module Lipsiadmin
  module Attachment
    module Storage

      # The default place to store attachments is in the filesystem. Files on the local
      # filesystem can be very easily served by Apache without requiring a hit to your app.
      # They also can be processed more easily after they've been saved, as they're just
      # normal files. There is one Filesystem-specific option for has_attached_file.
      # * +path+: The location of the repository of attachments on disk. This can (and, in
      #   almost all cases, should) be coordinated with the value of the +url+ option to
      #   allow files to be saved into a place where Apache can serve them without
      #   hitting your app. Defaults to 
      #   ":rails_root/public/:attachment/:id/:style/:basename.:extension"
      #   By default this places the files in the app's public directory which can be served 
      #   directly. If you are using capistrano for deployment, a good idea would be to 
      #   make a symlink to the capistrano-created system directory from inside your app's 
      #   public directory.
      #   See Attachment::Attachment#interpolate for more information on variable interpolaton.
      #     :path => "/var/app/attachments/:class/:id/:style/:basename.:extension"
      module Filesystem
        def self.extended base
        end

        def exists?(style = default_style)
          if original_filename
            File.exist?(path(style))
          else
            false
          end
        end

        # Returns representation of the data of the file assigned to the given
        # style, in the format most representative of the current storage.
        def to_file(style = default_style)
          @queued_for_write[style] || (File.new(path(style), 'rb') if exists?(style))
        end
        alias_method :to_io, :to_file

        def flush_writes #:nodoc:
          logger.info("[Attachment] Writing files for #{name}")
          @queued_for_write.each do |style, file|
            file.close
            logger.info "[Attachment] Directory for file is #{File.dirname(path(style))}"
            FileUtils.mkdir_p(File.dirname(path(style)))
            logger.info("[Attachment] -> #{path(style)}")
            FileUtils.mv(file.path, path(style))
            FileUtils.chmod(0644, path(style))
          end
          @queued_for_write = {}
        end

        def flush_deletes #:nodoc:
          logger.info("[Attachment] Deleting files for #{name}")
          @queued_for_delete.each do |path|
            begin
              logger.info("[Attachment] -> #{path}")
              FileUtils.rm(path) if File.exist?(path)
            rescue Errno::ENOENT => e
              # ignore file-not-found, let everything else pass
            end
            begin
              while(true)
                path = File.dirname(path)
                FileUtils.rmdir(path)
              end
            rescue Errno::ENOTEMPTY, Errno::ENOENT, Errno::EINVAL, Errno::ENOTDIR
              # Stop trying to remove parent directories
            rescue SystemCallError => e
              logger.info("[Attachment] There was an unexpected error while deleting directories: #{e.class}")
              # Ignore it
            end
          end
          @queued_for_delete = []
        end
      end

      # Amazon's S3 file hosting service is a scalable, easy place to store files for
      # distribution. You can find out more about it at http://aws.amazon.com/s3
      # There are a few S3-specific options for has_attached_file:
      # * +s3_credentials+: Takes a path, a File, or a Hash. The path (or File) must point
      #   to a YAML file containing the +access_key_id+ and +secret_access_key+ that Amazon
      #   gives you. You can 'environment-space' this just like you do to your
      #   database.yml file, so different environments can use different accounts:
      #     development:
      #       access_key_id: 123...
      #       secret_access_key: 123... 
      #     test:
      #       access_key_id: abc...
      #       secret_access_key: abc... 
      #     production:
      #       access_key_id: 456...
      #       secret_access_key: 456... 
      #   This is not required, however, and the file may simply look like this:
      #     access_key_id: 456...
      #     secret_access_key: 456... 
      #   In which case, those access keys will be used in all environments. You can also
      #   put your bucket name in this file, instead of adding it to the code directly.
      #   This is useful when you want the same account but a different bucket for 
      #   development versus production.
      # * +s3_permissions+: This is a String that should be one of the "canned" access
      #   policies that S3 provides (more information can be found here:
      #   http://docs.amazonwebservices.com/AmazonS3/2006-03-01/RESTAccessPolicy.html#RESTCannedAccessPolicies)
      #   The default for Attachment is "public-read".
      # * +s3_protocol+: The protocol for the URLs generated to your S3 assets. Can be either 
      #   'http' or 'https'. Defaults to 'http' when your :s3_permissions are 'public-read' (the
      #   default), and 'https' when your :s3_permissions are anything else.
      # * +s3_headers+: A hash of headers such as {'Expires' => 1.year.from_now.httpdate}
      # * +bucket+: This is the name of the S3 bucket that will store your files. Remember
      #   that the bucket must be unique across all of Amazon S3. If the bucket does not exist
      #   Attachment will attempt to create it. The bucket name will not be interpolated.
      # * +url+: There are two options for the S3 url. You can choose to have the bucket's name
      #   placed domain-style (bucket.s3.amazonaws.com) or path-style (s3.amazonaws.com/bucket).
      #   Normally, this won't matter in the slightest and you can leave the default (which is
      #   path-style, or :s3_path_url). But in some cases paths don't work and you need to use
      #   the domain-style (:s3_domain_url). Anything else here will be treated like path-style.
      # * +path+: This is the key under the bucket in which the file will be stored. The
      #   URL will be constructed from the bucket and the path. This is what you will want
      #   to interpolate. Keys should be unique, like filenames, and despite the fact that
      #   S3 (strictly speaking) does not support directories, you can still use a / to
      #   separate parts of your file name.
      module S3
        def self.extended base
          require 'right_aws'
          base.instance_eval do
            @s3_credentials = parse_credentials(@options[:s3_credentials])
            @bucket         = @options[:bucket]         || @s3_credentials[:bucket]
            @s3_options     = @options[:s3_options]     || {}
            @s3_permissions = @options[:s3_permissions] || 'public-read'
            @s3_protocol    = @options[:s3_protocol]    || (@s3_permissions == 'public-read' ? 'http' : 'https')
            @s3_headers     = @options[:s3_headers]     || {}
            @url            = ":s3_path_url" unless @url.to_s.match(/^:s3.*url$/)
          end
          base.class.interpolations[:s3_path_url] = lambda do |attachment, style|
            "#{attachment.s3_protocol}://s3.amazonaws.com/#{attachment.bucket_name}/#{attachment.path(style).gsub(%r{^/}, "")}"
          end
          base.class.interpolations[:s3_domain_url] = lambda do |attachment, style|
            "#{attachment.s3_protocol}://#{attachment.bucket_name}.s3.amazonaws.com/#{attachment.path(style).gsub(%r{^/}, "")}"
          end
          ActiveRecord::Base.logger.info("[Attachment] S3 Storage Initalized.")
        end

        def s3
          @s3 ||= RightAws::S3.new(@s3_credentials[:access_key_id],
                                   @s3_credentials[:secret_access_key],
                                   @s3_options)
        end

        def s3_bucket
          @s3_bucket ||= s3.bucket(@bucket, true, @s3_permissions)
        end

        def bucket_name
          @bucket
        end

        def parse_credentials(creds)
          creds = find_credentials(creds).stringify_keys
          (creds[ENV['RAILS_ENV']] || creds).symbolize_keys
        end

        def exists?(style = default_style)
          s3_bucket.key(path(style)) ? true : false
        end

        def s3_protocol
          @s3_protocol
        end

        # Returns representation of the data of the file assigned to the given
        # style, in the format most representative of the current storage.
        def to_file(style = default_style)
          @queued_for_write[style] || s3_bucket.key(path(style))
        end
        alias_method :to_io, :to_file

        def flush_writes #:nodoc:
          logger.info("[Attachment] Writing files for #{name}")
          @queued_for_write.each do |style, file|
            begin
              logger.info("[Attachment] -> #{path(style)}")
              key = s3_bucket.key(path(style))
              key.data = file
              key.put(nil, @s3_permissions, {'Content-type' => instance_read(:content_type)}.merge(@s3_headers))
            rescue RightAws::AwsError => e
              raise
            end
          end
          @queued_for_write = {}
        end

        def flush_deletes #:nodoc:
          logger.info("[Attachment] Writing files for #{name}")
          @queued_for_delete.each do |path|
            begin
              logger.info("[Attachment] -> #{path}")
              if file = s3_bucket.key(path)
                file.delete
              end
            rescue RightAws::AwsError
              # Ignore this.
            end
          end
          @queued_for_delete = []
        end

        def find_credentials(creds)
          case creds
          when File:
            YAML.load_file(creds.path)
          when String:
            YAML.load_file(creds)
          when Hash:
            creds
          else
            raise ArgumentError, "Credentials are not a path, file, or hash."
          end
        end
        private :find_credentials

      end
    end
  end
end