import { readFileSync } from 'node:fs';
import { fromHex, toBase64Url, toHex, type Bytes } from '../src/bytes.js';
import { ChannelSession, collectFrames, type EncodedFrame, type ItemPlan } from '../src/index.js';

/* eslint-disable @typescript-eslint/no-explicit-any */

export const vectors: any = JSON.parse(readFileSync(new URL('../../../test-vectors/vectors.json', import.meta.url), 'utf8'));

export const h = (s: string): Bytes => fromHex(s);
export { toHex };

/** 向量里的固定输入。 */
export const inputs = {
  channelId: h(vectors.inputs.channel_id),
  channelIdB64: vectors.inputs.channel_id_b64 as string,
  k: h(vectors.inputs.k),
  a: h(vectors.inputs.a),
  w: h(vectors.inputs.w),
  endpointSecret: h(vectors.inputs.endpoint_secret),
  itemA: h(vectors.inputs.item_a),
  itemB: h(vectors.inputs.item_b),
  itemC: h(vectors.inputs.item_c),
};

export const ORIGIN = 'https://app.example.test';

/** 用向量里的 channel_id / K(/A) 打开一个会话,终端密钥也取向量值。 */
export function openVectorSession(opts: { owner?: boolean } = {}): Promise<ChannelSession> {
  const parts = [`k=${toBase64Url(inputs.k)}`];
  if (opts.owner) parts.push(`a=${toBase64Url(inputs.a)}`);
  return ChannelSession.open(`${ORIGIN}/c/${inputs.channelIdB64}#${parts.join('&')}`, { endpointSecret: inputs.endpointSecret });
}

export async function framesOf(plan: ItemPlan): Promise<EncodedFrame[]> {
  return collectFrames(plan);
}

/** 随机但可复现的字节(线性同余),测试里需要「看起来随机」的内容时用。 */
export function pseudoRandom(length: number, seed = 1): Bytes {
  const out = new Uint8Array(length);
  let x = seed >>> 0 || 1;
  for (let i = 0; i < length; i++) {
    x = (Math.imul(x, 1664525) + 1013904223) >>> 0;
    out[i] = x >>> 24;
  }
  return out;
}

/** 把字节流在随机位置切成小块,模拟网络分片。 */
export function* splitAt(bytes: Uint8Array, seed = 7): Generator<Uint8Array> {
  let x = seed >>> 0 || 1;
  let offset = 0;
  while (offset < bytes.length) {
    x = (Math.imul(x, 1664525) + 1013904223) >>> 0;
    const size = 1 + (x >>> 8) % 4096;
    yield bytes.subarray(offset, offset + size);
    offset += size;
  }
}

export async function* asyncChunks(chunks: Iterable<Uint8Array>): AsyncGenerator<Uint8Array> {
  for (const c of chunks) yield c;
}

export async function readAll(stream: ReadableStream<Uint8Array>): Promise<Bytes> {
  const parts: Uint8Array[] = [];
  const reader = stream.getReader();
  for (;;) {
    const { done, value } = await reader.read();
    if (done) break;
    parts.push(value);
  }
  const out = new Uint8Array(parts.reduce((n, p) => n + p.length, 0));
  let o = 0;
  for (const p of parts) {
    out.set(p, o);
    o += p.length;
  }
  return out;
}

export function concatAll(parts: Uint8Array[]): Bytes {
  const out = new Uint8Array(parts.reduce((n, p) => n + p.length, 0));
  let o = 0;
  for (const p of parts) {
    out.set(p, o);
    o += p.length;
  }
  return out;
}