#!/usr/bin/env python3

"""
Connects to the graph query service and dumps all graph edges.
"""

import argparse
import os
from trustgraph.clients.triples_query_client import TriplesQueryClient
import rdflib
import io
import sys

default_pulsar_host = os.getenv("PULSAR_HOST", 'pulsar://localhost:6650')

def show_graph(pulsar):

    tq = TriplesQueryClient(pulsar_host=pulsar)

    rows = tq.request(None, None, None, limit=10_000_000)

    g = rdflib.Graph()

    for row in rows:

        sv = rdflib.term.URIRef(row.s.value)
        pv = rdflib.term.URIRef(row.p.value)

        if row.o.is_uri:

            # Skip malformed URLs with spaces in
            if " " in row.o.value:
                continue

            ov = rdflib.term.URIRef(row.o.value)
        else:
            ov = rdflib.term.Literal(row.o.value)

        g.add((sv, pv, ov))

    g.serialize(destination="output.ttl", format="turtle")

    buf = io.BytesIO()

    g.serialize(destination=buf, format="turtle")

    sys.stdout.write(buf.getvalue().decode("utf-8"))


def main():

    parser = argparse.ArgumentParser(
        prog='graph-show',
        description=__doc__,
    )

    parser.add_argument(
        '-p', '--pulsar-host',
        default=default_pulsar_host,
        help=f'Pulsar host (default: {default_pulsar_host})',
    )

    args = parser.parse_args()

    try:

        show_graph(args.pulsar_host)

    except Exception as e:

        print("Exception:", e, flush=True)

main()