import { readFileSync } from "node:fs";
import { join } from "node:path";
import { describe, expect, it } from "vitest";

const source = readFileSync(
  join(import.meta.dirname, "../src/tailwind.css"),
  "utf8",
);

function block(selector: string): string {
  const at = source.indexOf(`\n${selector} {`);
  if (at === -1) return "";
  const open = source.indexOf("{", at);
  const close = source.indexOf("\n}", open);
  return source.slice(open, close);
}

describe("theme aliases", () => {
  const OBSIDIAN_VARS = [
    "--background-primary",
    "--background-secondary",
    "--background-modifier-border",
    "--text-normal",
    "--text-muted",
    "--color-accent",
    "--text-on-accent",
    "--text-error",
  ];

  it("are declared on .bcal-root, not :root", () => {
    const root = block(".bcal-root");
    expect(root).not.toBe("");
    for (const name of OBSIDIAN_VARS) {
      expect(root, `${name} must be aliased on .bcal-root`).toContain(name);
    }
  });

  it("never reference Obsidian variables from :root", () => {
    const rootBlocks = [...source.matchAll(/(^|\n):root\s*\{([^}]*)\}/g)];
    for (const [, , body] of rootBlocks) {
      for (const name of OBSIDIAN_VARS) {
        expect(body, `:root must not reference ${name}`).not.toContain(name);
      }
    }
  });

  it("scopes the dark override under the view root", () => {
    expect(source).toContain(".theme-dark .bcal-root");
    expect(source).not.toMatch(/\n\.theme-dark\s*\{/);
  });
});

describe("reset specificity", () => {
  it("does not use :where() for element resets", () => {
    expect(source).not.toMatch(/\.bcal-root\s+:where\(/);
  });

  it("uses a doubled class to outrank app and theme styles", () => {
    expect(source).toContain(".bcal-root.bcal-root");
  });

  it("neutralises the native search affordance", () => {
    expect(source).toContain("-webkit-search-cancel-button");
  });
});

describe("cascade against Obsidian", () => {
  it("marks utilities important so they outrank app.css", () => {
    expect(source).toMatch(
      /@import "tailwindcss\/utilities\.css"[^;]*\bimportant\b/,
    );
  });

  it("keeps the element reset out of a cascade layer", () => {
    const reset = source.indexOf(".bcal-root.bcal-root :is(button");
    expect(reset).toBeGreaterThan(-1);
    const before = source.slice(0, reset);
    const opens = (before.match(/@layer[^;{]*\{/g) ?? []).length;
    const closes = (before.match(/\n\}/g) ?? []).length;
    expect(opens, "reset must be unlayered").toBeLessThanOrEqual(closes);
  });
});

describe("preflight stays out", () => {
  it("imports only the theme and utility layers", () => {
    expect(source).toContain('@import "tailwindcss/theme.css"');
    expect(source).toContain('@import "tailwindcss/utilities.css"');
    expect(source).not.toMatch(/@import "tailwindcss"\s*[;l]/);
    expect(source).not.toMatch(/@import\s+"tailwindcss\/preflight/);
  });
});