"""

Part of the bsie module.
A copy of the license is provided with the project.
Author: Matthias Baumgartner, 2022
"""
# imports
import argparse
import os
import typing

# bsie imports
from bsie.base import errors
from bsie.lib import BSIE
from bsie.tools import builder
from bsie.utils import bsfs

# exports
__all__: typing.Sequence[str] = (
    'main',
    )


## code ##

def main(argv):
    """Index files or directories into BSFS."""
    parser = argparse.ArgumentParser(description=main.__doc__, prog='index')
    parser.add_argument('--user', type=bsfs.URI, default=bsfs.URI('http://example.com/me'),
        help='')
    parser.add_argument('--collect', action='append', default=[],
        help='')
    parser.add_argument('--discard', action='append', default=[],
        help='')
    parser.add_argument('-r', '--recursive', action='store_true', default=False,
        help='')
    parser.add_argument('--follow', action='store_true', default=False,
        help='')
    parser.add_argument('--print', action='store_true', default=False,
        help='')
    parser.add_argument('input_file', nargs=argparse.REMAINDER,
        help='')
    args = parser.parse_args(argv)

    # FIXME: Read reader/extractor configs from a config file
    # reader builder
    rbuild = builder.ReaderBuilder({})
    # extractor builder
    ebuild = builder.ExtractorBuilder([
        {'bsie.extractor.generic.path.Path': {}},
        {'bsie.extractor.generic.stat.Stat': {}},
        {'bsie.extractor.generic.constant.Constant': dict(
            tuples=[('http://bsfs.ai/schema/Entity#author', 'Me, myself, and I')],
            schema='''
                bse:author rdfs:subClassOf bsfs:Predicate ;
                    rdfs:domain bsfs:Entity ;
                    rdfs:range xsd:string ;
                    bsfs:unique "true"^^xsd:boolean .
                ''',
            )},
        ])
    # pipeline builder
    pbuild = builder.PipelineBuilder(
        bsfs.Namespace(args.user + ('/' if not args.user.endswith('/') else '')),
        rbuild,
        ebuild,
        )

    # build pipeline
    pipeline = pbuild.build()
    # build BSIE frontend
    bsie = BSIE(pipeline, args.collect, args.discard)


    def walk(handle):
        """Walk through given input files."""
        # FIXME: collect all triples by node, set all predicates at once
        # FIXME: simplify code (below but maybe also above)
        # FIXME: How to handle dependencies between data?
        #        E.g. do I still want to link to a tag despite not being permitted to set its label?
        # FIXME: node renaming?

        # index input paths
        for path in args.input_file:
            if os.path.isdir(path) and args.recursive:
                for dirpath, _, filenames in os.walk(path, topdown=True, followlinks=args.follow):
                    for filename in filenames:
                        for node, pred, value in bsie.from_file(os.path.join(dirpath, filename)):
                            handle(node, pred, value)
            elif os.path.isfile(path):
                for node, pred, value in bsie.from_file(path):
                    handle(node, pred, value)
            else:
                raise errors.UnreachableError()


    if args.print:
        walk(print)
        return None

    else:
        # initialize bsfs
        # NOTE: With presistent storages, the schema migration will be a seaparte operation.
        # Here, we'd simply examine the schema and potentially discard more predicates.
        store = bsfs.Open({
            'Graph': {
                'user': args.user,
                'backend': {
                    'SparqlStore': {}},
                }})
        store.migrate(bsie.schema)
        # process files
        def handle(node, pred, value):
            store.node(node.node_type, node.uri).set(pred.uri, value)
        walk(handle)
        # return store
        return store



## main ##

if __name__ == '__main__':
    import sys
    main(sys.argv[1:])

## EOF ##