# frozen_string_literal: true

# Copyright, 2018, by Samuel G. D. Williams. <http://www.codeotaku.com>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

require_relative 'wrapper'

require 'digest/sha2'

module Protocol
	module HTTP
		module Body
			# Invokes a callback once the body has finished reading.
			class Digestable < Wrapper
				def self.wrap(message, digest = Digest::SHA256.new, &block)
					if body = message&.body and !body.empty?
						message.body = self.new(message.body, digest, block)
					end
				end
				
				def initialize(body, digest = Digest::SHA256.new, callback = nil)
					super(body)
					
					@digest = digest
					@callback = callback
				end
				
				def digest
					@digest
				end
				
				def etag
					@digest.hexdigest.dump
				end
				
				def read
					if chunk = super
						@digest.update(chunk)
						
						return chunk
					else
						@callback&.call(self)
						
						return nil
					end
				end
			end
		end
	end
end
