# -*- coding: utf-8 -*-

"""

Diseasome data import module.

Its interface is the ``entities_from_rdf`` function.

"""

import re

RE_RELS = re.compile(r'^<(.*?)>\s<(.*?)>\s<(.*?)>\s*\.')

RE_ATTS = re.compile(r'^<(.*?)>\s<(.*?)>\s"(.*)"(\^\^<(.*?)>|)\s*\.')

MAPPING_ATTS = {'bio2rdfSymbol': 'bio2rdf_symbol',

                'label': 'label',

                'name': 'name',

                'classDegree': 'class_degree',

                'degree': 'degree',

                'size': 'size'}

MAPPING_RELS = {'geneId': 'gene_id',

                'hgncId': 'hgnc_id', 

                'hgncIdPage': 'hgnc_page', 

                'sameAs': 'same_as', 

                'class': 'classes', 

                'diseaseSubtypeOf': 'subtype_of', 

                'associatedGene': 'associated_genes', 

                'possibleDrug': 'possible_drugs',

                'type': 'types',

                'omim': 'omim', 

                'omimPage': 'omim_page', 

                'chromosomalLocation': 'chromosomal_location'}

def _retrieve_reltype(uri):

    """

    Retrieve a relation type from an URI.

    Internal function which takes an URI containing a relation type as input

    and returns the name of the relation.

    If no URI string is given, then the function returns None.

    """

    if uri:

        return uri.rsplit('/', 1)[-1].rsplit('#', 1)[-1]

def _retrieve_etype(tri_uri):

    """

    Retrieve entity type from a triple of URIs.

    Internal function whith takes a tuple of three URIs as input

    and returns the type of the entity, as obtained from the

    first member of the tuple.

    """

    if tri_uri:

        return tri_uri.split('> <')[0].rsplit('/', 2)[-2].rstrip('s')

def _retrieve_structure(filename, etypes):

    """

    Retrieve a (subject, relation, object) tuples iterator from a file.

    Internal function which takes as input a file name and a tuple of 

    entity types, and returns an iterator of (subject, relation, object)

    tuples.

    """

    with open(filename) as fil:

        for line in fil:

            if _retrieve_etype(line) not in etypes:

                continue

            match = RE_RELS.match(line)

            if not match:

                match = RE_ATTS.match(line)

            subj = match.group(1)

            relation = _retrieve_reltype(match.group(2))

            obj = match.group(3)

            yield subj, relation, obj

def entities_from_rdf(filename, etypes):

    """

    Return entities from an RDF file.

    Module interface function which takes as input a file name and

    a tuple of entity types, and returns an iterator on the 

    attributes and relations of each entity. The attributes

    and relations are retrieved as dictionaries.

    >>> for entities, relations in entities_from_rdf('data_file', 

                                                     ('type_1', 'type_2')):

        ...

    """

    entities = {}

    for subj, rel, obj in _retrieve_structure(filename, etypes):

        entities.setdefault(subj, {})

        entities[subj].setdefault('attributes', {})

        entities[subj].setdefault('relations', {})

        entities[subj]['attributes'].setdefault('cwuri', unicode(subj))

        if rel in MAPPING_ATTS:

            entities[subj]['attributes'].setdefault(MAPPING_ATTS[rel], 

                                                    unicode(obj))

        if rel in MAPPING_RELS:

            entities[subj]['relations'].setdefault(MAPPING_RELS[rel], set())

            entities[subj]['relations'][MAPPING_RELS[rel]].add(unicode(obj))

    return ((ent.get('attributes'), ent.get('relations')) 

            for ent in entities.itervalues())