from crontab import CronTab
import random
import re
import sys
import json
import os
import datetime
import syslog

from django.apps import apps

DJANGO_IP = "127.0.0.1:8000"
for arg in sys.argv:
    if re.search('(((1?[0-9]{1,2})|(2[0-4]\d)|(25[0-5]))\.){3}((1?[0-9]{1,2})|(2[0-4]\d)|(25[0-5]))', arg):
        DJANGO_IP = arg


class Task(object):
    """

        Class that contain utils for the cron tasks

        Attributes
        ----------
        ID_LENGTH: int
            Length of id string.

    """

    ID_LENGTH = 10
    @classmethod
    def create(cls, period):
        """

            Parse period and create task id.

        Parameters
        ----------
        period: str
            Cron formatted string.
        Returns
        -------
        _id: str
            Id of task
        cron_period_string: str
            Cron formatted string.

        Examples
        --------

        >>> #Creating a task that runs every minute:
        >>> _id, cron_period_string = Task.create('minute.every(1)')
        >>> print(_id, cron_period_string)
        IoVbRe minute.every(1)

        >>> #Creating a task that runs every month:
        >>> _id, cron_period_string = Task.create('minute.month(1)')
        >>> print(_id, cron_period_string)
        IoVbRe minute.month(1)

        >>> #Creating a task that runs every 2 month
        >>> _id, cron_period_string = Task.create('minute.month(2)')
        >>> print(_id, cron_period_string)
        IoVbRe minute.month(2)

        """

        _id = cls.create_id()
        cron_period_string = cls.parse_period(period)
        return _id, cron_period_string

    @classmethod
    def parse_period(cls, period):
        """

            Method to parse own schedule structure.
            #TODO

        Parameters
        ----------
        period: str
            Cron formatted string.
        Returns
        -------
        period: str
            Cron formatted string.

        """

        return period

    @classmethod
    def create_id(cls):
        """

            Create random string id of length `Task.ID_LENGTH` from `possible`.
            Exists len(`possible`)*`Task.ID_LENGTH` (3.40506e^16) combinations.

        Returns
        -------
        string: str
            Random id string.

        """

        possible = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"#$¿&/=¡-_+<>'
        string = ''.join(random.sample(possible, cls.ID_LENGTH))
        return string

    @staticmethod
    def get_last_run(user, task):
        """

            Get last run of a given task. Seek over /var/log/syslog cron processes and then filter it by
            user and task id.

        Parameters
        ----------
        user: str
            Task user
        task: str
            Task id
        Returns
        -------
        last_run: str
            Last run date. Format: Month Day Time

        """

        last_run = None
        for line in open('/var/log/syslog', 'r').readlines():
            if re.search('CRON', line):

                # Replace regex special characters
                user_taskid = r'{}:{}'.format(user, task)
                user_taskid = user_taskid.replace('¿', '\¿')
                user_taskid = user_taskid.replace('+', '\+')
                user_taskid = user_taskid.replace('%', '\%')
                user_taskid = user_taskid.replace(')', '\)')
                user_taskid = user_taskid.replace('(', '\(')
                if re.search(user_taskid, line):

                    last_run = line[0:15]
        return last_run

    @staticmethod
    def clean_string(string):
        """

            Method to clean some special characters

        Parameters
        ----------
        string: str
            String to clean

        Returns
        -------
        string: str
            Cleaned string

        """

        string = string.replace('$', '\$')
        string = string.replace('+', '\+')
        string = string.replace('%', '\%')
        string = string.replace(')', '\)')
        string = string.replace('(', '\(')

        return string


def post(user=None, geom=None, params=None, period=None):
    """

        Create a geomicroservice routine

    Parameters
    ----------
    user : str
        User id
    geom : str
        Geomicroservice in URL format
    params : dict
        Dict containing the parameters to feed `geom` geomicroservice
    period : str
        Cron formatted string scheduling the task

    Returns
    -------
    result : dict
        Dict containing task_id field with id of created task

    Notes
    -----
    % in any of string make script falls.

    Examples
    --------

    >>> import requests
    >>> import json
    >>> ints = list(open('AOI_TEST.kml', 'rb').read())
    >>> date = '02/18'
    >>> params = {"user": 'test', "geom": 'MG/update/staticBase', "params": {"user": 'I6', "base": 'sentinel', "params": {"AOI": ints,"date": date}}, "period": 'minute.every(1)'}
    >>> requests.post(url='<IP:PORT>/MG/routines/create', json=params)
    {'task_id':'oij89&!0'}

    """

    check_user = True
    user = Task.clean_string(user)
    user_cron = CronTab(user=True)
    task_id, cron_period_string = Task.create(period)
    # params['user'] = Task.clean_string(params['user'])
    command = r'{} {}/cronGeomExecute.py {} {} "{}"'.format(sys.executable,apps.get_app_config('routines').path, geom, DJANGO_IP,params)
    os.system(command)
    syslog.syslog(r'CRON {}:{}'.format(user, task_id))
    new_task = user_cron.new(command=command, comment=r'{}:{}'.format(user, task_id))
    eval('new_task.{}'.format(cron_period_string))
    user_cron.write()
    results = {'task_id': task_id}
    return results