export interface PDFOptions {
  format?: string;
  landscape?: boolean;
  margin?: { top: number; right: number; bottom: number; left: number };
  printBackground?: boolean;
  headerTemplate?: string;
  footerTemplate?: string;
}

const DOC_WORKER_URL = (process.env.DOC_WORKER_URL || "http://document-worker:3000").replace(/\/+$/, "");

function getTimeout(): number {
  const env = process.env.DOC_WORKER_TIMEOUT_MS;
  return env ? parseInt(env, 10) : 30000;
}

/**
 * Конвертирует HTML в PDF через внешний document-worker сервис.
 * Возвращает Buffer или null при ошибке.
 */
export async function convertHtmlToPdf(html: string, options: PDFOptions = {}): Promise<Buffer | null> {
  try {
    const response = await fetch(`${DOC_WORKER_URL}/convert/pdf`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ html, options }),
      signal: AbortSignal.timeout(getTimeout()),
    });

    if (!response.ok) {
      const text = await response.text().catch(() => "");
      console.error("[doc-worker] PDF conversion HTTP error:", response.status, text);
      return null;
    }

    const data = await response.json();
    if (!data.success || !data.pdf) {
      console.error("[doc-worker] PDF conversion failed:", data.error || "unknown");
      return null;
    }

    return Buffer.from(data.pdf, "base64");
  } catch (err) {
    console.error("[doc-worker] PDF conversion request failed:", err);
    return null;
  }
}

/**
 * Конвертирует DOCX (Buffer) в PDF через внешний document-worker сервис.
 * Возвращает Buffer или null при ошибке.
 */
export async function convertDocxToPdf(docxBuffer: Buffer): Promise<Buffer | null> {
  try {
    const response = await fetch(`${DOC_WORKER_URL}/convert/docx-to-pdf`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ docxBase64: docxBuffer.toString("base64") }),
      signal: AbortSignal.timeout(getTimeout()),
    });

    if (!response.ok) {
      const text = await response.text().catch(() => "");
      console.error("[doc-worker] DOCX→PDF conversion HTTP error:", response.status, text);
      return null;
    }

    const data = await response.json();
    if (!data.success || !data.pdf) {
      console.error("[doc-worker] DOCX→PDF conversion failed:", data.error || "unknown");
      return null;
    }

    return Buffer.from(data.pdf, "base64");
  } catch (err) {
    console.error("[doc-worker] DOCX→PDF conversion request failed:", err);
    return null;
  }
}

/**
 * Конвертирует EMF/WMF (Buffer) в PNG через внешний document-worker сервис.
 * Возвращает Buffer или null при ошибке.
 */
export async function convertEmfToPng(emfBuffer: Buffer): Promise<Buffer | null> {
  try {
    const response = await fetch(`${DOC_WORKER_URL}/convert/emf-to-png`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ emfBase64: emfBuffer.toString("base64") }),
      signal: AbortSignal.timeout(getTimeout()),
    });

    if (!response.ok) {
      const text = await response.text().catch(() => "");
      console.error("[doc-worker] EMF→PNG conversion HTTP error:", response.status, text);
      return null;
    }

    const data = await response.json();
    if (!data.success || !data.png) {
      console.error("[doc-worker] EMF→PNG conversion failed:", data.error || "unknown");
      return null;
    }

    return Buffer.from(data.png, "base64");
  } catch (err) {
    console.error("[doc-worker] EMF→PNG conversion request failed:", err);
    return null;
  }
}

/**
 * Проверяет доступность document-worker сервиса.
 */
export async function checkDocumentWorkerHealth(): Promise<{ ok: boolean; error?: string }> {
  try {
    const response = await fetch(`${DOC_WORKER_URL}/health`, {
      signal: AbortSignal.timeout(5000),
    });
    if (!response.ok) {
      return { ok: false, error: `HTTP ${response.status}` };
    }
    return { ok: true };
  } catch (err) {
    return { ok: false, error: err instanceof Error ? err.message : String(err) };
  }
}