import json
from datetime import datetime, timedelta

import jwt

from django.views.decorators.csrf import csrf_exempt
from Student.models import *
from teacher.models import Teacher
from EduSystemServer.settings import TOKEN_KEY
from EduSystemServer.utils import *


# 用户登录成功后生成 JWT Token
def generate_jwt_token(user, _type):
    # 设置 Token 的有效期
    expiration_time = datetime.utcnow() + timedelta(hours=1)
    print(datetime.utcnow())
    print(expiration_time)

    # 构建 Token 数据
    payload = {
        'type': _type,
        'username': user.username,
        'exp': expiration_time
    }
    # 使用密钥对数据进行签名生成 Token
    token = jwt.encode(payload, TOKEN_KEY, algorithm='HS256')
    return token

@csrf_exempt
def login(request):
    """
    登录
    """
    username = request.POST.get("username")
    password = request.POST.get("password")
    _type = request.POST.get("type")
    if _type == "student":
        student = Student.objects.filter(username=username,
                                      password=password).first()
        if student:
            result = student.to_dict()
            result = ResponseUtil.ok(result, "login success!")
            result["token"] = generate_jwt_token(student, "student").decode("utf-8")
        else:
            result = {"code": -1, "message": "username or password error!"}
    elif _type == "teacher":
        teacher = Teacher.objects.filter(username=username,
                                         password=password).first()
        if teacher:
            result = teacher.to_dict()
            result = ResponseUtil.ok(result, "login success!")
            result["token"] = generate_jwt_token(teacher, "teacher").decode("utf-8")
        else:
            result = ResponseUtil.error("username or password error!")
    else:
        result = ResponseUtil.error("type error!")
    response = JsonResponse(result)
    return response

@csrf_exempt
def get_user_info(request):
    """
    返回用户信息
    """
    _type = request.jwt_payload.get("type")
    username = request.jwt_payload.get("username")
    if _type == "student":
        student = Student.objects.filter(username=username).first()
        result = ResponseUtil.ok(student.to_dict())
    elif _type == "teacher":
        teacher = Teacher.objects.filter(username=username).first()
        result = ResponseUtil.ok(teacher.to_dict())
    else:
        result = ResponseUtil.error("type error")
        request.session.clear()
    return JsonResponse(result)