STEP 2-7

main.swift

import Foundation


enum Unit : String {
    
    
    case    cm =   "cm"
    case    m =    "m"
    case inch = "inch"
    case yard = "yard"
    
    case g  = "g"
    case kg = "kg"
    case oz = "oz"
    case lb = "lb"
    
    
    case L = "L"
    case pt = "pt"
    case qt = "qt"
    case gal = "gal"
    
    
    case error = "error"
    
    func defaultUnit ()->Unit{
        
        switch self {
        case .cm,.m,.inch,.yard:
            return .m
            
        case .g,.kg,.oz,.lb:
            return .kg
            
        case .L,.pt,.qt,.gal :
            return .L
            
        case .error:
            return .error
        }
    }
}


typealias value = Double

typealias UnitRatio = Double

typealias beforeUnit = Unit

typealias afterUnit = Unit


struct units {
    var beforeUnit  : beforeUnit
    var afterUnit   : afterUnit
}

func getUnitRatioTable()->[beforeUnit:[afterUnit:UnitRatio]]{
    let unitRatioTable : [beforeUnit:[afterUnit:UnitRatio]] =
        [
            .m:
                [      .cm:   100,
                       .inch:   0.393701,
                       .yard:   0.0109361
            ],
            .cm:
                [    .m:   0.01,
                     .inch:   39.3701,
                     .yard:   1.09361
            ],
            .inch:
                [
                    .m:    0.0254,
                    .cm:    2.54,
                    .yard:  0.0277778
            ],
            .yard:
                [
                    .cm:    91.44,
                    .m:     0.9144,
                    .inch:  36
            ],
            .g:
                [
                    .kg:    1000,
                    .oz:    0.035274,
                    .lb:    0.00220462
            ],
            .kg:
                [
                    .g:     0.001,
                    .oz:    35.274,
                    .lb:    2.20462
            ],
            .oz:
                [
                    .g:     28.3495,
                    .kg:    0.0283495,
                    .lb:    0.0625
            ],
            .lb:[
                .g:     453.592,
                .kg:    0.453592,
                .oz:    16
            ],
            .L:[
                .pt:    2.11338,
                .qt:    1.05669,
                .gal:   0.21997
            ],
            .pt:[
                .L:     0.56826,
                .qt:    0.516027,
                .gal:   0.129007
            ],
            .qt:[
                .L:     1.136520,
                .pt:    2.401895,
                .gal:   0.300237
            ],
            .gal:[
                .L:     4.404884,
                .pt:    9.309178,
                .qt:    4.654589
            ]
            
            
    ]
    
    return unitRatioTable
}


func getRatio( units: (beforeUnit,afterUnit)) ->(Double){
    
    var unitRatioTable = getUnitRatioTable()
    
    let (beforeUnit,afterUnit) = units
    
    
    let ratio = beforeUnit == afterUnit ? 1 :(unitRatioTable[beforeUnit])![afterUnit]
    
    return ratio!
    
    
}


func convert(userInput:String)->String{
    
    let (value,units) = recognize(userInput: userInput)
    if units == (.error,.error){
        return "지원하지 않는 단위 입니다."
    }
    let ratio  = getRatio(units:units)
    
    return "\(calculatedValueString(value: value, ratio: ratio))\(units.1)"
    
    
}

func calculatedValueString(value:Double,ratio:Double)->String{
    
    let result = value * ratio
    
    return confirmNumber(number: result)
    
    
}

func confirmNumber(number:Double)->String{
    
    if(number.remainder(dividingBy: 1)==0){
        return "\(Int.init(number))"
    }else{
        return "\(number)"
    }
    
}


func recognize(userInput : String)->(value,(beforeUnit,afterUnit)){
    
    let value = getValue(userInput: userInput)
    let units = getUnits(userInput: userInput)
    
    return (value,units)
}

func getValue (userInput:String)->Double{
    let pattern = "[0-9.]+"
    let value = usingRegex(userInput: userInput, pattern: pattern)
    return Double.init(value)!
}

func getUnits(userInput:String)->(beforeUnit,afterUnit){
    let pattern = "[^0-9.]+"
    let units =  usingRegex(userInput: userInput, pattern: pattern)
    
    let unitArray = units.split(separator: " ")
    
    guard let beforeUnit = Unit.init(rawValue: String(unitArray[0])) else{
        return (.error,.error)
    }
    
    let afterUnit:Unit
    if  unitArray.count == 2 {
        
        afterUnit = Unit.init(rawValue: String(unitArray[1]))!
        
    }else{
        afterUnit = beforeUnit.defaultUnit()
    }
    
    return (beforeUnit,afterUnit)
    
}

func usingRegex( userInput:String ,pattern:String ) -> String{
    
    let regexUnits = try! NSRegularExpression.init(pattern: pattern, options: [])
    let matchs = regexUnits.firstMatch(in: userInput, options: [], range: NSRange.init(location: 0, length: userInput.count))
    let part = NSString.init(string: userInput).substring(with: (matchs?.range)!)
    
    return part
    
}

func unitConverter(){
    
    let quitCommends = ["q","quit"]
    
    while(true){
        
        let units = getUnitRatioTable().keys.map{
            unit in
            return unit.rawValue
        }
        
        print(" 변환할 값을 입력하세요 \n 가능한 단위: \(units)\n")
        let inputValue = readLine()
        
        for quitCommend in quitCommends {
            if(quitCommend == inputValue){
                break
                
            }
        }
        print(convert(userInput: inputValue!))
        
        
    }
}

unitConverter()