"""Infer Atlas canonical types from Wikidata classes via ontology reasoning."""

from __future__ import annotations

from functools import lru_cache
from pathlib import Path
from typing import Iterable, Optional

from rdflib import Graph, URIRef
from rdflib.namespace import RDFS

ONTOLOGY_PATH = Path(__file__).resolve().parents[1] / "ontology" / "wikidata_subclassof.ttl"

ROOT_CLASS_MAP: dict[str, str] = {
    "http://dbpedia.org/ontology/Person": "Person",
    "http://dbpedia.org/ontology/Artist": "Person",
    "http://dbpedia.org/ontology/Politician": "Person",
    "http://dbpedia.org/ontology/Organisation": "Organization",
    "http://dbpedia.org/ontology/Company": "Organization",
    "http://dbpedia.org/ontology/University": "Organization",
    "http://dbpedia.org/ontology/Place": "Location",
    "http://dbpedia.org/ontology/Location": "Location",
    "http://dbpedia.org/ontology/PopulatedPlace": "Location",
    "http://dbpedia.org/ontology/Settlement": "Location",
    "http://dbpedia.org/ontology/CreativeWork": "CreativeWork",
    "http://dbpedia.org/ontology/Film": "CreativeWork",
    "http://dbpedia.org/ontology/MusicalWork": "CreativeWork",
    "http://dbpedia.org/ontology/Album": "CreativeWork",
    "http://dbpedia.org/ontology/Event": "Event",
    "http://dbpedia.org/ontology/Product": "Product",
    "http://dbpedia.org/ontology/Species": "Taxon",
    "http://dbpedia.org/ontology/Taxon": "Taxon",
}


@lru_cache(maxsize=1)
def _load_graph() -> Graph:
    graph = Graph()
    if ONTOLOGY_PATH.exists():
        graph.parse(ONTOLOGY_PATH, format="turtle")
    return graph


def _qid_to_uri(qid: str) -> URIRef:
    return URIRef(f"http://wikidata.dbpedia.org/resource/{qid}")


def infer_atlas_type_from_p31(qids: Iterable[str]) -> Optional[str]:
    """Infer the Atlas type from Wikidata P31 classes using the ontology graph."""
    graph = _load_graph()
    if len(graph) == 0:
        return None

    root_nodes = {URIRef(uri): atlas_type for uri, atlas_type in ROOT_CLASS_MAP.items()}
    for qid in qids:
        if not qid:
            continue
        start = _qid_to_uri(qid)
        inferred = _walk_to_root(graph, start, root_nodes)
        if inferred:
            return inferred
    return None


def _walk_to_root(graph: Graph, start: URIRef, roots: dict[URIRef, str]) -> Optional[str]:
    visited: set[URIRef] = set()
    queue: list[URIRef] = [start]
    while queue:
        node = queue.pop(0)
        if node in visited:
            continue
        visited.add(node)
        if node in roots:
            return roots[node]
        for parent in graph.objects(node, RDFS.subClassOf):
            if isinstance(parent, URIRef):
                queue.append(parent)
    return None