import datetime
import hashlib
import operator
from copy import deepcopy
from random import shuffle
from typing import Union, List, Dict, Optional

import dateutil.parser
import pytest
from pytz import timezone, utc

from sync_ics2gcal import CalendarSync


def sha1(string: Union[str, bytes]) -> str:
    if isinstance(string, str):
        string = string.encode('utf8')
    h = hashlib.sha1()
    h.update(string)
    return h.hexdigest()


def gen_events(start: int,
               stop: int,
               start_time: Union[datetime.datetime, datetime.date],
               no_time: bool = False) -> List[Dict[str, Union[str, Dict[str, str]]]]:
    if no_time:
        start_time = datetime.date(
            start_time.year, start_time.month, start_time.day)
        duration: datetime.timedelta = datetime.date(1, 1, 2) - datetime.date(1, 1, 1)
        date_key: str = "date"
        date_end: str = ''
    else:
        start_time = utc.normalize(
            start_time.astimezone(utc)).replace(tzinfo=None)
        duration: datetime.timedelta = datetime.datetime(1, 1, 1, 2) - datetime.datetime(1, 1, 1, 1)
        date_key: str = "dateTime"
        date_end: str = 'Z'

    result: List[Dict[str, Union[str, Dict[str, str]]]] = []
    for i in range(start, stop):
        event_start = start_time + (duration * i)
        event_end = event_start + duration

        updated: Union[datetime.datetime, datetime.date] = event_start
        if no_time:
            updated = datetime.datetime(
                updated.year, updated.month, updated.day, 0, 0, 0, 1, tzinfo=utc)

        event: Dict[str, Union[str, Dict[str, str]]] = {
            'summary': 'test event __ {}'.format(i),
            'location': 'la la la {}'.format(i),
            'description': 'test TEST -- test event {}'.format(i),
            "iCalUID": "{}@test.com".format(sha1("test - event {}".format(i))),
            "updated": updated.isoformat() + 'Z',
            "created": updated.isoformat() + 'Z',
            'start': {date_key: event_start.isoformat() + date_end},
            'end': {date_key: event_end.isoformat() + date_end}
        }
        result.append(event)
    return result


def gen_list_to_compare(start: int, stop: int) -> List[Dict[str, str]]:
    result: List[Dict[str, str]] = []
    for i in range(start, stop):
        result.append({'iCalUID': 'test{:06d}'.format(i)})
    return result


def get_start_date(event: Dict[str, Union[str, Dict[str, str]]]) -> Union[datetime.datetime, datetime.date]:
    event_start: Dict[str, str] = event['start']
    start_date: Optional[str] = None
    is_date = False
    if 'date' in event_start:
        start_date = event_start['date']
        is_date = True
    if 'dateTime' in event_start:
        start_date = event_start['dateTime']

    result = dateutil.parser.parse(start_date)
    if is_date:
        result = datetime.date(result.year, result.month, result.day)

    return result


def test_compare():
    part_len = 20
    # [1..2n]
    lst_src = gen_list_to_compare(1, 1 + part_len * 2)
    # [n..3n]
    lst_dst = gen_list_to_compare(
        1 + part_len, 1 + part_len * 3)

    lst_src_rnd = deepcopy(lst_src)
    lst_dst_rnd = deepcopy(lst_dst)

    shuffle(lst_src_rnd)
    shuffle(lst_dst_rnd)

    to_ins, to_upd, to_del = CalendarSync._events_list_compare(
        lst_src_rnd, lst_dst_rnd)

    assert len(to_ins) == part_len
    assert len(to_upd) == part_len
    assert len(to_del) == part_len

    assert sorted(to_ins, key=lambda x: x['iCalUID']) == lst_src[:part_len]
    assert sorted(to_del, key=lambda x: x['iCalUID']) == lst_dst[part_len:]

    to_upd_ok = list(zip(lst_src[part_len:], lst_dst[:part_len]))
    assert len(to_upd) == len(to_upd_ok)
    for item in to_upd_ok:
        assert item in to_upd


@pytest.mark.parametrize("no_time", [True, False], ids=['date', 'dateTime'])
def test_filter_events_by_date(no_time: bool):
    msk = timezone('Europe/Moscow')
    now = utc.localize(datetime.datetime.utcnow())
    msk_now = msk.normalize(now.astimezone(msk))

    part_len = 5

    if no_time:
        duration = datetime.date(
            1, 1, 2) - datetime.date(1, 1, 1)
    else:
        duration = datetime.datetime(
            1, 1, 1, 2) - datetime.datetime(1, 1, 1, 1)

    date_cmp = msk_now + (duration * part_len)

    if no_time:
        date_cmp = datetime.date(
            date_cmp.year, date_cmp.month, date_cmp.day)

    events = gen_events(
        1, 1 + (part_len * 2), msk_now, no_time)
    shuffle(events)

    events_pending = CalendarSync._filter_events_by_date(
        events, date_cmp, operator.ge)
    events_past = CalendarSync._filter_events_by_date(
        events, date_cmp, operator.lt)

    assert len(events_pending) == 1 + part_len
    assert len(events_past) == part_len - 1

    for event in events_pending:
        assert get_start_date(event) >= date_cmp

    for event in events_past:
        assert get_start_date(event) < date_cmp


def test_filter_events_to_update():
    msk = timezone('Europe/Moscow')
    now = utc.localize(datetime.datetime.utcnow())
    msk_now = msk.normalize(now.astimezone(msk))

    one_hour = datetime.datetime(
        1, 1, 1, 2) - datetime.datetime(1, 1, 1, 1)
    date_upd = msk_now + (one_hour * 5)

    count = 10
    events_old = gen_events(1, 1 + count, msk_now)
    events_new = gen_events(1, 1 + count, date_upd)

    sync1 = CalendarSync(None, None)
    sync1.to_update = list(zip(events_new, events_old))
    sync1._filter_events_to_update()

    sync2 = CalendarSync(None, None)
    sync2.to_update = list(zip(events_old, events_new))
    sync2._filter_events_to_update()

    assert len(sync1.to_update) == count
    assert sync2.to_update == []