module JamRuby

  # describes an audio track (like the drums, or guitar) that comprises a JamTrack
  class JamTrackTrack < ActiveRecord::Base
    include JamRuby::S3ManagerMixin

    # there should only be one Master per JamTrack, but there can be N Track per JamTrack
    TRACK_TYPE = %w{Master Track}

    mount_uploader :url, JamTrackTrackUploader

    attr_accessible :track_type, :instrument, :instrument_id, :position, :part, :url, as: :admin

    validates :position,        presence: true, numericality: {only_integer: true}, length: {in: 1..1000}
    validates :part,            length: {maximum: 20}
    validates :track_type,      inclusion: {in: TRACK_TYPE }
    validates_uniqueness_of     :position, scope: :jam_track_id
    validates_uniqueness_of     :part, scope: :jam_track_id
    # validates :jam_track,       presence: true

    belongs_to :instrument, class_name: "JamRuby::Instrument"
    belongs_to :jam_track, class_name: "JamRuby::JamTrack"

    # create storage directory that will house this jam_track, as well as
    def store_dir
      "#{jam_track.store_dir}/tracks"
    end

    # create name of the file
    def filename
      track_type == 'Master' ? 'master.ogg' : "#{part}.ogg"
    end

    # creates a short-lived URL that has access to the object.
    # the idea is that this is used when a user who has the rights to this tries to download this JamTrack
    # we would verify their rights (can_download?), and generates a URL in response to the click so that they can download
    # but the url is short lived enough so that it wouldn't be easily shared
    def sign_url(expiration_time = 120)
      s3_manager.sign_url(self[:url], {:expires => expiration_time, :response_content_type => 'audio/ogg', :secure => false})
    end

    def can_download?(user)
      # I think we have to make a special case for 'previews', but maybe that's just up to the controller to not check can_download?
      jam_track.owners.include?(user)
    end
  end
end