/*
24:00
23:59
...
20:59
19:59
...
10:59
09:59
...
00:01
*/
/*
options:
ab:cd
a = 0, 1, 2                      |
b = (a=0-1, b=0-9), (a=2, b=0-3) |
c = 0-5                          |
d = 0-9                          |
*/

const allDigits = [0,1,2,3,4,5,6,7,8,9];

function getMaxTime(numbers){
    if(!areValidNumbers(numbers)){
        return 'Invalid values!';
    }

    const a = getBestFirstDigit(numbers);
    const b = getBestSecondDigit(a, numbers);
    const c = getBestThirdDigit(numbers);
    const d = numbers[0];
    return `${a}${b}:${c}${d}`
    return '{a}{b}:{c}{d}'
        .replace('{a}', a)
        .replace('{b}', b)
        .replace('{c}', c)
        .replace('{d}', d);
}

function getBestFirstDigit(numbers){
    numbers.sort();
    const [a, b, c, d] = numbers;
    switch(true){
        case a === 2: numbers.splice(0,1); return a;
        case b === 2: numbers.splice(1,1); return b;
        case c === 2: numbers.splice(2,1); return c;
        case d === 2: numbers.splice(3,1); return d;
        case a === 1: numbers.splice(0,1); return a;
        case b === 1: numbers.splice(1,1); return b;
        case c === 1: numbers.splice(2,1); return c;
        case d === 1: numbers.splice(3,1); return d;
        default: numbers.splice(0,1); return a;
    }
}

function getBestSecondDigit(first, numbers){
    const secondAllowedByFirstIsTwo = [3,2,1,0];
    const secondAllowedByFirstIsElse = [9,8,7,6,5,4,3,2,1,0];
    const list = first === 2 ? secondAllowedByFirstIsTwo : secondAllowedByFirstIsElse;
    const temp = numbers.filter(n => list.includes(n));
    const max = Math.max(...temp);
    const i = numbers.indexOf(max);
    numbers.splice(i, 1);
    return max;
}

function getBestThirdDigit(numbers){
    const list = [5,4,3,2,1,0];
    const temp = numbers.filter(n => list.includes(n));
    const max = Math.max(...temp);
    const i = numbers.indexOf(max);
    numbers.splice(i, 1);
    return max;
}

function areValidNumbers(numbers){
    if(!numbers || !Array.isArray(numbers) || numbers.length > 4 || numbers.filter(n => typeof n === 'number').length !== 4){
        return false;
    }
    numbers.sort();
    const [a, b, c, d] = numbers;
    const valid_a = [0,1,2].includes(a);
    const valid_b = ([0,1].includes(a) && allDigits.includes(b)) || (a === 2 && [0,1,2,3].includes(b));
    const valid_bc = ([0,1].includes(a) && allDigits.includes(c)) || (a === 2 && [0,1,2,3].includes(c));
    const valid_c = [0,1,2,3,4,5].includes(c);
    const valid_cb = [0,1,2,3,4,5].includes(b);
    const valid_d = allDigits.includes(d);

    return valid_a && ((valid_b && valid_c) || (valid_bc && valid_cb)) && valid_d;
}

module.exports = getMaxTime;