import_bib

#!/usr/bin/python3

from pathlib import Path
import bibtexparser
import time
import hashlib
import pickle

def try_load_bibtex_pickle(filename, filename_pickle):
    sha1sum = hashlib.sha1()
    with open(filename, "rb") as fd:
        sha1sum.update(fd.read())
    new_sha1sum = sha1sum.digest()
    data = None

    try:
        with open(filename_pickle, 'rb') as fd:
            old_sha1sum, data = pickle.load(fd)
        if old_sha1sum != new_sha1sum:
            data = None
    except Exception as e:
        pass
    return new_sha1sum, data


def load_bibtex(filename, modify_data=None):
    """Loads a bibtex file, and exposes it as a dict, to be included by
       !bibtex.
    """
    parser_start = time.time()
    fd = open(filename)
    filename_pickle = str(filename) + ".pickle"
    sha1sum, data = try_load_bibtex_pickle(filename, filename_pickle)
    if data is None:
        parser = bibtexparser.bparser.BibTexParser(common_strings=True)
        parser.ignore_nonstandard_types = False
        data = bibtexparser.load(fd, parser)
        with open(filename_pickle, "wb+") as pickle_fd:
            pickle.dump((sha1sum, data), pickle_fd)
    parser_end = time.time()
    pickle.dumps(data)
    return {e['ID']: e for e in data.entries}


if __name__ == "__main__":
    import sys
    _dir = Path(__file__).parent
    existing     = load_bibtex(_dir / 'sra-ext.bib')
    new_entries  = load_bibtex(sys.argv[1])

    for key in list(new_entries):
        if key in existing:
            del new_entries[key]
    # Generate pretty printed bibtex entry for inclusion into pages.
    db = bibtexparser.bibdatabase.BibDatabase()
    db.entries = new_entries.values()
    print(bibtexparser.dumps(db).strip())