import html2canvas from 'html2canvas';
import type { Options as Html2canvasOptions } from 'html2canvas';
import JsPDF from 'jspdf';
import type { jsPDFOptions as JsPDFOptions } from 'jspdf';

type GeneratePDFOptions = {
  /** 文件名称 */
  fileName?: string;
  /** 单页高度 */
  heightPerPage?: number;
  /** tml2canvas配置 */
  html2canvasOptions?: Partial<Html2canvasOptions>;
  /** jspdf配置 */
  jsPDFOptions?: Partial<JsPDFOptions>;
  /** 生成成功的回调方法 */
  onSuccess?: () => void;
  /** 生成错误的回调方法 */
  onError?: (error: unknown) => void;
  /** 生成之后的回调方法 */
  onSettled?: () => void;
  /** 生成之前的回调方法 */
  onBeforeCapture?: () => void;
};

const htmlToPdf = async (element: HTMLElement | null, options: GeneratePDFOptions) => {
  const {
    heightPerPage = 840,
    fileName = 'document.pdf',
    html2canvasOptions = {},
    jsPDFOptions = {},
    onSuccess,
    onError,
    onSettled,
    onBeforeCapture,
  } = options;

  if (!element) return;

  const CANVAS_CHROME_FF_LIMIT = 32_767;
  const CANVAS_SAFARI_LIMIT = 4096;
  // eslint-disable-next-line no-param-reassign
  element.style.gap = '0px';

  const MAX_CANVAS_HEIGHT =
    navigator.userAgent.includes('Chrome') || navigator.userAgent.includes('Firefox')
      ? (CANVAS_CHROME_FF_LIMIT % heightPerPage) * heightPerPage
      : (CANVAS_SAFARI_LIMIT % heightPerPage) * heightPerPage;

  onBeforeCapture?.();

  try {
    const pdf = new JsPDF({
      orientation: 'l',
      unit: 'px',
      format: [element.offsetWidth, heightPerPage],
      compress: true,
      ...jsPDFOptions,
    });

    const totalHeight = element.scrollHeight;
    const totalWidth = element.scrollWidth;
    let capturedHeight = 0;
    const canvasPromises: Promise<HTMLCanvasElement>[] = [];

    while (capturedHeight < totalHeight) {
      const remainingHeight = totalHeight - capturedHeight;
      const captureHeight = Math.min(remainingHeight, MAX_CANVAS_HEIGHT);

      const canvasPromise = html2canvas(element, {
        logging: false,
        windowWidth: totalWidth,
        windowHeight: totalHeight,
        x: 0,
        y: capturedHeight,
        width: totalWidth,
        height: captureHeight,
        ...html2canvasOptions,
      });

      canvasPromises.push(canvasPromise);
      capturedHeight += captureHeight;
    }

    const canvases = await Promise.all(canvasPromises);

    canvases.forEach((canvas) => {
      const contentWidth = canvas.width;
      let contentHeight = canvas.height;
      const pageHeight = (contentWidth / element.offsetWidth) * heightPerPage;
      let position = 0;
      const imgWidth = element.offsetWidth;
      const imgHeight = (element.offsetWidth / contentWidth) * contentHeight;
      const imgData = canvas.toDataURL('image/jpeg');

      if (contentHeight < pageHeight) {
        pdf.addImage(imgData, 'JPEG', 0, 0, imgWidth, imgHeight, undefined, 'FAST');
      } else {
        while (contentHeight > 0) {
          pdf.addImage(
            imgData,
            'JPEG',
            0,
            position,
            imgWidth,
            imgHeight,
            undefined,
            'FAST',
          );
          contentHeight -= pageHeight;
          position -= heightPerPage;
          if (contentHeight > 0) {
            pdf.addPage();
          }
        }
      }
    });

    pdf.save(fileName);
    onSuccess?.();
  } catch (error) {
    onError?.(error);
  } finally {
    onSettled?.();
  }
};

export default htmlToPdf;