# standard imports
import sys
import enum

# external imports
from rdflib import Graph, RDF
from rdflib.term import URIRef
from rdflib.collection import Collection


class CIC(enum.Enum):
    voucherContract = URIRef('https://defalsify.org/rdf-eth/0.1/voucherContract')
    voucherTransfer = URIRef('https://defalsify.org/rdf-eth/0.1/voucherTransfer')


class Attestation:

    def __init__(self):
        self.g = Graph()
        self.txs = {}
        self.typ = None


    @classmethod
    def from_path(cls, path):
        c = cls()
        c.g.parse(path, format='turtle')
        c.__apply_graph()
        return c


    def __apply_graph(self):
        current_subject = None
        for (s, p, o) in self.g:
            if s != current_subject: 
                current_subject = s
            if p == RDF.first:
                pass
            print('{} {} {}'.format(s, p, o))
                

    def export(self, w=sys.stdout):
        v = self.g.serialize(format='xml')
        w.write(v)