#Install a library to help us run some SPARQL queries if we haven't already installed it
#http://rdflib.github.io/sparqlwrapper/
#!pip3 install sparqlwrapper

#Import the necessary packages
from SPARQLWrapper import SPARQLWrapper, JSON

#Declare the Open University open Linked Data endpoint
endpoint="http://data.open.ac.uk/query"

#A helper...
def runQuery(endpoint,prefix,q):
    ''' Run a SPARQL query with a declared prefix over a specified endpoint '''
    sparql = SPARQLWrapper(endpoint)
    sparql.setQuery(prefix+q)
    sparql.setReturnFormat(JSON)
    return sparql.query().convert()

import pandas as pd
#And some more helpers
def dict2df(results):
    ''' Hack a function to flatten the SPARQL query results and return the column values '''
    data=[]
    for result in results["results"]["bindings"]:
        tmp={}
        for el in result:
            tmp[el]=result[el]['value']
        data.append(tmp)

    df = pd.DataFrame(data)
    return df

def dfResults(endpoint,prefix,q):
    ''' Generate a data frame containing the results of running
        a SPARQL query with a declared prefix over a specified endpoint '''
    return dict2df( runQuery( endpoint, prefix, q ) )

#Sometimes it's convenient to build a default prefix to handle most queries to the endpoint
prefix='''
'''

#Prices (ordered) with currency of OU level 1 courses in Arts and Humanities as available in France.
#via http://data.open.ac.uk/site/queries.html
q='''
#We're looking for some course identifiers along with the value and currency of their price
select ?course ?price ?cur
from <http://data.open.ac.uk/context/course>
where {
    #The course must be at level 1
    ?course <http://data.open.ac.uk/saou/ontology#OUCourseLevel> "1"^^<http://www.w3.org/2001/XMLSchema#string>.
    #The course must be in in Arts and Humanities
    ?course <http://purl.org/dc/terms/subject> <http://data.open.ac.uk/topic/arts_and_humanities>.
    #The course must be part of an offering
    ?off <http://purl.org/goodrelations/v1#includes> ?course.
    #And that offering must have a price
    ?off <http://purl.org/goodrelations/v1#hasPriceSpecification> ?ps.
    #The course must be located(?) in France
    ?course <http://purl.org/net/mlo/location> <http://sws.geonames.org/3017382/>.
    #And the offering must be available in France
    ?off <http://purl.org/goodrelations/v1#availableAtOrFrom> <http://sws.geonames.org/3017382/>.
    #The price must have a value
    ?ps <http://purl.org/goodrelations/v1#hasCurrencyValue> ?price.
    #The price must also be in a particular currency
    ?ps <http://purl.org/goodrelations/v1#hasCurrency> ?cur
} order by ?price
#The ordering ranks the results in increasing price order
'''

#We can now run the query over the endpoint with the desired prefix
#and get the results back as a pandas dataframe
dfResults(endpoint,prefix,q)

q='DESCRIBE <http://data.open.ac.uk/course/aa100>'
ans=runQuery(endpoint,prefix,q)

print(ans.decode('utf-8'))

prefix='''
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX aiiso: <http://purl.org/vocab/aiiso/schema#>
'''

q='''
SELECT ?code ?title ?desc WHERE {
    <http://data.open.ac.uk/course/aa100> aiiso:code ?code.
    <http://data.open.ac.uk/course/aa100> rdfs:label ?title.
    <http://data.open.ac.uk/course/aa100> dcterms:description ?desc.
}
'''

runQuery(endpoint,prefix,q)

def printQuery(endpoint,prefix,q):
    ''' Print the results from the SPARQL query '''
    results=runQuery(endpoint,prefix,q)
    for result in results["results"]["bindings"]:
        for ans in result:
            print('{0}: {1}'.format(ans,result[ans]['value']))
        print()

printQuery(endpoint,prefix,q)

prefix='''
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX aiiso: <http://purl.org/vocab/aiiso/schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
'''

q='''
SELECT ?code ?title ?desc WHERE {
    ?module aiiso:code 'AA100'^^xsd:string.
    ?module rdf:type aiiso:Module.
        
    ?module aiiso:code ?code.
    ?module aiiso:code ?code.
    ?module rdfs:label ?title.
    ?module dcterms:description ?desc.
}
'''

printQuery(endpoint,prefix,q)

prefix='''
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX aiiso: <http://purl.org/vocab/aiiso/schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX saou: <http://data.open.ac.uk/saou/ontology#>
'''

q='''
SELECT ?code ?book WHERE {
    ?module aiiso:code 'AA100'^^xsd:string.
    ?module rdf:type aiiso:Module.
        
    ?module aiiso:code ?code.
    ?module aiiso:code ?code.
    ?module rdfs:label ?title.
    ?module dcterms:description ?desc.
    ?module saou:hasBook ?book.
}
'''
printQuery(endpoint,prefix,q)

q='DESCRIBE <http://data.open.ac.uk/book/9780571195473>'

def printDesc(endpoint,q):
    ans=runQuery(endpoint,prefix,q)
    print(ans.decode('utf-8'))
    
printDesc(endpoint,q)

prefix='''
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX aiiso: <http://purl.org/vocab/aiiso/schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX saou: <http://data.open.ac.uk/saou/ontology#>
PREFIX bibo: <http://purl.org/ontology/bibo/>
'''

q='''
SELECT ?booktitle ?isbn13 ?publisher WHERE {
    ?module aiiso:code 'AA100'^^xsd:string.
    ?module rdf:type aiiso:Module.
        
    ?module aiiso:code ?code.
    ?module aiiso:code ?code.
    ?module rdfs:label ?title.
    ?module dcterms:description ?desc.
    ?module saou:hasBook ?book.
    
    ?book dcterms:title ?booktitle.
    ?book bibo:ISBN13 ?isbn13.
    ?book dcterms:publisher ?publisher.
}
'''
printQuery(endpoint,prefix,q)