# GOV.UK Mini Environment Admin
# Copyright © 2018  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::TerraformAws::MiniEnvironmentMethods
  def build(mini_environment)
    slug = mini_environment.name.parameterize

    GovukGuix::BuildMiniEnvironment.build(
      mini_environment.id,
      services: mini_environment.services.map(&:build_argument_string),
      arguments: {
        type: 'container-start-script',
        app_domain: "#{slug}.#{domain}",
        web_domain: "www.#{slug}.#{domain}",
        use_https: 'certbot',
        http_ports_mode: 'alternative',
        read_bundle_install_input_as_tar_archive: true,
        signon_instance_name: slug,
        admin_environment_label: mini_environment.name,
        use_error_pages: 'true',
        origin_basic_auth: "#{slug}=#{slug}",
        share: [
          '/var/cache/govuk-mini-environment-admin=/var/cache',
          '/var/lib/govuk-mini-environment-admin=/var/lib',
          '/var/log/govuk-mini-environment-admin=/var/log'
        ]
      },
      run_remotely_on_host: mini_environment.backend.build_remote_host
    )
  end

  def start(mini_environment)
    logger.info "Setting up #{mini_environment.name}"

    within_terraform_working_directory(mini_environment) do
      RubyTerraform.apply(
        vars: terraform_variables(mini_environment),
        auto_approve: true
      )
    end
  end

  def destroy(mini_environment)
    within_terraform_working_directory(mini_environment) do
      RubyTerraform.destroy(
        vars: terraform_variables(mini_environment),
        force: true
      )
    end
  end

  def refresh(mini_environment)
    within_terraform_working_directory(mini_environment) do
      RubyTerraform.refresh(
        vars: terraform_variables(mini_environment)
      )
    end
  end

  def terraform_states(mini_environment)
    TerraformState.where(
      state_id: mini_environment_state_id(mini_environment)
    )
  end

  def within_terraform_working_directory(mini_environment, &block)
    with_advisory_lock(
      "aws_mini_environment_terraform_working_directory/#{mini_environment.id}"
    ) do
      TerraformWorkingDirectory.new(
        mini_environment_state_id(mini_environment),
        'terraform/aws/mini_environment'
      ).within_working_directory(&block)
    end
  end

  def mini_environment_state_id(mini_environment)
    "mini_environment/#{mini_environment.id}"
  end

  def signon_url(mini_environment)
    "https://signon.#{mini_environment.name.parameterize}.#{domain}"
  end

  def terraform_variables(mini_environment)
    credentials = TerraformHttpBackendController.credentials

    common_terraform_variables.merge(
      slug: mini_environment.name.parameterize,
      start_command: mini_environment.backend_data['build_output'],
      backend_remote_state_address: (
        Plek.new.external_url_for('mini-environment-admin') +
        Rails
          .application
          .routes
          .url_helpers
          .terraform_http_backend_path(terraform_state_id)
      ),
      backend_remote_state_username: credentials[:name],
      backend_remote_state_password: credentials[:password]
    )
  end
end