from physics.decorators import user_is_author_or_physics_checker
from physics.filters import QuestionFilter, UserAnswerFilter
from generic.mixins import SuperuserRequiredMixin
from physics.tables import QuestionTable, UserAnswerTable
from django.shortcuts import render, get_object_or_404, redirect
from django.views.decorators.csrf import csrf_exempt
from django import forms

# from django.contrib.auth.models import User
from django.contrib.auth.decorators import login_required, user_passes_test
from django.contrib.auth.models import User

from django.contrib.auth.mixins import LoginRequiredMixin
from django.views.generic.detail import DetailView

from django.views.generic.edit import CreateView, UpdateView, DeleteView
from django.views.generic import ListView

from django.db.models.functions import Lower

from django.core.cache import cache

from django.urls import reverse_lazy, reverse

from django.http import Http404, JsonResponse

from django.http import HttpResponseRedirect, HttpResponse
from django_filters.views import FilterView
from django_tables2.views import SingleTableMixin
from reversion.views import RevisionMixin

from .models import Question, Category, Exam, CidUserAnswer

from collections import defaultdict
import os
import base64
import mimetypes
import json
import statistics
import plotly.express as px

from generic.views import ExamCloneMixin, ExamViews, GenericViewBase

from rest_framework import viewsets, permissions
from rest_framework.pagination import PageNumberPagination

from django.core.exceptions import PermissionDenied

from .forms import CidUserAnswerForm, ExamForm
from .decorators import user_is_author_or_physics_checker, user_is_exam_author_or_physics_checker

class AuthorOrCheckerRequiredMixin(object):
    def get_object(self, *args, **kwargs):
        obj = super().get_object(*args, **kwargs)
        if self.request.user.groups.filter(name="physics_checker").exists():
            return obj
        if self.request.user not in obj.author.all():
            raise PermissionDenied()  # or Http404
        return obj

def question_list(request):
    questions = Question.objects.all()
    return render(request, "physics/question_list.html", {"questions": questions})


@login_required
@user_is_author_or_physics_checker
def question_detail(request, pk):
    question = get_object_or_404(Question, pk=pk)
    return render(request, "physics/question_detail.html", {"question": question})


def active_exams(request):
    exams = Exam.objects.all()
    print(exams)

    active_exams = []

    for exam in exams:
        if exam.active:
            active_exams.append(exam)
    return render(request, "physics/available_exam_list.html", {"exams": active_exams})


@login_required
def exam_scores_cid(request, pk):
    exam = get_object_or_404(Exam, pk=pk)

    questions = exam.exam_questions.all()

    cids = (
        CidUserAnswer.objects.filter(question__in=questions)
        .order_by("cid")
        .values_list("cid", flat=True)
        .distinct()
    )

    user_answers_and_marks = defaultdict(list)
    user_answers_marks = defaultdict(list)
    user_answers = defaultdict(list)
    user_names = {}

    by_question = defaultdict(list)
    unmarked = set()

    # Loop through all candidates
    for cid in cids:
        # Convoluted (probably...)
        user_names[cid] = cid
        for q in questions:
            # Get user answer
            s = q.cid_user_answers.filter(cid=cid).first()
            if not s:
                # skip if no answer
                user_answers_marks[cid].append(0)
                user_answers[cid].append("")
                by_question[q].append(("", 0))
                continue

            ans = s.get_answers()
            answer_scores = s.get_answer_scores()

            user_answers[cid].append(ans)
            user_answers_marks[cid].append(answer_scores)
            user_answers_and_marks[cid].append((ans, answer_scores))

            zipped_ans_scores = zip(ans, answer_scores)

            by_question[q].append(zipped_ans_scores)

    user_scores = {}
    for user in user_answers_marks:
        user_scores[user] = sum([sum(i) for i in user_answers_marks[user]])

    user_scores_list = list(user_scores.values())

    if len(user_scores_list) < 1:
        mean = 0
        median = 0
        mode = 0
        fig_html = ""
    else:
        mean = statistics.mean(user_scores_list)
        median = statistics.median(user_scores_list)
        try:
            mode = statistics.mode(user_scores_list)
        except statistics.StatisticsError:
            mode = "No unique mode"

        df = user_scores_list
        fig = px.histogram(
            df,
            x=0,
            title="{}: distribution of scores".format(exam),
            labels={"0": "Score"},
            height=400,
            width=600,
        )
        fig_html = fig.to_html()

    max_score = len(questions)

    return render(
        request,
        "physics/exam_scores.html",
        {
            "cids": cids,
            "exam": exam,
            "unmarked": unmarked,
            "questions": questions,
            "by_question": by_question,
            "user_answers": dict(user_answers),
            "user_answers_marks": dict(user_answers_marks),
            "user_scores": user_scores,
            "user_scores_list": user_scores_list,
            "user_names": user_names,
            "user_answers_and_marks": user_answers_and_marks,
            "max_score": max_score,
            "mean": mean,
            "median": median,
            "mode": mode,
            "plot": fig_html,
        },
    )


def exam_scores_cid_user(request, pk, sk):
    exam = get_object_or_404(Exam, pk=pk)

    # TODO:Need some kind of test for cid
    cid = sk

    questions = exam.exam_questions.all()

    answers_and_marks = []
    answers_marks = []
    answers = []


    view_all_results = False
    if request.user.groups.filter(name="view_all_results").exists():
        view_all_results = True

    for q in questions:
        # Get user answer
        user_answer = q.cid_user_answers.filter(cid=cid).first()

        ans = user_answer.get_answers()

        answer_scores = user_answer.get_answer_scores()

        correct_answers = q.get_answers()

        if not exam.publish_results and not view_all_results:
            correct_answers = ("*****", "*****", "*****", "*****", "*****")
            answer_scores = (0, 0, 0, 0, 0)
        answers.append(ans)
        answers_marks.append(answer_scores)

        merged_ans = zip(q.get_questions(), ans, answer_scores, correct_answers)
        answers_and_marks.append((q, merged_ans))

    total_score = sum(sum(i) for i in answers_marks)

    max_score = len(questions) * 5

    return render(
        request,
        "physics/exam_scores_user.html",
        {
            "exam": exam,
            "cid": cid,
            "questions": questions,
            "answers": answers,
            "answers_marks": answers_marks,
            "total_score": total_score,
            "max_score": max_score,
            "answers_and_marks": answers_and_marks,
        },
    )


def exam_take_old(request, pk):

    exam = get_object_or_404(Exam, pk=pk)

    if not exam.active:
        raise Http404("Exam not found")

    questions = exam.exam_questions.all()

    return render(
        request,
        "physics/exam_take_old.html",
        {
            "exam": exam,
            "questions": questions,
        },
    )

def exam_start(request, pk):
    exam = get_object_or_404(Exam, pk=pk)

    if not exam.active:
        raise Http404("Exam not found")

    return render(
        request,
        "physics/exam_start.html",
        {
            "exam": exam,
        },
    )

def exam_finish(request, pk, cid):
    exam = get_object_or_404(Exam, pk=pk)

    questions = exam.exam_questions.all()

    answers = CidUserAnswer.objects.filter(
        cid=cid, exam=exam)

    answer_question_map = {}
    for ans in answers:
        answer_question_map[ans.question] = ans

    question_answer_tuples = []
    answer_count = 0
    for q in questions:
        if q in answer_question_map and answer_question_map[q].answer:
            question_answer_tuples.append((q, answer_question_map[q]))
            answer_count += 1
        else:
            question_answer_tuples.append((q, None))

    if not exam.active:
        raise Http404("Exam not found")

    return render(
        request,
        "physics/exam_finish.html",
        {
            "exam": exam,
            "cid": cid,
            "question_answer_tuples": question_answer_tuples,
            "answer_count": answer_count,
            "exam_length": len(questions),
        },
    )

def exam_take(request, pk, sk, cid):

    exam = get_object_or_404(Exam, pk=pk)

    if not exam.active:
        raise Http404("Exam not found")

    question = exam.exam_questions.all()[sk]

    exam_length = len(exam.exam_questions.all())

    pos = exam.get_question_index(question)

    answer = question.cid_user_answers.filter(
        cid=cid, exam=exam).first()

    if request.method == "POST":
        if answer:
            form = CidUserAnswerForm(request.POST, instance=answer)
        else:
            form = CidUserAnswerForm(request.POST)
        if form.is_valid():
            answer = form.save(commit=False)
            answer.cid = cid
            answer.question = question
            answer.exam = exam
            # answer.published_date = timezone.now()
            answer.save()
        if "next" in request.POST:
            return redirect("sbas:exam_take", pk=pk, sk=pos + 1, cid=cid)
        elif "previous" in request.POST:
            return redirect("sbas:exam_take", pk=pk, sk=pos - 1, cid=cid)
        elif "finish" in request.POST:
            return redirect("sbas:exam_finish", pk=pk, cid=cid)
        elif "goto" in request.POST:
            return redirect("sbas:exam_take", pk=pk, sk=int(request.POST.get("goto")), cid=cid)
    else:
        form = CidUserAnswerForm(instance=answer)

    previous = -1
    if sk > 0:
        previous = sk - 1
    next = sk + 1
    if sk == exam_length - 1:
        next = False

    saved_answer = False
    if answer is not None:
        saved_answer = [answer.a, answer.b, answer.c, answer.d, answer.e]


    return render(
        request,
        "physics/exam_take.html",
        {
            "form": form,
            "cid": cid,
            "exam": exam,
            "question": question,
            "next": next,
            "previous": previous,
            "exam_length": exam_length,
            "pos": pos,
            "saved_answer": saved_answer,
        },
    )

def loadJsonAnswer(answer):
    # As access is not restricted make sure the data appears valid
    if (not isinstance(answer["cid"], int)) or (not isinstance(answer["eid"], int)):
        return False, JsonResponse({"success": False, "error": "invalid"})

    # The model should catch invalid data but this should be less intensive
    max_int = 2147483647
    if answer["cid"] > max_int or answer["eid"] > max_int:
        return False, JsonResponse({"success": False, "error": "invalid candidate id"})

    exam = get_object_or_404(Exam, pk=answer["eid"])

    #if not exam.active:
    #    return False, JsonResponse(
    #        {"success": False, "error": "No active exam: {}".format(answer["eid"])}
    #    )

    questions = defaultdict(dict)

    for q, n, a in answer["ans"]:
        questions[q][n] = a
        pass

    for qid in questions:
        exiting_answers = CidUserAnswer.objects.filter(
            question__id=qid, exam__id=answer["eid"], cid=answer["cid"]
        )

        a = questions[qid]["a"]
        b = questions[qid]["b"]
        c = questions[qid]["c"]
        d = questions[qid]["d"]
        e = questions[qid]["e"]

        if not exiting_answers:
            ans = CidUserAnswer(a=a, b=b, c=c, d=d, e=e, cid=answer["cid"])
            ans.question_id = qid
            ans.exam_id = answer["eid"]

            ans.full_clean()

            ans.save()
        else:
            # Update an existing answer
            # should never be more than one (famous last words)
            ans = exiting_answers[0]
            ans.a = a
            ans.b = b
            ans.c = c
            ans.d = d
            ans.e = e
            ans.full_clean()
            ans.save()

    return True, None

PhysicsExamViews = ExamViews(Exam, Question, "physics", "physics", loadJsonAnswer)

GenericViews = GenericViewBase("physics", Question, CidUserAnswer, Exam)

class ExamCreate(RevisionMixin, LoginRequiredMixin, CreateView):
    model = Exam
    form_class = ExamForm

    def form_valid(self, form):
        self.object = form.save(commit=False)
        self.object.save()

        form.instance.author.add(self.request.user.id)
        return super().form_valid(form)

class ExamClone(AuthorOrCheckerRequiredMixin, ExamCloneMixin, ExamCreate):
    """Clone exam view"""

class QuestionView(LoginRequiredMixin, SingleTableMixin, FilterView, AuthorOrCheckerRequiredMixin):
    model = Question
    table_class = QuestionTable
    template_name = "physics/question_view.html"

    filterset_class = QuestionFilter

class UserAnswerView(AuthorOrCheckerRequiredMixin, LoginRequiredMixin, DetailView):
    model = CidUserAnswer


class UserAnswerTableView(AuthorOrCheckerRequiredMixin, LoginRequiredMixin, SingleTableMixin, FilterView):
    model = CidUserAnswer
    table_class = UserAnswerTable
    template_name = "physics/user_answer_question_view.html"

    filterset_class = UserAnswerFilter


class UserAnswerDelete(SuperuserRequiredMixin, DeleteView):
    model = CidUserAnswer
    template_name = "user_answer_delete.html"
    success_url = reverse_lazy("physics:user_answer_table_view")