require 'aws/s3'
require 'erb'

namespace :heroku do

  def latest_bundle_name(app)
    %x{ heroku bundles #{app_option(app)}| cut -f 1 -d ' ' }.chomp
  end

  def app_option(app)
    '--app ' + app if app
  end

  def app_name(app)
    return app if app

    %x{heroku info}.split("\n")[0].split(' ')[1]
  end

  desc "Capture a new bundle and back it up to S3."
  task :backup, :app do |t, args|
    app = args[:app]

    # Warn that we're about to blow out the latest bundle.

    print 'WARNING: This will destroy the most recent bundle.  Do you wish to proceed? (y/n) '
    answer = STDIN.gets.chomp
    exit unless answer == 'y'

    puts
    puts '===== Deleting most recent bundle from Heroku...'

    %x{ heroku bundles:destroy #{latest_bundle_name(app)} #{app_option(app)} }

    puts '===== Capturing a new bundle...'

    %x{ heroku bundles:capture #{app_option(app)} }

    while %x{ heroku bundles #{app_option(app)} | grep complete }.empty?
      sleep 10
    end

    puts '===== Downloading new bundle...'

    %x{ heroku bundles:download #{app_option(app)} }

    puts '===== Pushing the bundle up to S3...'

    # Establish a connection to S3.
    aws_creds =  YAML::load(ERB.new(File.read(File.join(Dir.getwd, 'config', 'amazon_s3.yml'))).result)["default"]

    AWS::S3::Base.establish_connection!(
      :access_key_id     => aws_creds["access_key_id"],
      :secret_access_key => aws_creds["secret_access_key"]
    )

    current_app_name = app_name(app)
    bundle_file_name = current_app_name + '.tar.gz'

    AWS::S3::S3Object.store(latest_bundle_name(app) + '.tar.gz', open(bundle_file_name), current_app_name + '-backups')

    puts '===== Deleting the temporary bundle file...'

    FileUtils.rm(bundle_file_name)
  end
end