//blocks

{
let a = 10
{
    let b = 20
    {
        let c = 30
        // a=100, b=21, c=30
        
        
        b++
        a *= 10
        console.log(a,b,c)
    }
    {
        let c = 50
        // a=10, b=521, c=50  
       
        b += 500
        console.log(a,b,c)
    }
    {
        const a = 100500
        const d = "value"
        // a=100500, b=521, c=undefined, d="value"  
        console.log(a,b,d)
        {
            let a = -50
            b     = 1000
            // a=-50, b=1000, c=undefined, d="value"  
            console.log(a,b,d)
        }
        // a=100500, b=1000, c=undefined, d="value"  
        console.log(a,b,d)
    }
    // a=10, b=1000, c=undefined, d=undefined  
    console.log(a,b)
}
//a=100, b=undefined, c=undefined, d=undefined
console.log(a)

//comparison if

var age = +prompt("Сколько вам лет?","")
if(age < 0){
    alert("Не бреши!")
}
else { if (age < 18){
    alert("школьник")
}
else { if (age > 18 && age < 30){
    alert("молодеж")
}
else {if (age > 30 && age < 45){
    alert("зрелость")
}
else {if (age > 45 && age < 60){
    alert("закат")
}
else {if (age > 60){
    alert("как пенсия?")
}
else {
    alert("то ли киборг, то ли KERNESS")
     }
    }
   }
  }
 }
}

}

//switch: sizes
{
let size = +prompt("Write your size of outerwear?(In USA)") + 2
let sizeSecond = confirm("Обхват вашей талии 63 - 65 см?") && confirm("Обхват ваших бедер 89-92 см?")

switch(size){
    case 6 :
        alert(`Your size in UK:   ${size}`)
        break ;
    case 8 :
        alert(`Your size in UK:  ${size}`)
        break ;
    case 10 :
        alert(`Your size in UK:   ${size}`)
        break ;
    case 12 :
        alert(`Your size in UK:  ${size}`)
        break ;
    case 14 :
        alert(`Your size in UK:  ${size}`)
        break ;
    case 16 :
        alert(`Your size in UK:   ${size}`)
        break ;
    case 18 :
        alert(`Your size in UK:   ${size}`)
        break ;
    
}

switch(sizeSecond){
    case true :
    alert("Ваш размер XS")
    break;
    case false :
    alert("Ваш размер больше XS")
    break;
}
}
   

//switch: if
{
let color = prompt("Введите цвет","")
if(color === "red" || color ==="black"){
    document.write("<div style='background-color: red;'>красный</div>")
    document.write("<div style='background-color: black; color: white;'>черный</div>")
}
if(color === "blue" || color === "green"){
    document.write("<div style='background-color: blue;'>синий</div>")
    document.write("<div style='background-color: green;'>зеленый</div>")
}
if(!color){ 
    document.write("<div style='background-color: gray;'>Я не понял</div>")
}}


//noswitch
{
const drink = prompt("Что вы любите пить")

const noSwitch = (key, cases, defaultKey='default') => {
    if(cases[key]){
        cases[key]()
    }
    else {
        cases[defaultKey]()
    }
    
    
    }
    

noSwitch(drink, {
    воду: () =>  console.log('Самый здоровый выбор!'),
    чай(){ 
        console.log('Вкусная и полезная штука. Не переусердствуйте с сахаром')
    },
    "пиво": () => console.log('Хорошо летом, да в меру'),
    виски: function(){
        console.log('Да вы, батенька, эстет! Не забудьте лед и сигару')
    },
    default(){
        console.log('шото я не понял')
    }
})


}


 //closure calc
 
 fetch('https://open.er-api.com/v6/latest/USD').then(res => res.json())
     .then(data => {
            const objOfCurrency = Object.entries(data.rates)
            for (let [key,value] of objOfCurrency){

                const button = document.createElement('button')
                button.innerHTML = `${key}`
                document.body.append(button)
                button.onclick = () => {
                    const sum = +prompt("Write sum for change: ")
                    const result = (sum / value).toFixed(2)
                    alert(`You get ${result}$`)
                }
            }
          
            console.log(data) 
        })



//closure calc 2
{
    fetch('https://open.er-api.com/v6/latest/USD').then(res => res.json())
        .then(data => {
          const obj =  data.rates
          let rate = {}

          for (let key in obj) {
            let option = document.createElement("option")
            option.innerHTML = key
            from.append(option)
  
            option = document.createElement("option")
            option.innerHTML = key
            to.append(option)
  
            let rateOfKeys = {}
            rate[key] = rateOfKeys

            for (let rateKey in obj) {
                rateOfKeys[rateKey] = obj[rateKey] / obj[key]
            }
          }
          const funcResult = () => {
            const fromValue = from.value
            const toValue = to.value
            const amountValue = amount.value

            let rates = rate[fromValue][toValue]
            result.innerHTML =`Your result is: ${amountValue * rates}`
            rate.innerHTML = amountValue
            
          }
          from.onchange = funcResult
          to.onchange = funcResult
          amount.oninput = funcResult
        })
  }


//countries and cities

fetch('https://raw.githubusercontent.com/russ666/all-countries-and-cities-json/master/countries.min.json').then(res => res.json())
     .then(data => {
            for(country in data){
                let option = document.createElement("option")
                option.innerHTML = country
                countries.append(option)
            }

            const funcCity = () => {
                cities.innerHTML = ""
            
              for(city of data[countries.value]) {    
                    let option = document.createElement("option")
                    option.innerHTML = city
                    cities.append(option)  
              }
            }
            

            countries.onchange = funcCity
            funcCity()
            


            console.log(data) 
        })