module Condo
	module Backend
		
		#
		# The following data needs to be stored in any backend
		# => provider_namespace (for handling multiple upload controllers, defaults to global)
		# => provider_name		(amazon, rackspace, google, azure etc)
		# => provider_location	(US West (Oregon) Region, Asia Pacific (Singapore) Region etc)
		# => user_id			(the identifier for the current user as a string)
		# => file_name			(the original upload file name)
		# => file_size			(the file size as indicated by the client)
		# => file_id			(some sort of identifying hash provided by the client)
		# => bucket_name		(the name of the users bucket)
		# => object_key			(the path to the object in the bucket)
		# => object_options		(custom options that were applied to this object - public/private etc)
		# => resumable_id		(the id of the chunked upload)
		# => resumable			(true if a resumable upload - must be set)
		# => custom_params		(application specific data - needs to be serialised and de-serialised)
		# => date_created		(the date the upload was started)
		#
		# => Each backend should have an ID that uniquely identifies an entry - id or upload_id
		#
		#
		#
		# Backends should inherit this class, set themselves as the backend and define the following:
		#
		# Class Methods:
		# => check_exists		({user_id, upload_id})							returns nil or an entry where all fields match
		# 		check_exists	({user_id, file_name, file_size, file_id})		so same logic for this
		# => add_entry ({user_id, file_name, file_size, file_id, provider_name, provider_location, bucket_name, object_key})
		#
		#			
		#
		# Instance Methods:
		# => update_entry ({upload_id, resumable_id})
		# => remove_entry (upload_id)
		#
		class ActiveRecord < ::ActiveRecord::Base
			
			attr_accessible :user_id, :file_name, :file_size, :file_id, :custom_params, 
				:provider_namespace, :provider_name, :provider_location, :bucket_name,
				:object_key, :object_options, :resumable_id, :resumable, :file_path
				
			
			self.table_name = "#{::ActiveRecord::Base.table_name_prefix}condo_uploads"
			

			serialize :custom_params, Hash
			serialize :object_options, Hash
			
			
			#
			# Checks for an exact match in the database given a set of parameters
			#
			def self.check_exists(params)
				params = {}.merge(params)
				params[:user_id] = params[:user_id].to_s if params[:user_id].present?
				params[:id] = params.delete(:upload_id).to_i if params[:upload_id].present?				
				
				self.where(params).first
			end
			
			#
			# Adds a new upload entry into the database
			#
			def self.add_entry(params)
				params = {}.merge(params)
				params.delete(:upload_id) if params[:upload_id].present?
				params.delete(:id) if params[:id].present?
				params.delete(:resumable_id) if params[:resumable_id].present?
				
				self.create!(params)
			end
			
			#
			# Updates self with the passed in parameters
			#
			def update_entry(params)
				result = self.update_attributes(params)
				raise ActiveResource::ResourceInvalid if result == false
				self
			end
			
			#
			# Deletes reference to the upload
			#
			def remove_entry
				self.destroy
			end
			
			
			#
			# Attribute accessors to comply with the backend spec
			#
			def upload_id
				self[:id]
			end
			
			def date_created
				self[:created_at]
			end
			
		end
	end
end