// love from https://github.com/LagrangeDev/lagrangejs & https://github.com/takayama-lily/oicq
import * as crypto from 'crypto';
import * as stream from 'stream';
import * as fs from 'fs';
import { CalculateStreamBytesTransform } from '@/napcat-core/packet/utils/crypto/sha1StreamBytesTransform';

function sha1Stream (readable: stream.Readable) {
  return new Promise<Buffer>((resolve, reject) => {
    readable.on('error', reject);
    readable.pipe(crypto.createHash('sha1').on('error', reject).on('data', resolve));
  });
}

function md5Stream (readable: stream.Readable) {
  return new Promise<Buffer>((resolve, reject) => {
    readable.on('error', reject);
    readable.pipe(crypto.createHash('md5').on('error', reject).on('data', resolve));
  });
}

export function calculateSha1 (filePath: string): Promise<Buffer> {
  const readable = fs.createReadStream(filePath);
  return sha1Stream(readable);
}

export function computeMd5AndLengthWithLimit (filePath: string, limit?: number): Promise<Buffer> {
  const readStream = fs.createReadStream(filePath, limit ? { start: 0, end: limit - 1 } : {});
  return md5Stream(readStream);
}

export function calculateSha1StreamBytes (filePath: string): Promise<Buffer[]> {
  return new Promise((resolve, reject) => {
    const readable = fs.createReadStream(filePath);
    const calculateStreamBytes = new CalculateStreamBytesTransform();
    const byteArrayList: Buffer[] = [];
    calculateStreamBytes.on('data', (chunk: Buffer) => {
      byteArrayList.push(chunk);
    });
    calculateStreamBytes.on('end', () => {
      resolve(byteArrayList);
    });
    calculateStreamBytes.on('error', (err: Error) => {
      reject(err);
    });
    readable.pipe(calculateStreamBytes);
  });
}