"""
Implementation of the 'index' subcommand.
"""
import os

from ..db import status
from ..db.connection import connect

# Do not repeat documentation of subcommand classes.
# pylint: disable=C0111
# Using non-top-level imports to avoid eventually unused imports.
# pylint: disable=E0012,C0415

def _num_system_cpus():
    try:
        cpus = len(os.sched_getaffinity(0))
    except NotImplementedError:
        cpus = None

    return cpus or os.cpu_count()


class UpdateIndex:
    """\
    Reindex all new and modified data.
    """

    @staticmethod
    def add_args(parser):
        group = parser.add_argument_group('Filter arguments')
        group.add_argument('--boundaries-only', action='store_true',
                           help="""Index only administrative boundaries.""")
        group.add_argument('--no-boundaries', action='store_true',
                           help="""Index everything except administrative boundaries.""")
        group.add_argument('--minrank', '-r', type=int, metavar='RANK', default=0,
                           help='Minimum/starting rank')
        group.add_argument('--maxrank', '-R', type=int, metavar='RANK', default=30,
                           help='Maximum/finishing rank')

    @staticmethod
    def run(args):
        from ..indexer.indexer import Indexer

        indexer = Indexer(args.config.get_libpq_dsn(),
                          args.threads or _num_system_cpus() or 1)

        if not args.no_boundaries:
            indexer.index_boundaries(args.minrank, args.maxrank)
        if not args.boundaries_only:
            indexer.index_by_rank(args.minrank, args.maxrank)

        if not args.no_boundaries and not args.boundaries_only \
           and args.minrank == 0 and args.maxrank == 30:
            conn = connect(args.config.get_libpq_dsn())
            status.set_indexed(conn, True)
            conn.close()

        return 0