#!/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');

const seed_messages = [{role: 'system', content: config.initialSystemMessage}];

// context is a list of strings that are used to seed the chatgpt api and it's responses
class Context {

    currentResponse = '';

    constructor(messages = seed_messages) {
        this.messages = messages;
    }

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

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

    end_line(line) {
        this.currentResponse += `${line}\n\n`;
        return line;
    }

    finish_current_response() {
        this.add_assistant_message(this.currentResponse);
        const theLine = this.currentLine;
        this.currentResponse = '';
        this.save_history();
        return theLine;
    }

    save_history() {
        const prettyData = JSON.stringify(this.messages, null, 2);
        fs.writeFileSync('./messages.json', prettyData);
    }

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

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

let context = new Context(savedMessages);
if (fs.existsSync('./messages.json')) {
    savedMessages = require('./messages.json');
    context = new Context(savedMessages);
} else {
    context = new Context(seed_messages);
}

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) => {
    let is_chat_cmd = message.startsWith('!chat');
    let is_cont_cmd = message.startsWith('!cont');

    if (is_chat_cmd || is_cont_cmd) {
        if (context.is_response_in_progress()) {
            message(`(chat from ${from} ignored, response in progress)`)
            return;
        }
        if(is_chat_cmd && !config.alwaysRemember) {
            context.clear();
        }
        context.add_user_prompt(query);
        const query = message.slice(6);
        try {
            await chatgpt(query, context.messages, handleChatGPTResponseLine);
            context.finish_current_response();
        } catch (e) {
            console.log(e);
            client.say(to, 'Error: ' + e);
        }
    }

    function handleChatGPTResponseLine(line) {
        context.end_line(line);
        client.say(to, line);
    }
});

// function that calls the chatgpt streaming api (with server send events) and calls the callback function for each line
function chatgpt(query, messages, callback) {
    const apiUrl = 'https://api.openai.com/v1/chat/completions';
    let currentLine = '';

    return new Promise((resolve, reject) => {
        axios.post(apiUrl, {
            messages: messages,
            model: 'gpt-3.5-turbo',
            stream: true,
        }, {
            headers: {
                Authorization: `Bearer ${config.openaiApiKey}`,
                'Content-Type': 'application/json',
            },
            responseType: 'stream',
        }).then(response => {
            response.data.on('data', (event) => {
                let data = event.toString();
                let parts = data.split('\n');
                // parse if starts with data:
                for (let part of parts) {
                    console.log(part);

                    if (part === 'data: [DONE]') {
                        callback(currentLine);
                        resolve();
                    } 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) {
                                continue;
                            }

                            const lines = chunk.split(/\r?\n/);
                            let hasStartNewline = chunk.startsWith("\n");
                            let hasEndNewline = chunk.endsWith("\n");

                            if (hasStartNewline) {
                                callback(currentLine);
                                currentLine = '';
                            }

                            for (let i = 0; i < lines.length - 1; i++) {
                                currentLine += lines[i];
                                callback(currentLine);
                                currentLine = '';
                            }

                            currentLine += lines[lines.length - 1];

                            if (hasEndNewline) {
                                callback(currentLine);
                                currentLine = '';
                            }

                            if (currentLine.length > 400) {
                                callback(currentLine);
                                currentLine = '';
                            }
                        } catch (e) {
                            console.log(e);
                            console.log(part);
                        }
                    }
                }
            });
        }).catch(error => {
            if (error.response) {
                console.log(error.toJSON());
            } else if (error.request) {
                console.log(error.request);
            } else {
                console.log('Error', error.message);
            }
            reject(error);
        });
    });
}