// @vitest-environment node
import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
import { randomBytes } from "node:crypto";
import { tmpdir } from "node:os";
import path from "node:path";
import { afterEach, beforeEach, describe, expect, it } from "vitest";
import { BUDGET_BYTES, checkBudget } from "./check-3d-budget.mjs";

const threeChunk = (filler: string) => `/*WebGLRenderer*/window.__THREE__="186";${filler}`;
// Hex of random bytes is barely compressible by gzip (about 50 %).
const noise = (bytes: number) => randomBytes(bytes).toString("hex");

describe("check-3d-budget", () => {
  let dir: string;
  beforeEach(() => {
    dir = mkdtempSync(path.join(tmpdir(), "budget-"));
  });
  afterEach(() => rmSync(dir, { recursive: true, force: true }));

  it("passes when the three.js chunk is under budget", () => {
    writeFileSync(path.join(dir, "a.js"), threeChunk("x".repeat(1000)));
    writeFileSync(path.join(dir, "other.js"), "console.log(1)");
    const result = checkBudget(dir);
    expect(result.ok).toBe(true);
    expect(result.file).toBe("a.js");
  });

  it("fails when the three.js chunk is over budget", () => {
    writeFileSync(path.join(dir, "big.js"), threeChunk(noise(1000)));
    const result = checkBudget(dir, 100);
    expect(result.ok).toBe(false);
    expect(result.gzipBytes).toBeGreaterThan(100);
  });

  it("measures the largest of several three.js chunks", () => {
    writeFileSync(path.join(dir, "small.js"), threeChunk("x"));
    writeFileSync(path.join(dir, "large.js"), threeChunk(noise(2000)));
    expect(checkBudget(dir).file).toBe("large.js");
  });

  it("fails when no three.js chunk exists", () => {
    writeFileSync(path.join(dir, "app.js"), "export const a = 1; // WebGLRenderer only");
    const result = checkBudget(dir);
    expect(result.ok).toBe(false);
    expect(result.file).toBeNull();
  });

  it("uses the spec budget of 320 kB by default", () => {
    expect(BUDGET_BYTES).toBe(320_000);
  });
});