from datetime import timedelta
from django.contrib.auth import update_session_auth_hash
from django.contrib.auth.decorators import login_required
from django.contrib.auth.forms import PasswordChangeForm
from django.contrib.auth.views import PasswordChangeView
from django.shortcuts import get_object_or_404, redirect, render
from django.urls import reverse_lazy
from web.models import Event, Availability


@login_required()
def index(request):
    parsed_events = []

    for active_event in Event.objects.filter(active=True).order_by('start_date'):
        data = {
            'id': active_event.id,
            'name': active_event.name,
            'start_date': active_event.start_date,
            'end_date': active_event.end_date,
            'responses': ', '.join([x.user.username for x in active_event.availability_set.all()])
        }

        parsed_events.append(data)

    context = {
        'events': parsed_events
    }

    return render(request, "index.html", context)


def change_password(request):
    if request.method == 'POST':
        form = PasswordChangeForm(request.user, request.POST)
        if form.is_valid():
            user = form.save()
            update_session_auth_hash(request, user)
            return redirect('password_change_done')
    else:
        form = PasswordChangeForm(request.user)
    return render(request, 'change-password/change_password.html', {'form': form})

def password_change_done(request):
    return render(request, 'change-password/password_change_done.html')


@login_required()
def event(request, event_id):

    event = get_object_or_404(Event, pk=event_id)

    if request.method == 'POST':
        handle_availability_update(event, request)
        return redirect('event', event_id=event_id)

    elif request.method == 'GET':
        day_count = (event.end_date - event.start_date).days + 1
        morning = {}
        noon = {}
        night = {}
        all_availabilities = {}
        requesting_user_submitted = False

        context = {
            'event': event,
            'morning': morning,
            'noon': noon,
            'night': night,
            'user_availability': None,
            'active_dates': None,
            'user_responses': 0,
            'best_days': {},
            'no_overlap_message': ''
        }

        user_availability = Availability.objects.filter(event_id=event)
        if user_availability:
            for user_avail in user_availability:
                context['user_responses'] += 1

                for time in user_avail.time_table.get('active', []):
                    if time not in all_availabilities:
                        all_availabilities[time] = []

                    all_availabilities[time].append(user_avail.user.username)

                if request.user == user_avail.user:
                    requesting_user_submitted = True
                    context['active_dates'] = user_avail.time_table['active']

        context['all_availabilities'] = all_availabilities

        for i in range(day_count):
            date = event.start_date + timedelta(days=i)

            human_readable_date = date.strftime('%m/%d/%Y %A')
            for idx, time_period_array in enumerate([morning, noon, night]):
                date_id = date.strftime(f'%m/%d/%Y %A-{idx}')
                users = ', '.join(all_availabilities.get(date_id, []))

                if not requesting_user_submitted:
                    users = ''

                time_period_array[human_readable_date] = (date_id, users)

        if all_availabilities:
            most_avail = None
            for day in sorted(all_availabilities, key=lambda k: len(all_availabilities[k]), reverse=True):
                if not most_avail:
                    most_avail = len(all_availabilities[day])

                if len(all_availabilities[day]) >= most_avail - 1 and len(all_availabilities[day]) != 1:

                    day_arr = day.split('-')
                    if day_arr[-1] == '0':
                        hday = day_arr[0] + ' Morning'

                    if day_arr[-1] == '1':
                        hday = day_arr[0] + ' Noon'

                    if day_arr[-1] == '2':
                        hday = day_arr[0] + ' Night'

                    context['best_days'][hday] = ', '.join(all_availabilities[day])

        if not requesting_user_submitted:
            all_availabilities = {}

        if context['best_days'] == {}:
            context['no_overlap_message'] = 'There are currently no overlapping times or dates!'

    return render(request, "event.html", context)

def handle_availability_update(event, request):
    availability_data = {
        'active': []
    }

    for date, value in request.POST.items():
        if date != 'csrfmiddlewaretoken':
            availability_data['active'].append(date)

    user_availability = Availability.objects.filter(event_id=event).filter(user=request.user)
    if not user_availability:
        a = Availability(
            event_id=event,
            user=request.user,
            time_table=availability_data
        )
        a.save()
    else:
        avail = user_availability[0]
        avail.time_table = availability_data
        avail.save()