Unit Conversion

distanceConversion

enum Unit: Int {
    case Millimeters, Centimeters, Meters, Kilometers, Inches, Feet
    
    func baseUnit() -> Double {
        switch self {
        case .Millimeters:
            return 0.001
        case .Centimeters:
            return 0.01
        case .Meters:
            return 1.0
        case .Kilometers:
            return 1000
        case .Inches:
            return 0.0254
        case .Feet:
            return 0.3048
        default:
            return 1.0
        }
    }
    
    func simpleDescription() -> String {
        switch self {
        case .Millimeters:
            return "Millimeters"
        case .Centimeters:
            return "Centimeters"
        case .Meters:
            return "Meters"
        case .Kilometers:
            return "Kilometers"
        case .Inches:
            return "Inches"
        case .Feet:
            return "Feet"
        }
        
    }
}


class Distance  {
    var value: Double = 0.0
    var unit: Unit
    
    init (value: Double, unit: Unit) {
        self.value = value
        self.unit = unit
    }
    
    func convertTo(to: Unit) -> Distance {
        let convertedValue = (self.value * self.unit.baseUnit()) / to.baseUnit()
        return  Distance(value: convertedValue, unit: to)
    }
}


var meters = Distance(value: 1000, unit: Unit.Meters)
var kilometers = meters.convertTo(Unit.Kilometers)

println("\(meters.value) \(meters.unit.simpleDescription()) == \(kilometers.value) \(kilometers.unit.simpleDescription())")