require "resource_support/aws/aws_singular_resource_mixin"
require "resource_support/aws/aws_backend_base"
require "aws-sdk-kms"

class AwsKmsKey < Inspec.resource(1)
  name "aws_kms_key"
  desc "Verifies settings for an individual AWS KMS Key"
  example <<~EXAMPLE
    describe aws_kms_key('arn:aws:kms:us-east-1::key/4321dcba-21io-23de-85he-ab0987654321') do
      it { should exist }
    end
  EXAMPLE

  supports platform: "aws"

  include AwsSingularResourceMixin
  attr_reader :key_id, :arn, :creation_date, :key_usage, :key_state, :description,
              :deletion_date, :valid_to, :external, :has_key_expiration, :managed_by_aws,
              :has_rotation_enabled, :enabled
  # Use aliases for matchers
  alias deletion_time deletion_date
  alias invalidation_time valid_to
  alias external? external
  alias enabled? enabled
  alias managed_by_aws? managed_by_aws
  alias has_key_expiration? has_key_expiration
  alias has_rotation_enabled? has_rotation_enabled

  def to_s
    "KMS Key #{@key_id}"
  end

  def created_days_ago
    ((Time.now - creation_date) / (24 * 60 * 60)).to_i unless creation_date.nil?
  end

  private

  def validate_params(raw_params)
    validated_params = check_resource_param_names(
      raw_params: raw_params,
      allowed_params: [:key_id],
      allowed_scalar_name: :key_id,
      allowed_scalar_type: String
    )

    if validated_params.empty?
      raise ArgumentError, "You must provide the parameter 'key_id' to aws_kms_key."
    end

    validated_params
  end

  def fetch_from_api
    backend = BackendFactory.create(inspec_runner)

    query = { key_id: @key_id }
    catch_aws_errors do

      resp = backend.describe_key(query)

      @exists = true
      @key = resp.key_metadata.to_h
      @key_id = @key[:key_id]
      @arn = @key[:arn]
      @creation_date = @key[:creation_date]
      @enabled = @key[:enabled]
      @description = @key[:description]
      @key_usage = @key[:key_usage]
      @key_state = @key[:key_state]
      @deletion_date = @key[:deletion_date]
      @valid_to = @key[:valid_to]
      @external = @key[:origin] == "EXTERNAL"
      @has_key_expiration = @key[:expiration_model] == "KEY_MATERIAL_EXPIRES"
      @managed_by_aws = @key[:key_manager] == "AWS"

      resp = backend.get_key_rotation_status(query)
      @has_rotation_enabled = resp.key_rotation_enabled unless resp.empty?
    rescue Aws::KMS::Errors::NotFoundException
      @exists = false
      return

    end
  end

  class Backend
    class AwsClientApi < AwsBackendBase
      BackendFactory.set_default_backend(self)
      self.aws_client_class = Aws::KMS::Client

      def describe_key(query)
        aws_service_client.describe_key(query)
      end

      def get_key_rotation_status(query)
        aws_service_client.get_key_rotation_status(query)
      end
    end
  end
end