import { describe, expect, it } from 'bun:test';
import {
  CHUNK_HEADER_LEN,
  bytesEqual,
  decodeFrame,
  encodeChunkAckFrame,
  encodeChunkFrame,
  encodeErrorFrame,
  encodePingFrame,
  encodePongFrame,
  encodeResumeQueryFrame,
  encodeResumeStateFrame,
  randomRequestId,
  REQUEST_ID_LEN,
  STREAM_ID_LEN,
  streamIdBytesToString,
  streamIdStringToBytes,
  WIRE_CHUNK,
  WIRE_CHUNK_ACK,
  WIRE_ERROR,
  WIRE_PING,
  WIRE_PONG,
  WIRE_RESUME_QUERY,
  WIRE_RESUME_STATE,
} from '../src/wire.js';

describe('wire format', () => {
  it('roundtrips a chunk frame', () => {
    const requestId = randomRequestId();
    const streamId = new Uint8Array(STREAM_ID_LEN).fill(0xab);
    const envelope = new Uint8Array(1024);
    for (let i = 0; i < envelope.length; i++) envelope[i] = i & 0xff;
    const buf = encodeChunkFrame({
      type: WIRE_CHUNK,
      requestId,
      streamId,
      laneId: 7,
      seq: 12345n,
      envelope,
    });
    expect(buf.length).toBe(CHUNK_HEADER_LEN + envelope.length);

    const decoded = decodeFrame(buf);
    expect(decoded.type).toBe(WIRE_CHUNK);
    if (decoded.type !== WIRE_CHUNK) throw new Error('type narrow failed');
    expect(bytesEqual(decoded.requestId, requestId)).toBe(true);
    expect(bytesEqual(decoded.streamId, streamId)).toBe(true);
    expect(decoded.laneId).toBe(7);
    expect(decoded.seq).toBe(12345n);
    expect(bytesEqual(decoded.envelope, envelope)).toBe(true);
  });

  it('roundtrips a resume-query frame', () => {
    const requestId = randomRequestId();
    const streamId = new Uint8Array(STREAM_ID_LEN).fill(0x33);
    const buf = encodeResumeQueryFrame({
      type: WIRE_RESUME_QUERY,
      requestId,
      streamId,
    });
    const decoded = decodeFrame(buf);
    if (decoded.type !== WIRE_RESUME_QUERY) throw new Error('type narrow failed');
    expect(bytesEqual(decoded.requestId, requestId)).toBe(true);
    expect(bytesEqual(decoded.streamId, streamId)).toBe(true);
  });

  it('roundtrips chunk-ack', () => {
    const requestId = randomRequestId();
    const buf = encodeChunkAckFrame({
      type: WIRE_CHUNK_ACK,
      requestId,
      lastSeq: 42,
      bytesReceived: 1024,
    });
    const decoded = decodeFrame(buf);
    if (decoded.type !== WIRE_CHUNK_ACK) throw new Error('type narrow failed');
    expect(decoded.lastSeq).toBe(42);
    expect(decoded.bytesReceived).toBe(1024);
  });

  it('roundtrips resume-state frame', () => {
    const json = JSON.stringify({
      streamId: 'abc',
      lanes: [{ laneId: 0, lastSeqAcked: 5 }],
    });
    const buf = encodeResumeStateFrame({
      type: WIRE_RESUME_STATE,
      requestId: randomRequestId(),
      json,
    });
    const decoded = decodeFrame(buf);
    if (decoded.type !== WIRE_RESUME_STATE) throw new Error('type narrow failed');
    expect(decoded.json).toBe(json);
  });

  it('roundtrips ping/pong frames', () => {
    const requestId = randomRequestId();
    const ping = encodePingFrame({ type: WIRE_PING, requestId, nonce: 99n });
    const decodedPing = decodeFrame(ping);
    if (decodedPing.type !== WIRE_PING) throw new Error('type narrow failed');
    expect(decodedPing.nonce).toBe(99n);

    const pong = encodePongFrame({ type: WIRE_PONG, requestId, nonce: 99n });
    const decodedPong = decodeFrame(pong);
    if (decodedPong.type !== WIRE_PONG) throw new Error('type narrow failed');
    expect(decodedPong.nonce).toBe(99n);
  });

  it('roundtrips error frame', () => {
    const buf = encodeErrorFrame({
      type: WIRE_ERROR,
      requestId: randomRequestId(),
      json: '{"error":"oh no"}',
    });
    const decoded = decodeFrame(buf);
    if (decoded.type !== WIRE_ERROR) throw new Error('type narrow failed');
    expect(JSON.parse(decoded.json)).toEqual({ error: 'oh no' });
  });

  it('rejects truncated frames', () => {
    const tiny = new Uint8Array(8);
    expect(() => decodeFrame(tiny)).toThrow();
  });

  it('rejects unknown type', () => {
    const bad = new Uint8Array(REQUEST_ID_LEN + 1);
    bad[0] = 0x77;
    expect(() => decodeFrame(bad)).toThrow();
  });
});

describe('streamId base64url codec', () => {
  it('roundtrips arbitrary 16-byte ids', () => {
    const original = new Uint8Array(STREAM_ID_LEN);
    globalThis.crypto.getRandomValues(original);
    const s = streamIdBytesToString(original);
    const back = streamIdStringToBytes(s);
    expect(bytesEqual(back, original)).toBe(true);
  });
});
