# app/utils/decorators.py
from functools import wraps
from flask_jwt_extended import get_jwt, verify_jwt_in_request, get_jwt_identity
from flask import jsonify, g, request, current_app, has_request_context
import logging
import json

def _verify_token_in_redis():
    """
    验证当前 Token 是否与 Redis 中存储的 Token 一致（单设备登录互踢）
    """
    from app.extensions import redis_client
    from flask import current_app

    if redis_client is None:
        return True

    try:
        auth_header = request.headers.get('Authorization', '')
        if not auth_header.startswith('Bearer '):
            return True

        request_token = auth_header[7:]
        claims = get_jwt()
        user_id = claims.get('sub')
        if user_id is None:
            return True

        stored_token = redis_client.get(f"user_token_{user_id}")
        if stored_token is None:
            return True

        if request_token != stored_token:
            current_app.logger.warning(f"Token mismatch for user {user_id}: request token != stored token")
            return False

        return True
    except Exception as e:
        current_app.logger.error(f"Redis token verification error: {e}")
        return True

def _raise_token_mismatch_error():
    """抛出 Token 不一致的错误"""
    return jsonify({
        'msg': '您的账号已在其他设备登录，请重新登录',
        'code': 401,
        'reason': 'token_mismatch'
    }), 401

def role_required(*roles):
    """自定义装饰器：检查用户角色"""
    def wrapper(fn):
        @wraps(fn)
        def decorator(*args, **kwargs):
            claims = get_jwt()
            user_role = claims.get('role')
            user_role_upper = user_role.upper() if user_role else None

            if user_role_upper == 'SUPER_ADMIN':
                return fn(*args, **kwargs)

            if user_role_upper not in [r.upper() for r in roles]:
                return jsonify(msg='权限不足：您没有访问此资源的权限'), 403

            return fn(*args, **kwargs)
        return decorator
    return wrapper

def login_required(fn):
    """验证 JWT 令牌是否存在且有效"""
    @wraps(fn)
    def decorator(*args, **kwargs):
        try:
            verify_jwt_in_request()
        except Exception as e:
            logging.warning(f"JWT verification failed: {e}")
            return jsonify(msg='登录已过期，请重新登录'), 401

        if not _verify_token_in_redis():
            return _raise_token_mismatch_error()

        return fn(*args, **kwargs)
    return decorator

def permission_required(permission_code):
    """检查当前用户是否拥有指定权限码"""
    def wrapper(fn):
        @wraps(fn)
        def decorator(*args, **kwargs):
            try:
                verify_jwt_in_request()
            except Exception as e:
                logging.warning(f"JWT verification failed: {e}")
                return jsonify(msg='登录已过期，请重新登录'), 401

            if not _verify_token_in_redis():
                return _raise_token_mismatch_error()

            claims = get_jwt()
            user_role = claims.get('role')
            if user_role and user_role.upper() == 'SUPER_ADMIN':
                return fn(*args, **kwargs)

            try:
                from app.services.auth_service import AuthService
                perm_dict = AuthService.get_user_permissions(user_role)
            except Exception as e:
                logging.warning(f"Failed to fetch permissions for role {user_role}: {e}")
                return jsonify(msg='权限查询失败'), 403

            all_perms = perm_dict.get('menus', []) + perm_dict.get('elements', [])
            if permission_code not in all_perms:
                logging.warning(f"权限检查失败: 角色={user_role}, 所需权限={permission_code}")
                return jsonify(msg='权限不足：您没有访问此资源的权限'), 403
            return fn(*args, **kwargs)
        return decorator
    return wrapper

def audit_log(module: str = None, action: str = None, get_target_id_fn=None, get_target_name_fn=None, get_details_fn=None):
    """
    已废弃！
    由 SQLAlchemy 底层监听器（app/core/audit_listener.py）全面接管审计日志入库。
    此装饰器保留空壳以防项目中其他文件 import 引用时报错。
    """
    def wrapper(fn):
        from functools import wraps
        @wraps(fn)
        def decorator(*inner_args, **inner_kwargs):
            return fn(*inner_args, **inner_kwargs)
        return decorator
    return wrapper