# Copyright 2015 Vinicius Chiele. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Utility module."""

import dateutil.parser
import six

from apscheduler.triggers.cron import CronTrigger
from apscheduler.triggers.date import DateTrigger
from apscheduler.triggers.interval import IntervalTrigger
from collections import OrderedDict


def job_to_dict(job):
    """Converts a job to an OrderedDict."""

    data = OrderedDict()
    data['id'] = job.id
    data['name'] = job.name
    data['func'] = job.func_ref
    data['args'] = job.args
    data['kwargs'] = job.kwargs

    data.update(trigger_to_dict(job.trigger))

    if not job.pending:
        data['misfire_grace_time'] = job.misfire_grace_time
        data['max_instances'] = job.max_instances
        data['next_run_time'] = None if job.next_run_time is None else job.next_run_time

    return data


def pop_trigger(data):
    """Pops trigger and trigger args from a given dict."""

    trigger_name = data.pop('trigger')
    trigger_args = {}

    if trigger_name == 'date':
        trigger_arg_names = ('run_date', 'timezone')
    elif trigger_name == 'interval':
        trigger_arg_names = ('weeks', 'days', 'hours', 'minutes', 'seconds', 'start_date', 'end_date', 'timezone')
    elif trigger_name == 'cron':
        trigger_arg_names = ('year', 'month', 'day', 'week', 'day_of_week', 'hour', 'minute', 'second', 'start_date', 'end_date', 'timezone')
    else:
        raise Exception('Trigger %s is not supported.' % trigger_name)

    for arg_name in trigger_arg_names:
        if arg_name in data:
            trigger_args[arg_name] = data.pop(arg_name)

    return trigger_name, trigger_args


def trigger_to_dict(trigger):
    """Converts a trigger to an OrderedDict."""

    data = OrderedDict()

    if isinstance(trigger, DateTrigger):
        data['trigger'] = 'date'
        data['run_date'] = trigger.run_date
    elif isinstance(trigger, IntervalTrigger):
        data['trigger'] = 'interval'
        data['start_date'] = trigger.start_date

        if trigger.end_date:
            data['end_date'] = trigger.end_date

        w, d, hh, mm, ss = extract_timedelta(trigger.interval)

        if w > 0:
            data['weeks'] = w
        if d > 0:
            data['days'] = d
        if hh > 0:
            data['hours'] = hh
        if mm > 0:
            data['minutes'] = mm
        if ss > 0:
            data['seconds'] = ss
    elif isinstance(trigger, CronTrigger):
        data['trigger'] = 'cron'

        if trigger.start_date:
            data['start_date'] = trigger.start_date

        if trigger.end_date:
            data['end_date'] = trigger.end_date

        for field in trigger.fields:
            if not field.is_default:
                data[field.name] = str(field)
    else:
        data['trigger'] = str(trigger)

    return data


def fix_job_def(job_def):
    """
    Replaces the datetime in string by datetime object.
    """
    if six.PY2 and isinstance(job_def.get('func'), six.text_type):
        # when a job comes from the endpoint, strings are unicode
        # because that's how json package deserialize the bytes.
        # we had a case where APScheduler failed to import the func based
        # on its name because Py2 expected a str and not unicode on __import__().
        # it happened only for a user, I wasn't able to determine why that occurred for him,
        # a workaround is to convert the func to str.

        # full story: https://github.com/viniciuschiele/flask-apscheduler/issues/75

        job_def['func'] = str(job_def.get('func'))

    if isinstance(job_def.get('start_date'), six.string_types):
        job_def['start_date'] = dateutil.parser.parse(job_def.get('start_date'))

    if isinstance(job_def.get('end_date'), six.string_types):
        job_def['end_date'] = dateutil.parser.parse(job_def.get('end_date'))

    if isinstance(job_def.get('run_date'), six.string_types):
        job_def['run_date'] = dateutil.parser.parse(job_def.get('run_date'))

    # it keeps compatibility backward
    if isinstance(job_def.get('trigger'), dict):
        trigger = job_def.pop('trigger')
        job_def['trigger'] = trigger.pop('type', 'date')
        job_def.update(trigger)


def extract_timedelta(delta):
    w, d = divmod(delta.days, 7)
    mm, ss = divmod(delta.seconds, 60)
    hh, mm = divmod(mm, 60)
    return w, d, hh, mm, ss