import { describe, expect, test } from "bun:test";
import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { assertDiskFileIsAllowedRasterImage, IMAGE_MAGIC_MISMATCH_MESSAGE } from "./image-magic-bytes";

describe("assertDiskFileIsAllowedRasterImage", () => {
  test("rejects non-image bytes", () => {
    const dir = mkdtempSync(join(tmpdir(), "img-magic-"));
    try {
      const p = join(dir, "x.bin");
      writeFileSync(p, Buffer.from("not an image"));
      expect(() => assertDiskFileIsAllowedRasterImage(p)).toThrow(IMAGE_MAGIC_MISMATCH_MESSAGE);
    } finally {
      rmSync(dir, { recursive: true });
    }
  });

  test("accepts jpeg magic prefix", () => {
    const dir = mkdtempSync(join(tmpdir(), "img-magic-"));
    try {
      const p = join(dir, "x.jpg");
      const buf = Buffer.alloc(20, 0);
      buf[0] = 0xff;
      buf[1] = 0xd8;
      buf[2] = 0xff;
      buf[3] = 0xe0;
      writeFileSync(p, buf);
      expect(() => assertDiskFileIsAllowedRasterImage(p)).not.toThrow();
    } finally {
      rmSync(dir, { recursive: true });
    }
  });
});