const express = require('express');
const bodyParser = require('body-parser');
const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
const { ActivityPubRouter, createActor } = require('activitypub-express');
const uuid = require('uuid');
const db = require('quick.db'); // Import quick.db
const fetch = require('node-fetch');

const app = express();
const port = 3000;

const SECRET_KEY = 'your_secret_key'; // Replace with a secure key in a real app

// Middleware to parse JSON
app.use(bodyParser.json());

// Helper function to create an actor URL
const actorURL = (username) => `http://localhost:${port}/users/${username}`;

// Helper function to generate JWT token
const generateToken = (user) => {
    return jwt.sign({ id: user.username }, SECRET_KEY, { expiresIn: '1h' });
};

// Middleware to protect routes
const authenticate = (req, res, next) => {
    const token = req.headers['authorization']?.split(' ')[1];
    if (!token) {
        return res.status(401).json({ error: 'Unauthorized' });
    }

    jwt.verify(token, SECRET_KEY, (err, decoded) => {
        if (err) {
            return res.status(403).json({ error: 'Invalid or expired token' });
        }
        req.user = decoded;
        next();
    });
};

// Route to create a new user (actor with password)
app.post('/users', async (req, res) => {
    const { username, displayName, password } = req.body;

    // Check if user already exists
    const existingUser = db.get(`user_${username}`);
    if (existingUser) {
        return res.status(400).json({ error: 'User already exists' });
    }

    // Hash the password before saving
    const hashedPassword = await bcrypt.hash(password, 10);

    // Create the actor and store it in the DB
    const actor = createActor({
        id: actorURL(username),
        username,
        displayName,
        inbox: `http://localhost:${port}/users/${username}/inbox`,
        outbox: `http://localhost:${port}/users/${username}/outbox`,
        followers: `http://localhost:${port}/users/${username}/followers`,
        following: `http://localhost:${port}/users/${username}/following`,
    });

    // Store actor info and password in the database
    db.set(`user_${username}`, { ...actor, password: hashedPassword });

    res.status(201).json(actor);
});

// Route to log in a user and get a token
app.post('/login', async (req, res) => {
    const { username, password } = req.body;

    // Retrieve user from the database
    const user = db.get(`user_${username}`);
    if (!user) {
        return res.status(404).json({ error: 'User not found' });
    }

    // Compare hashed password
    const isPasswordValid = await bcrypt.compare(password, user.password);
    if (!isPasswordValid) {
        return res.status(401).json({ error: 'Invalid password' });
    }

    // Generate and return JWT token
    const token = generateToken(user);
    res.json({ token });
});

// Route to create a post (status update) with authentication
app.post('/users/:username/posts', authenticate, (req, res) => {
    const { username } = req.params;
    const { content } = req.body;

    if (req.user.id !== username) {
        return res.status(403).json({ error: 'You can only post as yourself' });
    }

    // Retrieve the user from the database
    const user = db.get(`user_${username}`);
    if (!user) {
        return res.status(404).json({ error: 'User not found' });
    }

    // Create a post and store it in the database
    const post = {
        id: `http://localhost:${port}/posts/${uuid.v4()}`,
        type: 'Note',
        content,
        author: user,
        published: new Date().toISOString(),
    };

    // Store the post in the database
    db.set(`post_${post.id}`, post);

    res.status(201).json(post);
});

// Route to get a user’s posts
app.get('/users/:username/posts', authenticate, (req, res) => {
    const { username } = req.params;

    if (req.user.id !== username) {
        return res.status(403).json({ error: 'You can only view your own posts' });
    }

    // Retrieve all posts from the database
    const userPosts = Object.values(db.get("posts") || {}).filter(post => post.author.username === username);
    res.json(userPosts);
});

// ActivityPub setup
const activityPubRouter = new ActivityPubRouter();

// Handle incoming Follow activity
activityPubRouter.post('/users/:username/inbox', authenticate, async (req, res) => {
    const { username } = req.params;
    const activity = req.body;

    if (!db.get(`user_${username}`)) {
        return res.status(404).json({ error: 'User not found' });
    }

    if (activity.type === 'Follow') {
        const actor = activity.actor;

        // Retrieve followers list and add new follower
        const followersList = db.get(`followers_${username}`) || [];
        followersList.push(actor.id);

        // Store the updated followers list in the database
        db.set(`followers_${username}`, followersList);

        res.status(200).json({ status: 'Followed successfully' });

        // Optionally, notify the actor that the follow was accepted
        await sendFollowResponse(actor, username);
    } else {
        res.status(400).json({ error: 'Unsupported activity type' });
    }
});

// Federated actor info endpoint
activityPubRouter.get('/users/:username', (req, res) => {
    const { username } = req.params;

    const user = db.get(`user_${username}`);
    if (!user) {
        return res.status(404).json({ error: 'User not found' });
    }

    res.json(user);
});

// Outbox endpoint to send posts
activityPubRouter.get('/users/:username/outbox', (req, res) => {
    const { username } = req.params;

    const user = db.get(`user_${username}`);
    if (!user) {
        return res.status(404).json({ error: 'User not found' });
    }

    // Fetch posts from this user’s outbox (from the DB)
    const userPosts = Object.values(db.get("posts") || {}).filter(post => post.author.username === username);
    res.json(userPosts);
});

app.use(activityPubRouter.router);

// Start the server
app.listen(port, () => {
    console.log(`Federated social network with SQLite (quick.db) running at http://localhost:${port}`);
});