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import type { ExportFormat } from "../types";
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export interface LoadedImage {
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  file: File;
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  /** Object URL for display in the cropper. Revoke when replaced. */
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  url: string;
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  width: number;
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  height: number;
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}
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const ACCEPTED = /^image\/(jpeg|png|webp|avif|gif|bmp|x-icon|svg\+xml)$/;
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export function isImageFile(file: File): boolean {
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  return file.type ? ACCEPTED.test(file.type) : /\.(jpe?g|png|webp|avif|gif|bmp|ico|svg)$/i.test(file.name);
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}
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function readSize(url: string): Promise<{ width: number; height: number }> {
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  return new Promise((resolve, reject) => {
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    const img = new Image();
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    img.onload = () => resolve({ width: img.naturalWidth, height: img.naturalHeight });
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    img.onerror = () => reject(new Error("Could not decode this image."));
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    img.src = url;
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  });
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}
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export async function loadImage(file: File): Promise<LoadedImage> {
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  const url = URL.createObjectURL(file);
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  try {
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    const { width, height } = await readSize(url);
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    return { file, url, width, height };
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  } catch (err) {
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    URL.revokeObjectURL(url);
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    throw err;
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  }
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}
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const EXT: Record<ExportFormat, string> = {
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  jpeg: "jpg",
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  webp: "webp",
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  png: "png",
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  avif: "avif",
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};
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export function buildFilename(sourceName: string, templateId: string, format: ExportFormat): string {
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  const base = sourceName.replace(/\.[^./\\]+$/, "") || "image";
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  const suffix = templateId === "original" ? "edited" : templateId;
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  return `${base}-${suffix}.${EXT[format]}`;
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}
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export function triggerDownload(blob: Blob, filename: string): void {
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  const url = URL.createObjectURL(blob);
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  const a = document.createElement("a");
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  a.href = url;
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  a.download = filename;
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  document.body.appendChild(a);
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  a.click();
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  a.remove();
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  // Defer revocation so the download has time to start.
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  setTimeout(() => URL.revokeObjectURL(url), 10_000);
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}
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export function formatBytes(bytes: number): string {
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  if (bytes < 1024) return `${bytes} B`;
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  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
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  return `${(bytes / (1024 * 1024)).toFixed(2)} MB`;
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}
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export function megapixels(width: number, height: number): string {
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  const mp = (width * height) / 1_000_000;
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  return mp >= 1 ? `${mp.toFixed(1)} MP` : `${(mp * 1000).toFixed(0)} KP`;
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}