"""
    SoftLayer.utils
    ~~~~~~~~~~~~~~~
    Utility function/classes.

    :license: MIT, see LICENSE for more details.
"""
import datetime
import re
import time

# pylint: disable=no-member, invalid-name

UUID_RE = re.compile(r'^[0-9a-f\-]{36}$', re.I)
KNOWN_OPERATIONS = ['<=', '>=', '<', '>', '~', '!~', '*=', '^=', '$=', '_=']


def lookup(dic, key, *keys):
    """A generic dictionary access helper.

    This helps simplify code that uses heavily nested dictionaries. It will
    return None if any of the keys in *keys do not exist.

    ::

        >>> lookup({'this': {'is': 'nested'}}, 'this', 'is')
        nested

        >>> lookup({}, 'this', 'is')
        None

    """
    if keys:
        return lookup(dic.get(key, {}), keys[0], *keys[1:])
    return dic.get(key)


class NestedDict(dict):
    """This helps with accessing a heavily nested dictionary.

    Dictionary where accessing keys that don't exist will return another
    NestedDict object.

    """

    def __getitem__(self, key):
        if key in self:
            return self.get(key)
        return self.setdefault(key, NestedDict())

    def to_dict(self):
        """Converts a NestedDict instance into a real dictionary.

        This is needed for places where strict type checking is done.
        """
        return {key: val.to_dict() if isinstance(val, NestedDict) else val
                for key, val in self.items()}


def query_filter(query):
    """Translate a query-style string to a 'filter'.

    Query can be the following formats:

    Case Insensitive
      'value' OR '*= value'    Contains
      'value*' OR '^= value'   Begins with value
      '*value' OR '$= value'   Ends with value
      '*value*' OR '_= value'  Contains value

    Case Sensitive
      '~ value'   Contains
      '!~ value'  Does not contain
      '> value'   Greater than value
      '< value'   Less than value
      '>= value'  Greater than or equal to value
      '<= value'  Less than or equal to value

    :param string query: query string

    """
    try:
        return {'operation': int(query)}
    except ValueError:
        pass

    if isinstance(query, str):
        query = query.strip()
        for operation in KNOWN_OPERATIONS:
            if query.startswith(operation):
                query = "%s %s" % (operation, query[len(operation):].strip())
                return {'operation': query}
        if query.startswith('*') and query.endswith('*'):
            query = "*= %s" % query.strip('*')
        elif query.startswith('*'):
            query = "$= %s" % query.strip('*')
        elif query.endswith('*'):
            query = "^= %s" % query.strip('*')
        else:
            query = "_= %s" % query

    return {'operation': query}


def query_filter_date(start, end):
    """Query filters given start and end date.

    :param start:YY-MM-DD
    :param end: YY-MM-DD
    """
    sdate = datetime.datetime.strptime(start, "%Y-%m-%d")
    edate = datetime.datetime.strptime(end, "%Y-%m-%d")
    startdate = "%s/%s/%s" % (sdate.month, sdate.day, sdate.year)
    enddate = "%s/%s/%s" % (edate.month, edate.day, edate.year)
    return {
        'operation': 'betweenDate',
        'options': [
            {'name': 'startDate', 'value': [startdate + ' 0:0:0']},
            {'name': 'endDate', 'value': [enddate + ' 0:0:0']}
        ]
    }


def format_event_log_date(date_string, utc):
    """Gets a date in the format that the SoftLayer_EventLog object likes.

    :param string date_string: date in mm/dd/yyyy format
    :param string utc: utc offset. Defaults to '+0000'
    """
    user_date_format = "%m/%d/%Y"

    user_date = datetime.datetime.strptime(date_string, user_date_format)
    dirty_time = user_date.isoformat()

    if utc is None:
        utc = "+0000"

    iso_time_zone = utc[:3] + ':' + utc[3:]
    cleaned_time = "{}.000000{}".format(dirty_time, iso_time_zone)

    return cleaned_time


def event_log_filter_between_date(start, end, utc):
    """betweenDate Query filter that SoftLayer_EventLog likes

    :param string start: lower bound date in mm/dd/yyyy format
    :param string end: upper bound date in mm/dd/yyyy format
    :param string utc: utc offset. Defaults to '+0000'
    """
    return {
        'operation': 'betweenDate',
        'options': [
            {'name': 'startDate', 'value': [format_event_log_date(start, utc)]},
            {'name': 'endDate', 'value': [format_event_log_date(end, utc)]}
        ]
    }


def event_log_filter_greater_than_date(date, utc):
    """greaterThanDate Query filter that SoftLayer_EventLog likes

    :param string date: lower bound date in mm/dd/yyyy format
    :param string utc: utc offset. Defaults to '+0000'
    """
    return {
        'operation': 'greaterThanDate',
        'options': [
            {'name': 'date', 'value': [format_event_log_date(date, utc)]}
        ]
    }


def event_log_filter_less_than_date(date, utc):
    """lessThanDate Query filter that SoftLayer_EventLog likes

    :param string date: upper bound date in mm/dd/yyyy format
    :param string utc: utc offset. Defaults to '+0000'
    """
    return {
        'operation': 'lessThanDate',
        'options': [
            {'name': 'date', 'value': [format_event_log_date(date, utc)]}
        ]
    }


class IdentifierMixin(object):
    """Mixin used to resolve ids from other names of objects.

    This mixin provides an interface to provide multiple methods for
    converting an 'indentifier' to an id

    """
    resolvers = []

    def resolve_ids(self, identifier):
        """Takes a string and tries to resolve to a list of matching ids.

        What exactly 'identifier' can be depends on the resolvers

        :param string identifier: identifying string
        :returns list:
        """

        return resolve_ids(identifier, self.resolvers)


def resolve_ids(identifier, resolvers):
    """Resolves IDs given a list of functions.

    :param string identifier: identifier string
    :param list resolvers: a list of functions
    :returns list:
    """

    # Before doing anything, let's see if this is an integer
    try:
        return [int(identifier)]
    except ValueError:
        pass  # It was worth a shot

    # This looks like a globalIdentifier (UUID)
    if len(identifier) == 36 and UUID_RE.match(identifier):
        return [identifier]

    for resolver in resolvers:
        ids = resolver(identifier)
        if ids:
            return ids

    return []


class UTC(datetime.tzinfo):
    """UTC timezone."""

    def utcoffset(self, _):
        return datetime.timedelta(0)

    def tzname(self, _):
        return "UTC"

    def dst(self, _):
        return datetime.timedelta(0)


def is_ready(instance, pending=False):
    """Returns True if instance is ready to be used

    :param Object instance: Hardware or Virt with transaction data retrieved from the API
    :param bool pending: Wait for ALL transactions to finish?
    :returns bool:
    """

    last_reload = lookup(instance, 'lastOperatingSystemReload', 'id')
    active_transaction = lookup(instance, 'activeTransaction', 'id')

    reloading = all((
        active_transaction,
        last_reload,
        last_reload == active_transaction,
    ))
    outstanding = False
    if pending:
        outstanding = active_transaction
    if instance.get('provisionDate') and not reloading and not outstanding:
        return True
    return False


def clean_string(string):
    """Returns a string with all newline and other whitespace garbage removed.

    Mostly this method is used to print out objectMasks that have a lot of extra whitespace
    in them because making compact masks in python means they don't look nice in the IDE.

    :param string: The string to clean.
    :returns string: A string without extra whitespace.
    """
    if string is None:
        return ''
    else:
        return " ".join(string.split())


def clean_splitlines(string):
    """Returns a string where \r\n is replaced with \n"""
    if string is None:
        return ''
    else:
        return "\n".join(string.splitlines())


def clean_time(sltime, in_format='%Y-%m-%dT%H:%M:%S%z', out_format='%Y-%m-%d %H:%M'):
    """Easy way to format time strings

    :param string sltime: A softlayer formatted time string
    :param string in_format: Datetime format for strptime
    :param string out_format: Datetime format for strftime
    """
    if sltime is None:
        return None
    try:
        clean = datetime.datetime.strptime(sltime, in_format)
        return clean.strftime(out_format)
    # The %z option only exists with py3.6+
    except ValueError:
        return sltime


def timestamp(date):
    """Converts a datetime to timestamp

    :param datetime date:
    :returns int: The timestamp of date.
    """

    _timestamp = time.mktime(date.timetuple())

    return int(_timestamp)


def days_to_datetime(days):
    """Returns the datetime value of last N days.

    :param int days: From 0 to N days
    :returns int: The datetime of last N days or datetime.now() if days <= 0.
    """

    date = datetime.datetime.now()

    if days > 0:
        date -= datetime.timedelta(days=days)

    return date
