// ---------------------------------------------------------------------------
// Memory Graph — v1 hybrid Qdrant search over graph nodes
// ---------------------------------------------------------------------------

import { getConfig } from "../../../../../config/loader.js";
import { usesConceptPageMemory } from "../../../../../config/memory-v3-gate.js";
import { isQdrantBreakerOpen } from "../../../../../persistence/embeddings/qdrant-circuit-breaker.js";
import { withQdrantBreaker } from "../../../../../persistence/embeddings/qdrant-circuit-breaker.js";
import {
  getQdrantClient,
  type QdrantSearchResult,
  type QdrantSparseVector,
} from "../../../../../persistence/embeddings/qdrant-client.js";
import { getLogger } from "../../logging.js";

// Distinct from the all-tier `graph/graph-search.ts` module, which owns the
// bare `graph-search` scope. The tier split left both emitting under one name;
// log scopes are observable, so the v1 half takes its own.
const log = getLogger("v1-graph-search");

export interface GraphSearchResult {
  nodeId: string;
  score: number;
  text: string;
}

/**
 * Semantic search across graph nodes in Qdrant. Returns scored node IDs
 * that the caller can hydrate from the graph store.
 *
 * Filters to `target_type: "graph_node"`.
 */
export async function searchGraphNodes(
  queryVector: number[],
  limit: number,
  sparseVector?: QdrantSparseVector,
  dateRange?: { afterMs?: number; beforeMs?: number },
): Promise<GraphSearchResult[]> {
  // Concept-page memory owns the read path when active. The v1 `memory`
  // collection is in active retirement and a corrupted sparse segment can
  // OOM-crash the shared Qdrant process — short-circuiting here keeps v1
  // background work and stale callers from taking it down.
  if (usesConceptPageMemory(getConfig().memory)) {
    return [];
  }

  if (isQdrantBreakerOpen()) {
    log.warn("Qdrant circuit breaker open, skipping graph search");
    return [];
  }

  const client = getQdrantClient();

  const mustNot: Record<string, unknown>[] = [
    { key: "_meta", match: { value: true } },
  ];

  // Use hybrid search (dense + sparse with RRF fusion) when a non-empty
  // sparse vector is available; otherwise fall back to dense-only search.
  if (sparseVector && sparseVector.indices.length > 0) {
    const must: Record<string, unknown>[] = [
      { key: "target_type", match: { value: "graph_node" } },
    ];
    if (dateRange?.afterMs != null) {
      must.push({ key: "created_at", range: { gte: dateRange.afterMs } });
    }
    if (dateRange?.beforeMs != null) {
      must.push({ key: "created_at", range: { lte: dateRange.beforeMs } });
    }
    const filter = { must, must_not: mustNot };

    // RRF fuses per-modality top-N. A small prefetch (e.g. limit*3) silently
    // truncates good matches when the query is wordy or low-similarity, so
    // give RRF a meaningful candidate window with a generous floor.
    const prefetchLimit = Math.max(limit * 10, 200);

    const results: QdrantSearchResult[] = await withQdrantBreaker(() =>
      client.hybridSearch({
        denseVector: queryVector,
        sparseVector,
        filter,
        limit,
        prefetchLimit,
      }),
    );

    return results.map((r) => ({
      nodeId: r.payload.target_id,
      score: r.score,
      text: r.payload.text,
    }));
  }

  // Dense-only fallback
  const denseMusts: Record<string, unknown>[] = [
    {
      key: "target_type",
      match: { value: "graph_node" },
    },
  ];

  if (dateRange?.afterMs != null) {
    denseMusts.push({ key: "created_at", range: { gte: dateRange.afterMs } });
  }
  if (dateRange?.beforeMs != null) {
    denseMusts.push({ key: "created_at", range: { lte: dateRange.beforeMs } });
  }

  const filter: Record<string, unknown> = {
    must: denseMusts,
    must_not: mustNot,
  };

  const results: QdrantSearchResult[] = await withQdrantBreaker(async () => {
    return client.search(queryVector, limit, filter);
  });

  return results.map((r) => ({
    nodeId: r.payload.target_id,
    score: r.score,
    text: r.payload.text,
  }));
}