%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  
% The Rule-based Service for the GoPubMed Services
%
% http://www.gopubmed.org/
%
% It allows to query the GoPubMed services and retrieve the 
% data in the selected output format
%
% Currently the queries to GoPubMed are written in the native
% GoPubMed query syntax, but it is straightforward to
% add further transformation rules, which translate from a
% common platform-independent query language such as 
% XQuery, SQL, SPARQL into the platform-specific query language
% of the service (following the idea of web service and RPC 
% calls wrapped in SOAP)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% import of additional ContractLog libraries (modules)
:-eval(consult('ContractLog/utils.prova')).


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Meta-data facts about services
% TODO outsource this data to a Semantic Web description
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
service(goPubMed,"http://www.gopubmed.org/",text).
service(goPubMed,"http://www.gopubmed.org/",rdf).
service(goPubMed,"http://www.gopubmed.org/",xml).
service(goPubMedStatistic,"http://www.gopubmed.org/",xml).

% public function interfaces of this rule service
% describes the function signatures and types (untyped variables are also supported)
% and the mode declarations and gives a narrative description for human
% consumption
interface(performative(Performative), performative("?"), "pragmatic performatives of this agent/service").
interface(service(ServiceName,ServiceURL,ServiceOutputFormat),service("?","?","?"), "service description including the supported output formats").
interface(interface(Signature,ModeDeclaration,Description),service("?","?","?"), "interface description of the public rule functions of this rule service").
interface(retrieveData(Result, Service, Format, Query), retrieveDate("-","+","+","+"), "submits a Query to the W3C HCLS SPARQL service and returns the Result data in the selected Format").
	

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% general rule for receiving query messages
% the rules first tries to understand the pragmatic context
% and then tries to answer the query
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
rcvMsg(XID,esb ,From, Performative, [X|Args]) :-
    understandPerformative(XID, From, Performative, [X|Args]),
    answerQuery(XID, From, Performative, [X|Args]).
rcvMsg(XID,esb ,From, Performative, [X|Args]):-
	sendMsg(XID,esb,From,no_further_answers,[X|Args]).


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% rules for processing the query
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%	
	
% simple taxonomy of performatives for queries
% query = request	
performative(request):-performative(query).
performative(query).
	
understandPerformative(XID, From, Performative, PayLoad) :-
	performative(Performative).
understandPerformative(XID, From, Performative, PayLoad) :-
	not(performative(Performative)),
	sendMsg(XID,esb,From,answer, notUnderstood(Performative)),
	fail().	
	

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% rules for answering the query
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	
% answers query
answerQuery(XID, From, Performative, [X|Args]):-
	derive([X|Args]),
	sendMsg(XID,esb,From, answer, [X|Args]).
		
	

	
	
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Internal non-public rule base of the GoPubMed Rule Service
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Submits a Query to a GoPubMed Service
% and returns the Result data in the selected
% Format
%
% modes signature: retrieveDate(-, +,+,+)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
retrieveData(Result, Service, Format, Query):-
   bound(Service),
   bound(Query),
   bound(Format),
   buildServiceURL(URL,Service, Format, Query),
   InputStream = URL.openStream(),
   OutStream = java.io.ByteArrayOutputStream(),
   copy_stream(InputStream,OutStream),
   byte_stream(Result1,"UTF-8",OutStream),
   Result =  java.net.URLEncoder.encode(Result1,"UTF-8").


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Submits a Query to a GoPubMed Service
% and returns the Result as a StreamReader
%
% modes signature: retrieveReader(-, +,+,+)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
retrieveReader(Reader, Service, Format, Query):-
   bound(Service),
   bound(Query),
   bound(Format),
   buildServiceURL(URL,Service, Format, Query),
   InputStream = URL.openStream(),
   Reader=java.io.InputStreamReader(InputStream).