function truncateFraction (number) {
    try {
        let strNum = String(number).split('.')
        if(strNum[1].length > 2) {
            strNum[1] = strNum[1].slice(0, 2)
        }
        return Number(strNum.join('.'))
    } catch (e) {
        return number
    }
}

var loop = true

while(loop) {
    switch(prompt('input task name:', '')) {
        case 'switch: sizes':
            let usSize = [
                {
                    number: [6],
                    men: 'S',
                    woman:['XXS']
                },
                {
                    number: [8, 10],
                    men: 'M',
                    woman:['XXS', 'XS']
                },
                {
                    number: [12, 14],
                    men: 'L',
                    woman:['S', 'M']
                },
                {
                    number: [16, 18],
                    men: 'XL',
                    woman:['L','XL']
                },
                {
                    number: [20, 22],
                    men: 'XXL',
                    woman:['XXL', 'XXXL']
                },
            ]
            
            let rusSize = prompt('Введите НАШ формат размера для переводa на на Американский формат','')
            console.log(isNaN(rusSize))
            switch(!isNaN(rusSize) && +rusSize >= 40 && +rusSize <= 56) {
                case true:
                    rusSize = +rusSize
                    let flag = 0
            
                    switch(rusSize % 2 !== 0) {
                        case true:
                            rusSize--
                            flag++
                    }
            
                    for(let i = 0; i < usSize.length; i++) {
                        let temp = usSize[i].number.findIndex(element => { return element === (rusSize - 34)})
                        switch( temp >= 0) {
                            case true:
                                    alert(`
                                        ${rusSize+flag}-й размер в американском формате:
                                        +---------------------------------------+
                                            Размер: ${usSize[i].number[temp]}
                                            Мужчины: ${usSize[i].men}
                                            Женщины: ${usSize[i].woman[temp]}
                                        +---------------------------------------+
                                    `)
                                    i = usSize.length
                                break;
            
                            default:
                                continue;
                        }
                    }
                    break;
            
                case false:
                    alert('Неправильный размер.')
                    break;
            }
            break;
     
        case 'switch: if':
            let color = prompt("Введите цвет","");
    
            if(color === 'red') {
                document.write("<div style='background-color: red;'>красный</div>");
                document.write("<div style='background-color: black; color: white;'>черный</div>");    
            } else if(color === 'blue') {
                document.write("<div style='background-color: blue;'>синий</div>");
                document.write("<div style='background-color: green;'>зеленый</div>");
            } else if(color === 'green') {
                document.write("<div style='background-color: green;'>зеленый</div>");
            } else if(color === 'black') {
                document.write("<div style='background-color: black; color: white;'>черный</div>");
            } else {
                document.write("<div style='background-color: gray;'>Я не понял</div>");
            }
            alert('aborting execution to make changes. Reload page to return to select mode')
            loop = false
            
            break;
    
        case 'prompt: or':
            let age = prompt('Введите свой возраст', '') || alert('Вы не ввели ничего!')
            if (age && isNaN(age) || age > 200 || age < 0){
                alert('Вы ввели неверные данные!')    
            } else if(age){
                age = age = Math.trunc(Number(age))
                res = new Date().getFullYear() - age
                alert(`Исходя из введенного вами возраста вы родились в ${res}г. либо ${res-1}г.`)
            }
            break;
    
        case 'confirm: or this days':
            confirm('шоппинг') || alert('ты-бяка')
            break;
        
        case 'confirm: if this days':
            if(!confirm('шоппинг')) {
                alert('ты-бяка')
            }
            break;
    
        case 'triple prompt':
            let Name = prompt('your Name:','')
            let surname = prompt('your Surname:','')
            let patronymic = prompt('your Patronymic:','')
            alert(`${surname} ${Name} ${patronymic}`)
            break;
    
        case 'default: or':
            let defaultName = prompt('your Name:','') || 'Иван'
            let defaultSurname = prompt('your Surname:','') || 'Иванов'
            let defaultPatronymic = prompt('your Patronymic:','')  || 'Иванович'
            alert(`${defaultSurname} ${defaultName} ${defaultPatronymic}`)
            break;
    
        case 'default: if':
            let NameIf = prompt('your Name:','')
            let surnameIf = prompt('your Surname:','')
            let patronymicIf = prompt('your Patronymic:','')
    
            if(NameIf) {
                NameIf = NameIf
            } else {
                NameIf = 'Ivan'
            }
            if(surnameIf) {
                surnameIf = surnameIf
            } else {
                surnameIf = 'Ivanov'
            }
            if (patronymicIf) {
                patronymicIf = patronymicIf
            } else {
                patronymicIf = 'Ivanovich'
            }
            
            alert(`"if else" to add default values:
            ${surnameIf} ${NameIf} ${patronymicIf}`)
    
            break;
        
        case 'login and password':
            if(prompt('login','') === 'admin') {
                alert('correct login')
                if(prompt('password','') === 'qwerty') {
                    alert('correct password')
                } else {
                    alert('wrong password')
                }
            } else {
                alert('wrong login')
            }
            break;
        
        case 'currency calc':
            let curr = prompt('type currency: "eur" or "usd"','')
            let transferLog = {
                initial: 'hrn',
                to: '',
                ratios: {
                    sold: {
                        usd: 0.032,
                        eur: 0.037,
                        setUsd: function(value) {
                            this.usd = value
                        },
                        setEur: function(value) {
                            this.eur = value
                        }
                    },
                    bought: {
                        usd: 0.033,
                        eur: 0.038
                    }
                }
            }
            
            if(curr) {
                // switch(curr.toLowerCase()) {
                //     case 'eur':
                //         transferLog.to = 'eur'
                //         confirm('Sell  press "Ok" | Buy press "Cancel"')? transferLog.curr = [transferLog.ratios['sold']['usd'], 'sold'] : transferLog.curr = [transferLog.ratios['bought']['usd'], 'bought']
                //         break;
                //     case 'usd':
                //         transferLog.to = 'usd'
                //         confirm('Sell  press "Ok" | Buy press "Cancel"')? transferLog.curr = [transferLog.ratios['sold']['eur'], 'sold'] : transferLog.curr = [transferLog.ratios['bought']['eur'], 'bought']
                //         break;
                // }
            
                if(curr.toLowerCase() === 'eur') {
                    transferLog.to = 'eur'
                    confirm('Sell  press "Ok" | Buy press "Cancel"')? transferLog.curr = [transferLog.ratios['sold']['usd'], 'sold'] : transferLog.curr = [transferLog.ratios['bought']['usd'], 'bought']
                }
                if(curr.toLowerCase() === 'usd') {
                    transferLog.to = 'usd'
                    confirm('Sell  press "Ok" | Buy press "Cancel"')? transferLog.curr = [transferLog.ratios['sold']['eur'], 'sold'] : transferLog.curr = [transferLog.ratios['bought']['eur'], 'bought']
                }
                
                if(transferLog.to === 'eur' || transferLog.to === 'usd') {
                    transferLog.money = prompt('input amount of money to give', '')
    
                    if(!+transferLog.money) {
                        alert('invalid input')
                    } else {
                        transferLog.given = Number(transferLog.money)
                        if(transferLog.curr[1] === 'sold') {
                            transferLog.money = truncateFraction(transferLog.given / transferLog.curr[0])
                            transferLog.message = `You've ${transferLog.curr[1]} ${transferLog.given}${transferLog.to} for ${transferLog.money}${transferLog.initial}`
                
                        } else if(transferLog.curr[1] === 'bought') {
                            transferLog.money = truncateFraction(transferLog.given * transferLog.curr[0])
                            transferLog.message = `You've ${transferLog.curr[1]} ${transferLog.money}${transferLog.to} for ${transferLog.given}${transferLog.initial}`
                        }
                        transferLog.money > 0? alert(transferLog.message) : alert(`Looks like there is too little amount of hrn given to translate to ${transferLog.to}`)
                    }
                } else {
                    alert('invalid input')
                }
            } else {
                alert('No input.')
            }
            break;
    
        case 'scissors':
            let combos = {
                paper: {
                    conter: 'scissors'
                },
                scissors: {
                    conter: 'rock'
                },
                rock: {
                    conter: 'paper'
                }
            }
            
            let user = prompt('rock, paper, scissors?').toLowerCase()
            
            if(user === 'rock' || user === 'paper' || user === 'scissors') {
                let computer = Math.random()
            
                if(computer >= 0.6) {
                    computer = 'scissors'
                } else if(computer <= 0.3) {
                    computer = 'paper'
                } else {
                    computer = 'rock'
                }
                alert(`computer: ${computer}`)
            
                if(user === computer) {
                    alert('TIE')
                } else {
                    combos[computer].conter === user ? alert('USER WINS.') : alert('COMPUTER WINS.')
                }
            } else {
                alert('user disqualified! Compuer wins!')
            }
            break;
    
            
        case 'real data':
            let currReal = prompt('type currency: "eur" or "usd"','')
            
            if(currReal && currReal.toLowerCase() === 'eur' || currReal.toLowerCase() === 'usd') {
                currReal = currReal.toLowerCase()
                let sellReal = confirm('Sell  press "Ok" | Buy press "Cancel"')
                let operationReal = sellReal? 'sold' : 'bought'
                let givenReal = prompt('input amount of money you give:','')
                
                if(givenReal && !isNaN(givenReal)) {
                    givenReal = truncateFraction(Number(givenReal))
    
                    fetch(`https://open.er-api.com/v6/latest/${currReal.toUpperCase()}`).then(res => res.json())
                        .then(data => {
                            let got = sellReal ? truncateFraction(givenReal * data.rates.UAH) : truncateFraction(givenReal / data.rates.UAH)
                            if(got > 0) {
                                sellReal ? 
                                    alert(`You've ${operationReal} ${givenReal}${currReal} for ${got}hrn`):
                                    alert(`You've ${operationReal} ${got}${currReal} for ${givenReal}hrn`)
                            } else {
                                alert(`Looks like there is too little amount of money been given to make such operation`)
                            }
                        })
                } else {
                    alert('invalid input')
                }
    
            } else {
                alert('invalid input')
            }
            break;
    
        case 'black belt':
            let combos2 = {
                paper: {
                    conter: 'scissors'
                },
                scissors: {
                    conter: 'rock'
                },
                rock: {
                    conter: 'paper'
                }
            }
            let user2 = prompt('rock, paper, scissors?').toLowerCase()
            let computer2 = Math.random() >= 0.6 ? 'scissors' : (Math.random() <= 0.3 ? 'paper' : 'rock')
            alert(`computer: ${computer2}`)
    
            user2 === 'rock' || user2 === 'paper' || user2 === 'scissors'? (computer2 === user2? alert('TIE') : combos2[computer2].conter === user2 ? alert('USER WINS.') : alert('COMPUTER WINS.')) : alert('user disqualified! Compuer wins!')
            
            break;
        
        case null:
            loop = false
            break;
        
        default:
            alert('no matches found:(')
    }
}