// SearXNG's API client — searxng's own code, living in the module (novox/hq ADR 0044). SearXNG is a
// privacy-respecting metasearch engine: it forwards a query to many upstream engines and returns the
// merged results. Its JSON API (`/search?q=...&format=json`) is what makes a `searxng_search` tool
// useful; the client speaks only that. No credential — the instance is reached inside the mesh.

export interface SearxResult {
  title: string;
  url: string;
  content?: string;
  engine?: string;
  category?: string;
  score?: number;
}

export interface SearxSearch {
  query: string;
  numberOfResults: number;
  results: SearxResult[];
  suggestions: string[];
  answers: string[];
}

export interface SearxOptions {
  categories?: string;
  language?: string;
  pageno?: number;
}

export class SearxngClient {
  readonly baseUrl: string;

  constructor(url: string) {
    this.baseUrl = url.replace(/\/$/, "");
  }

  /** Build from the module's environment. No key: SearXNG's search API is open on the mesh, so a URL
   *  is all it takes — defaulting to the container's own listen port. */
  static fromEnv(env: NodeJS.ProcessEnv = process.env): SearxngClient {
    const url = env.MESH_SEARXNG_URL ?? `http://127.0.0.1:${env.SEARXNG_PORT ?? "8080"}`;
    return new SearxngClient(url);
  }

  async search(query: string, opts: SearxOptions = {}): Promise<SearxSearch> {
    const params = new URLSearchParams({ q: query, format: "json" });
    if (opts.categories) params.set("categories", opts.categories);
    if (opts.language) params.set("language", opts.language);
    if (opts.pageno) params.set("pageno", String(opts.pageno));

    const res = await fetch(`${this.baseUrl}/search?${params.toString()}`, {
      headers: { Accept: "application/json" },
    });
    if (!res.ok) throw new Error(`SearXNG search: ${res.status} ${await res.text()}`);
    const data = (await res.json()) as {
      results?: SearxResult[];
      suggestions?: string[];
      answers?: string[];
      number_of_results?: number;
    };
    const results = data.results ?? [];
    return {
      query,
      // SearXNG's own count is often 0 even with results; fall back to what we actually got.
      numberOfResults: data.number_of_results || results.length,
      results: results.map((r) => ({
        title: r.title,
        url: r.url,
        content: r.content,
        engine: r.engine,
        category: r.category,
        score: r.score,
      })),
      suggestions: data.suggestions ?? [],
      answers: data.answers ?? [],
    };
  }
}