import net from 'node:net';
import stream from 'node:stream';
import crypto from 'node:crypto';
import { NapProtoMsg } from 'snowcat-protobuf';
import { BlockSize } from '@/snowcat-core/packet/highway/highwayContext';
import { Frame } from '@/snowcat-core/packet/highway/frame';
import { IHighwayUploader } from '@/snowcat-core/packet/highway/uploader/highwayUploader';
import * as proto from '@/snowcat-core/packet/transformer/proto';

class HighwayTcpUploaderTransform extends stream.Transform {
  uploader: HighwayTcpUploader;
  offset: number;

  constructor (uploader: HighwayTcpUploader) {
    super();
    this.uploader = uploader;
    this.offset = 0;
  }

  override _transform (data: Buffer, _: BufferEncoding, callback: stream.TransformCallback) {
    let chunkOffset = 0;
    while (chunkOffset < data.length) {
      const chunkSize = Math.min(BlockSize, data.length - chunkOffset);
      const chunk = data.subarray(chunkOffset, chunkOffset + chunkSize);
      const chunkMd5 = crypto.createHash('md5').update(chunk).digest();
      const head = this.uploader.buildPicUpHead(this.offset, chunk.length, chunkMd5);
      chunkOffset += chunk.length;
      this.offset += chunk.length;
      this.push(Frame.pack(Buffer.from(head), chunk));
    }
    callback(null);
  }
}

export class HighwayTcpUploader extends IHighwayUploader {
  async upload (): Promise<void> {
    const controller = new AbortController();
    const { signal } = controller;
    const upload = new Promise<void>((resolve, reject) => {
      const highwayTransForm = new HighwayTcpUploaderTransform(this);
      const socket = net.connect(this.trans.port, this.trans.server, () => {
        this.trans.data.pipe(highwayTransForm).pipe(socket, { end: false });
      });
      const handleRspHeader = (header: Buffer) => {
        const rsp = new NapProtoMsg(proto.RespDataHighwayHead).decode(header);
        if (rsp.errorCode !== 0) {
          socket.end();
          reject(new Error(`[Highway] tcpUpload failed (code=${rsp.errorCode})`));
        }
        const percent = ((Number(rsp.msgSegHead?.dataOffset) + Number(rsp.msgSegHead?.dataLength)) / Number(rsp.msgSegHead?.filesize)).toFixed(2);
        this.logger.debug(`[Highway] tcpUpload ${rsp.errorCode} | ${percent} | ${Buffer.from(header).toString('hex')}`);
        if (Number(rsp.msgSegHead?.dataOffset) + Number(rsp.msgSegHead?.dataLength) >= Number(rsp.msgSegHead?.filesize)) {
          this.logger.debug('[Highway] tcpUpload finished.');
          socket.end();
          resolve();
        }
      };
      socket.on('data', (chunk: Buffer) => {
        if (signal.aborted) {
          socket.end();
          reject(new Error('Upload aborted due to timeout'));
        }

        const [head, _] = Frame.unpack(chunk);
        handleRspHeader(head);
      });
      socket.on('close', () => {
        this.logger.debug('[Highway] tcpUpload socket closed.');
        resolve();
      });
      socket.on('error', (err) => {
        socket.end();
        reject(new Error(`[Highway] tcpUpload socket.on error: ${err}`));
      });
      this.trans.data.on('error', (err) => {
        socket.end();
        reject(new Error(`[Highway] tcpUpload readable error: ${err}`));
      });
    });
    const timeout = this.timeout().catch((err) => {
      controller.abort();
      throw new Error(err.message);
    });
    await Promise.race([upload, timeout]);
  }
}