require 'ms_rest_azure'
require 'azure_mgmt_resources'
require 'azure_mgmt_compute'
require 'azure_mgmt_network'
require 'inifile'

# Class to manage the connection to Azure to retrieve the information required about the resources
#
# @author Russell Seymour
#
# @attr_reader [String] subscription_id ID of the subscription in which resources are to be tested
class AzureConnection
  attr_reader :subscription_id

  # Constructor which reads in the credentials file
  #
  # @author Russell Seymour
  def initialize
    # If an INSPEC_AZURE_CREDS environment has been specified set the
    # the credentials file to that, otherwise set the one in home
    azure_creds_file = ENV['AZURE_CREDS_FILE']
    if azure_creds_file.nil?

      # The environment file has not be set, so default to one in the home directory
      azure_creds_file = File.join(Dir.home, '.azure', 'credentials')
    end

    # Check to see if the credentials file exists
    if File.file?(azure_creds_file)
      @credentials = IniFile.load(File.expand_path(azure_creds_file))
    else
      warn format('%s was not found or not accessible', azure_creds_file)
    end
  end

  # Connect to Azure using the specified credentials
  #
  # @author Russell Seymour
  def connection
    # If a connection already exists then return it
    return @conn if defined?(@conn)

    # Determine if more than one subscription is specified in the configuration file, if so use the first one
    if @credentials.sections.length >= 1
      @subscription_id = @credentials.sections[0]
    else
      @subscription_id = ENV['AZURE_SUBSCRIPTION_ID']
    end

    # Determine the client_id, tenant_id and the client_secret
    tenant_id = ENV['AZURE_TENANT_ID'] || @credentials[@subscription_id]['tenant_id']
    client_id = ENV['AZURE_CLIENT_ID'] || @credentials[@subscription_id]['client_id']
    client_secret = ENV['AZURE_CLIENT_SECRET'] || @credentials[@subscription_id]['client_secret']

    # Create a new connection
    token_provider = MsRestAzure::ApplicationTokenProvider.new(tenant_id, client_id, client_secret)
    @conn = MsRest::TokenCredentials.new(token_provider)
  end
end

# Helper class to configure and give access to the various management components of Azure
# Also provides shortcuts for certain components, such as returing the VM object and performing
# all the checks that need to be done before retrieving the VM
#
# @author Russell Seymour
# @attr_reader [MsRest::TokenCredentials] azure Azure connection credentials
# @attr_reader [ComputeManagement] compute_mgmt Compute object for retrieving details about VMs
# @attr_reader [ResourceManagement] resource_mgmt Resource object for accessing specific resources and resoure groups
# @attr_reader [NetworkManagement] network_mgmt Network object for retrieving all information about Network cards and IP configurations
class Helpers
  attr_reader :azure, :compute_mgmt, :resource_mgmt, :network_mgmt

  # Constructor to configure the various objects that are required for Inspec testing
  #
  # @author Russell Seymour
  def initialize
    # Azure connection
    @azure = AzureConnection.new

    # Create the necessary clients
    @compute_mgmt = ComputeManagement.new(azure)
    @resource_mgmt = ResourceManagement.new(azure)
    @network_mgmt = NetworkManagement.new(azure)
  end

  # Retrieve the named virtual machine from Azure
  #
  # This is specified here as it combines two different resource types, Compute and Resource Groups
  #
  # @author Russell Seymour
  #
  # @return [] VM object
  #
  def get_vm(name, rg_name)
    # Ensure that the resource group exists
    unless resource_mgmt.client.resource_groups.check_existence(rg_name)
      raise "The Resource group cannot be found: #{rg_name}"
    end

    # get a vm from the named resource group
    begin
      compute_mgmt.client.virtual_machines.get(rg_name, name)
    rescue => e
      e.error_message
    end
  end
end

# Class to return a NetworkManagement client for use with NICs and Public IP Addresses
#
# @author Russell Seymour
# @attr_reader [Azure::ARM::Network::NetworkManagementClient] client Azure Network Management cient
class ResourceManagement
  attr_reader :client

  # Constructor for the class.  Creates the new Network Management client object
  #
  # @author Russell Seymour
  #
  # @param [MsRest::TokenCredentials] azure Connection object for Azure
  def initialize(azure)
    @client = Azure::ARM::Resources::ResourceManagementClient.new(azure.connection)
    client.subscription_id = azure.subscription_id
  end

  # Determine if the specified resource group exists in the subscription_id
  #
  # @author Russell Seymour
  #
  # @param [String] name Name of the resource group
  #
  # @return [Boolean] Whether the resource group exists or not
  def exists(name)
    client.resource_groups.check_existence(name)
  end

  # Retrieve the named resource group if it exists
  #
  # @author Russell Seymour
  #
  # @param [String] name Name of the resource group
  #
  # @return [Azure::ARM::Resources::Models::ResourceGroup] Object containing information about the resource group
  def get_resource_group(name)
    client.resource_groups.get(name) if exists(name)
  end

  # Get all of the resources that are contained within the resource group if it exists
  #
  # @author Russell Seymour
  #
  # @param [String] name Name of the resource group
  #
  # @return [Azure::ARM::Resources::Models::ResourceListResult] Object containing array of all the resources
  def get_resources(name)
    client.resource_groups.list_resources_as_lazy(name) if exists(name)
  end
end

# Class to return a ComputeManagement client to get information about VMs
#
# @author Russell Seymour
#
# @attr_reader [Azure::ARM::Compute::ComputeManagementClient] client ComputeManagement client object
class ComputeManagement
  attr_reader :client

  # Constructor for the class.  Creates the new Network Management client object
  #
  # @author Russell Seymour
  #
  # @param [MsRest::TokenCredentials] azure Connection object for Azure
  def initialize(azure)
    @client = Azure::ARM::Compute::ComputeManagementClient.new(azure.connection)
    client.subscription_id = azure.subscription_id
  end
end

# Class to return a NetworkManagement client for use with NICs and Public IP Addresses
#
# @author Russell Seymour
# @attr_reader [Azure::ARM::Network::NetworkManagementClient] client Azure Network Management cient
class NetworkManagement
  attr_reader :client

  # Constructor for the class.  Creates the new Network Management client object
  #
  # @author Russell Seymour
  #
  # @param [MsRest::TokenCredentials] azure Connection object for Azure
  def initialize(azure)
    @client = Azure::ARM::Network::NetworkManagementClient.new(azure.connection)
    client.subscription_id = azure.subscription_id
  end
end