# GOV.UK Mini Environment Admin
# Copyright © 2018, 2019  Christopher Baines <mail@cbaines.net>
#
# This file is part of the GOV.UK Mini Environment Admin.
#
# The GOV.UK Mini Environment Admin is free software: you can
# redistribute it and/or modify it under the terms of the GNU Affero
# General Public License as published by the Free Software Foundation,
# either version 3 of the License, or (at your option) any later
# version.
#
# The GOV.UK Mini Environment Admin is distributed in the hope that it
# will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public
# License along with the GOV.UK Mini Environment Admin.  If not, see
# <http://www.gnu.org/licenses/>.

module Backends::TerraformAwsUsingAmi::BackendMethods
  def create_data_snapshot
    GovukGuix::CreateDataSnapshotJob.enqueue(
      backend_type: self.class.name,
      backend_id: id
    )
  end

  def backend_terraform_variables
    public_ip_addresses = ENV[
      'GOVUK_MINI_ENVIRONMENT_ADMIN_PUBLIC_IP_ADDRESSES'
    ].split(',')

    raise 'missing public ip addresses' if public_ip_addresses.nil?

    egress_cidr_blocks = public_ip_addresses.map { |x| "#{x}/32" }

    common_terraform_variables.merge(
      aws_vpc_id: vpc_id,
      ssh_public_key: ssh_public_key,
      backend_slug: label.parameterize,
      mini_environment_admin_guix_public_key: guix_public_key,
      mini_environment_admin_egress_cidr_blocks: egress_cidr_blocks
    )
  end

  def deploy_backend
    within_backend_terraform_working_directory do
      RubyTerraform.apply(
        vars: backend_terraform_variables,
        auto_approve: true
      )
    end
  end

  def refresh_backend_state
    within_backend_terraform_working_directory do
      RubyTerraform.refresh(
        vars: backend_terraform_variables
      )
    end
  end

  def destroy_backend
    within_backend_terraform_working_directory do
      RubyTerraform.destroy(
        vars: backend_terraform_variables,
        force: true
      )
    end
  end

  def stop_backend
    within_backend_terraform_working_directory do
      RubyTerraform.destroy(
        vars: backend_terraform_variables,
        target: 'aws_spot_instance_request.main',
        force: true
      )
    end
  end

  def in_use_store_paths
    [
      GovukGuix::Revision.where(archived: false).pluck(:store_path),
      available_data_snapshots.pluck(:store_path),
      mini_environments
        .where(archived: false)
        .pluck(:backend_data)
        .map { |x| x&.dig('build_output') }
    ].flatten.compact
  end

  def update_guix_gcroots
    GovukGuix::UpdateGcrootsDirectory.set_in_use_store_paths(
      in_use_store_paths,
      run_remotely_on_host: build_remote_host
    )
  end

  def add_in_use_store_path(store_path)
    GovukGuix::UpdateGcrootsDirectory.add_store_path(
      store_path,
      run_remotely_on_host: build_remote_host
    )
  end

  def within_backend_terraform_working_directory(&block)
    with_advisory_lock(
      "terraform"
    ) do
      TerraformWorkingDirectory.new(
        terraform_state_id,
        'terraform/aws_using_ami/backend'
      ).within_working_directory(&block)
    end
  end

  def available_data_snapshots
    GovukGuix::DataSnapshot.where(backend: self)
  end

  def backend_terraform_states
    TerraformState.where(
      state_id: terraform_state_id
    )
  end

  def backend_latest_terraform_state
    backend_terraform_states.order(:id).last
  end

  def status
    latest_terraform_state = backend_terraform_states.order(:id).last

    running = (
      latest_terraform_state &&
      (latest_terraform_state.output_value('backend_up') == 'true')
    )

    {
      running: running,
      updated_at: latest_terraform_state.try(:created_at)
    }
  end
end