# 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/>.

# == Schema Information
#
# Table name: terraform_libvirt_backends
#
#  id         :integer          not null, primary key
#  label      :string
#  uri        :string
#  created_at :datetime         not null
#  updated_at :datetime         not null
#  domain     :string
#

require 'ruby_terraform'

class Backends::TerraformLibvirt < ApplicationRecord
  has_many :mini_environments, as: :backend

  self.table_name = 'terraform_libvirt_backends'

  def self.label
    'libvirt'
  end

  def type_and_id
    "#{self.class.name}=#{id}"
  end

  def build(mini_environment)
    slug = mini_environment.name.parameterize

    GovukGuix::BuildJob.enqueue(
      mini_environment.id,
      services: mini_environment.services.map(&:build_argument_string),
      arguments: {
        type: 'vm-image-and-system',
        app_domain: "#{slug}.#{domain}",
        web_domain: "www.#{slug}.#{domain}",
        # Assume that this is a local environment, and not externally
        # accessible
        use_https: 'development',
        http_ports_mode: 'standard',
        host_name: "#{slug}.#{domain}",
        admin_environment_label: mini_environment.name,
        signon_instance_name: slug,
        use_error_pages: 'true',
        origin_basic_auth: "#{slug}=#{slug}",
        data_snapshot: mini_environment.data_snapshot.try(:store_path)
      }.compact
    )
  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 deploy_backend
    TerraformWorkingDirectory.new(
      terraform_state_id,
      'terraform/libvirt/backend'
    ).within_working_directory do
      RubyTerraform.apply(
        vars: {
          uri: uri,
          domain: domain
        },
        auto_approve: true
      )
    end
  end

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

  def terraform_state_id
    "backend/terraform_libvirt/#{id}"
  end

  def within_terraform_working_directory(mini_environment, &block)
    TerraformWorkingDirectory.new(
      "mini_environment/#{mini_environment.id}",
      'terraform/libvirt/mini_environment'
    ).within_working_directory(&block)
  end

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

  def terraform_variables(mini_environment)
    slug = mini_environment.name.parameterize

    {
      uri: uri,
      machine_name: slug,
      host_name: "#{slug}.#{domain}",
      vm_image_and_system: mini_environment.backend_data['build_output'],
      backend_remote_state_address: (
        'http://localhost:3000' +
        Rails
          .application
          .routes
          .url_helpers
          .terraform_http_backend_path(terraform_state_id)
      )
    }
  end
end