// ANN/HNSW backend for ultra-fast RAG and semantic search
use pyo3::prelude::*;
use pyo3::exceptions::PyValueError;
use numpy::{PyReadonlyArray2};

// Placeholder type for index handle
struct HNSWIndex {
    // Would hold HNSW* or data
}

#[pyfunction]
pub fn ann_build_index(_embeddings: PyReadonlyArray2<'_, f32>, _ef_construction: Option<usize>, _m: Option<usize>) -> PyResult<u64> {
    // Construct and return a handle/id for the index (in global/static for now)
    Ok(1)
}

#[pyfunction]
pub fn ann_query_topk(_handle: u64, _query: PyReadonlyArray2<'_, f32>, _top_k: usize) -> PyResult<Vec<(usize, f32)>> {
    // Run a search query over ANN index
    Ok(Vec::new())
}

#[pyfunction]
pub fn ann_add_docs(_handle: u64, _docs: PyReadonlyArray2<'_, f32>) -> PyResult<()> {
    Ok(())
}

#[pyfunction]
pub fn ann_save_index(_handle: u64, _filepath: &str) -> PyResult<()> {
    Ok(())
}

#[pyfunction]
pub fn ann_load_index(_filepath: &str) -> PyResult<u64> {
    Ok(1)
}
