image.rb

class Image < ActiveRecord::Base
  
  belongs_to :user
  belongs_to :attachment, :polymorphic => true
  
  # validates_presence_of :url
  
  before_save :check_for_defaults
  
  default_scope :order => 'id asc'
  
  META = { :small => { :width => 150, :height => 150, :prefix => 's_', :watermark => File.join(Rails.root,'public','images',"watermark-small.png")},
           :large => { :width => 500, :height => 500, :prefix => 'l_', :watermark => File.join(Rails.root,'public','images',"watermark-large.png")}}

  DEFAULTS = { :title => 'Title', :description => 'Description' }
  OUTPUT_FORMAT = 'jpg'
  PROFILE_PHOTO_NAME = 'profile.' + OUTPUT_FORMAT
  PATH_PREFIX = '/images'
  DEFAULT_IMAGES = {:workout => Image.new(:image_path => 'default_workout.png', :attachment_type => 'Workout'),
                    :plan => Image.new(:image_path => 'default_workout.png', :attachment_type => 'Plan')}
  
  
  # for holding a file that's about to be uploaded (this isn't actually saved to the DB)
  attr_accessor :file
  
  
  def full_path_prefix
    S3_CONFIG[:object_prefix].to_s + PATH_PREFIX + '/' + self.attachment_type.downcase 
  end
  
  
  def url(size=:small)
    S3_CONFIG[:url] + self.full_path_prefix + '/' + META[size][:prefix] + self.image_path
  end
  
  
  # the date to display for this photo
  def display_date
    if self.taken_on
      "Taken on #{self.taken_on.to_s(:long)}"
    else
      "Uploaded on #{self.created_at.to_s(:long)}"
    end
  end
  
  
  # takes the current instance and uploaded its attached file to S3
  def upload
    if self.file
      remote_filename = UUID.new.generate + '.' + OUTPUT_FORMAT # filename becomes the timestamp to avoid name conflicts
      
      # upload the large size and then, assuming it works, upload the rest
      #begin
        if self.image_path = create_and_upload_image(:large, remote_filename)
          create_and_upload_image(:small, remote_filename)
          return true
        else
          return false
        end
      #rescue => e
      #  logger.error("** ERROR: Problem uploading to S3: #{e.message}\n\n#{e.backtrace}\n\n")
        # HoptoadNotifier.notify(e)
      #end

    else
      raise 'No file attached to photo'
    end
  end
  
  
  private
    # since we populate the title and description text boxes with default values, we need to set them to blank if they still contain the defaults
    def check_for_defaults
      DEFAULTS.each do |key,value|
        self.send(key.to_s+'=','') if self.send(key.to_s) == value
      end
    end

    
    # Creates and uploads a single image (the model should know everything it needs to about an image, including how to save itself wherever)
    # Returns the name of the file it just uploaded (or throws an error if something goes wrong)
    def create_and_upload_image(size,filename)
      #begin
        image = MiniMagick::Image.from_file(self.file.tempfile)                       # get the uploaded image
        final_image_name = META[size][:prefix] + filename                               # figure out the final name
        s3_path = File.join(self.full_path_prefix, final_image_name)                    # figure out the final S3 path
        image.resize "#{META[size][:width]}x#{META[size][:height]}>"                    # 250x188> standard ImageMagick geometry
        AWS::S3::S3Object.store(s3_path, image.tempfile.open, S3_CONFIG[:bucket_name], :access => :public_read)   # reopen the tempfile and write directly to S3
        return filename
      #rescue => e
      #  logger.error("** ERROR: Problem uploading to S3: #{e.message}\n\n#{e.backtrace}\n\n")
        # HoptoadNotifier.notify(e)
      #ensure
        #File.delete(composite_output_path)    # the final composited file
        #[watermark.tempfile, image.tempfile, output.tempfile].each { |f| f.close! unless f.nil? }   # any temp files that mini_magick was using
      #  image.tempfile.close! unless image.tempfile.nil?
      #end
    end
    
end