from __future__ import annotations

from ..graph_export import edge_retrieval_query, graph_from_sparql_bindings
from ..models import GraphResponse
from ..sparql_engine import SparqlEngine
from ..settings import Settings
from .layout_spiral import spiral_positions


async def fetch_graph_snapshot(
    sparql: SparqlEngine,
    *,
    settings: Settings,
    node_limit: int,
    edge_limit: int,
) -> GraphResponse:
    """
    Fetch a graph snapshot (nodes + edges) via SPARQL, independent of whether the
    underlying engine is RDFLib or AnzoGraph.
    """
    edges_q = edge_retrieval_query(edge_limit=edge_limit, include_bnodes=settings.include_bnodes)
    res = await sparql.query_json(edges_q)
    bindings = (((res.get("results") or {}).get("bindings")) or [])
    nodes, edges = graph_from_sparql_bindings(
        bindings,
        node_limit=node_limit,
        include_bnodes=settings.include_bnodes,
    )

    # Add positions so the frontend doesn't need to run a layout.
    xs, ys = spiral_positions(len(nodes))
    for i, node in enumerate(nodes):
        node["x"] = float(xs[i])
        node["y"] = float(ys[i])

    meta = GraphResponse.Meta(
        backend=sparql.name,
        ttl_path=settings.ttl_path if settings.graph_backend == "rdflib" else None,
        sparql_endpoint=settings.effective_sparql_endpoint() if settings.graph_backend == "anzograph" else None,
        include_bnodes=settings.include_bnodes,
        node_limit=node_limit,
        edge_limit=edge_limit,
        nodes=len(nodes),
        edges=len(edges),
    )
    return GraphResponse(nodes=nodes, edges=edges, meta=meta)