# Copyright 2015 Google LLC
#
# 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.

"""User friendly container for Google Cloud Bigtable Cluster."""


import re
from google.cloud.bigtable_admin_v2.types import instance_pb2
from google.api_core.exceptions import NotFound


_CLUSTER_NAME_RE = re.compile(r'^projects/(?P<project>[^/]+)/'
                              r'instances/(?P<instance>[^/]+)/clusters/'
                              r'(?P<cluster_id>[a-z][-a-z0-9]*)$')


class Cluster(object):
    """Representation of a Google Cloud Bigtable Cluster.

    We can use a :class:`Cluster` to:

    * :meth:`reload` itself
    * :meth:`create` itself
    * :meth:`update` itself
    * :meth:`delete` itself

    :type cluster_id: str
    :param cluster_id: The ID of the cluster.

    :type instance: :class:`~google.cloud.bigtable.instance.Instance`
    :param instance: The instance where the cluster resides.

    :type location_id: str
    :param location_id: (Creation Only) The location where this cluster's
                        nodes and storage reside . For best performance,
                        clients should be located as close as possible to
                        this cluster.
                        For list of supported locations refer to
                        https://cloud.google.com/bigtable/docs/locations

    :type serve_nodes: int
    :param serve_nodes: (Optional) The number of nodes in the cluster.

    :type default_storage_type: int
    :param default_storage_type: (Optional) The type of storage
                                 Possible values are represented by the
                                 following constants:
                                 :data:`google.cloud.bigtable.enums.StorageType.SSD`.
                                 :data:`google.cloud.bigtable.enums.StorageType.SHD`,
                                 Defaults to
                                 :data:`google.cloud.bigtable.enums.StorageType.UNSPECIFIED`.

    :type _state: int
    :param _state: (`OutputOnly`)
                   The current state of the cluster.
                   Possible values are represented by the following constants:
                   :data:`google.cloud.bigtable.enums.Cluster.State.NOT_KNOWN`.
                   :data:`google.cloud.bigtable.enums.Cluster.State.READY`.
                   :data:`google.cloud.bigtable.enums.Cluster.State.CREATING`.
                   :data:`google.cloud.bigtable.enums.Cluster.State.RESIZING`.
                   :data:`google.cloud.bigtable.enums.Cluster.State.DISABLED`.
    """

    def __init__(self,
                 cluster_id,
                 instance,
                 location_id=None,
                 serve_nodes=None,
                 default_storage_type=None,
                 _state=None):
        self.cluster_id = cluster_id
        self._instance = instance
        self.location_id = location_id
        self.serve_nodes = serve_nodes
        self.default_storage_type = default_storage_type
        self._state = _state

    @classmethod
    def from_pb(cls, cluster_pb, instance):
        """Creates an cluster instance from a protobuf.

        :type cluster_pb: :class:`instance_pb2.Cluster`
        :param cluster_pb: An instance protobuf object.

        :type instance: :class:`google.cloud.bigtable.instance.Instance`
        :param instance: The instance that owns the cluster.

        :rtype: :class:`Cluster`
        :returns: The Cluster parsed from the protobuf response.
        :raises: :class:`ValueError <exceptions.ValueError>` if the cluster
                 name does not match
                 ``projects/{project}/instances/{instance_id}/clusters/{cluster_id}``
                 or if the parsed instance ID does not match the istance ID
                 on the client.
                 or if the parsed project ID does not match the project ID
                 on the client.
        """
        match_cluster_name = _CLUSTER_NAME_RE.match(cluster_pb.name)
        if match_cluster_name is None:
            raise ValueError('Cluster protobuf name was not in the '
                             'expected format.', cluster_pb.name)
        if match_cluster_name.group('instance') != instance.instance_id:
            raise ValueError('Instance ID on cluster does not match the '
                             'instance ID on the client')
        if match_cluster_name.group('project') != instance._client.project:
            raise ValueError('Project ID on cluster does not match the '
                             'project ID on the client')
        cluster_id = match_cluster_name.group('cluster_id')

        result = cls(cluster_id, instance)
        result._update_from_pb(cluster_pb)
        return result

    def _update_from_pb(self, cluster_pb):
        """Refresh self from the server-provided protobuf.
        Helper for :meth:`from_pb` and :meth:`reload`.
        """

        self.location_id = cluster_pb.location.split('/')[-1]
        self.serve_nodes = cluster_pb.serve_nodes
        self.default_storage_type = cluster_pb.default_storage_type
        self._state = cluster_pb.state

    @property
    def name(self):
        """Cluster name used in requests.

        .. note::
          This property will not change if ``_instance`` and ``cluster_id``
          do not, but the return value is not cached.

        The cluster name is of the form

            ``"projects/{project}/instances/{instance}/clusters/{cluster_id}"``

        :rtype: str
        :returns: The cluster name.
        """
        return self._instance._client.instance_admin_client.cluster_path(
            self._instance._client.project, self._instance.instance_id,
            self.cluster_id)

    @property
    def state(self):
        """google.cloud.bigtable.enums.Cluster.State: state of cluster."""
        return self._state

    def __eq__(self, other):
        if not isinstance(other, self.__class__):
            return NotImplemented
        # NOTE: This does not compare the configuration values, such as
        #       the serve_nodes. Instead, it only compares
        #       identifying values instance, cluster ID and client. This is
        #       intentional, since the same cluster can be in different states
        #       if not synchronized. Clusters with similar instance/cluster
        #       settings but different clients can't be used in the same way.
        return (other.cluster_id == self.cluster_id and
                other._instance == self._instance)

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

    def reload(self):
        """Reload the metadata for this cluster."""
        cluster_pb = self._instance._client.instance_admin_client.get_cluster(
            self.name)

        # NOTE: _update_from_pb does not check that the project and
        #       cluster ID on the response match the request.
        self._update_from_pb(cluster_pb)

    def exists(self):
        """Check whether the cluster already exists.

        :rtype: bool
        :returns: True if the table exists, else False.
        """
        client = self._instance._client
        try:
            client.instance_admin_client.get_cluster(name=self.name)
            return True
        # NOTE: There could be other exceptions that are returned to the user.
        except NotFound:
            return False

    def create(self):
        """Create this cluster.

        .. note::

            Uses the ``project``, ``instance`` and ``cluster_id`` on the
            current :class:`Cluster` in addition to the ``serve_nodes``.
            To change them before creating, reset the values via

            .. code:: python

                cluster.serve_nodes = 8
                cluster.cluster_id = 'i-changed-my-mind'

            before calling :meth:`create`.

        :rtype: :class:`~google.api_core.operation.Operation`
        :returns: The long-running operation corresponding to the
                  create operation.
        """
        client = self._instance._client
        cluster_pb = self._to_pb()

        return client.instance_admin_client.create_cluster(
            self._instance.name, self.cluster_id, cluster_pb)

    def update(self):
        """Update this cluster.

        .. note::

            Updates the ``serve_nodes``. If you'd like to
            change them before updating, reset the values via

            .. code:: python

                cluster.serve_nodes = 8

            before calling :meth:`update`.

        :type location: :str:``CreationOnly``
        :param location: The location where this cluster's nodes and storage
                reside. For best performance, clients should be located as
                close as possible to this cluster. Currently only zones are
                supported, so values should be of the form
                ``projects/<project>/locations/<zone>``.

        :type serve_nodes: :int
        :param serve_nodes: The number of nodes allocated to this cluster.
                More nodes enable higher throughput and more consistent
                performance.

        :rtype: :class:`Operation`
        :returns: The long-running operation corresponding to the
                  update operation.
        """
        client = self._instance._client
        # We are passing `None` for second argument location.
        # Location is set only at the time of creation of a cluster
        # and can not be changed after cluster has been created.
        return client.instance_admin_client.update_cluster(
            self.name, None, self.serve_nodes)

    def delete(self):
        """Delete this cluster.

        Marks a cluster and all of its tables for permanent deletion in 7 days.

        Immediately upon completion of the request:

        * Billing will cease for all of the cluster's reserved resources.
        * The cluster's ``delete_time`` field will be set 7 days in the future.

        Soon afterward:

        * All tables within the cluster will become unavailable.

        At the cluster's ``delete_time``:

        * The cluster and **all of its tables** will immediately and
          irrevocably disappear from the API, and their data will be
          permanently deleted.
        """
        client = self._instance._client
        client.instance_admin_client.delete_cluster(self.name)

    def _to_pb(self):
        """ Create cluster proto buff message for API calls """
        client = self._instance._client
        location = client.instance_admin_client.location_path(
            client.project, self.location_id)
        cluster_pb = instance_pb2.Cluster(
            location=location,
            serve_nodes=self.serve_nodes,
            default_storage_type=self.default_storage_type)
        return cluster_pb
