"use strict"

const crypto = require('crypto');
const { v4: uuidv4 } = require('uuid');
const UserAgent = require('fake-useragent');
const {HttpsProxyAgent} = require('https-proxy-agent');

class ChatCompletion {
  static async create(messages) {
    const url = "https://chat.getgpt.world/api/chat/stream";
    // const url = "https://api.ipify.org";
    const headers = {
      "Content-Type": "application/json",
      "Referer": "https://chat.getgpt.world/",
      'User-Agent': UserAgent(),
      "agent": new HttpsProxyAgent("https://qmvnozfp:jgr74lg0t6hn@185.199.229.156:5074")
    };
    const data = JSON.stringify({
      "messages": messages,
      "frequency_penalty": 0,
      "max_tokens": 5000,
      "model": "gpt-3.5-turbo",
      "presence_penalty": 0,
      "temperature": 1,
      "top_p": 1,
      // "stream": true,
      "uuid": uuidv4()
    });
    const signature = ChatCompletion.encrypt(data);
    const response = await fetch(url, {
      method: 'post',
      headers: headers,
      body: JSON.stringify({ "signature": signature }),
    });

    const reader = response.body.getReader();
    let content = '';

    while (true) {
      const { done, value } = await reader.read();
      if (done) break;
      const chunk = new TextDecoder().decode(value);
      content += chunk;
    }

    const chunks = content.split('data: ');
    let final = "";
    for (let i = 1; i < chunks.length; i++) {
      const data = chunks[i];
      if (!data || data.includes("[DONE]")) {
        return final;
      }
      const dataJson = JSON.parse(data);
      const content = dataJson.choices[0].delta.content;
      if (content) {
        final += content
      }
    }
  }

  static randomToken(e) {
    const token = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    const n = token.length;
    let result = "";
    for (let i = 0; i < e; i++) {
      const randomIndex = Math.floor(Math.random() * n);
      result += token.charAt(randomIndex);
    }
    return result;
  }

  static encrypt(e) {
    const t = ChatCompletion.randomToken(16);
    const n = ChatCompletion.randomToken(16);
    const r = Buffer.from(e, 'utf-8');
    const cipher = crypto.createCipheriv('aes-128-cbc', t, n);
    let ciphertext = cipher.update(r, 'utf-8', 'hex');
    ciphertext += cipher.final('hex');
    return ciphertext + t + n;
  }

  static __padData(data) {
    const block_size = 16;
    const padding_size = block_size - (data.length % block_size);
    const padding = Buffer.alloc(padding_size, padding_size);
    return Buffer.concat([data, padding]);
  }
}

module.exports = ChatCompletion