#!/usr/bin/env node
//IRC bot that responds to !chat, queries the chatgpt api, and prints the response line by line
const irc = require('irc');
const axios = require('axios');
const config = require('./config.json');

// context is a list of strings that are used to seed the chatgpt api and it's responses
class Context {
    messages = [];
    currentResponse = '';

    add_user_message(message) {
        this.messages.push({ role: 'user', content: message });
    }

    add_assistant_message(message) {
        this.messages.push({ role: 'assistant', content: message });
    }

    append_current_response(message) {
        this.currentResponse += message;
    }

    end_line() {
        const response_so_far = this.currentResponse;
        this.currentResponse += "\n\n"
        return response_so_far;
    }

    finish_current_response() {
        this.add_assistant_message(this.currentResponse);
        const the_response = this.currentResponse;
        this.currentResponse = '';
        return the_response;
    }

    is_response_in_progress() {
        return this.currentResponse !== '';
    }

    clear() {
        this.messages = [];
        this.currentResponse = '';
    }
}

const context = new Context();

const client = new irc.Client(config.server, config.nick, {
    channels: config.channels,
});

// listen for messages that start with !chat and call the chatgpt api with a callback that prints the response line by line
client.addListener('message', async (from, to, message) => {
    is_chat_cmd = message.startsWith('!chat');
    is_cont_cmd = message.startsWith('!cont');
    if (is_chat_cmd || is_cont_cmd) {
        if(context.is_response_in_progress()) { return; }
        if(is_chat_cmd) {
            context.clear();
        }
        const query = message.slice(6);
        chatgpt(query, (line) => {
            client.say(to, line);
        });
    }
});

// function that calls the chatgpt streaming api (with server send events) and calls the callback function for each line
async function chatgpt(query, callback) {
    // a very primitive mutex to prevent multiple calls to the api at once
    if(context.is_response_in_progress()) { return; }
    context.add_user_message(query);
    const apiUrl = 'https://api.openai.com/v1/chat/completions';

    const response = await axios.post(apiUrl, {
        messages: [context.messages],
        model: 'gpt-3.5-turbo',
        stream: true,
    }, {
        headers: {
            Authorization: `Bearer ${config.openaiApiKey}`,
            'Content-Type': 'application/json',
        },
        responseType: 'stream',
    });

    response.data.on('data', (event) => {
        let data = event.toString();
        let parts = data.split('\n');
        // parse if starts with data:
        for(part of parts) {
            console.log(part);
            if(part === 'data: [DONE]') {
                callback(context.finish_current_response());
            } else if(part.startsWith('data: ')) {
                let jsonString = part.slice(part.indexOf('{'), part.lastIndexOf('}') + 1);
                try {
                    let json = JSON.parse(jsonString);
                    let chunk = json.choices[0].delta.content;
                    if (!chunk) {
                        callback(context.end_line());
                        continue;
                    }
                    //split the chunk into lines leaving the delimiter in the array
                    const lines = chunk.split(/\r?\n/); // split by new lines

                    let hasStartNewline = chunk.startsWith("\n");
                    let hasEndNewline = chunk.endsWith("\n");

                    if(hasStartNewline) {
                        callback(context.end_line())
                    }
                    
                    for (let i = 0; i < lines.length - 1; i++) {
                        context.append_current_response(lines[i]);
                        callback(context.end_line());
                    }

                    context.append_current_response(lines[lines.length - 1]);

                    if(hasEndNewline) {
                        callback(context.end_line());
                    }

                    if (line.length > 400) {
                        callback(context.end_line());
                    }
                } catch (e) {
                    console.log(e);
                    console.log(part);
                }
            }
        }
    });
}