const { Client, LocalAuth } = require('whatsapp-web.js');
const fs = require('fs');
const path = require('path');

const DATA_DIR = './data';
const MESSAGES_FILE = path.join(DATA_DIR, 'messages.jsonl');
const CHATS_FILE = path.join(DATA_DIR, 'chats.json');
const LIMIT_PER_CHAT = 50; // messages to fetch per chat per run

fs.mkdirSync(DATA_DIR, { recursive: true });

// Load already saved message IDs to avoid duplicates
function loadSavedIds() {
    if (!fs.existsSync(MESSAGES_FILE)) return new Set();
    const lines = fs.readFileSync(MESSAGES_FILE, 'utf8').trim().split('\n').filter(Boolean);
    return new Set(lines.map(l => JSON.parse(l).id));
}

// Append new messages to jsonl
function saveMessages(messages) {
    const lines = messages.map(m => JSON.stringify(m)).join('\n') + '\n';
    fs.appendFileSync(MESSAGES_FILE, lines);
}

// Save chat index
function saveChats(chats) {
    fs.writeFileSync(CHATS_FILE, JSON.stringify(chats, null, 2));
}

const client = new Client({
    authStrategy: new LocalAuth(),
    puppeteer: {
        executablePath: '/usr/sbin/chromium',
        args: ['--no-sandbox', '--disable-setuid-sandbox', '--disable-dev-shm-usage']
    }
});

client.on('qr', (qr) => {
    // Only needed first time — after that LocalAuth handles it
    const qrcode = require('qrcode-terminal');
    qrcode.generate(qr, { small: true });
});

client.on('ready', async () => {
    console.log('✅ Connected — starting sync...');

    const savedIds = loadSavedIds();
    const chats = await client.getChats();
    const chatIndex = [];
    const newMessages = [];

    for (const chat of chats) {
        console.log(`📥 Fetching: ${chat.name}`);
        chatIndex.push({
            id: chat.id._serialized,
            name: chat.name,
            isGroup: chat.isGroup,
            lastSync: new Date().toISOString()
        });

        try {
            const messages = await chat.fetchMessages({ limit: LIMIT_PER_CHAT });
            for (const msg of messages) {
                if (savedIds.has(msg.id._serialized)) continue; // skip duplicates
                newMessages.push({
                    id: msg.id._serialized,
                    chat: chat.name,
                    chatId: chat.id._serialized,
                    from: msg.from,
                    fromName: msg.author || msg.from,
                    timestamp: msg.timestamp,
                    date: new Date(msg.timestamp * 1000).toISOString(),
                    body: msg.body,
                    type: msg.type,
                    isGroup: chat.isGroup,
                    hasMedia: msg.hasMedia
                });
            }
        } catch (err) {
            console.error(`❌ Failed on ${chat.name}:`, err.message);
        }
    }

    saveChats(chatIndex);
    saveMessages(newMessages);
    console.log(`✅ Sync done — ${newMessages.length} new messages saved.`);
    process.exit(0);
});

client.initialize();