import json

from django.core.paginator import Paginator, PageNotAnInteger, EmptyPage
from django.db.models import F, Subquery, Max
from django.shortcuts import render


from EduSystemServer.utils import *
from course.models import *
from django.views.decorators.csrf import csrf_exempt


def search_course(request):
    """
    通过条件查询课程，并且分页显示
    """
    if not request.method == "GET":
        return JsonResponse(ResponseUtil.error("request method error!"))
    teacher_name = request.GET.get("tName")
    course_name = request.GET.get("cName")
    course_type = request.GET.get("cType")
    current_page = request.GET.get("currentPage")
    filter_course = Course.objects
    if not teacher_name == "" and teacher_name is not None:
        filter_course = Course.objects.filter(tid__name__contains=teacher_name)
    if not course_name == "" and course_name is not None:
        filter_course = Course.objects.filter(name__contains=course_name)
    if not course_type == "" and course_type is not None:
        filter_course = Course.objects.filter(type__contains=course_type)
    filter_course = filter_course.values("name", "tid__name", "type", "credit",
                                         "tid__title", "tid__education", "tid__dept", "cid").all()
    paginator = Paginator(filter_course, 10)
    try:
        courses = paginator.page(current_page).object_list
    except PageNotAnInteger:
        courses = paginator.page(1).object_list
    except EmptyPage:
        courses = paginator.page(paginator.num_pages).object_list
    courses_data = []
    for course in courses:
        courses_data.append(course)
    result = ResponseUtil.ok(courses_data, "success!")
    result["pageTotal"] = paginator.count
    result["pageNum"] = paginator.num_pages
    return JsonResponse(result)


@permission(allowed_roles=["student"])
def get_course_by_student_id(request):
    """
    通过学生ID获取学生的选课
    """
    if not request.method == "GET":
        return JsonResponse(ResponseUtil.error("request method error!"))
    s_username = request.jwt_payload.get("username")
    student = Student.objects.filter(username=s_username).first()
    sc_list = SC.objects.filter(sid=student.sid).values("sid__name", "cid__name", "cid__tid__name", "sid", "cid",
                                                        "cid__credit", "cid__tid__title", "cid__tid__dept", "cid__type").all()
    data = []
    for sc in sc_list:
        data.append(sc)
    result = ResponseUtil.ok(data)
    return JsonResponse(result)


@permission(allowed_roles=["student"])
def delete_select_course(request):
    """
    删除选课
    """
    if not request.method == "GET":
        return JsonResponse(ResponseUtil.error("request method error!"))
    try:
        sid = request.GET.get("sid")
        cid = request.GET.get("cid")
        sc = SC.objects.filter(cid=cid, sid=sid).first()
        sc.delete()
        return JsonResponse(ResponseUtil.ok(None, "退出选课成功！"))
    except Exception as E:
        return JsonResponse(ResponseUtil.error(E))


@csrf_exempt
@permission(allowed_roles=["teacher", "admin"])
def get_student_select_course(request):
    """
    获取所有学生的所有选课
    """
    if not request.method == "POST":
        return JsonResponse(ResponseUtil.error("request method error!"))
    current_page = request.GET.get("currentPage")
    sname = request.POST.get("sname")
    className = request.POST.get("className")
    courseName = request.POST.get("courseName")
    courseType = request.POST.get("courseType")
    sc_list = SC.objects.all().filter(
        sid__name__contains=sname,
        sid__class_name__contains=className,
        cid__name__contains=courseName,
        cid__type__contains=courseType
    ).annotate(
        sname=F("sid__name"),
        className=F("sid__class_name"),
        cname=F("cid__name"), ctype=F("cid__type"),
        endGrade=F("end_grade"),
        middleGrade=F("middle_grade")
    ).values(
        "sname", "className", "cname",
        "ctype", "endGrade", "middleGrade",
        "sid", "cid"
        ).distinct()
    paginator = Paginator(sc_list, 10)
    try:
        sc_list = paginator.page(current_page).object_list
    except PageNotAnInteger:
        sc_list = paginator.page(1)
    except EmptyPage:
        sc_list = paginator.page(paginator.num_pages).object_list
    data = []
    for student in sc_list:
        data.append(student)
    result = ResponseUtil.ok(data, "success!")
    result["pageTotal"] = paginator.count
    result["pageNum"] = paginator.num_pages
    return JsonResponse(result)

@permission(allowed_roles=["teacher", "admin"])
@csrf_exempt
def edit_grade(request):
    """
    成绩录入
    """
    if not request.method == "POST":
        return JsonResponse(ResponseUtil.error("request method error!"))
    try:
        sid = request.POST.get("sid")
        cid = request.POST.get("cid")
        sc = SC.objects.filter(sid=sid, cid=cid).first()
        sc.middle_grade = request.POST.get("middleGrade")
        sc.end_grade = request.POST.get("endGrade")
        sc.save()
        return JsonResponse(ResponseUtil.ok(None, "成绩修改成功！"))
    except Exception as E:
        return JsonResponse(ResponseUtil.error(str(E)))