import datetime as dt
from django.conf import settings
from django.utils import timezone
from django.db import models
from django.shortcuts import render, reverse, redirect, get_object_or_404
from django.urls import reverse, reverse_lazy
from django.views.generic.base import TemplateView
from django.views.generic.detail import DetailView
from django.views.generic.list import ListView
from django.views.generic.dates import YearArchiveView
from django.views.generic.edit import (
    FormView, CreateView, UpdateView, DeleteView, FormMixin
)
from django.contrib import messages
from django.contrib.auth.mixins import (
    LoginRequiredMixin, PermissionRequiredMixin
)
from django.contrib.messages.views import SuccessMessageMixin
from django.contrib.contenttypes.models import ContentType
from django.db.models import (
    Exists, OuterRef, Prefetch, Subquery, Count, Sum, Avg, F, Q, Value
)

from .models import (
    SchoolYear,
    StudentTag,
    Student,
    Subject,
    Tag,
    Component,
    Score,
    SchoolDay,
    AttendanceEntry,
)

from .forms import (
    SchoolYearCreateForm,
    ComponentCreateForm,
    SchoolDayForm,
    AttendanceEntryForm
)


class TodayView(LoginRequiredMixin, TemplateView):
    template_name = 'core/today.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        today = timezone.localtime(timezone.now()).date()
        enddate = today + dt.timedelta(days=7)

        context['birthdays'] = Student.objects.filter(
                dob__month=today.month,
                dob__day__range=[today.day, enddate.day]
            ).order_by('dob')

        context['components'] = Component.objects.filter(
            due_date=today
            ).select_related('subject')

        context['attendance'] = SchoolDay.objects.filter(
            date=today
            ).prefetch_related('attendanceentry_set', 'attendanceentry_set__student')

        context['ungraded_components'] = Component.objects.filter(
            due_date__lte=today,
            finished_grading=False
            ).select_related('subject')

        return context


class SchoolYearListView(LoginRequiredMixin, ListView):
    model = SchoolYear
    paginate_by = 10

    def get_queryset(self):
        queryset = SchoolYear.objects.annotate(
            models.Count('student', distinct=True),
            models.Count('subject', distinct=True)
        ).order_by('-year')
        return queryset


class SchoolYearCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = SchoolYear
    success_message = 'SchoolYear created.'
    form_class = SchoolYearCreateForm
    template_name_suffix = '_create_form'


class SchoolYearDetailView(LoginRequiredMixin, DetailView):
    model = SchoolYear
    slug_url_kwarg = 'year'
    slug_field = 'year'


class SchoolYearUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = SchoolYear
    slug_url_kwarg = 'year'
    slug_field = 'year'
    success_message = 'SchoolYear saved.'
    fields = '__all__'


class StudentListView(LoginRequiredMixin, ListView):
    model = Student
    paginate_by = 50

    def get_queryset(self):
        queryset = Student.objects.filter(
            school_year__year=self.kwargs['year']
        )
        return queryset

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class StudentCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = Student
    success_message = 'Student created.'
    template_name_suffix = '_create_form'
    fields = [
        'student_id',
        'first_name',
        'last_name',
        'address',
        'dob',
    ]

    def form_valid(self, form):
        form.instance.school_year = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return super().form_valid(form)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(SchoolYear, year=self.kwargs['year'])
        return context


class StudentDetailView(LoginRequiredMixin, DetailView):
    model = Student

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)

        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )

        context['score_list'] = Score.objects.select_related(
            'student'
        ).prefetch_related(
            'component'
        ).select_related(
            'component__subject'
        ).filter(
            student=self.object
        ).order_by(
            'component__subject',
            '-component__due_date'
        )

        context['subject_list'] = Subject.objects.filter(
            component__score__student=self.object
        ).annotate(
            grade=Sum(F('component__score__value')),
            grade_total=Sum('component__grade_total')
        )

        context['entry_list'] = AttendanceEntry.objects.select_related(
            'school_day'
        ).filter(
            student=self.object
        ).order_by('status', '-school_day__date').select_related('student')

        return context


class StudentUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = Student
    success_message = 'Student saved.'
    fields = '__all__'


class StudentDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = Student
    success_message = 'Student deleted.'
    success_url = reverse_lazy('student-list')


class StudentTagListView(LoginRequiredMixin, ListView):
    model = StudentTag

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class StudentTagCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = StudentTag
    success_message = 'Tag created.'
    template_name_suffix = '_create_form'
    fields = '__all__'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context

    def get_success_url(self):
        return reverse('core:stag-list', kwargs={
            'year': self.kwargs['year']
        })


class StudentTagDetailView(LoginRequiredMixin, DetailView):
    model = StudentTag
    pk_url_kwarg = 'stag_pk'
    context_object_name = 'tag'

    def get_object(self):
        queryset = StudentTag.objects.filter(
            pk=self.kwargs.get(self.pk_url_kwarg)
        ).prefetch_related(
            Prefetch(
                'student_set',
                queryset=Student.objects.filter(
                    school_year__year=self.kwargs['year']
                )
            )
        )
        obj = queryset.get()
        return obj

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class StudentTagUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = StudentTag
    pk_url_kwarg = 'stag_pk'
    context_object_name = 'tag'
    success_message = 'Tag saved.'
    fields = '__all__'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context

    def get_success_url(self):
        return reverse('core:stag-list', kwargs={
            'year': self.kwargs['year']
        })


class StudentTagDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = StudentTag
    pk_url_kwarg = 'stag_pk'
    context_object_name = 'tag'
    success_message = 'Tag deleted.'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context

    def get_success_url(self):
        return reverse('core:stag-list', kwargs={
            'year': self.kwargs['year']
        })


class SubjectListView(LoginRequiredMixin, ListView):
    model = Subject
    paginate_by = 50

    def get_queryset(self):
        queryset = Subject.objects.filter(
            school_year__year=self.kwargs['year']
        ).annotate(
            models.Count('component')
        ).order_by('name')
        return queryset

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class SubjectCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = Subject
    success_message = 'Subject created.'
    template_name_suffix = '_create_form'
    fields = [
        'name',
        'description'
    ]

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context

    def form_valid(self, form):
        form.instance.school_year = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return super().form_valid(form)


class SubjectDetailView(LoginRequiredMixin, DetailView):
    model = Subject

    def get_object(self):
        queryset = Subject.objects.filter(
            pk=self.kwargs.get(self.pk_url_kwarg)
        ).prefetch_related(
            Prefetch(
                'component_set',
                queryset=Component.objects.prefetch_related(
                    'score_set'
                ).annotate(
                    grade_avg_pre=Avg('score__value')
                )
            )
        )
        obj = queryset.get()
        return obj


class SubjectUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = Subject
    success_message = 'Subject saved.'
    fields = '__all__'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class SubjectDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = Subject
    success_message = 'Subject deleted.'
    success_url = reverse_lazy('subject-list')

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class ComponentListView(LoginRequiredMixin, ListView):
    model = Component


class ComponentCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = Component
    success_message = 'Component created.'
    template_name_suffix = '_create_form'
    form_class = ComponentCreateForm

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        context['subject'] = get_object_or_404(
            Subject, pk=self.kwargs['pk']
        )
        return context

    def form_valid(self, form):
        form.instance.school_year = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        form.instance.subject = get_object_or_404(
            Subject, pk=self.kwargs['pk']
        )
        return super().form_valid(form)


class ComponentDetailView(LoginRequiredMixin, DetailView):
    model = Component
    pk_url_kwarg = 'component_pk'

    def get_object(self):
        queryset = Component.objects.filter(
            pk=self.kwargs.get(self.pk_url_kwarg)
        ).prefetch_related(
            Prefetch(
                'score_set',
                queryset=Score.objects.select_related('student')
            ),
            'tags'
        ).annotate(
            grade_avg_pre=Avg('score__value')
        )
        obj = queryset.get()
        return obj

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        cscores = Score.objects.filter(
            component=self.object,
            student=OuterRef('pk')
        )
        context['scoreless'] = Student.objects.filter(
            school_year__year=self.kwargs['year']
        ).exclude(
            score__in=cscores
        )
        return context


class ComponentUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = Component
    pk_url_kwarg = 'component_pk'
    success_message = 'Component saved.'
    fields = '__all__'

    def get_success_url(self):
        return reverse('core:component-detail', kwargs={
            'year': self.object.subject.school_year.year,
            'pk': self.object.subject.pk,
            'component_pk': self.object.pk
        })


class ComponentDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = Component
    pk_url_kwarg = 'component_pk'
    success_message = 'Component deleted.'
    success_url = reverse_lazy('core:component-list')


class ComponentManagerView(LoginRequiredMixin, UpdateView):
    model = Component
    pk_url_kwarg = 'component_pk'
    template_name_suffix = '_manager'
    fields = ['finished_grading']

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        cscores = Score.objects.filter(
            component=self.object,
            student=OuterRef('pk')
            )
        context['student_list'] = Student.objects.filter(
            school_year__year=self.kwargs['year']
        ).annotate(
            cscore=Subquery(cscores.values('value')),
            cscore_pk=Subquery(cscores.values('pk'))
            )
        return context

    def get_success_url(self):
        return reverse('core:component-detail', kwargs={
            'year': self.object.subject.school_year.year,
            'pk': self.object.subject.pk,
            'component_pk': self.object.pk
        })

    def form_valid(self, form):
        form.save()
        for key, value in self.request.POST.items():
            if 'student' in key and value:
                s_pk = key.split('_')[1]
                obj, created = Score.objects.update_or_create(
                    component=self.object,
                    student=Student.objects.get(pk=s_pk),
                    defaults={'value': value}
                )
        return super().form_valid(form)


class ScoreListView(LoginRequiredMixin, ListView):
    model = Score


class ScoreCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = Score
    success_message = 'Score created.'
    template_name_suffix = '_create_form'
    fields = '__all__'


class ScoreDetailView(LoginRequiredMixin, DetailView):
    model = Score


class ScoreUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = Score
    success_message = 'Score saved.'
    fields = [
        'component',
        'value'
    ]

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class ScoreDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = Score
    success_message = 'Score deleted.'

    def get_success_url(self):
        return reverse('core:schoolyear-detail', kwargs={
            'year': self.kwargs['year']
        })

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class SchoolDayListView(LoginRequiredMixin, ListView):
    model = SchoolDay
    paginate_by = 7

    def get_queryset(self):
        queryset = SchoolDay.objects.filter(
            school_year__year=self.kwargs['year']
        )
        return queryset

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class SchoolDayCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = SchoolDay
    success_message = 'SchoolDay created.'
    template_name_suffix = '_create_form'
    form_class = SchoolDayForm

    def get_initial(self):
        today = timezone.localtime(timezone.now()).date()
        initial = {
            'date': today,
        }
        return initial

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['student_list'] = Student.objects.filter(
            school_year__year=self.kwargs['year']
        )
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context

    def form_valid(self, form):
        form.instance.school_year = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        form.save()
        for key, value in self.request.POST.items():
            if 'student' in key:
                s = key.split('_')[1]
                AttendanceEntry.objects.create(
                    school_day=form.instance,
                    student=Student.objects.get(pk=s),
                    status=value,
                )
        return super().form_valid(form)


class SchoolDayDetailView(LoginRequiredMixin, DetailView):
    model = SchoolDay


class SchoolDayUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = SchoolDay
    success_message = 'SchoolDay saved.'
    form_class = SchoolDayForm

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context

    def form_valid(self, form):
        form.save()
        for key, value in self.request.POST.items():
            if 'student' in key:
                s = key.split('_')[1]
                AttendanceEntry.objects.filter(
                    school_day=self.object,
                    student=Student.objects.get(pk=s)
                ).update(status=value)
        return super().form_valid(form)


class SchoolDayDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = SchoolDay
    success_message = 'SchoolDay deleted.'

    def get_success_url(self):
        return reverse('core:schoolday-list', kwargs={
            'year': self.kwargs['year']
        })

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['school_year'] = get_object_or_404(
            SchoolYear, year=self.kwargs['year']
        )
        return context


class AttendanceEntryListView(LoginRequiredMixin, ListView):
    model = AttendanceEntry


class AttendanceEntryCreateView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = AttendanceEntry
    success_message = 'Entry created.'
    template_name_suffix = '_create_form'
    fields = '__all__'


class AttendanceEntryDetailView(LoginRequiredMixin, DetailView):
    model = AttendanceEntry
    pk_url_kwarg = 'entry_pk'
    context_object_name = 'entry'


class AttendanceEntryUpdateView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = AttendanceEntry
    pk_url_kwarg = 'entry_pk'
    context_object_name = 'entry'
    success_message = 'Entry saved.'
    form_class = AttendanceEntryForm

    def get_success_url(self):
        return reverse('core:schoolday-detail', kwargs={
            'year': self.kwargs['year'],
            'pk': self.kwargs['pk']
        })


class AttendanceEntryDeleteView(LoginRequiredMixin, SuccessMessageMixin, DeleteView):
    model = AttendanceEntry
    pk_url_kwarg = 'entry_pk'
    context_object_name = 'entry'
    success_message = 'Entry deleted.'

    def get_success_url(self):
        return reverse('core:schoolday-detail', kwargs={
            'year': self.kwargs['year'],
            'pk': self.kwargs['pk']
        })