from dateutil.relativedelta import relativedelta

from courses.api import CourseProgressApi, CourseParamsApi
from progress.models import ProgressLesson

from django.utils import timezone
import os
import csv

from lms import celery_app
from django.conf import settings
from django.core.mail import EmailMessage


def add_next_lesson(progress):
    lesson_list = CourseProgressApi.get_next(
        progress.course_token,
        [i.lesson_token for i in progress.progresslesson_set.all()]
    )

    pl = None

    for lesson, is_hw in lesson_list:
        if is_hw:
            pl, _c = ProgressLesson.objects.get_or_create(
                progress=progress,
                lesson_token=lesson,
                checker=progress.teacher,
            )
        else:
            pl, _c = ProgressLesson.objects.get_or_create(
                progress=progress,
                lesson_token=lesson,
                checker=progress.user,
            )

    return pl


@celery_app.task
def statistic_teachers():
    file_dir = "%s/analytics/teachers/" % (settings.MEDIA_ROOT,)
    os.makedirs(os.path.dirname(file_dir), exist_ok=True)
    # TODO Почему-то при выставлении расширения всё ломается
    path = '%s%s' % (file_dir, timezone.now().strftime('%Y-%m-%d__%H-%M'))

    progresses = ProgressLesson.objects.filter(status='wait')

    with open(path, 'w') as csv_file:
        csv_writer = csv.writer(csv_file)
        csv_writer.writerow(
            ['Курс', 'Препод', 'Ранее', '6 Дней', '5 Дней', "4 Дня", "3 Дня", "2 Дня", "Вчера", "Сегодня"])
        for i in progresses.values('progress__teacher__email', 'progress__course_token').distinct():
            row = []
            course_token = i['progress__course_token']
            teacher_email = i['progress__teacher__email']
            progresses_sub = progresses.filter(progress__course_token=course_token, progress__teacher__email=teacher_email)

            row.append(CourseParamsApi(course_token).get_slug_and_title()['title'])
            row.append(teacher_email)
            row.append(progresses_sub.filter(last_update__lt=(timezone.now() - relativedelta(days=7))).count())
            for j in range(7):
                from_d = timezone.now() - relativedelta(days=(7 - j))
                to_d = timezone.now() - relativedelta(days=(6 - j))
                row.append(progresses_sub.filter(last_update__gte=from_d, last_update__lt=to_d).count())

            csv_writer.writerow(row)

    message = EmailMessage(
        'Выгрузка по преподам.',
        'Файл приложен',
        'robo@skillbox.ru',
        [settings.SUPPORT_EMAIL,],
        ['andrey.korolev@skillbox.ru',],
        reply_to=['andrey.korolev@skillbox.ru'],
    )
    message.attach_file(path)
    message.send()