const net = require("net")
const User = require("../src/user.js")

const RPL_WELCOME = '001'
const ERR_NOSUCHNICK = '401'
const ERR_NOSUCHCHANNEL = '403'
const ERR_CANNOTSENDTOCHAN = '404'
const ERR_UNKNOWNCOMMAND = '421'
const ERR_ERRONEUSNICKNAME = '432'
const ERR_NONICKNAMEGIVEN = '431'
const ERR_NICKNAMEINUSE = '433'
const ERR_NEEDMOREPARAMS = '461'

let server = {}

server.create = function create() {
    let userlist = {}
    let server = net.createServer((socket) => {
        const user = new User(socket)
        socket.on('data', function (data) {
            let splitted = data.toString("ascii").split("\r\n")[0].split(" ")
            let tokenized = []
            let lastParam = -1
            for (let i = 0; i < splitted.length; i++) {
                if (lastParam > 0) {
                    tokenized[lastParam] = tokenized[lastParam] + " " + splitted[i]
                } else if (splitted[i].charAt(0) == ":" && i > 0) {
                    lastParam = i
                    tokenized[lastParam] = splitted[i].slice(1)
                } else {
                    tokenized[i] = splitted[i]
                }
            }
            let command = tokenized[0].toUpperCase()
            switch (command) {
                case  "PING":
                    if (tokenized[1] && tokenized[1] === "irc.example.com") {
                        socket.write("PONG irc.example.com\r\n")
                    }
                    break;
                case "NICK":
                    if (tokenized[1]) {
                        let nickname = tokenized[1]
                        // nick collision test
                        if (!Object.keys(userlist).includes(nickname)) {
                            user.setNickname(nickname)
                            userlist[user.nickname] = user
                        } else {
                            socket.write(ERR_NICKNAMEINUSE, " nickname in use")
                        }


                    } else {
                        socket.write(ERR_NONICKNAMEGIVEN, "ERROR: NO NICKNAME PROVIDED")
                    }

                    break;

                case "USER":
                    // ignoring servername and hostname, not useful these days
                    user.register(tokenized[1], tokenized[4])
                    let address = user.getAddress()
                    socket.write(`001 ${user.nickname} :Welcome to the example IRC Project ${user.nickname}!~${user.username}@${address}`)
                    break;
                case "PRIVMSG":
                    let target = userlist[tokenized[1]]
                    let message = tokenized[2]

                    target.sendMsg(user, message)
                    break;
                case "QUIT":
                    server.closeConnection(user.nickname)
                    break;
                default:
                    console.error(`Unknown command: ${command}`);
            }
        }).on('error', (err) => {
            console.error(err);
        })
    }).on('error', (err) => {
        console.error(err);
        throw err;
    });

    server.getUserlist = function () {
        return userlist
    }

    server.closeConnection = function (user_nickname) {
        let user = userlist[user_nickname]
        user.closeConnection()
        delete userlist[user_nickname];
    }

    return server
}


module.exports = server