
    # 验证JWT token
    payload = jwt_service.verify_token(token)
    if not payload:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid or expired token",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    # 从数据库验证用户是否仍然存在且有效
    user_id = payload.get("user_id")
    with get_db_connection() as connection:
        cursor = connection.cursor(dictionary=True)
        cursor.execute(
            "SELECT user_id, username, caption, email, role_id FROM users WHERE user_id = %s",
            (user_id,)
        )
        user = cursor.fetchone()
        
        if not user:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="User not found",
                headers={"WWW-Authenticate": "Bearer"},
            )
    
    return user

def get_optional_current_user(request: Request) -> Optional[dict]:
    """可选的用户认证（不强制要求登录）"""
    auth_header = request.headers.get("Authorization")
    if not auth_header or not auth_header.startswith("Bearer "):
        return None
    
    try:
        token = auth_header.split(" ")[1]
        payload = jwt_service.verify_token(token)
        if not payload:
            return None
        
        user_id = payload.get("user_id")
        with get_db_connection() as connection:
            cursor = connection.cursor(dictionary=True)
            cursor.execute(
                "SELECT user_id, username, caption, email FROM users WHERE user_id = %s",
                (user_id,)
            )
            return cursor.fetchone()
    except:
        return None