module Gitlab
  module Kubernetes
    class Helm::Pod
      def initialize(command, namespace_name, kubeclient)
        @command = command
        @namespace_name = namespace_name
        @kubeclient = kubeclient
      end

      def generate
        spec = { containers: [container_specification], restartPolicy: 'Never' }
        if command.chart_values_file
          generate_config_map
          spec['volumes'] = volumes_specification
        end
        ::Kubeclient::Resource.new(metadata: metadata, spec: spec)
      end

      private

      attr_reader :command, :namespace_name, :kubeclient

      def container_specification
        container = {
          name: 'helm',
          image: 'alpine:3.6',
          env: generate_pod_env(command),
          command: %w(/bin/sh),
          args: %w(-c $(COMMAND_SCRIPT))
        }
        container[:volumeMounts] = volume_mounts_specification if command.chart_values_file
        container
      end

      def labels
        { 'gitlab.org/action': 'install', 'gitlab.org/application': command.name }
      end

      def metadata
        { name: command.pod_name, namespace: namespace_name, labels: labels }
      end

      def volume_mounts_specification
        [{ name: 'config-volume', mountPath: '/etc/config' }]
      end

      def volumes_specification
        [{ name: 'config-volume', configMap: { name: 'values-config' } }]
      end

      def generate_pod_env(command)
        {
          HELM_VERSION: Gitlab::Kubernetes::Helm::HELM_VERSION,
          TILLER_NAMESPACE: namespace_name,
          COMMAND_SCRIPT: command.generate_script(namespace_name)
        }.map { |key, value| { name: key, value: value } }
      end

      def generate_config_map
        resource = ::Kubeclient::Resource.new
        resource.metadata = { name: 'values-config', namespace: namespace_name }
        resource.data = YAML.load_file(command.chart_values_file)
        kubeclient.create_config_map(resource)
      end
    end
  end
end