import { Notify, platformIsAIO, Toast } from '@/platform/index';
import { useShowScanCode } from '@/composables/useShowScanCode';

export interface DownloadFromUrlOptions {
  /** 保存时的文件名；不传则从响应头或 URL 路径推断 */
  filename?: string;
  /** 传给 fetch 的额外配置（如 credentials、headers） */
  fetchInit?: RequestInit;
}

function filenameFromContentDisposition(header: string | null): string | undefined {
  if (!header) return;
  const utf8 = /filename\*=UTF-8''([^;\s]+)/i.exec(header);
  if (utf8?.[1]) {
    try {
      return decodeURIComponent(utf8[1].replace(/['"]/g, ''));
    } catch {
      return utf8[1];
    }
  }
  const plain = /filename\s*=\s*("?)([^";\n]+)\1/i.exec(header);
  return plain?.[2];
}

function filenameFromUrl(url: string): string {
  try {
    const path = new URL(url, typeof location !== 'undefined' ? location.href : undefined).pathname;
    const seg = path.split('/').filter(Boolean).pop();
    return seg || 'download';
  } catch {
    return 'download';
  }
}

/**
 * 根据文件 URL 下载到本地（通过 fetch 取 Blob 后触发浏览器保存）。
 * 跨域资源需服务端允许 CORS，否则 fetch 会失败。
 */
export function downloadFromUrl(url: string, options?: DownloadFromUrlOptions): Promise<void> {
  return (async () => {
    const res = await fetch(url, options?.fetchInit);
    if (!res.ok) throw new Error(`下载失败: ${res.status} ${res.statusText}`);

    const blob = await res.blob();
    const filename = options?.filename ?? filenameFromContentDisposition(res.headers.get('content-disposition')) ?? filenameFromUrl(url);

    const objectUrl = URL.createObjectURL(blob);
    try {
      const a = document.createElement('a');
      a.href = objectUrl;
      a.download = filename;
      a.rel = 'noopener';
      document.body.appendChild(a);
      a.click();
      a.remove();
    } finally {
      URL.revokeObjectURL(objectUrl);
    }
  })();
}

export async function printFromUrl(url: string, options?: { rollback?: boolean; title?: string }) {
  let closed = false;
  if (platformIsAIO()) {
    try {
      try {
        await Bridge.print({ url });
      } catch {
        window.AIO?.print?.(url);
      }
    } catch (e) {
      Notify.warning(`打印失败 (${e.message})`, { duration: 1500 });
      closed = true;
    }
  } else {
    try {
      const current = window.open(url, '_blank');
      closed = current.closed;
      current.location.href;
    } catch (e) {
      Notify.warning(`无法打开窗口 (${e.message})`, { duration: 1500 });
      closed = true;
    }
  }
  if (closed && options?.rollback) {
    Toast.close();
    await useShowScanCode().open({ url, title: options?.title });
  }
}