from __future__ import generators
import Triple as t

class RDFDB:

    def __init__(self):
        # a RDF db is a list of triples.
        self.db = []
        self.infDB = None
        self.varPred = []

    def addTriple(self, triple):
        self.db = self.db + [triple]

    def addTriples(self, tripleset):
        self.db = self.db + tripleset

    def genTriples(self):
        for counter in self.db:
            yield self.db[counter]

    def toString(self):
        out = "\nTriples in store:\n\n"
        for triple in self.db:
            out = out + triple.toString() + "\n"
        if self.infDB <> None:
            out = out + "\nPredicate dictionary:\n\n"
            out = out + predDicToString(self.infDB)
        out = out + "\nVariable predicates:\n\n"
        out = out + varPredToString(self.varPred)
        return out    

    def toN3(self):
        out = "\nTriples in store:\n\n"
        out = out + Triple.tsToString(self.db)
        return out

def predDicToString(predDic):
      out = ""  
      for key in predDic.keys():
            out = out + "\nkey: " + str(key) + " content:\n" + t.tsToStringVar(predDic[key])
      return out

def varPredToString(varPred):
          out = ""
          for triple in varPred:
                out = out + "\n" + triple.toStringVar()
          return out