from __future__ import absolute_import, unicode_literals
from celery import task, shared_task
from celery.utils.log import get_task_logger

import os
import sys
import datetime
import fileinput
import smtplib
from pathlib import Path

from email.feedparser import FeedParser
from email.message import EmailMessage
from email.header import decode_header, make_header

import django
from django.conf import settings
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'procat2.settings')
django.setup()

from .utils import clean_path, ensure_dir, set_file_perms, WORKDIR
from .email import reply, reply_missing, reply_no_matches, send_error_email
from .matching import find_marked_products
from .spreadsheet import write_spreadsheet
from procat2.settings import TREE_NAME

logger = get_task_logger(__name__)


def on_fail_handler(self, exc, task_id, args, kwargs, einfo):
    """Send an email if a task throws an exception."""
    print(str(einfo))
    send_error_email(f'ERROR: {TREE_NAME} celery task {task_id}', str(einfo))


# @shared_task(on_failure=on_fail_handler)
# def test_fail(x, y):
#     test_fail_internal()

# def test_fail_internal():
#     raise KeyError()


@shared_task(on_failure=on_fail_handler)
def process_message(path):
    parser = FeedParser()
    with open(path) as f:
        for line in f:
            parser.feed(line)
    msg = parser.close()

    frm = str(make_header(decode_header(msg['From'])))
    subject = str(make_header(decode_header(msg['Subject'])))

    found_pdf = False
    for attach in msg.walk():
        if attach.get_content_type() == 'application/pdf':
            process_attachment(frm, subject, attach)
            found_pdf = True

    if not found_pdf:
        reply_missing(frm, subject)


def process_attachment(from_address, subject, attachment):
    # write out pdf
    pdf_name = attachment.get_filename()
    pdf_base = Path(pdf_name).stem

    workdir = os.path.join(WORKDIR, clean_path(from_address), pdf_base)
    ensure_dir(workdir)
    pdf_path = os.path.join(workdir, pdf_name)
    print(f'saving pdf to {pdf_path}')
    with open(pdf_path, 'wb') as att:
        att.write(attachment.get_payload(decode=True))
    set_file_perms(pdf_path)

    # find matches
    matches = find_marked_products(pdf_path, workdir, debug=0)
    if not matches:
        print('no product matches')
        reply_no_matches(from_address, subject)
        return

    print(f'{len(matches)} product matches')

    # write spreadsheet
    xls_path = write_spreadsheet(matches, workdir, pdf_base)

    if xls_path:
        # send reply
        print(f'wrote spreadsheet: {xls_path}')
        reply(from_address, subject, xls_path, pdf_path)
    else:
        # send error
        print(f'error creating spreadsheet')