write-ups-challenges-2020-2021/gotta_catch_em_all/backend/index.js

const WebSocket = require('ws');
const pokemon = require('pokemon')
const pokeTypes = require('./poketypes.json')

const wss = new WebSocket.Server({
    port: 5000
})

function flatten(obj) {
    if(obj !== null && obj !== undefined) {
        let ret = {};
        for (let i in obj) {
            ret[i] = obj[i];
        }
        return ret;
    } else {
        return obj
    }
}

function badObjectCopy(values, object) {
    if(values !== undefined && object !== undefined && values !== null && object !== null) {
        for(let i in values) {
            if(typeof values[i] === "object") {
                badObjectCopy(values[i], object[i])
            } else {
                object[i] = values[i]
            }
        }
    }
}

function flattenObject(obj) {
    return Object.fromEntries(Object.entries(obj).map(([key, val]) => [key, flatten(val)]))
}

wss.on('connection', ws => {
    try {
        const timeStarted = new Date();

        const Pokemon = {}

        const types = {
            grass:    {type: 'grass'   , __proto__: Pokemon},
            fire:     {type: 'fire'    , __proto__: Pokemon},
            water:    {type: 'water'   , __proto__: Pokemon},
            poison:   {type: 'poison'  , __proto__: Pokemon},
            flying:   {type: 'flying'  , __proto__: Pokemon},
            bug:      {type: 'bug'     , __proto__: Pokemon},
            normal:   {type: 'normal'  , __proto__: Pokemon},
            electric: {type: 'electric', __proto__: Pokemon},
            ground:   {type: 'ground'  , __proto__: Pokemon},
            fairy:    {type: 'fairy'   , __proto__: Pokemon},
            fighting: {type: 'fighting', __proto__: Pokemon},
            psychic:  {type: 'psychic' , __proto__: Pokemon},
            rock:     {type: 'rock'    , __proto__: Pokemon},
            steel:    {type: 'steel'   , __proto__: Pokemon},
            ice:      {type: 'ice'     , __proto__: Pokemon},
            ghost:    {type: 'ghost'   , __proto__: Pokemon},
            dragon:   {type: 'dragon'  , __proto__: Pokemon}
        }

        const pokedex = Object.fromEntries(pokemon.all().slice(0, 151).map(poke => {
            const type = types[pokeTypes[poke]]
            return [poke, {__proto__: type}]
        }))

        const send = async(msg, data) => await ws.send(JSON.stringify({msg, data}))

        const checkIfAllCaptured = async () => {
            if(Object.values(pokedex).every(poke => poke["captured"])) {
                const diff = new Date() - timeStarted;
                if(diff < 60000) {
                    send("pokedexCompleted", {
                        msg: "I can't believe you beat my near impossible 60 second speedrun! It's impossible! I am the best trainer to have ever lived! Urgh... I guess I don't have a choice but to give you this item...\n\n*You obtained the key IGCTF{MissingNo}!*\n\nHave fun with it... I guess.\n\n-Gary"
                    })
                } else {
                    send("pokedexCompleted", {
                        msg: "Hah, you did good, but not nearly as good as I did. You still got a long way to beat my 1 minute run, loser.\n\n-Gary"
                    })
                }
                ws.close()
            }
        }

        let messagesReceived = 0;
        let timeOfLastMessage = 0;
        let poisonMessageSent = false;
        ws.on('message', evt => {
            messagesReceived++;
            const currentTime = new Date()
            console.log(currentTime - timeOfLastMessage)
            if(currentTime - timeOfLastMessage < 500) {
                send("error", {msg: "You are sending messages too fast to the backend. Please slow down."})
                timeOfLastMessage = currentTime
                return
            } else {
                timeOfLastMessage = currentTime
            }
            const {msg, data} = JSON.parse(evt)
            switch (msg) {
                case "initializePokedex": send('pokedexInitialized', flattenObject(pokedex)); break;
                case "updatePokedex": {
                    const {pokemon, values} = data;

                    if(pokemon !== '__proto__') {
                        if(pokeTypes[pokemon] === 'poison') {
                            badObjectCopy(values, pokedex[pokemon].__proto__);
                            if(!poisonMessageSent) {
                                send("error", {msg: "Dear Pokémon trainer,\n\n There seems to be a bug when adding a Poison type Pokémon: it automatically registers all Poison type Pokémon in the Pokédex as captured! Somehow the poison seems to affect the shared prototype...\n\nYours truly,\nProfessor Oak"})
                                poisonMessageSent = true
                            }
                        } else {
                            badObjectCopy(values, pokedex[pokemon]);
                        }
                    } else {
                        send("error", {msg: "I read somewhere that letting the client change the __proto__ property isn't such a good idea, so I'll just add this check here. I sure hope that I didn't forget to check this anywhere else... \n\n -Professor Oak"})
                    }

                    send('pokedexUpdated', flattenObject(pokedex))
                    checkIfAllCaptured()
                    break;
                }
            }
        });
    } catch(e) {
        console.error(e)
    }
})