/**
 Just reversed string
*/
func revesedString(_ str: String) -> String {
    return String(str.reversed())
}

/**
 If str has brakets, methods remove them.
 If method hasn't brakets, this method makes only reversed
*/
func removeBrakets(_ str: String) -> String {
    guard let rangeBrakets = findRangeBrakets(str) else { return revesedString(str) }
    let start = str.index(after: rangeBrakets.startIndex)
    let end = str.index(before: rangeBrakets.endIndex)
    let rangeWithoutBrakets = start...end
    let strWithoutBrakets = String(str[rangeWithoutBrakets])
    return strWithoutBrakets
}


/**
 This method find range brakets.
 For Example: we have str equal to 12(34(56)78)90,
 in the first we searching braket ")", we got index 8
 after it we searching braket "(" in deapeason 0..<8 (12(34(56)
 end the end we have indexes 5 and 8
 str[5..<8] equal "(56)"
*/
func findRangeBrakets(_ str: String) -> (startIndex: String.Index, endIndex: String.Index)? {
    guard let lastIndex = str.firstIndex(of: ")") else { return nil }
    let leftSideArrange = str.startIndex..<lastIndex
    let leftSideStr = String(str[leftSideArrange])
    guard let firstIndex = leftSideStr.lastIndex(of: "(") else { return nil }
    return (firstIndex, lastIndex)
}

func reversedService(_ str: String) -> String {

    //if brakets didn't find, makes reverse string and return
    guard let rangeBrakets = findRangeBrakets(str) else { return revesedString(str) }

    let rightFirstIndex = str.index(after: rangeBrakets.endIndex)

    let leftStr = String(str[str.startIndex..<rangeBrakets.startIndex])
    let rightStr = String(str[rightFirstIndex..<str.endIndex])

    let midleStrWithoutBrakets = removeBrakets(str)
    let newStr = leftStr + midleStrWithoutBrakets + rightStr
    return reversedService(newStr)
}

let str1 = "56"
print(reversedService(str1))

let str2 = "(56)"
print(reversedService(str2))

var str = "12(34(56)78)90"
print(reversedService(str))

str = "(bar)"
print(reversedService(str))

str = "foo(bar)baz"
print(reversedService(str))

str = "foo(bar(baz))blim"
print(reversedService(str))

str = "foo(bar)baz(blim)"
print(reversedService(str))

str = "(abc)d(efg)"
print(reversedService(str))