/** Which files open in which viewer, and the editor inputs of the viewers. */
import type { EditorInput } from "@/workbench/contributions";
import type { FileProbe } from "@/platform/ipc";

export const IMAGE_KIND = "image";
export const BINARY_KIND = "binary";

const IMAGE_EXTENSIONS = new Set(["png", "jpg", "jpeg", "gif", "webp", "svg", "ico", "bmp", "avif"]);
const MARKDOWN_EXTENSIONS = new Set(["md", "markdown", "mdown", "mkd", "mkdn", "mdwn"]);

function extension(path: string): string {
  const name = path.slice(path.lastIndexOf("/") + 1);
  const dot = name.lastIndexOf(".");
  return dot > 0 ? name.slice(dot + 1).toLowerCase() : "";
}

export const isImagePath = (path: string) => IMAGE_EXTENSIONS.has(extension(path));
export const isSvgPath = (path: string) => extension(path) === "svg";
export const isMarkdownPath = (path: string) => MARKDOWN_EXTENSIONS.has(extension(path));

export const imageInput = (path: string): EditorInput => ({ kind: IMAGE_KIND, key: `image:${path}`, path });

export interface BinaryInputData {
  size: number;
  /** False for huge text files shown in the hex view (they may still open as text). */
  binary: boolean;
}

export const binaryInput = (path: string, probe: FileProbe): EditorInput => ({
  kind: BINARY_KIND,
  key: `binary:${path}`,
  path,
  data: { size: probe.size, binary: probe.binary } satisfies BinaryInputData,
});

/** Binary content or past the size where the text editor turns read-only → hex view. */
export const wantsHexView = (probe: FileProbe) => probe.binary || probe.tooLarge;

export function formatSize(bytes: number): string {
  if (bytes < 1024) return `${bytes} B`;
  const units = ["KB", "MB", "GB", "TB"];
  let v = bytes / 1024;
  let i = 0;
  while (v >= 1024 && i < units.length - 1) {
    v /= 1024;
    i++;
  }
  return `${v >= 100 ? v.toFixed(0) : v.toFixed(1)} ${units[i]}`;
}