import logging

from django.contrib.auth.decorators import login_required
from django.db.models import Count, Case, When, Min
from django.db.models import Q
from django.http import JsonResponse

from web.models import StudySubject, Visit, Appointment
from web.models.constants import SUBJECT_TYPE_CHOICES
from web.views import e500_error
from web.views.notifications import get_subjects_with_no_visit, get_subjects_with_reminder, get_today_midnight_date
from web.views.subject import SUBJECT_LIST_GENERIC, SUBJECT_LIST_NO_VISIT, SUBJECT_LIST_REQUIRE_CONTACT

logger = logging.getLogger(__name__)


@login_required
def cities(request):
    result_subjects = StudySubject.objects.filter(city__isnull=False).values_list('city').distinct()
    return JsonResponse({
        "cities": [x[0] for x in result_subjects]
    })


@login_required
def referrals(request):
    result_subjects = StudySubject.objects.filter(referral__isnull=False).values_list('referral').distinct()
    return JsonResponse({
        "referrals": [x[0] for x in result_subjects]
    })


@login_required
def get_subjects(request, type):
    if type == SUBJECT_LIST_GENERIC:
        return StudySubject.objects.all()
    elif type == SUBJECT_LIST_NO_VISIT:
        return get_subjects_with_no_visit(request.user)
    elif type == SUBJECT_LIST_REQUIRE_CONTACT:
        return get_subjects_with_reminder(request.user)
    else:
        raise TypeError("Unknown query type: " + type)


def order_by_visit(subjects_to_be_ordered, order_direction, visit_number):
    return subjects_to_be_ordered.annotate(
        sort_visit_date=Min(Case(When(visit__visit_number=visit_number, then='visit__datetime_begin')))).order_by(
        order_direction + 'sort_visit_date')


def get_subjects_order(subjects_to_be_ordered, order_column, order_direction):
    result = subjects_to_be_ordered
    if order_direction == "asc":
        order_direction = ""
    else:
        order_direction = "-"
    if order_column == "first_name":
        result = subjects_to_be_ordered.order_by(order_direction + 'first_name')
    elif order_column == "last_name":
        result = subjects_to_be_ordered.order_by(order_direction + 'last_name')
    elif order_column == "nd_number":
        result = subjects_to_be_ordered.order_by(order_direction + 'nd_number')
    elif order_column == "screening_number":
        result = subjects_to_be_ordered.order_by(order_direction + 'screening_number')
    elif order_column == "default_location":
        result = subjects_to_be_ordered.order_by(order_direction + 'default_location')
    elif order_column == "dead":
        result = subjects_to_be_ordered.order_by(order_direction + 'subject__dead')
    elif order_column == "resigned":
        result = subjects_to_be_ordered.order_by(order_direction + 'resigned')
    elif order_column == "information_sent":
        result = subjects_to_be_ordered.order_by(order_direction + 'information_sent')
    elif order_column == "postponed":
        result = subjects_to_be_ordered.order_by(order_direction + 'postponed')
    elif order_column == "type":
        result = subjects_to_be_ordered.order_by(order_direction + 'type')
    elif order_column == "id":
        result = subjects_to_be_ordered.order_by(order_direction + 'id')
    elif order_column == "date_born":
        result = subjects_to_be_ordered.order_by(order_direction + 'date_born')
    elif order_column == "visit_1":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 1)
    elif order_column == "visit_2":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 2)
    elif order_column == "visit_3":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 3)
    elif order_column == "visit_4":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 4)
    elif order_column == "visit_5":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 5)
    elif order_column == "visit_6":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 6)
    elif order_column == "visit_7":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 7)
    elif order_column == "visit_8":
        result = order_by_visit(subjects_to_be_ordered, order_direction, 8)
    else:
        logger.warn("Unknown sort column: " + order_column)
    return result


def filter_by_visit(result, visit_number, visit_type):
    # we need to give custom names for filtering params that contain visit_number in it
    # because we might want to filter by few visits  and they shouldn't collide
    datetime_begin_filter = 'visit_' + str(visit_number) + '_datetime_begin'
    datetime_end_filter = 'visit_' + str(visit_number) + '_datetime_end'
    is_finished_filter = 'visit_' + str(visit_number) + '_is_finished'
    finished_appointments_filter = 'visit_' + str(visit_number) + '_finished_appointments'
    scheduled_appointments_filter = 'visit_' + str(visit_number) + '_scheduled_appointments'

    # this is hack... instead of providing True/False value this field contain 1/0 value, the problem is that we need
    # to provide aggregate function for the interacting parameter
    # If we try to assign it with pure Case(When...) (without Count/Min/Max/Avg) we obtain duplicates
    # of the results which are later on messing up with the subject list
    result = result.annotate(**{
        is_finished_filter: Count(Case(When(Q(visit__is_finished=True) & Q(visit__visit_number=visit_number), then=1)))
    })

    # number of finished appointments
    result = result.annotate(**{finished_appointments_filter: Count(Case(When(
        Q(visit__appointment__status=Appointment.APPOINTMENT_STATUS_FINISHED) & Q(visit__visit_number=visit_number),
        then=1)))})
    # number of scheduled appointments
    result = result.annotate(**{scheduled_appointments_filter: Count(Case(When(
        Q(visit__appointment__status=Appointment.APPOINTMENT_STATUS_SCHEDULED) & Q(visit__visit_number=visit_number),
        then=1)))})

    # when visit starts
    result = result.annotate(
        **{datetime_begin_filter: Min(Case(When(visit__visit_number=visit_number, then='visit__datetime_begin')))})
    # when visit finish
    result = result.annotate(
        **{datetime_end_filter: Min(Case(When(visit__visit_number=visit_number, then='visit__datetime_end')))})

    if visit_type == "DONE":
        result = result.filter(**{datetime_begin_filter + "__lt": get_today_midnight_date()}). \
            filter(**{is_finished_filter + "__gt": 0}). \
            filter(**{finished_appointments_filter + "__gt": 0})
    elif visit_type == "MISSED":
        result = result.filter(**{datetime_begin_filter + "__lt": get_today_midnight_date()}). \
            filter(**{is_finished_filter + "__gt": 0}). \
            filter(**{finished_appointments_filter: 0})
    elif visit_type == "EXCEED":
        result = result.filter(**{datetime_begin_filter + "__lt": get_today_midnight_date()}). \
            filter(**{is_finished_filter: 0}). \
            filter(**{datetime_end_filter + "__lt": get_today_midnight_date()})
    elif visit_type == "IN_PROGRESS":
        result = result.filter(**{datetime_begin_filter + "__lt": get_today_midnight_date()}). \
            filter(**{is_finished_filter: 0}). \
            filter(**{datetime_end_filter + "__gt": get_today_midnight_date()}). \
            filter(**{scheduled_appointments_filter + "__gt": 0})
    elif visit_type == "SHOULD_BE_IN_PROGRESS":
        result = result.filter(**{datetime_begin_filter + "__lt": get_today_midnight_date()}). \
            filter(**{is_finished_filter: 0}). \
            filter(**{datetime_end_filter + "__gt": get_today_midnight_date()}). \
            filter(**{scheduled_appointments_filter: 0})
    elif visit_type == "UPCOMING":
        result = result.filter(**{datetime_begin_filter + "__gt": get_today_midnight_date()})

    return result


def get_subjects_filtered(subjects_to_be_filtered, filters):
    result = subjects_to_be_filtered
    for row in filters:
        column = row[0]
        value = row[1]
        if column == "first_name":
            result = result.filter(first_name__icontains=value)
        elif column == "last_name":
            result = result.filter(last_name__icontains=value)
        elif column == "nd_number":
            result = result.filter(nd_number__icontains=value)
        elif column == "screening_number":
            result = result.filter(screening_number__icontains=value)
        elif column == "dead":
            result = result.filter(subject__dead=(value == "true"))
        elif column == "resigned":
            result = result.filter(resigned=(value == "true"))
        elif column == "postponed":
            result = result.filter(postponed=(value == "true"))
        elif column == "information_sent":
            result = result.filter(information_sent=(value == "true"))
        elif column == "default_location":
            result = result.filter(default_location=value)
        elif column == "type":
            result = result.filter(type=value)
        elif column == "visit_1":
            result = filter_by_visit(result, 1, value)
        elif column == "visit_2":
            result = filter_by_visit(result, 2, value)
        elif column == "visit_3":
            result = filter_by_visit(result, 3, value)
        elif column == "visit_4":
            result = filter_by_visit(result, 4, value)
        elif column == "visit_5":
            result = filter_by_visit(result, 5, value)
        elif column == "visit_6":
            result = filter_by_visit(result, 6, value)
        elif column == "visit_7":
            result = filter_by_visit(result, 7, value)
        elif column == "visit_8":
            result = filter_by_visit(result, 8, value)
        elif column == "":
            pass
        else:
            message = "UNKNOWN filter: "
            if column is None:
                message += "[None]"
            else:
                message += str(column)
            logger.warn(message)

    return result


@login_required
def subjects(request, type):
    try:
        # id of the query from dataTable: https://datatables.net/manual/server-side
        draw = int(request.GET.get("draw", "-1"))

        start = int(request.GET.get("start", "0"))
        length = int(request.GET.get("length", "10"))
        order = int(request.GET.get("order[0][column]", "0"))
        order_dir = request.GET.get("order[0][dir]", "asc")
        order_column = request.GET.get("columns[" + str(order) + "][data]", "last_name")

        filters = []
        column_id = 0
        while request.GET.get("columns[" + str(column_id) + "][search][value]", "unknown") != "unknown":
            val = request.GET.get("columns[" + str(column_id) + "][search][value]", "unknown")
            if val != "":
                filters.append([request.GET.get("columns[" + str(column_id) + "][data]"), val])
            column_id += 1

        all_subjects = get_subjects(request, type)

        count = all_subjects.count()

        ordered_subjects = get_subjects_order(all_subjects, order_column, order_dir)
        filtered_subjects = get_subjects_filtered(ordered_subjects, filters)
        sliced_subjects = filtered_subjects[start:(start + length)]

        result_subjects = sliced_subjects

        count_filtered = filtered_subjects.count()

        data = []
        for subject in result_subjects:
            data.append(serialize_subject(subject))

        return JsonResponse({
            "draw": draw,
            "recordsTotal": count,
            "recordsFiltered": count_filtered,
            "data": data,
        })
    except Exception as e:
        logger.error(e, exc_info=True)
        return e500_error(request)


@login_required
def types(request):
    data = [{"id": subject_type_id, "name": subject_type_name} for subject_type_id, subject_type_name in
            SUBJECT_TYPE_CHOICES.items()]
    return JsonResponse({
        "types": data
    })


def get_yes_no(val):
    if val:
        return "YES"
    else:
        return "NO"


def serialize_subject_visit(visit):
    status = "---"
    appointments = visit.appointment_set.filter()
    pass


def serialize_subject(subject):
    location = ""
    if subject.default_location is not None:
        location = subject.default_location.name
    visits = Visit.objects.filter(subject=subject).order_by('visit_number')
    serialized_visits = []
    for visit in visits:
        if visit.datetime_begin < get_today_midnight_date():
            if visit.is_finished:
                finished_appointments_count = visit.appointment_set.filter(
                    status=Appointment.APPOINTMENT_STATUS_FINISHED).count()
                if finished_appointments_count > 0:
                    status = "DONE"
                else:
                    status = "MISSED"
            elif visit.datetime_end < get_today_midnight_date():
                status = "EXCEEDED"
            else:
                scheduled_appointments_count = visit.appointment_set.filter(
                    status=Appointment.APPOINTMENT_STATUS_SCHEDULED).count()
                if scheduled_appointments_count > 0:
                    status = "IN_PROGRESS"
                else:
                    status = "SHOULD_BE_IN_PROGRESS"
        else:
            status = "UPCOMING"
        serialized_visits.append({
            "status": status,
            "datetime_start": visit.datetime_begin.strftime('%Y-%m-%d'),
            "datetime_end": visit.datetime_end.strftime('%Y-%m-%d'),
        })

    result = {
        "first_name": subject.first_name,
        "last_name": subject.last_name,
        "date_born": subject.date_born,
        "nd_number": subject.nd_number,
        "screening_number": subject.screening_number,
        "default_location": location,
        "dead": get_yes_no(subject.subject.dead),
        "resigned": get_yes_no(subject.resigned),
        "postponed": get_yes_no(subject.postponed),
        "information_sent": get_yes_no(subject.information_sent),
        "type": subject.get_type_display(),
        "id": subject.id,
        "visits": serialized_visits,
    }
    return result