require 'cgi'

module Aws
  module Plugins

    # This plugin auto-populates the `:encoding_type` request parameter
    # to all calls made to Amazon S3 that accept it.
    #
    # This enables Amazon S3 to return object keys that might contain
    # invalid XML characters as URL encoded strings.  This plugin also
    # automatically decodes these keys so that the key management is
    # transparent to the user.
    #
    # If you specify the `:encoding_type` parameter, then this plugin
    # will be disabled, and you will need to decode the keys yourself.
    #
    # The following operations are managed:
    #
    # * {S3::Client#list_objects}
    # * {S3::Client#list_multipart_uploads}
    # * {S3::Client#list_object_versions}
    #
    class S3UrlEncodedKeys < Seahorse::Client::Plugin

      class Handler < Seahorse::Client::Handler

        def call(context)
          if context.params.key?(:encoding_type)
            @handler.call(context) # user managed
          else
            manage_keys(context)
          end
        end

        private

        def manage_keys(context)
          context.params[:encoding_type] = 'url'
          @handler.call(context).on_success do |resp|
            send("decode_#{resp.context.operation_name}_keys", resp.data)
          end
        end

        def decode_list_objects_keys(data)
          decode(:marker, data)
          decode(:next_marker, data)
          decode(:prefix, data)
          decode(:delimiter, data)
          data.contents.each { |o| decode(:key, o) } if data.contents
          data.common_prefixes.each { |o| decode(:prefix, o) } if data.common_prefixes
        end

        def decode_list_object_versions_keys(data)
          decode(:key_marker, data)
          decode(:next_key_marker, data)
          decode(:prefix, data)
          decode(:delimiter, data)
          data.versions.each { |o| decode(:key, o) } if data.versions
          data.delete_markers.each { |o| decode(:key, o) } if data.delete_markers
          data.common_prefixes.each { |o| decode(:prefix, o) } if data.common_prefixes
        end

        def decode_list_multipart_uploads_keys(data)
          decode(:key_marker, data)
          decode(:next_key_marker, data)
          decode(:prefix, data)
          decode(:delimiter, data)
          data.uploads.each { |o| decode(:key, o) } if data.uploads
          data.common_prefixes.each { |o| decode(:prefix, o) } if data.common_prefixes
        end

        def decode(member, struct)
          if struct[member]
            struct[member] = CGI.unescape(struct[member])
          end
        end

      end

      handler(Handler,
        step: :build,
        priority: 60, # run this just before/after the XML builder/parser
        operations: [
          :list_objects,
          :list_object_versions,
          :list_multipart_uploads,
        ]
      )

    end
  end
end