# Copyright 2010 Jacob Kaplan-Moss

# Copyright 2011 OpenStack Foundation
# 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.

"""
Base utilities to build API operation managers and objects on top of.
"""

import abc
import contextlib
import copy
import hashlib
import os

from manilaclient import api_versions
from manilaclient.common import cliutils
from manilaclient import exceptions
from manilaclient import utils


def getid(obj):
    """Return id if argument is a Resource.

    Abstracts the common pattern of allowing both an object or an object's ID
    (UUID) as a parameter when dealing with relationships.
    """
    try:
        if obj.uuid:
            return obj.uuid
    except AttributeError:
        pass
    try:
        return obj.id
    except AttributeError:
        return obj


class Manager(utils.HookableMixin):
    """Manager for CRUD operations.

    Managers interact with a particular type of API (shares, snapshots,
    etc.) and provide CRUD operations for them.
    """
    resource_class = None

    def __init__(self, api):
        self.api = api
        self.client = api.client

    @property
    def api_version(self):
        return self.api.api_version

    def _list(self, url, response_key, manager=None, body=None,
              return_raw=None):
        """List the collection.

        :param url: a partial URL, e.g., '/shares'
        :param response_key: the key to be looked up in response dictionary,
            e.g., 'shares'. If response_key is None - all response body
            will be used.
        :param manager: manager instance for constructing the returned objects
            (self will be used by default)
        :param body: data that will be encoded as JSON and passed in POST
            request (GET will be sent by default)
        """
        resp = None
        if body:
            resp, body = self.api.client.post(url, body=body)
        else:
            resp, body = self.api.client.get(url)

        if manager is None:
            manager = self

        obj_class = manager.resource_class

        data = body[response_key]
        # NOTE(ja): keystone returns values as list as {'values': [ ... ]}
        #           unlike other services which just return the list...
        if isinstance(data, dict):
            try:
                data = data['values']
            except KeyError:
                pass
        with self.completion_cache('human_id', obj_class, mode="w"):
            with self.completion_cache('uuid', obj_class, mode="w"):
                if return_raw:
                    return data
                resource = [obj_class(manager, res, loaded=True)
                            for res in data if res]
                if 'count' in body:
                    return resource, body['count']
                else:
                    return resource

    @contextlib.contextmanager
    def completion_cache(self, cache_type, obj_class, mode):
        """Bash autocompletion items storage.

        The completion cache store items that can be used for bash
        autocompletion, like UUIDs or human-friendly IDs.

        A resource listing will clear and repopulate the cache.

        A resource create will append to the cache.

        Delete is not handled because listings are assumed to be performed
        often enough to keep the cache reasonably up-to-date.
        """
        base_dir = cliutils.env('manilaclient_UUID_CACHE_DIR',
                                'MANILACLIENT_UUID_CACHE_DIR',
                                default="~/.cache/manilaclient")

        # NOTE(sirp): Keep separate UUID caches for each username + endpoint
        # pair
        username = cliutils.env('OS_USERNAME', 'MANILA_USERNAME')
        url = cliutils.env('OS_URL', 'MANILA_URL')
        uniqifier = hashlib.sha256(username.encode('utf-8') +
                                   url.encode('utf-8')).hexdigest()

        cache_dir = os.path.expanduser(os.path.join(base_dir, uniqifier))

        try:
            os.makedirs(cache_dir, 0o755)
        except OSError:
            # NOTE(kiall): This is typically either permission denied while
            #              attempting to create the directory, or the directory
            #              already exists. Either way, don't fail.
            pass

        resource = obj_class.__name__.lower()
        filename = "%s-%s-cache" % (resource, cache_type.replace('_', '-'))
        path = os.path.join(cache_dir, filename)

        cache_attr = "_%s_cache" % cache_type

        try:
            setattr(self, cache_attr, open(path, mode))
        except IOError:
            # NOTE(kiall): This is typically a permission denied while
            #              attempting to write the cache file.
            pass

        try:
            yield
        finally:
            cache = getattr(self, cache_attr, None)
            if cache:
                cache.close()
                delattr(self, cache_attr)

    def write_to_completion_cache(self, cache_type, val):
        cache = getattr(self, "_%s_cache" % cache_type, None)
        if cache:
            try:
                cache.write("%s\n" % val)
            except UnicodeEncodeError:
                pass

    def _get(self, url, response_key, return_raw=False):
        resp, body = self.api.client.get(url)
        if response_key:
            if return_raw:
                return body[response_key]
            return self.resource_class(self, body[response_key], loaded=True)
        else:
            return self.resource_class(self, body, loaded=True)

    def _get_with_base_url(self, url, response_key=None):
        resp, body = self.api.client.get_with_base_url(url)
        if response_key:
            return [self.resource_class(self, res, loaded=True)
                    for res in body[response_key] if res]
        else:
            return self.resource_class(self, body, loaded=True)

    def _create(self, url, body, response_key, return_raw=False, **kwargs):
        self.run_hooks('modify_body_for_create', body, **kwargs)
        resp, body = self.api.client.post(url, body=body)
        if return_raw:
            return body[response_key]

        with self.completion_cache('human_id', self.resource_class, mode="a"):
            with self.completion_cache('uuid', self.resource_class, mode="a"):
                return self.resource_class(self, body[response_key])

    def _accept(self, url, body):
        resp, body = self.api.client.post(url, body=body)

    def _delete(self, url):
        resp, body = self.api.client.delete(url)

    def _update(self, url, body, response_key=None, **kwargs):
        self.run_hooks('modify_body_for_update', body, **kwargs)
        resp, body = self.api.client.put(url, body=body)
        if body:
            if response_key:
                return self.resource_class(self, body[response_key])
            else:
                return self.resource_class(self, body)

    def _build_query_string(self, search_opts):
        search_opts = search_opts or {}
        params = sorted(
            [(k, v) for (k, v) in search_opts.items() if v])
        query_string = "?%s" % utils.safe_urlencode(params) if params else ''
        return query_string


class ManagerWithFind(Manager):
    """Like a `Manager`, but with additional `find()`/`findall()` methods."""
    def find(self, **kwargs):
        """Find a single item with attributes matching ``**kwargs``.

        This isn't very efficient: it loads the entire list then filters on
        the Python side.
        """
        matches = self.findall(**kwargs)
        num_matches = len(matches)
        if num_matches == 0:
            msg = "No %s matching %s." % (self.resource_class.__name__, kwargs)
            raise exceptions.NotFound(404, msg)
        elif num_matches > 1:
            raise exceptions.NoUniqueMatch
        else:
            return matches[0]

    def findall(self, **kwargs):
        """Find all items with attributes matching ``**kwargs``.

        This isn't very efficient: it loads the entire list then filters on
        the Python side.
        """
        found = []
        searches = list(kwargs.items())

        search_opts = {'all_tenants': 1}
        resources = self.list(search_opts=search_opts)
        if ('v2.shares.ShareManager' in str(self.__class__) and
                self.api_version >= api_versions.APIVersion("2.69")):
            search_opts_2 = {'all_tenants': 1,
                             'is_soft_deleted': True}
            shares_soft_deleted = self.list(search_opts=search_opts_2)
            resources += shares_soft_deleted
        for obj in resources:
            try:
                if all(getattr(obj, attr) == value
                       for (attr, value) in searches):
                    found.append(obj)
            except AttributeError:
                continue

        return found

    def list(self, search_opts=None):
        raise NotImplementedError


class Resource(object):
    """Base class for OpenStack resources (tenant, user, etc.).

    This is pretty much just a bag for attributes.
    """

    HUMAN_ID = False
    NAME_ATTR = 'name'

    def __init__(self, manager, info, loaded=False):
        """Populate and bind to a manager.

        :param manager: BaseManager object
        :param info: dictionary representing resource attributes
        :param loaded: prevent lazy-loading if set to True
        """
        self.manager = manager
        self._info = info
        self._add_details(info)
        self._loaded = loaded

    def __repr__(self):
        reprkeys = sorted(k
                          for k in self.__dict__.keys()
                          if k[0] != '_' and k != 'manager')
        info = ", ".join("%s=%s" % (k, getattr(self, k)) for k in reprkeys)
        return "<%s %s>" % (self.__class__.__name__, info)

    @property
    def human_id(self):
        """Human-readable ID which can be used for bash completion."""
        if self.HUMAN_ID:
            name = getattr(self, self.NAME_ATTR, None)
            if name is not None:
                return strutils.to_slug(name)
        return None

    def _add_details(self, info):
        for (k, v) in info.items():
            try:
                setattr(self, k, v)
                self._info[k] = v
            except AttributeError:
                # In this case we already defined the attribute on the class
                pass

    def __getattr__(self, k):
        if k not in self.__dict__:
            # NOTE(bcwaldon): disallow lazy-loading if already loaded once
            if not self.is_loaded():
                self.get()
                return self.__getattr__(k)

            raise AttributeError(k)
        else:
            return self.__dict__[k]

    def get(self):
        """Support for lazy loading details.

        Some clients, such as novaclient have the option to lazy load the
        details, details which can be loaded with this function.
        """
        # set_loaded() first ... so if we have to bail, we know we tried.
        self.set_loaded(True)
        if not hasattr(self.manager, 'get'):
            return

        new = self.manager.get(self.id)
        if new:
            self._add_details(new._info)

    def __eq__(self, other):
        if not isinstance(other, Resource):
            return NotImplemented
        # two resources of different types are not equal
        if not isinstance(other, self.__class__):
            return False
        if hasattr(self, 'id') and hasattr(other, 'id'):
            return self.id == other.id
        return self._info == other._info

    def __ne__(self, other):
        return not self == other

    def is_loaded(self):
        return self._loaded

    def set_loaded(self, val):
        self._loaded = val

    def to_dict(self):
        return copy.deepcopy(self._info)


class MetadataCapableResource(Resource, metaclass=abc.ABCMeta):

    superresource = None

    def _get_subresource_and_resource(self, superresource):
        resource = self
        subresource = None
        superresource = superresource or self.superresource
        if superresource is not None:
            resource = superresource
            subresource = self
        return resource, subresource

    def get_metadata(self, superresource=None):
        """Get metadata of a resource

        :param superresource: either a parent resource object or text with
            its ID. Required for sub-resources such as share export
            locations which do not include a reference to the parent object
            by default
        """

        resource, subresource = self._get_subresource_and_resource(
            superresource)

        return self.manager.get_metadata(resource, subresource=subresource)

    def set_metadata(self, metadata, superresource=None):
        """Set or update metadata for the resource.

        :param metadata: A dictionary of key:value pairs to be set as
            resource metadata
        :param superresource: either a parent resource object or text with
            its ID. Required for sub-resources such as share share export
            locations which do not include a reference to the parent object
            by default
        """
        resource, subresource = self._get_subresource_and_resource(
            superresource)

        return self.manager.set_metadata(resource, metadata,
                                         subresource=subresource)

    def delete_metadata(self, keys, superresource=None):
        """Delete specified keys from the given resource.

        :param keys: An iterable with keys of metadata items to be deleted
        :param superresource: either a parent resource object or text with
            its ID. Required for sub-resources such as share share export
            locations which do not include a reference to the parent object
            by default
        """
        resource, subresource = self._get_subresource_and_resource(
            superresource)

        return self.manager.delete_metadata(resource, keys,
                                            subresource=subresource)

    def update_all_metadata(self, metadata, superresource=None):
        """Update all metadata for this resource.

        :param metadata: A dictionary of key:value pairs of resource metadata
            to be updated
        :param superresource: either a parent resource object or text with
            its ID. Required for sub-resources such as share share export
            locations which do not include a reference to the parent object
            by default
        """
        resource, subresource = self._get_subresource_and_resource(
            superresource)

        return self.manager.update_all_metadata(resource,
                                                metadata,
                                                subresource=subresource)


class MetadataCapableManager(ManagerWithFind, metaclass=abc.ABCMeta):
    """Provides extended behavior to objects to handle key=value metadata."""

    resource_path = None
    subresource_path = None

    def get_metadata(self, resource, subresource=None):
        """Get metadata of a resource.

        :param resource: either resource object or text with its ID.
        :param subresource: either a child resource object or text with its ID
        """
        resource = getid(resource)
        if subresource:
            subresource = getid(subresource)
            resource = f"{resource}{self.subresource_path}/{subresource}"

        return self._get(f"{self.resource_path}/{resource}/metadata",
                         "metadata")

    def set_metadata(self, resource, metadata, subresource=None):
        """Set or update metadata for resource.

        :param resource: either resource object or text with its ID.
        :param metadata: A dictionary of key:value pairs to be set as
            resource metadata
        :param subresource: either a child resource object or text with its ID
        """
        body = {'metadata': metadata}
        resource = getid(resource)
        if subresource:
            subresource = getid(subresource)
            resource = f"{resource}{self.subresource_path}/{subresource}"

        return self._create(f"{self.resource_path}/{resource}/metadata",
                            body,
                            "metadata")

    def delete_metadata(self, resource, keys, subresource=None):
        """Delete specified keys from resource metadata.

        :param resource: either resource object or text with its ID.
        :param keys: An iterable with keys of metadata items to be deleted
        :param subresource: either a child resource object or text with its ID
        """
        resource = getid(resource)
        if subresource:
            subresource = getid(subresource)
            resource = f"{resource}{self.subresource_path}/{subresource}"

        for key in keys:
            self._delete(f"{self.resource_path}/{resource}/metadata/{key}")

    def update_all_metadata(self, resource, metadata, subresource=None):
        """Update all metadata of a resource.

        :param resource: either resource object or text with its ID.
        :param metadata: A dictionary of key:value pairs of resource metadata
            to be updated
        :param subresource: either a child resource object or text with its ID
        """
        body = {'metadata': metadata}
        resource = getid(resource)
        if subresource:
            subresource = getid(subresource)
            resource = f"{resource}{self.subresource_path}/{subresource}"

        return self._update(f"{self.resource_path}/{resource}/metadata",
                            body)
