images.rake

# aws-sdk
# aws-sdk-resources
# rmagick

class ResizeImages

  attr_reader :all_image_names, :s3
  attr_accessor :width, :height, :image_file_name

  def initialize args
    @image_file_name = args.fetch(:image_file_name, nil)
    @height = args.fetch(:height, 'normal')
    @width  = args.fetch(:width, 'normal')
    @all_image_names = ::Image.select 'asset_file_name'
    @s3 = S3Client.new
    set_constraints
  end

  # The height and width can be given in string format
  # or numeric. The string format takes just the arg height: 'constraint'
  # or width: 'constraint' with the same result
  def set_constraints
    case self.height || self.width
      when 'normal'
        @height, @width = 930, 350
      when 'medium'
        @height, @width = 500, 250
      when 'thumb'
        @height, @width = 100, 100
    end
  end

  def all prefix='thumb'
    self.all_image_names.each do |name|
      unless self.s3.has_thumbnail?(name.asset_file_name)
        image = self.to_magick_object name.asset_file_name
        resized_image = self.resize image
        self.s3.put_image name.asset_file_name, prefix, resized_image
      else
        s3.found_image_message
      end
    end
  end

  def single prefix='thumb'
    unless self.s3.has_thumbnail?(self.image_file_name)
      image = self.to_magick_object self.image_file_name
      resized_image = self.resize image
      self.s3.put_image self.image_file_name, prefix, resized_image
    else
      s3.found_image_message
    end
  end

  def to_magick_object image_name
    # TODO figure out the IO errors for reading the file
    image = self.s3.get_image(image_name, 'normal')
    Magick::Image.read(image.read).first
  end

  def resize! magick_image
    magick_image.resize self.width, self.height
  end

end

class S3Client
  attr_reader :id, :secret, :creds, :client, :bucket_name, :resource, :bucket

  def initialize bucket_name='field-journal'
    @bucket_name = bucket_name
    @id     = ENV['aws_access_key_id']
    @secret = ENV['aws_secret_access_key']
    @creds  = Aws::Credentials.new(@id, @secret)
    @client = Aws::S3::Client.new(region: 'us-west-2', credentials: @creds)
    @resource = Aws::S3::Resource.new(region: 'us-west-2', credentials: @creds)
    @bucket =  @resource.bucket(@bucket_name)
  end

  def object_exists? key, prefix
    self.bucket.object(add_prefix(key, prefix)).exists?
  end

  def has_thumbnail? key
    object_exists? key, 'thumb'
  end

  def get_image key, prefix
    if object_exists? key, prefix
      self.client.get_object(bucket: self.bucket_name, key: add_prefix(key, prefix)).body
    else
      raise "Unable to find #{add_prefix(key, prefix)}".colorize(:red)
    end
  end

  def put_image key, prefix, body
    self.client.put_object(bucket: self.bucket_name,
                       key: add_prefix(key, prefix),
                       body: body)
    created_image_message
  rescue
    puts "Something went horrible wrong contact Jonan, or we could not create an image"
  end

  def found_image_message
    puts "A thumbnail has been found for this image at:".colorize(:green)
    puts "http://s3-us-west-2.amazonaws.com/field-journal/uploads/thumb/#{name}"
  end

  def created_image_message height, width, image_name
    puts "you have successfully created an image".colorize(:green)
    puts "height: #{height}"
    puts "width: #{width}"
    puts "image_name: #{image_name}"
  end

  def add_prefix name, prefix
    "uploads/#{prefix}/#{name}"
  end

end

desc 'resize all images into thumbnails if the thumbnail key does not exist'
namespace :images do
  task 'resize:all' => :environment do
    ResizeImages.new(thumb: 'thumb').all
  end
end

# Takes an argument as rake images:resize:single image_name='name'
desc "resize a single image with the arg imge_name='file_name'"
namespace :images do
  task 'resize:single' => :environment do
    resize = ResizeImages.new(image_file_name: ENV["image_name"], height: 'thumb')
    resize.single
  end
end