module JamRuby
  class Mix < ActiveRecord::Base
    include S3ManagerMixin

    MAX_MIX_TIME = 7200     # 2 hours

    before_destroy :delete_s3_files

    self.primary_key = 'id'
    belongs_to :recording, :class_name => "JamRuby::Recording", :inverse_of => :mixes



    def self.schedule(recording)
      raise if recording.nil?

      mix = Mix.new
      mix.recording = recording
      mix.save
      mix.url = construct_filename(mix.created_at, recording.id, mix.id)
      if mix.save
        mix.enqueue
      end

      mix
    end

    def enqueue
      begin
        Resque.enqueue(AudioMixer, self.id, self.sign_put)
      rescue
        # implies redis is down. we don't update started_at
        false
      end

      Mix.where(:id => self.id).update_all(:started_at => Time.now)

      true
    end

    def can_download?(some_user)
      !ClaimedRecording.find_by_user_id_and_recording_id(some_user.id, recording_id).nil?
    end


    def errored(reason, detail)
      self.error_reason = reason
      self.error_detail = detail
      self.error_count = self.error_count + 1
      save
    end

    def finish(length, md5)
      self.completed_at = Time.now
      self.length = length
      self.md5 = md5
      self.completed = true
      if save
        recording.users.each do |user|
          Notification.send_download_available(user.id)
        end
      end
    end

    # valid for 1 day; because the s3 urls eventually expire
    def manifest
      one_day = 60 * 60 * 24

      manifest = { "files" => [], "timeline" => [] }
      mix_params = []
      recording.recorded_tracks.each do |recorded_track|
        manifest["files"] << { "filename" => recorded_track.sign_url(one_day), "codec" => "vorbis", "offset" => 0 }
        mix_params << { "level" => 100, "balance" => 0 }
      end

      manifest["timeline"] << { "timestamp" => 0, "mix" => mix_params }
      manifest["output"] = { "codec" => "vorbis" }
      manifest["recording_id"] = self.id
      manifest
    end

    def s3_url
      s3_manager.s3_url(url)
    end
    
    def is_completed
      completed
    end

    def sign_url(expiration_time = 120)
      # expire link in 1 minute--the expectation is that a client is immediately following this link
      s3_manager.sign_url(self.url, {:expires => expiration_time, :response_content_type => 'audio/ogg', :secure => false})
    end

    def sign_put(expiration_time = 3600 * 24)
      s3_manager.sign_url(self.url, {:expires => expiration_time, :content_type => 'audio/ogg', :secure => false}, :put)
    end

    def self.queue_jobs_needing_retry
      Mix.find_each(:conditions => 'should_retry = TRUE or started_at is NULL', :batch_size => 100) do |mix|
        mix.enqueue
      end
    end

    private

    def delete_s3_files
      s3_manager.delete(filename)
    end

    def filename
      # construct a path for s3
      Mix.construct_filename(self.created_at, self.recording.id, self.id)
    end

    def self.construct_filename(created_at, recording_id, id)
      raise "unknown ID" unless id
      "recordings/#{created_at.strftime('%m-%d-%Y')}/#{recording_id}/mix-#{id}.ogg"
    end
  end
end