export interface SearchResult {
  title: string;
  url: string;
  snippet: string;
  source: string;
  published_date: string | null;
}

function hostnameOf(url: string): string {
  try {
    return new URL(url).hostname;
  } catch {
    return "";
  }
}

async function fetchWithTimeout(url: string, timeoutMs: number, init?: RequestInit) {
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), timeoutMs);
  try {
    return await fetch(url, { ...init, signal: controller.signal });
  } finally {
    clearTimeout(timer);
  }
}

export async function searchSearxng(
  baseUrl: string,
  query: string,
  count: number,
  timeoutMs: number,
): Promise<SearchResult[]> {
  const url = new URL(baseUrl);
  url.pathname = "/search";
  url.searchParams.set("q", query);
  url.searchParams.set("format", "json");

  const response = await fetchWithTimeout(url.toString(), timeoutMs);
  if (!response.ok) {
    throw new Error(`SearXNG returned HTTP ${response.status}`);
  }
  const data = await response.json();
  const results: any[] = data.results ?? [];

  return results.slice(0, count).map((result) => ({
    title: result.title ?? "",
    url: result.url ?? "",
    snippet: result.content ?? "",
    source: hostnameOf(result.url ?? ""),
    published_date: result.publishedDate ?? null,
  }));
}

export async function searchBrave(
  baseUrl: string,
  apiKey: string,
  query: string,
  count: number,
  timeoutMs: number,
): Promise<SearchResult[]> {
  const url = new URL(baseUrl);
  url.pathname = "/res/v1/web/search";
  url.searchParams.set("q", query);
  url.searchParams.set("count", String(count));

  const response = await fetchWithTimeout(url.toString(), timeoutMs, {
    headers: {
      Accept: "application/json",
      "X-Subscription-Token": apiKey,
    },
  });
  if (!response.ok) {
    throw new Error(`Brave Search returned HTTP ${response.status}`);
  }
  const data = await response.json();
  const results: any[] = data.web?.results ?? [];

  return results.slice(0, count).map((result) => ({
    title: result.title ?? "",
    url: result.url ?? "",
    snippet: result.description ?? "",
    source: hostnameOf(result.url ?? ""),
    published_date: result.page_age ?? result.age ?? null,
  }));
}

export interface WebSearchOutcome {
  provider: "searxng" | "brave";
  results: SearchResult[];
  warnings: string[];
}

export async function searchWeb(options: {
  searxngBaseUrl: string;
  braveBaseUrl: string;
  braveApiKey: string;
  query: string;
  count: number;
  timeoutMs: number;
}): Promise<WebSearchOutcome> {
  const { searxngBaseUrl, braveBaseUrl, braveApiKey, query, count, timeoutMs } = options;
  const warnings: string[] = [];

  try {
    const results = await searchSearxng(searxngBaseUrl, query, count, timeoutMs);
    return { provider: "searxng", results, warnings };
  } catch (error) {
    warnings.push(`SearXNG search failed: ${(error as Error).message}`);
  }

  if (!braveApiKey) {
    throw new Error(
      `${warnings.join(" ")} No Brave API key configured, so no fallback is available.`,
    );
  }

  try {
    const results = await searchBrave(braveBaseUrl, braveApiKey, query, count, timeoutMs);
    return { provider: "brave", results, warnings };
  } catch (error) {
    warnings.push(`Brave search fallback failed: ${(error as Error).message}`);
    throw new Error(warnings.join(" "));
  }
}

export interface SearchResult {
  title: string;
  url: string;
  snippet: string;
  source: string;
  published_date: string | null;
}

function hostnameOf(url: string): string {
  try {
    return new URL(url).hostname;
  } catch {
    return "";
  }
}

async function fetchWithTimeout(url: string, timeoutMs: number, init?: RequestInit) {
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), timeoutMs);
  try {
    return await fetch(url, { ...init, signal: controller.signal });
  } finally {
    clearTimeout(timer);
  }
}

export async function searchSearxng(
  baseUrl: string,
  query: string,
  count: number,
  timeoutMs: number,
): Promise<SearchResult[]> {
  const url = new URL(baseUrl);
  url.pathname = "/search";
  url.searchParams.set("q", query);
  url.searchParams.set("format", "json");

  const response = await fetchWithTimeout(url.toString(), timeoutMs);
  if (!response.ok) {
    throw new Error(`SearXNG returned HTTP ${response.status}`);
  }
  const data = await response.json();
  const results: any[] = data.results ?? [];

  return results.slice(0, count).map((result) => ({
    title: result.title ?? "",
    url: result.url ?? "",
    snippet: result.content ?? "",
    source: hostnameOf(result.url ?? ""),
    published_date: result.publishedDate ?? null,
  }));
}

export async function searchBrave(
  baseUrl: string,
  apiKey: string,
  query: string,
  count: number,
  timeoutMs: number,
): Promise<SearchResult[]> {
  const url = new URL(baseUrl);
  url.pathname = "/res/v1/web/search";
  url.searchParams.set("q", query);
  url.searchParams.set("count", String(count));

  const response = await fetchWithTimeout(url.toString(), timeoutMs, {
    headers: {
      Accept: "application/json",
      "X-Subscription-Token": apiKey,
    },
  });
  if (!response.ok) {
    throw new Error(`Brave Search returned HTTP ${response.status}`);
  }
  const data = await response.json();
  const results: any[] = data.web?.results ?? [];

  return results.slice(0, count).map((result) => ({
    title: result.title ?? "",
    url: result.url ?? "",
    snippet: result.description ?? "",
    source: hostnameOf(result.url ?? ""),
    published_date: result.page_age ?? result.age ?? null,
  }));
}

export interface WebSearchOutcome {
  provider: "searxng" | "brave";
  results: SearchResult[];
  warnings: string[];
}

export async function searchWeb(options: {
  searxngBaseUrl: string;
  braveBaseUrl: string;
  braveApiKey: string;
  query: string;
  count: number;
  timeoutMs: number;
}): Promise<WebSearchOutcome> {
  const { searxngBaseUrl, braveBaseUrl, braveApiKey, query, count, timeoutMs } = options;
  const warnings: string[] = [];

  try {
    const results = await searchSearxng(searxngBaseUrl, query, count, timeoutMs);
    return { provider: "searxng", results, warnings };
  } catch (error) {
    warnings.push(`SearXNG search failed: ${(error as Error).message}`);
  }

  if (!braveApiKey) {
    throw new Error(
      `${warnings.join(" ")} No Brave API key configured, so no fallback is available.`,
    );
  }

  try {
    const results = await searchBrave(braveBaseUrl, braveApiKey, query, count, timeoutMs);
    return { provider: "brave", results, warnings };
  } catch (error) {
    warnings.push(`Brave search fallback failed: ${(error as Error).message}`);
    throw new Error(warnings.join(" "));
  }
}