const User = require("../../models/User");
const config = require("../../config");
const secret = require("../../secret");
const { authenticateEndpoint } = require("./../../common/auth/authfunctions");

// TODO: Might want to use something else (https://blog.benpri.me/blog/2019/01/13/why-you-shouldnt-be-using-bcrypt-and-scrypt/)
const bcrypt = require("bcrypt");
const mongoose = require("mongoose");
const { body, param, validationResult } = require("express-validator");
const express = require("express");
const jwt = require("jsonwebtoken");
const rateLimit = require("express-rate-limit");

const app = express.Router();
const createAccountLimiter = rateLimit({
    windowMs: 60 * 60 * 1000, // 1 hour window
    max: 10, // start blocking after 10 requests
});

mongoose.connect(config.mongoUrl, {useNewUrlParser: true, useUnifiedTopology: true});

app.get("/account/create/info", async (req, res) => {
    let requiresCode = false;
    if (config.restrictions) {
        const restrictions = config.restrictions.signup;
        if (restrictions && restrictions.specialCode) {
            requiresCode = true;
        }
    }

    res.json({
        error: false,
        message: "SUCCESS_ACCOUNT_CREATE_INFO_FETCH",
        requiresSpecialCode: requiresCode
    });
});

app.post("/account/create", [
    createAccountLimiter,
    body("username").not().isEmpty().trim().isLength({ min: 3, max: 32 }).isAlphanumeric(),
    body("email").not().isEmpty().isEmail().normalizeEmail(),
    body("password").not().isEmpty().isLength({ min: 8, max: 128 }),
    body("specialCode").optional().isLength({ min: 12, max: 12 }).isAlphanumeric()
], async (req, res) => {
    if (!config.policies.allowAccountCreation) return res.status(403).json({ error: true, message: "ERROR_FORBIDDEN_BY_POLICY" });

    try {
        const errors = validationResult(req);
        if (!errors.isEmpty()) {
            res.status(400).json({ error: true, message: "ERROR_REQUEST_INVALID_DATA", errors: errors.array() });
            return;
        }

        if (config.restrictions) {
            const restrictions = config.restrictions.signup;
            if (restrictions && restrictions.specialCode) {
                const passedSpecialCode = req.body.specialCode;
                const specialCode = restrictions.specialCode;
    
                if (passedSpecialCode && specialCode) {
                    if (specialCode !== passedSpecialCode) {
                        res.status(401).json({ error: true, message: "ERROR_REQUEST_SPECIAL_CODE_MISSING", errors: [{ msg: "No specialCode passed", param: "specialCode", location: "body" }] });
                        return false;
                    }
                } else {
                    res.status(401).json({ error: true, message: "ERROR_REQUEST_SPECIAL_CODE_MISSING", errors: [{ msg: "No specialCode passed", param: "specialCode", location: "body" }] });
                    return false;
                }
            }
        }
    
        const username = req.body.username;
    
        const existingUser = await User.findByUsername(username);
        if (existingUser) {
            res.status(400).json({ error: true, message: "ERROR_REQUEST_USERNAME_EXISTS", errors: [{ value: username, msg: "Username exists", param: "username", location: "body" }] });
            return;
        }
    
        const unhashedPassword = req.body.password;
        const email = req.body.email;
        const startingRole = "USER";
    
        const hashedPassword = await bcrypt.hash(unhashedPassword, config.bcryptRounds);
    
        const user = await User.create({
            username,
            email,
            password: hashedPassword,
            role: startingRole
        });

        const userObject = await user.getPublicObject();

        if (config.logAccountCreation) console.log("users: user created", userObject);
    
        res.status(200).json({
            error: false,
            message: "SUCCESS_USER_CREATED",
            user: userObject
        });
    } catch (e) {
        console.error("Internal server error", e);
        res.status(500).json({ error: true, message: "INTERNAL_SERVER_ERROR" });
        return;
    }
});

app.post("/token/create", [
    createAccountLimiter,
    body("username").not().isEmpty().trim().isAlphanumeric(),
    body("password").not().isEmpty()
], async (req, res) => {
    if (!config.policies.allowLogin) return res.status(403).json({ error: true, message: "ERROR_FORBIDDEN_BY_POLICY" });

    const errors = validationResult(req);
    if (!errors.isEmpty()) {
        res.status(400).json({ error: true, message: "ERROR_REQUEST_LOGIN_INVALID" });
        return;
    }

    const username = req.body.username;

    const existingUser = await User.findByUsername(username);
    if (!existingUser) {
        res.status(403).json({ error: true, message: "ERROR_REQUEST_LOGIN_INVALID" });
        return;
    }

    const password = req.body.password;

    let passwordCheck;
    try {
        passwordCheck = await bcrypt.compare(password, existingUser.password);
    } catch(e) {
        passwordCheck = false;
    }
    if (!passwordCheck) {
        res.status(403).json({ error: true, message: "ERROR_REQUEST_LOGIN_INVALID" });
        return;
    }

    jwt.sign({ username }, secret.jwtPrivateKey, { expiresIn: config.tokenExpiresIn }, async (err, token) => {
        if (err) {
            res.status(500).json({
                error: true,
                message: "INTERNAL_SERVER_ERROR"
            });
            return;
        }

        const userObject = await existingUser.getPublicObject();

        if (config.logAccountCreation) console.log("users: token created", userObject);
        
        res.status(200).json({
            error: false,
            message: "SUCCESS_TOKEN_CREATED",
            user: userObject,
            token
        });
    });
});

app.get("/current/info", authenticateEndpoint(async (req, res, user) => {
    const userObject = await user.getPublicObject();

    res.status(200).json({
        error: false,
        message: "SUCCESS_USER_DATA_FETCHED",
        user: userObject
    });
}, undefined, 0));

app.get("/user/:userid/info", [
    param("userid").not().isEmpty().trim().escape().isLength({ min: 24, max: 24 })
], authenticateEndpoint(async (req, res) => {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
        res.status(400).json({ error: true, message: "ERROR_REQUEST_INVALID_DATA", errors: errors.array() });
        return;
    }

    const userid = req.params.userid;
    if (!userid) {
        res.sendStatus(400).json({
            error: true,
            message: "ERROR_REQUEST_INVALID_DATA"
        });
        return;
    }
    const otherUser = await User.findById(userid);

    res.status(200).json({
        error: false,
        message: "SUCCESS_USER_DATA_FETCHED",
        user: await otherUser.getPublicObject(),
    });
}, undefined, config.roleMap.USER));

module.exports = app;