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const players = [
    { name: 'Anna', score: 1 },
    { name: 'Bartek', score: 2 },
    { name: 'Cezary', score: 1 },
    { name: 'Dawid', score: 1 },
    { name: 'Ewa', score: 1 },
    { name: 'Asia', score: 1 },
    { name: 'Kasia', score: 2 },
    { name: 'Basia', score: 1 },
    { name: 'Wojtek', score: 0 },
    { name: 'Tomek', score: 0 }
];

const playerBye = {name: 'BYE', score: 0}


const getRandomByGroup = (group) => {
    const random = Math.floor(Math.random() * group.length)
    const result = group.splice(random, 1)
    return result[0]
}

players.sort((a, b) => b.score - a.score)

const pointGroups = []
for (let i = 0; i < players.length; i++) {
    const player = players[i];
    pointGroups[player.score]
        ? pointGroups[player.score].push(player)
        : pointGroups[player.score] = [player]
}

console.log('pointGroups:', pointGroups)

const pairs = [];
let i = pointGroups.length-1
for(i; i >= 0; i--) {
    const currentGroup = pointGroups[i]
   
    if (currentGroup.length % 2 === 1) {
        const nextGroup = pointGroups[i-1]
        if ( nextGroup ) {
            const tmpPlayer = nextGroup.splice(Math.floor(Math.random() * nextGroup.length), 1)
            currentGroup.push(tmpPlayer[0])
        } else {
            currentGroup.push(playerBye)
        }
    }
    console.log(i+' Group:', currentGroup)

    for (let i = 0; i < currentGroup.length; i++) {
        const playerOne = getRandomByGroup(currentGroup)
        const playerTwo = getRandomByGroup(currentGroup)
        pairs.push([playerOne, playerTwo])
    }
}
console.log('Pairs:', pairs)