import { toPng } from "html-to-image";

export async function loadImageAsDataUrl(src: string): Promise<string | null> {
  try {
    const img = new Image();
    img.crossOrigin = "anonymous";
    img.src = src;
    await new Promise<void>((resolve, reject) => {
      img.onload = () => resolve();
      img.onerror = () => reject();
    });
    const canvas = document.createElement("canvas");
    canvas.width = img.naturalWidth;
    canvas.height = img.naturalHeight;
    const ctx = canvas.getContext("2d")!;
    ctx.drawImage(img, 0, 0);
    return canvas.toDataURL("image/jpeg", 0.85);
  } catch (e) {
    console.error("proxyToDataUrl failed:", e);
    return null;
  }
}

export async function generateImage(el: HTMLElement): Promise<string> {
  return toPng(el, {
    pixelRatio: 2,
    quality: 0.95,
    cacheBust: true,
    skipAutoScale: true,
    filter: (node) => {
      if (node instanceof HTMLElement && node.dataset.shareExclude === "true") {
        return false;
      }
      return true;
    },
  });
}

export function downloadDataUrl(dataUrl: string, filename: string) {
  const link = document.createElement("a");
  link.download = filename;
  link.href = dataUrl;
  link.click();
}

export function dataUrlToFile(dataUrl: string, filename: string): File {
  const arr = dataUrl.split(",");
  const mime = arr[0].match(/:(.*?);/)?.[1] || "image/png";
  const bstr = atob(arr[1]);
  const u8 = new Uint8Array(bstr.length);
  for (let i = 0; i < bstr.length; i++) u8[i] = bstr.charCodeAt(i);
  return new File([u8], filename, { type: mime });
}