// Search layer — 3-tier progressive disclosure.

import {
  getObservationsByIds,
  getRecentObservations,
  getRecentSummaries,
  getTimelineAround,
  searchObservationsFts,
  searchObservationsRecency,
} from "../store/db.js";
import { DEFAULT_SEARCH_LIMIT, DEFAULT_TIMELINE_WINDOW_MS } from "../config.js";
import type { SearchHit, FullObservation, Summary } from "../types.js";

export interface SearchResult {
  hits: SearchHit[];
  query: string;
  totalCandidates: number;
}

/**
 * Hybrid search: union of FTS keyword matches + recency fallback.
 * De-duplicates by id, score = max(ftsScore, recencyScore).
 */
export function search(
  query: string,
  project: string | null,
  limit: number = DEFAULT_SEARCH_LIMIT,
): SearchResult {
  const ftsHits = query.trim().length > 0
    ? searchObservationsFts(query, project, limit * 2)
    : [];
  const recencyHits = searchObservationsRecency(project, limit * 2);

  const byId = new Map<number, SearchHit>();
  for (const h of ftsHits) {
    byId.set(h.id, h);
  }
  for (const h of recencyHits) {
    const existing = byId.get(h.id);
    if (!existing) {
      byId.set(h.id, h);
    } else {
      byId.set(h.id, {
        ...existing,
        score: Math.max(existing.score, h.score),
        matchedVia: "both",
      });
    }
  }

  const merged = Array.from(byId.values()).sort((a, b) => b.score - a.score);
  const total = merged.length;
  const hits = merged.slice(0, limit);
  return { hits, query, totalCandidates: total };
}

export function timeline(id: number, windowMs: number = DEFAULT_TIMELINE_WINDOW_MS): FullObservation[] {
  return getTimelineAround(id, windowMs);
}

export function getByIds(ids: number[]): FullObservation[] {
  // Preserve input order.
  const byId = new Map(getObservationsByIds(ids).map((o) => [o.id, o]));
  return ids.map((id) => byId.get(id)).filter((o): o is FullObservation => o !== undefined);
}

export interface ContextSnapshot {
  recentObservations: FullObservation[];
  recentSummaries: Summary[];
}

/**
 * Pull a "recent context" snapshot for session-start injection.
 * Heuristic: recent observations in current project (if any) + recent summary.
 */
export function getRecentContext(project: string, limit: number = DEFAULT_SEARCH_LIMIT): ContextSnapshot {
  return {
    recentObservations: getRecentObservations(project, limit),
    recentSummaries: getRecentSummaries(project, 1),
  };
}