#
#    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.

import contextlib
import os
import re
import textwrap
import time
from urllib import parse

from oslo_serialization import jsonutils
from oslo_utils import encodeutils
from oslo_utils import uuidutils
import prettytable

from novaclient import exceptions
from novaclient.i18n import _


VALID_KEY_REGEX = re.compile(r"[\w\.\- :]+$", re.UNICODE)


def env(*args, **kwargs):
    """Returns the first environment variable set.

    If all are empty, defaults to '' or keyword arg `default`.
    """
    for arg in args:
        value = os.environ.get(arg)
        if value:
            return value
    return kwargs.get('default', '')


def get_service_type(f):
    """Retrieves service type from function."""
    return getattr(f, 'service_type', None)


def unauthenticated(func):
    """Adds 'unauthenticated' attribute to decorated function.

    Usage:

    >>> @unauthenticated
    ... def mymethod(f):
    ...     pass
    """
    func.unauthenticated = True
    return func


def isunauthenticated(func):
    """Checks if the function does not require authentication.

    Mark such functions with the `@unauthenticated` decorator.

    :returns: bool
    """
    return getattr(func, 'unauthenticated', False)


def arg(*args, **kwargs):
    """Decorator for CLI args.

    Example:

    >>> @arg("name", help="Name of the new entity")
    ... def entity_create(args):
    ...     pass
    """
    def _decorator(func):
        add_arg(func, *args, **kwargs)
        return func
    return _decorator


def add_arg(func, *args, **kwargs):
    """Bind CLI arguments to a shell.py `do_foo` function."""

    if not hasattr(func, 'arguments'):
        func.arguments = []

    # NOTE(sirp): avoid dups that can occur when the module is shared across
    # tests.
    if (args, kwargs) not in func.arguments:
        # Because of the semantics of decorator composition if we just append
        # to the options list positional options will appear to be backwards.
        func.arguments.insert(0, (args, kwargs))


def service_type(stype):
    """Adds 'service_type' attribute to decorated function.

    Usage:

    .. code-block:: python

       @service_type('volume')
       def mymethod(f):
       ...
    """
    def inner(f):
        f.service_type = stype
        return f
    return inner


def pretty_choice_list(l):
    return ', '.join("'%s'" % i for i in l)


def pretty_choice_dict(d):
    """Returns a formatted dict as 'key=value'."""
    return pretty_choice_list(['%s=%s' % (k, d[k]) for k in sorted(d.keys())])


def print_list(objs, fields, formatters={}, sortby_index=None):
    if sortby_index is None:
        sortby = None
    else:
        sortby = fields[sortby_index]
    mixed_case_fields = ['serverId']
    pt = prettytable.PrettyTable([f for f in fields], caching=False)
    pt.align = 'l'

    for o in objs:
        row = []
        for field in fields:
            if field in formatters:
                row.append(formatters[field](o))
            else:
                if field in mixed_case_fields:
                    field_name = field.replace(' ', '_')
                else:
                    field_name = field.lower().replace(' ', '_')
                data = getattr(o, field_name, '')
                if data is None:
                    data = '-'
                # '\r' would break the table, so remove it.
                data = str(data).replace("\r", "")
                row.append(data)
        pt.add_row(row)

    if sortby is not None:
        result = encodeutils.safe_encode(pt.get_string(sortby=sortby))
    else:
        result = encodeutils.safe_encode(pt.get_string())

    result = result.decode()

    print(result)


def _flatten(data, prefix=None):
    """Flatten a dict, using name as a prefix for the keys of dict.

    >>> _flatten('cpu_info', {'arch':'x86_64'})
    [('cpu_info_arch': 'x86_64')]

    """
    if isinstance(data, dict):
        for key, value in data.items():
            new_key = '%s_%s' % (prefix, key) if prefix else key
            if isinstance(value, (dict, list)) and value:
                for item in _flatten(value, new_key):
                    yield item
            else:
                yield new_key, value
    else:
        yield prefix, data


def flatten_dict(data):
    """Return a new dict whose sub-dicts have been merged into the
    original.  Each of the parents keys are prepended to the child's
    to prevent collisions.  Any string elements will be JSON parsed
    before flattening.

    >>> flatten_dict({'service': {'host':'cloud9@compute-068', 'id': 143}})
    {'service_host': colud9@compute-068', 'service_id': 143}

    """
    data = data.copy()
    # Try and decode any nested JSON structures.
    for key, value in data.items():
        if isinstance(value, str):
            try:
                data[key] = jsonutils.loads(value)
            except ValueError:
                pass

    return dict(_flatten(data))


def print_dict(d, dict_property="Property", dict_value="Value", wrap=0):
    pt = prettytable.PrettyTable([dict_property, dict_value], caching=False)
    pt.align = 'l'
    for k, v in sorted(d.items()):
        # convert dict to str to check length
        if isinstance(v, (dict, list)):
            v = jsonutils.dumps(v, ensure_ascii=False)
        if wrap > 0:
            v = textwrap.fill(str(v), wrap)
        # if value has a newline, add in multiple rows
        # e.g. fault with stacktrace
        if v and isinstance(v, str) and (r'\n' in v or '\r' in v):
            # '\r' would break the table, so remove it.
            if '\r' in v:
                v = v.replace('\r', '')
            lines = v.strip().split(r'\n')
            col1 = k
            for line in lines:
                pt.add_row([col1, line])
                col1 = ''
        else:
            if v is None:
                v = '-'
            pt.add_row([k, v])

    result = encodeutils.safe_encode(pt.get_string())

    result = result.decode()

    print(result)


def find_resource(manager, name_or_id, wrap_exception=True, **find_args):
    """Helper for the _find_* methods."""
    # for str id which is not uuid (for Flavor, Keypair and hypervsior in cells
    # environments search currently)
    if getattr(manager, 'is_alphanum_id_allowed', False):
        try:
            return manager.get(name_or_id)
        except exceptions.NotFound:
            pass

    # first try to get entity as uuid
    try:
        tmp_id = encodeutils.safe_encode(name_or_id)

        tmp_id = tmp_id.decode()

        if uuidutils.is_uuid_like(tmp_id):
            return manager.get(tmp_id)
    except (TypeError, exceptions.NotFound):
        pass

    # then try to get entity as name
    try:
        try:
            resource = getattr(manager, 'resource_class', None)
            name_attr = resource.NAME_ATTR if resource else 'name'
            kwargs = {name_attr: name_or_id}
            kwargs.update(find_args)
            return manager.find(**kwargs)
        except exceptions.NotFound:
            pass

        # then try to find entity by human_id
        try:
            return manager.find(human_id=name_or_id, **find_args)
        except exceptions.NotFound:
            pass
    except exceptions.NoUniqueMatch:
        msg = (_("Multiple %(class)s matches found for '%(name)s', use an ID "
                 "to be more specific.") %
               {'class': manager.resource_class.__name__.lower(),
                'name': name_or_id})
        if wrap_exception:
            raise exceptions.CommandError(msg)
        raise exceptions.NoUniqueMatch(msg)

    # finally try to get entity as integer id
    try:
        return manager.get(int(name_or_id))
    except (TypeError, ValueError, exceptions.NotFound):
        msg = (_("No %(class)s with a name or ID of '%(name)s' exists.") %
               {'class': manager.resource_class.__name__.lower(),
                'name': name_or_id})
        if wrap_exception:
            raise exceptions.CommandError(msg)
        raise exceptions.NotFound(404, msg)


def format_servers_list_networks(server):
    output = []
    for (network, addresses) in server.networks.items():
        if len(addresses) == 0:
            continue
        addresses_csv = ', '.join(addresses)
        group = "%s=%s" % (network, addresses_csv)
        output.append(group)

    return '; '.join(output)


def format_security_groups(groups):
    return ', '.join(group['name'] for group in groups)


def _format_field_name(attr):
    """Format an object attribute in a human-friendly way."""
    # Split at ':' and leave the extension name as-is.
    parts = attr.rsplit(':', 1)
    name = parts[-1].replace('_', ' ')
    # Don't title() on mixed case
    if name.isupper() or name.islower():
        name = name.title()
    parts[-1] = name
    return ': '.join(parts)


def make_field_formatter(attr, filters=None):
    """
    Given an object attribute, return a formatted field name and a
    formatter suitable for passing to print_list.

    Optionally pass a dict mapping attribute names to a function. The function
    will be passed the value of the attribute and should return the string to
    display.
    """
    filter_ = None
    if filters:
        filter_ = filters.get(attr)

    def get_field(obj):
        field = getattr(obj, attr, '')
        if field and filter_:
            field = filter_(field)
        return field

    name = _format_field_name(attr)
    formatter = get_field
    return name, formatter


def safe_issubclass(*args):
    """Like issubclass, but will just return False if not a class."""

    try:
        if issubclass(*args):
            return True
    except TypeError:
        pass

    return False


def _get_resource_string(resource):
    if hasattr(resource, 'human_id') and resource.human_id:
        if hasattr(resource, 'id') and resource.id:
            return "%s (%s)" % (resource.human_id, resource.id)
        else:
            return resource.human_id
    elif hasattr(resource, 'id') and resource.id:
        return resource.id
    else:
        return resource


def do_action_on_many(action, resources, success_msg, error_msg):
    """Helper to run an action on many resources."""
    failure_flag = False

    for resource in resources:
        try:
            action(resource)
            print(success_msg % _get_resource_string(resource))
        except Exception as e:
            failure_flag = True
            print(encodeutils.safe_encode(str(e)))

    if failure_flag:
        raise exceptions.CommandError(error_msg)


def is_integer_like(val):
    """Returns validation of a value as an integer."""
    try:
        int(val)
        return True
    except (TypeError, ValueError, AttributeError):
        return False


def validate_flavor_metadata_keys(keys):
    for key in keys:
        valid_name = VALID_KEY_REGEX.match(key)
        if not valid_name:
            msg = _('Invalid key: "%s". Keys may only contain letters, '
                    'numbers, spaces, underscores, periods, colons and '
                    'hyphens.')
            raise exceptions.CommandError(msg % key)


@contextlib.contextmanager
def record_time(times, enabled, *args):
    """Record the time of a specific action.

    :param times: A list of tuples holds time data.
    :param enabled: Whether timing is enabled.
    :param args: Other data to be stored besides time data, these args
        will be joined to a string.
    """
    if not enabled:
        yield
    else:
        start = time.time()
        yield
        end = time.time()
        times.append((' '.join(args), start, end))


def prepare_query_string(params):
    """Convert dict params to query string"""
    # Transform the dict to a sequence of two-element tuples in fixed
    # order, then the encoded string will be consistent in Python 2&3.
    if not params:
        return ''
    params = sorted(params.items(), key=lambda x: x[0])
    return '?%s' % parse.urlencode(params) if params else ''


def get_url_with_filter(url, filters):
    query_string = prepare_query_string(filters)
    url = "%s%s" % (url, query_string)
    return url
