import { describe, expect, test } from "vitest";
import {
  COURSE_CHAT_NONCE_HEADER,
  COURSE_CHAT_SIGNATURE_HEADER,
  COURSE_CHAT_TIMESTAMP_HEADER,
  CourseChatCapabilityVerifier,
  decodeCourseChatCapability,
  signCourseChatRequest,
} from "../src/courses/web-capability.js";

describe("course chat loopback capability", () => {
  test("binds one fresh nonce to the exact path and body", () => {
    const key = Buffer.alloc(32, 17);
    const body = Buffer.from('{"question":"What is SFT?"}');
    const path = "/api/courses/post-training/questions";
    const signature = signCourseChatRequest(key, {
      method: "POST",
      path,
      body,
      timestamp: 1_900_000_000_000,
      nonce: "A".repeat(32),
    });
    const headers = {
      [COURSE_CHAT_TIMESTAMP_HEADER]: signature.timestamp,
      [COURSE_CHAT_NONCE_HEADER]: signature.nonce,
      [COURSE_CHAT_SIGNATURE_HEADER]: signature.signature,
    };
    const verifier = new CourseChatCapabilityVerifier(key, { now: () => 1_900_000_000_000 });
    expect(verifier.verify(headers, "POST", path, body)).toBe(true);
    expect(verifier.verify(headers, "POST", path, body)).toBe(false);
    const changed = new CourseChatCapabilityVerifier(key, { now: () => 1_900_000_000_000 });
    expect(changed.verify(headers, "POST", `${path}/other`, body)).toBe(false);
    expect(changed.verify(headers, "POST", path, Buffer.from("{}"))).toBe(false);
  });

  test("decodes only canonical bounded base64", () => {
    const key = Buffer.alloc(32, 9);
    expect(decodeCourseChatCapability(key.toString("base64"))).toEqual(key);
    expect(() => decodeCourseChatCapability("not base64")).toThrow("canonical base64");
    expect(() => decodeCourseChatCapability(Buffer.alloc(16).toString("base64"))).toThrow("32 to 128 bytes");
  });
});