import { Request, Response } from 'express';
import { decode, sign, verify } from 'jsonwebtoken';

import { JWT_SECRET, logger, RABBITMQ_URI } from '../app';
import * as jwt from 'jsonwebtoken';
import { config } from '../config';
import { hashPassword, randomPepper, randomString, verifyPassword } from '../lib/crypto';
import { LivebeatRequest } from '../lib/request';
import { UserType } from '../models/user/user.interface';
import { User } from '../models/user/user.model';

export async function GetUser(req: LivebeatRequest, res: Response) {
    let user: any = req.params.id === undefined ? req.user : await User.findById(req.params.id);

    if (user === null) {
        res.status(404).send();
        return;
    }

    user.password = undefined;
    user.salt = undefined;
    user.__v = undefined;

    res.status(200).send(user);
}

export async function PostUser(req: LivebeatRequest, res: Response) {
    // Only admin can create new users
    if (req.user?.type !== UserType.ADMIN) {
        res.status(401).send({ message: 'Only admins can create new users.' });
        return;
    }

    const name = req.body.name;
    const password = req.body.password;
    const type = req.body.type;

    if (name === undefined || password === undefined || type === undefined) {
        res.status(400).send();
        return;
    }

    if (!Object.values(UserType).includes(type)) {
        res.status(400).send({ message: 'The user type can only be \'guest\', \'user\', \'admin\'.' });
        return;
    }

    if (await User.countDocuments({ name }) === 1) {
        res.status(409).send();
        return;
    }

    const salt = randomString(config.authentification.salt_length);
    const brokerToken = randomString(16);
    const hashedPassword = await hashPassword(password + salt + randomPepper()).catch(error => {
        res.status(400).send({ message: 'Provided password is too weak and cannot be used.' });
        return;
    }) as string;    

    const newUser = await User.create({
        name,
        password: hashedPassword,
        salt,
        brokerToken,
        type,
        lastLogin: new Date(0)
    });

    // Create setup token that the new user can use to change his password.
    const setupToken = jwt.sign({ setupForUser: newUser._id }, JWT_SECRET, { expiresIn: '1d' });

    res.status(200).send({ setupToken });
}

export async function DeleteUser(req: Request, res: Response) {
    
}

export async function PatchUser(req: Request, res: Response) {
    
}

export async function LoginUser(req: Request, res: Response) {
    const username = req.body.username;
    const password = req.body.password;
    const twoFA = req.body.twoFA;

    const user = await User.findOne({ name: username });

    // Check if user exists
    if (user == undefined) {
        setTimeout(() => {
            res.status(404).send({ message: "Either the username or password is wrong." });
        }, Math.random() * 1500 + 400);
        return;
    }

    // Check if 2FA is turned on (the attack doesn't know yet if the password is wrong)
    if (user.twoFASecret != undefined) {
        if (twoFA == undefined) {
            res.status(401).send({ message: "2FA code is required." });
            return;
        }
        // TODO: Implement 2FA logic here
    }

    // Check if password is wrong
    if (!await verifyPassword(password + user.salt, user.password)) {
        res.status(404).send({ message: 'Either the username or password is wrong.' });
        return;
    }

    // We're good. Create JWT token.
    const token = sign({ user: user._id }, JWT_SECRET, { expiresIn: '30d' });

    user.lastLogin = new Date(Date.now());
    await user.save();

    logger.info(`User ${user.name} logged in.`)
    res.status(200).send({ token });
}

/**
 * This function handles all logins to RabbitMQ since they need a differnt type of response
 * then requests from frontends (web and phone).
 */
export async function LoginRabbitUser(req: Request, res: Response) {
    const username = req.query.username;
    const password = req.query.password;
    res.status(200);

    if (username === undefined || password === undefined) {
        res.send('deny');
        return;
    }

    // Check if request comes from backend. Basicly, we permitting ourself to connect with RabbitMQ.
    if (username === "backend" && password === RABBITMQ_URI.split(':')[2].split('@')[0]) {
        res.send('allow administrator');
        return;
    }

    // Get user from database
    const user = await User.findOne({ name: username.toString() });

    // If we are here, it means we have a non-admin user.
    if (user === null) {
        res.send('deny');
        return;
    }

    // Auth token for message broker is stored in plain text since it's randomly generated and only grants access to the broker.
    if (user.brokerToken === password.toString()) {
        if (user.type === UserType.ADMIN) {
            res.send('allow administrator');
        } else {
            // Not an admin, grant user privilieges
            res.send('allow user')
        }
        return;
    }

    res.send('deny');
}

/**
 * This function basicly allows access to the root vhost if the user is known.
 */
export async function VHost(req: Request, res: Response) {
    const vhost = req.query.vhost;
    const username = req.query.username;

    if (vhost === undefined || username === undefined) {
        res.status(200).send('deny');
        return;
    }

    if (vhost != '/') {
        res.status(200).send('deny');
        return;
    }

    // Check if user is us
    if (username === 'backend') {
        res.status(200).send('allow');
        return;
    }

    const user = await User.findOne({ name: username.toString() });
    if (user === null) {
        // Deny if user doesn't exist.
        res.status(200).send('deny');
    } else {
        res.status(200).send('allow');
    }
}

export async function Resource(req: Request, res: Response) {
    const username = req.query.username;
    const vhost = req.query.vhost;
    const resource = req.query.resource;
    const name = req.query.name;
    const permission = req.query.permission;
    const tags = req.query.tags;

    if (username === undefined || vhost === undefined || resource === undefined || name === undefined || permission === undefined || tags === undefined) {
        res.status(200).send('deny');
        return;
    }

    // Check if it's us
    if (username.toString() == 'backend') {
        res.status(200).send('allow');
        return;
    }

    // Deny if not root vhost
    if (vhost.toString() != '/') {
        res.status(200).send('deny');
        return;
    }

    // Check if user exists
    const user = await User.findOne({ name: username.toString() });
    if (user == null) {
        res.status(200).send('deny');
        return;
    }

    if (tags.toString() == "administrator" && user.type != UserType.ADMIN) {
        res.status(200).send('deny');
        return;
    }

    // TODO: This has to change if we want to allow users to see the realtime movement of others. 
    if (resource.toString().startsWith('tracker-') && resource != 'tracker-' + username) {
        res.status(200).send('deny');
        return;
    }

    res.status(200).send('allow');
}

export async function Topic(req: Request, res: Response) {
    res.status(200);

    const username = req.query.username;
    const routingKey = req.query.routing_key;

    if (routingKey === undefined || username === undefined) {
        res.send('deny');
        return;
    }

    // Check if it's us
    if (username.toString() == 'backend') {
        res.status(200).send('allow');
        return;
    }

    // Check if user exists
    const user = await User.findOne({ name: username.toString() });
    if (user === null) {
        res.send('deny');
        return;
    }

    if (routingKey !== user.id) {
        res.send('deny');
        return;
    }

    res.status(200).send('allow');
}

/**
 * This middleware validates any tokens that are required to access most of the endpoints.
 * Note: This validation doesn't contain any permission checking. 
 */
export async function MW_User(req: LivebeatRequest, res: Response, next: () => void) {
    if (req.headers.token === undefined) {
        res.status(401).send({ message: "Token not specified" });
        return;
    }
    const token = req.headers.token.toString();

    try {
        // Verify token
        if(await verify(token, JWT_SECRET, { algorithms: ['HS256'] })) {
            // Token is valid, now look if user is in db (in case he got deleted)
            const id = decode(token, { json: true })!.user;
            const db = await User.findById(id);

            if (db !== undefined && db !== null) {
                req.user = db
                next();
                return;
            } else {
                res.status(401).send({ message: "Token is not valid" });
            }
        } else {
            res.status(401).send({ message: "Token is not valid" });
        }
    } catch (err) {
        if (err) {
            res.status(500).send({ message: "We failed validating your token for some reason." });
            logger.error(err);
        }
    }
}