import { describe, expect, it } from "vitest";
import {
  createPkcePair,
  deriveCodeChallenge,
  generateCodeVerifier,
  generateState,
  isValidCodeVerifier,
} from "../src";

describe("PKCE helpers", () => {
  it("derives the RFC 7636 S256 example", async () => {
    const verifier = "dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk";
    await expect(deriveCodeChallenge(verifier)).resolves.toBe(
      "E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM",
    );
  });

  it("generates valid verifier lengths", () => {
    for (const length of [43, 64, 128]) {
      const verifier = generateCodeVerifier(length);
      expect(verifier).toHaveLength(length);
      expect(isValidCodeVerifier(verifier)).toBe(true);
    }
  });

  it("rejects invalid verifier lengths and characters", async () => {
    expect(() => generateCodeVerifier(42)).toThrow(RangeError);
    expect(isValidCodeVerifier("a".repeat(42))).toBe(false);
    await expect(deriveCodeChallenge(`${"a".repeat(42)}!`)).rejects.toThrow(
      "Invalid RFC 7636 code verifier",
    );
  });

  it("creates an S256 pair and a high-entropy state", async () => {
    const pair = await createPkcePair();
    expect(pair.method).toBe("S256");
    expect(pair.challenge).toBe(await deriveCodeChallenge(pair.verifier));
    expect(generateState()).toMatch(/^[A-Za-z0-9_-]{43}$/);
  });
});