import datetime

from django.shortcuts import get_object_or_404, render
from django.http import HttpResponseRedirect, JsonResponse, Http404
from django.views import generic
from django.urls import reverse
from django.utils import timezone
from rest_framework import status, viewsets
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.decorators import action
from .serializers import MigrationSerializer, MigrationOverView


from .models import Migration

def checkLimit(limit):
    if limit == "":
        limit = None
    else:
        limit = int(limit)
    return limit

def getAllMigrations(limit):
    return Migration.objects.all()[:limit]

def getFilteredMigrations(limit, **kwargs):
    pass

class MigrationList(APIView):
    '''
    Returns a list of migrations with simpleData
    ''' 
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = getAllMigrations(limit)
        serializer = MigrationOverView(migrations, many=True)
        return Response(serializer.data)

    def post(self, request, format=None):
        serializer = MigrationSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

class MigrationDetails(APIView):
    '''
    Returns full migration details
    '''
    def getObject(self, pk):
        try:
            migration = Migration.objects.get(id=pk)
            return migration
        except Migration.DoesNotExist:
            raise Http404

    def get(self, request, pk, format=None):
        migration = self.getObject(pk)
        serializer = MigrationSerializer(migration)
        return Response(serializer.data)

    def put(self, request, pk, format=None):
        migration = self.getObject(pk)
        serializer = MigrationSerializer(migration, data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

class MigrationsBooked(APIView):
    '''
    Returns list of booked migrations
    '''
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = MigrationOverView(Migration.objects.filter(
            migration_status="Booked",)[:limit], many=True)
        return Response(migrations.data, status=status.HTTP_200_OK)

class MigrationsWaitingTerm(APIView):
    '''
    Returns list of booked migrations
    '''
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = MigrationOverView(Migration.objects.filter(
            migration_status="Waiting Termination",)[:limit], many=True)
        return Response(migrations.data, status=status.HTTP_200_OK)

class MigrationsCompleted(APIView):
    '''
    Returns list of booked migrations
    '''
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = MigrationOverView(Migration.objects.filter(
            migration_status="Completed",)[:limit], many=True)
        return Response(migrations.data, status=status.HTTP_200_OK)

class PendingMigrations(APIView):
    '''
    Returns list of 'pending' migrations (migrations that are booked for today (maybe before timezone.now))
    '''
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = Migration.objects.filter(
            migration_status="Booked", booked_time__lte=timezone.now() + datetime.timedelta(1),
            booked_time__gte=(timezone.now() + datetime.timedelta(-1))
        )[:limit]
        serializer = MigrationOverView(migrations, many=True)
        return Response(serializer.data, status=status.HTTP_200_OK)

class MissedMigrations(APIView):
    '''
    Returns a list of missed migrations
    '''
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = Migration.objects.filter(
        booked_time__lte=timezone.now() + datetime.timedelta(-1),
        migration_status="Booked"
        )[:limit]
        serializer = MigrationOverView(migrations, many=True)
        return Response(serializer.data)

class PendingTerm(APIView):
    '''
    Returns a list of accounts pending termination (might add an arg so we can specify how many days)
    '''
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = Migration.objects.filter(
            migration_status="Waiting Termination", term_date__lte=timezone.now() + datetime.timedelta(1) 
        )[:limit]
        serializer = MigrationOverView(migrations, many=True)
        return Response(serializer.data)

class MigrationListAll(APIView):
    def get(self, request, format=None):
        limit = checkLimit(request.GET.get('limit', ''))
        migrations = getAllMigrations(limit)
        serializer = MigrationSerializer(migrations, many=True)
        return Response(serializer.data)