/**
 * Regression guard for the theme-token format contract (fix for "Appearance
 * theme not working").
 *
 * The 19 core theme tokens in globals.css MUST be stored as raw oklch
 * channel triples (`--primary: 0.554 0.143 249.3`), because
 * tailwind.config.ts references them as `oklch(var(--token) /
 * <alpha-value>)`. Storing a full color (`oklch(0.554 0.143 249.3)`)
 * produces the invalid nested `oklch(oklch(…))` which the browser resolves
 * to TRANSPARENT — silently blanking every themed bg/text/border utility and
 * making dark mode look identical to light mode. This test pins both halves
 * of the contract so the regression cannot reappear.
 *
 * NOTE: the suite default is jsdom, but this test reads files via node:fs /
 * node:path — run it under the node environment so those modules are not
 * externalized (externalization made `resolve` undefined and the whole
 * suite no-op before any token was checked).
 */
// @vitest-environment node
import { readFileSync } from "node:fs";
import { resolve } from "node:path";
import { describe, expect, it } from "vitest";

const CORE_TOKENS = [
  "background",
  "foreground",
  "card",
  "card-foreground",
  "popover",
  "popover-foreground",
  "primary",
  "primary-foreground",
  "secondary",
  "secondary-foreground",
  "muted",
  "muted-foreground",
  "accent",
  "accent-foreground",
  "destructive",
  "destructive-foreground",
  "border",
  "input",
  "ring",
] as const;

/** "0.985 0.002 247.839" — three space-separated numbers, no color function. */
const RAW_TRIPLE = /^(\d+(?:\.\d+)?\s+){2}\d+(?:\.\d+)?$/;

function blockBody(css: string, selector: string): string {
  const i = css.indexOf(selector);
  if (i === -1) throw new Error(`${selector} not found in globals.css`);
  const open = css.indexOf("{", i);
  const close = css.indexOf("}", open);
  return css.slice(open + 1, close);
}

function tokenValues(body: string): Record<string, string> {
  const out: Record<string, string> = {};
  for (const name of CORE_TOKENS) {
    const m = body.match(new RegExp(`--${name}:\\s*([^;]+);`));
    const value = m?.[1];
    if (!value) throw new Error(`--${name} missing in block`);
    out[name] = value.trim();
  }
  return out;
}

describe("theme tokens (globals.css + tailwind.config.ts)", () => {
  const css = readFileSync(resolve(__dirname, "../globals.css"), "utf8");
  const config = readFileSync(
    resolve(__dirname, "../../../tailwind.config.ts"),
    "utf8",
  );

  const light = tokenValues(blockBody(css, ":root"));
  const dark = tokenValues(blockBody(css, ".dark"));

  it("stores every core token as a raw oklch channel triple in both themes", () => {
    for (const [name, value] of Object.entries({ ...light, ...dark })) {
      expect(value, `--${name} must be raw channels, got: ${value}`).toMatch(RAW_TRIPLE);
      expect(
        value.startsWith("oklch("),
        `--${name} must NOT be a full oklch() color`,
      ).toBe(false);
    }
  });

  it("defines the same 19 core tokens in light and dark", () => {
    expect(Object.keys(light).sort()).toEqual(Object.keys(dark).sort());
    expect(CORE_TOKENS).toHaveLength(19);
  });

  it("wraps the tokens in the tailwind config as oklch(var(--x) / <alpha-value>)", () => {
    // Spot-check the utilities most affected by the original bug.
    for (const name of ["background", "foreground", "border", "ring", "primary", "muted", "card"]) {
      expect(
        config,
        `tailwind.config must wrap --${name}`,
      ).toContain(`oklch(var(--${name}) / <alpha-value>)`);
    }
    // And none of them may be referenced as a bare var (which breaks /NN modifiers).
    expect(config).not.toMatch(/"(?:var\(--(background|foreground|border|ring|primary)\))"/);
  });
});