import express from 'express'
import cookieParser from 'cookie-parser'

const app = express()
app.use(cookieParser())

// ...

// Returns the user's userid, creating a random
// userid if there is none, storing it as a cookie.
function getUserId(req, res) {
    let userid = req.cookies.userid
    if (userid == undefined) {
        userid = crypto.randomUUID()  // random unique ID
        res.cookie('userid', userid)
    }
    return userid
}

// Create a copy of game to return and
// sets the 'color' and 'yourturn' entries
// according to the user id.
function sendGame(req, res) {
    // Join a game that is waiting for players.
    let userid = getUserId(req, res)
    if (game.player_X == undefined) {
        // Join game as X
        console.log(`User ${userid} joining game as X`)
        game.player_X = userid
    } else if (game.player_O == undefined && game.player_X != userid) {
        // Join game as O
        console.log(`User ${userid} joining game as O`)
        game.player_O = userid
    }
    
    // Create a copy and set the 'color' property
    let copy = structuredClone(game)
    if (game.player_X == userid) {
        // User is already assigned X
        copy.color = 'X'
    } else if (game.player_O == userid) {
        // User is already assigned O
        copy.color = 'O'
    } else {
        // game already has two other players
    }
    // Set the 'yourturn' property if applicable
    if (copy.state.next == copy.color) {
        copy.yourturn = true
    }
    res.json(copy)
}

app.get('/game/', (req, res) => {
    sendGame(req, res);
});