from django.shortcuts import render, reverse
from django.db.models import Avg, Count, Min, Sum
from django.db.models.functions import Round
from django.urls import reverse_lazy
from django.views.generic.base import TemplateView
from django.views.generic.edit import FormView, CreateView, UpdateView, DeleteView
from django.views.generic.detail import DetailView
from django.views.generic.list import ListView
from django.contrib.auth.decorators import login_required
from django.contrib.auth.mixins import LoginRequiredMixin, PermissionRequiredMixin
from django.utils import timezone
from django.contrib import messages
from django.contrib.auth.models import User
from accounts.models import Instructor, Student
from .models import Code, Period
from .forms import AttendanceUpdateForm, PeriodForm

# EXAMPLE PERMISSION MIXIN
# class MyView(PermissionRequiredMixin, View):
#     permission_required = 'polls.add_choice'
#     # Or multiple of permissions:
#     permission_required = ('polls.view_choice', 'polls.change_choice')

# OVERVIEW
class AttendanceOverview(LoginRequiredMixin, TemplateView):
    template_name = 'attendance/attendance_overview.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['user'] = User.objects.get(pk=self.request.user.id)
        if hasattr(self.request.user, 'instructor'):
            context['student_list'] = Student.objects.filter(
                department=self.request.user.instructor.department
            ).annotate(total_hours=Sum('period__duration'))
            context['period_list'] = Period.objects.order_by('-clocked_in')
        elif hasattr(self.request.user, 'student'):
            student = self.request.user.student
            # sum all duration fields for student
            periods_duration_sum = Period.objects.filter(
                student = student
                ).filter(
                    clocked_in__year=timezone.now().year
                ).filter(
                    clocked_in__month=timezone.now().month
                ).aggregate(total_duration=Sum('duration'))

            hours = 0
            # Convert to hours floating point
            if periods_duration_sum['total_duration'] != None:
                hours = round((periods_duration_sum['total_duration'].total_seconds() / 3600), 2)

            context['period_list'] = Period.objects.filter(
                student=student
                ).filter(
                    clocked_in__year=timezone.now().year
                ).filter(
                    clocked_in__month=timezone.now().month
                ).order_by('-clocked_in')
            context['period_total'] = hours
            if student.current_period_id != None:
                context['current_period'] = Period.objects.get(pk=student.current_period_id)
        return context

class AttendanceUpdateView(LoginRequiredMixin, FormView):
    template_name = 'attendance/attendance_form.html'
    form_class = AttendanceUpdateForm

    def form_valid(self, form):
        # update checked in
        student_number = form.cleaned_data['qr_string'].split(':')[0]
        station_number = form.cleaned_data['qr_string'].split(':')[1]
        student = Student.objects.get(student_number=student_number)
        if student.is_clocked_in:
            student.is_clocked_in=False
            period = student.period_set.get(pk=student.current_period_id)
            period.clocked_out=timezone.now()
            student.save()
            period.save()
            messages.add_message(self.request, messages.INFO, f'{student.user.first_name} {student.user.last_name} clocked out.')
        else:
            c_p = student.period_set.create(student=student, clocked_in=timezone.now(), station_number=station_number)
            student.current_period_id = c_p.id
            student.is_clocked_in=True
            student.save()
            messages.add_message(self.request, messages.INFO, f'{student.user.first_name} {student.user.last_name} clocked in.')
        return super().form_valid(form)

    def get_success_url(self):
        return reverse('attendance-update')




# PERIODS
class PeriodCreateView(LoginRequiredMixin, CreateView):
    model = Period
    form_class = PeriodForm
    template_name = 'attendance/period_form.html'

class PeriodDetailView(LoginRequiredMixin, DetailView):
    model = Period
    template_name = 'attendance/period_detail.html'

class PeriodUpdateView(LoginRequiredMixin, UpdateView):
    model = Period
    form_class = PeriodForm
    template_name = 'attendance/period_form.html'

    # When editing a period, check if it matches the current period of the student and clock them out
    def form_valid(self, form):
        student = form.instance.student
        if form.instance.id == student.current_period_id:
            student.is_clocked_in = False
            student.save()
        return super().form_valid(form)

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

class PeriodDeleteView(LoginRequiredMixin, DeleteView):
    model = Period
    success_url = '/attendance'



# CODES
class CodeCreateView(LoginRequiredMixin, CreateView):
    model = Code
    fields = ['station_number']
    template_name = 'attendance/code_form.html'

    def form_valid(self, form):
        form.instance.student = self.request.user.student
        return super().form_valid(form)

class CodeDetailView(LoginRequiredMixin, DetailView):
    model = Code
    template_name = 'attendance/code_detail.html'

class CodeUpdateView(LoginRequiredMixin, UpdateView):
    model = Code
    fields = ['station_number']
    template_name = 'attendance/code_update_form.html'

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