import type { ExtractionResult } from '@rareindex/shared';
import type { FetchOptions } from '../types.js';

export interface ScrapflyEngineOptions {
  apiKey: string;
  baseUrl?: string;
  defaultCountry?: string;
  defaultTimeoutMs?: number;
}

interface ScrapflyResponse {
  result?: {
    content?: string;
    status_code?: number;
    url?: string;
    success?: boolean;
    error?: { message?: string; code?: string } | null;
    format?: string;
    extracted_data?: { data?: unknown } | unknown;
  };
  context?: { cost?: { total?: number } };
  config?: Record<string, unknown>;
  cost?: number;
  message?: string;
}

/**
 * Scrapfly REST client (§104): secondary engine for JS-heavy or difficult public pages, with
 * geo routing and rendering. `asp` (anti-scraping protection) is only used on publicly accessible
 * pages within the source's terms — never to defeat logins, paywalls or CAPTCHAs (§179).
 */
export function createScrapflyEngine(opts: ScrapflyEngineOptions) {
  const base = (opts.baseUrl ?? 'https://api.scrapfly.io').replace(/\/$/, '');

  async function scrape(url: string, o: FetchOptions = {}): Promise<ExtractionResult> {
    const started = Date.now();
    const timeoutMs = o.timeoutMs ?? opts.defaultTimeoutMs ?? 90_000;
    const params = new URLSearchParams({
      key: opts.apiKey,
      url,
      asp: 'true',
      render_js: o.renderJs === false ? 'false' : 'true',
      country: (o.country ?? opts.defaultCountry ?? 'us').toLowerCase(),
      retry: 'true',
      format: 'raw',
    });
    if (o.waitForMs) params.set('rendering_wait', String(Math.min(o.waitForMs, 25_000)));
    if (o.extractionModel) params.set('extraction_model', o.extractionModel);
    if (o.headers) for (const [k, v] of Object.entries(o.headers)) params.append(`headers[${k}]`, v);
    if (o.method === 'POST') params.set('method', 'POST');
    const ctrl = new AbortController();
    const timer = setTimeout(() => ctrl.abort(), timeoutMs + 5_000);
    try {
      const res = await fetch(`${base}/scrape?${params.toString()}`, {
        method: o.method === 'POST' ? 'POST' : 'GET',
        body: o.method === 'POST' && o.body !== undefined ? JSON.stringify(o.body) : undefined,
        headers: o.method === 'POST' ? { 'content-type': 'application/json' } : undefined,
        signal: ctrl.signal,
      });
      const text = await res.text();
      let json: ScrapflyResponse | null = null;
      try {
        json = JSON.parse(text) as ScrapflyResponse;
      } catch {
        return fail(`scrapfly HTTP ${res.status}: ${text.slice(0, 200)}`, started, url);
      }
      const r = json.result;
      const status = r?.status_code ?? null;
      const cost = json.context?.cost?.total ?? json.cost ?? 1;
      if (!res.ok || !r) return fail(`scrapfly HTTP ${res.status}: ${json.message ?? r?.error?.message ?? 'no result'}`, started, url, cost);
      const ok = Boolean(r.success !== false && (status === null || status < 400));
      const content = r.content ?? null;
      const extracted = (r.extracted_data as { data?: unknown } | undefined)?.data ?? r.extracted_data ?? null;
      const looksJson = content && /^\s*[[{]/.test(content);
      let parsed: unknown = extracted;
      if (!parsed && looksJson) {
        try {
          parsed = JSON.parse(content!);
        } catch {
          parsed = null;
        }
      }
      return {
        success: ok,
        engine: 'scrapfly',
        url,
        finalUrl: r.url ?? null,
        httpStatus: status,
        html: content,
        markdown: null,
        json: parsed,
        qualityScore: 0,
        requiresReview: false,
        error: ok ? null : (r.error?.message ?? `status ${status}`),
        costCredits: cost,
        durationMs: Date.now() - started,
        fetchedAt: new Date(),
      };
    } catch (err) {
      return fail(err instanceof Error ? err.message : String(err), started, url);
    } finally {
      clearTimeout(timer);
    }
  }

  function fail(error: string, started: number, url: string, cost = 0): ExtractionResult {
    return { success: false, engine: 'scrapfly', url, finalUrl: null, httpStatus: null, html: null, markdown: null, json: null, qualityScore: 0, requiresReview: false, error, costCredits: cost, durationMs: Date.now() - started, fetchedAt: new Date() };
  }

  return { scrape };
}

export type ScrapflyEngine = ReturnType<typeof createScrapflyEngine>;