class Falcon::Adapters::Rack

def call(request)
	request_path, query_string = request.path.split('?', 2)
	server_name, server_port = (request.authority || '').split(':', 2)
	
	env = {
		'rack.version' => [2, 0, 0],
		
		'rack.input' => Input.new(request.body),
		'rack.errors' => $stderr,
		
		'rack.multithread' => true,
		'rack.multiprocess' => true,
		'rack.run_once' => false,
		
		# The HTTP request method, such as “GET” or “POST”. This cannot ever be an empty string, and so is always required.
		'REQUEST_METHOD' => request.method,
		
		# The initial portion of the request URL's “path” that corresponds to the application object, so that the application knows its virtual “location”. This may be an empty string, if the application corresponds to the “root” of the server.
		'SCRIPT_NAME' => '',
		
		# The remainder of the request URL's “path”, designating the virtual “location” of the request's target within the application. This may be an empty string, if the request URL targets the application root and does not have a trailing slash. This value may be percent-encoded when originating from a URL.
		'PATH_INFO' => request_path,
		
		# The portion of the request URL that follows the ?, if any. May be empty, but is always required!
		'QUERY_STRING' => query_string || '',
		
		# The server protocol, e.g. HTTP/1.1
		'SERVER_PROTOCOL' => request.version,
		'rack.url_scheme' => 'http',
		
		# I'm not sure what sane defaults should be here:
		'SERVER_NAME' => server_name || '',
		'SERVER_PORT' => server_port || '',
	}
	
	if content_type = request.headers.delete('content-type')
		env['CONTENT_TYPE'] = content_type
	end
	
	if content_length = request.headers.delete('content-length')
		env['CONTENT_LENGTH'] = content_length
	end
	
	self.unwrap_headers(request.headers, env)
	
	# HTTP/2 prefers `:authority` over `host`, so we do this for backwards compatibility.
	env['HTTP_HOST'] ||= request.authority
	
	if remote_address = request.remote_address
		env['REMOTE_ADDR'] = remote_address.ip_address if remote_address.ip?
	end
	
	if request.hijack?
		env['rack.hijack?'] = true
		
		env['rack.hijack'] = lambda do
			wrapper = request.hijack
			
			# We dup this as it might be taken out of the normal control flow, and the io will be closed shortly after returning from this method.
			io = wrapper.io.dup
			wrapper.close
			
			env['rack.hijack_io'] = io
		end
	else
		env['rack.hijack?'] = false
	end
	
	status, headers, body = @app.call(env)
	
	# if hijack = headers.delete('rack.hijack')
	# 	body = Async::HTTP::Body::Writable.new
	# 
	# 	Task.current.async do
	# 		hijack.call(body)
	# 	end
	# 	return nil
	# end
	
	# if env['rack.hijack_io']
	# 	return nil
	# end
	
	@logger.debug(request) {"Rack response: #{status} #{headers.inspect} #{body.class}"}
	return Response.wrap(status, headers, body)
rescue => exception
	@logger.error "#{exception.class}: #{exception.message}\n\t#{$!.backtrace.join("\n\t")}"
	
	return failure_response(exception)
end

def failure_response(exception)
	Async::HTTP::Response.for_exception(exception)
end

def initialize(app, logger = Async.logger)
	@app = app
	
	@logger = logger
end

def unwrap_headers(headers, env)
	headers.each do |key, value|
		http_key = "HTTP_#{key.upcase.tr('-', '_')}"
		
		if current_value = env[http_key]
			env[http_key] = "#{current_value}\n#{value}"
		else
			env[http_key] = value
		end
	end
end