module Deis
  module Commands
    # Deploy a deis repo
    class Deploy < Struct.new(:app, :ref)
      include Helpers

      LAST_MIGRATION_CMD = %{bundle exec rake db:migrate:status}
      MIGRATION_REGEX    = /up\s+(?<migration>[0-9]{8}[0-9])+/

      attr_reader :worker_count
      attr_reader :web_count

      def run
        status "Deploying `#{ref}` to `#{app}` on Deis"
        precheck_migrations!
        output = deploy info['git_url'], ref: ref
        if output.include? 'Another git push is ongoing'
          sleep 60 # one minute
          return run_util 'deploy', app, ref
        end
        run_migrations! if needs_migrations?
      rescue NonZeroExitError => e
        raise e unless e.message.include? 'Another git push is ongoing'
        remove_instance_variable :@needs_migrations
        sleep 60
        retry
      end

      private

      def debug?
        true
      end

      def info
        @info ||= super(app)
      end

      def run_migrations!
        # Todo: put the site in a readonly state but NEVER in maintenance mode
        status 'Running Migrations'
        deis_command(:run, 'rake "db:create"', app: app)
        deis_command(:run, 'rake "db:migrate"', app: app)
      end

      def precheck_migrations!
        needs_migrations?
      end

      def needs_migrations?
        return false if TRUTHY_STRINGS.include? ENV['SKIP_MIGRATIONS']
        return true if TRUTHY_STRINGS.include? ENV['FORCE_MIGRATIONS']
        @needs_migrations ||= begin
          status 'Checking Migration Status'
          (local_migration != remote_migration).tap do |val|
            if val
              puts 'Database out of date, Migrations are Required'
            else
              puts 'Database is up to date'
            end
          end
        end
      end

      def remote_migration
        @remote_migration ||= sha_from_migration_status deis_command("run #{LAST_MIGRATION_CMD}", app: app)
      rescue NonZeroExitError
        'error'
      end

      def local_migration
        @local_migration ||= sha_from_migration_status shell(LAST_MIGRATION_CMD)
      rescue NonZeroExitError
        'error'
      end

      def sha_from_migration_status(result)
        lines           = result.lines.reject { |line| line.include? '**** NO FILE ****' }
        migration_lines = lines.map(&:strip).select { |line| line =~ MIGRATION_REGEX }
        Digest::SHA2.hexdigest migration_lines.join
      end

    end
  end
end