const numberToWordMap = {
    0: "zero",
    1: "one",
    2: "two",
    3: "three",
    4: "four",
    5: "five",
    6: "six",
    7: "seven",
    8: "eight",
    9: "nine",
    10: "ten",
    11: "eleven",
    12: "twelve",
    13: "thirteen",
    14: "fourteen",
    15: "fifteen",
    16: "sixteen",
    17: "seventeen",
    18: "eighteen",
    19: "nineteen",
    20: "twenty",
    30: "thirty",
    40: "fourty",
    50: "fifty",
    60: "sixty",
    70: "seventy",
    80: "eighty",
    90: "ninety"
}

const test = (number) => {
    const result = checkWriter(number);
    console.log(`RESULT for: ${number}: `, result);
}

const checkWriter = number => {

    // ToDo: handle plurals

    const parts = parseFloat(number).toFixed(2).split('.');
    const [integerPartString, decimalPartString] = parts;
    const integerPart = parseInt(integerPartString, 10);
    const decimalPart = parseInt(decimalPartString, 10);

    let convertedDecimalPart = 'and zero cents';
    let convertedIntegerPart = '0 euros';

    if (integerPart > 0 && decimalPart > 0) {
        convertedDecimalPart = `and ${convertNumberToWord(decimalPart)} cents`;
    } else if(integerPart === 0 && decimalPart > 0) {
        convertedDecimalPart = `${convertNumberToWord(decimalPart)} cents`;
    }

    if (integerPart > 0) {
        convertedIntegerPart = `${convertNumberToWord(integerPart)} euros`
    }

    return `${convertedIntegerPart} ${convertedDecimalPart}`;

}

const convertNumberToWord = number => {
    if (numberToWordMap[number] !== undefined) {
        return `${numberToWordMap[number]} `;

    } else {
        const integers = Math.trunc(number % 10);
        const decimals = Math.trunc(number % 100 / 10);
        const hundreds = Math.trunc(number % 1000 / 100);
        const hundredThousands = Math.trunc(number % 1000000 / 1000);
        const hundredMillions = Math.trunc(number % 1000000000 / 1000000);

        let result = '';

        if (hundredMillions > 0) {
            result += convertNumberToWord(hundredMillions) + "million, ";
        }
        if (hundredThousands > 0) {
            result += convertNumberToWord(hundredThousands) + "thousand, ";
        }
        if (hundreds > 0) {
            result += convertNumberToWord(hundreds) + "hundred ";
        }
        if (decimals > 1) {
            result += convertNumberToWord(decimals * 10);

            if (integers > 0) {
                result += convertNumberToWord(integers);
            }

        } else if (decimals !== 0) {
            result += convertNumberToWord(decimals * 10 + integers);
        } else {
            result += convertNumberToWord(integers);
        }

        return result;
    }

}

test(0);
test(20001.1);
test(112.10);
test(874327.9);
test(978);
test(1.01);
test(999999.9);