import { readdirSync, readFileSync } from "node:fs";

import { describe, expect, it } from "vitest";

// E28 S3d4 (B9). The header + fade edge is one recipe, the `fade-below` / `fade-below-panel` /
// `fade-above-panel` utilities in index.css: a crisp band and a 1rem gradient of the colour under
// it. The table header carried its own arbitrary-value copy of it, which a change to the recipe (its
// height, its colour on a panel) would have left behind.
function sources(): Array<[string, string]> {
  const walk = (u: URL, prefix: string): Array<[string, string]> =>
    readdirSync(u, { withFileTypes: true }).flatMap((e) => {
      if (e.isDirectory()) return walk(new URL(`${e.name}/`, u), `${prefix}${e.name}/`);
      if (!/\.tsx?$/.test(e.name) || e.name.includes(".test.")) return [];
      return [
        [`${prefix}${e.name}`, readFileSync(new URL(e.name, u), "utf-8")] as [string, string],
      ];
    });
  return walk(new URL("../", import.meta.url), "");
}

describe("the fade edge", () => {
  it("is the utility, never an arbitrary gradient of a surface colour", () => {
    const copies = sources()
      .filter(([, src]) =>
        /linear-gradient\(to_(?:bottom|top),var\(--(?:bg|surface|card)\)/.test(src),
      )
      .map(([name]) => name);
    expect(copies).toEqual([]);
  });
});