from lcsh.namespaces import SKOS, DCTERMS
import simplejson

# TODO: replace this with some generic rdflib Resource type of object

class ConceptWidget:
    """
    This is a class that makes it easy to hand off a SKOS
    concept to a template.
    """

    def __init__(self, uri=None, graph=None, n=1):
        self.uri = uri
        self.doc_uri = uri.replace('#concept', '')
        self.created = None
        self.modifield = None
        self.lccn = uri.split('/')[-1].split('#')[0]
        self.pref_label = None
        self.lcc = None
        self.alt_labels = []
        self.broader = []
        self.narrower = []
        self.related = []
        self.editorial_notes = []
        self.scope_notes = []

        for p, o in graph.predicate_objects(subject=uri):
            if p == SKOS.prefLabel:
                self.pref_label = o
            elif p == SKOS.altLabel:
                self.alt_labels.append(o)
            elif p == SKOS.broader and n > 0: 
                self.broader.append(ConceptWidget(o, graph, n-1))
            elif p == SKOS.narrower and n > 0:
                self.narrower.append(ConceptWidget(o, graph, n-1))
            elif p == SKOS.related and n > 0:
                self.related.append(ConceptWidget(o, graph, n-1))
            elif p == SKOS.scopeNote:
                self.scope_notes.append(o)
            elif p == SKOS.editorialNote:
                self.editorial_notes.append(o)
            elif p == SKOS.changeNote:
                self.editorial_notes.append(o)
            elif p == DCTERMS.created:
                self.created = o
            elif p == DCTERMS.modified:
                self.modified = o
            elif p == DCTERMS.LCC:
                self.lcc = o
            
        def concept_sort(a,b):
            return cmp(a.pref_label, b.pref_label)

        self.alt_labels.sort()
        self.broader.sort(concept_sort)
        self.narrower.sort(concept_sort)
        self.related.sort(concept_sort)
        self.scope_notes.sort()
        self.editorial_notes.sort()

    def json(self):
        c = {}
        c['pref_label'] = self.pref_label
        c['alt_labels'] = self.alt_labels
        c['scope_notes'] = self.scope_notes
        c['editorial_notes'] = self.editorial_notes
        c['lccn'] = self.lccn
        c['created'] = self.created
        c['modified'] = self.modified
        c['lcc'] = self.lcc

        def unpack(c):
            return {'pref_label': c.pref_label, 'uri': c.uri}

        c['broader'] = map(unpack, self.broader)
        c['narrower'] = map(unpack, self.narrower)
        c['related'] = map(unpack, self.related)

        return simplejson.dumps(c, sort_keys=True, indent=2)