# vi: ts=4 expandtab
#
# Copyright (C) 2018 VMware Inc.
#
# Authors: Anish Swaminathan <anishs@vmware.com>
#          Andrew Kutz <akutz@vmware.com>
#
import os
import base64
import zlib
import json

from cloudinit import log as logging
from cloudinit import sources
from cloudinit import util
from cloudinit import safeyaml

from distutils.spawn import find_executable

LOG = logging.getLogger(__name__)

# This cloud-init datasource was designed for use with CentOS 7,
# which uses cloud-init 0.7.9. However, this datasource should
# work with any Linux distribution for which cloud-init is 
# avaialble.
#
# The documentation for cloud-init 0.7.9's datasource is 
# available at http://bit.ly/cloudinit-datasource-0-7-9. The
# current documentation for cloud-init is found at
# https://cloudinit.readthedocs.io/en/latest/.
#
# Setting the hostname:
#     The hostname is set by way of the metadata key "local-hostname".
#
# Setting the instance ID:
#     The instance ID may be set by way of the metadata key "instance-id".
#     However, if this value is absent then then the instance ID is
#     read from the file /sys/class/dmi/id/product_uuid.
#
# Configuring the network:
#     The network is configured by setting the metadata key "network"
#     with a value consistent with Network Config Versions 1 or 2,
#     depending on the Linux distro's version of cloud-init:
#
#         Network Config Version 1 - http://bit.ly/cloudinit-net-conf-v1
#         Network Config Version 2 - http://bit.ly/cloudinit-net-conf-v2
#
#     For example, CentOS 7's official cloud-init package is version
#     0.7.9 and does not support Network Config Version 2. However,
#     this datasource still supports supplying Network Config Version 2
#     data as long as the Linux distro's cloud-init package is new
#     enough to parse the data.
#
#     The metadata key "network.encoding" may be used to indicate the
#     format of the metadata key "network". Valid encodings are base64
#     and gzip+base64.
class DataSourceVMwareGuestInfo(sources.DataSource):
    def __init__(self, sys_cfg, distro, paths, ud_proc=None):
        sources.DataSource.__init__(self, sys_cfg, distro, paths, ud_proc)
        self.vmtoolsd = find_executable("vmtoolsd")
        if not self.vmtoolsd:
            LOG.error("Failed to find vmtoolsd")

    def get_data(self):
        if not self.vmtoolsd:
            LOG.error("vmtoolsd is required to fetch guestinfo value")
            return False

        # Get the JSON metadata. Can be plain-text, base64, or gzip+base64.
        metadata = self._get_encoded_guestinfo_data('metadata')
        if metadata:
            self.metadata = json.loads(metadata)

        # Get the YAML userdata. Can be plain-text, base64, or gzip+base64.
        self.userdata_raw = self._get_encoded_guestinfo_data('userdata')

        # Get the YAML vendordata. Can be plain-text, base64, or gzip+base64.
        self.vendordata_raw = self._get_encoded_guestinfo_data('vendordata')

        return True

    @property
    def network_config(self):
        # Pull the network configuration out of the metadata.
        if self.metadata and 'network' in self.metadata:
            data = self._get_encoded_metadata('network')
            if data:
                # Load the YAML-formatted network data into an object
                # and return it.
                net_config = safeyaml.load(data)
                LOG.debug("Loaded network config: %s", net_config)
                return net_config
        return None

    def get_instance_id(self):
        # Pull the instance ID out of the metadata if present. Otherwise
        # read the file /sys/class/dmi/id/product_uuid for the instance ID.
        if self.metadata and 'instance-id' in self.metadata:
            return self.metadata['instance-id']
        with open('/sys/class/dmi/id/product_uuid', 'r') as id_file:
            return str(id_file.read()).rstrip()

    def _get_encoded_guestinfo_data(self, key):
        data = self._get_guestinfo_value(key)
        if not data:
            return None
        enc_type = self._get_guestinfo_value(key + '.encoding')
        return self._get_encoded_data('guestinfo.' + key, enc_type, data)

    def _get_encoded_metadata(self, key):
        if not self.metadata or not key in self.metadata:
            return None
        data = self.metadata[key]
        enc_type = self.metadata.get(key + '.encoding')
        return self._get_encoded_data('metadata.' + key, enc_type, data)

    def _get_encoded_data(self, key, enc_type, data):
        LOG.debug("Getting encoded data for key=%s, enc=%s", key, enc_type)
        if enc_type == "gzip+base64" or enc_type == "gz+b64":
            LOG.debug("Decoding %s format %s", enc_type, key)
            return zlib.decompress(base64.b64decode(data), zlib.MAX_WBITS | 16)
        elif enc_type == "base64" or enc_type == "b64":
            LOG.debug("Decoding %s format %s", enc_type, key)
            return base64.b64decode(data)
        else:
            LOG.debug("Plain-text data %s", key)
            return data

    def _get_guestinfo_value(self, key):
        NOVAL = "No value found"
        LOG.debug("Getting guestinfo value for key %s", key)
        try:
            (stdout, stderr) = util.subp([self.vmtoolsd, "--cmd", "info-get guestinfo." + key])
            if stderr == NOVAL:
                LOG.debug("No value found for key %s", key)
            elif not stdout:
                LOG.error("Failed to get guestinfo value for key %s", key)
            else:
                return stdout.rstrip()
        except util.ProcessExecutionError as error:
            if error.stderr == NOVAL:
                LOG.debug("No value found for key %s", key)
            else:
                util.logexc(LOG,"Failed to get guestinfo value for key %s: %s", key, error)
        except Exception:
            util.logexc(LOG,"Unexpected error while trying to get guestinfo value for key %s", key)
        return None

def get_datasource_list(depends):
    """
    Return a list of data sources that match this set of dependencies
    """
    return [DataSourceVMwareGuestInfo]