open lazy var types: [CreditCardValidationType] = {
    var types = [CreditCardValidationType]()
    for object in CreditCardValidator.types {
        types.append(CreditCardValidationType(dict: object as [String : AnyObject]))
    }
    return types
    }()

public init() { }

/**
Get card type from string

- parameter string: card number string

- returns: CreditCardValidationType structure
*/
open func typeFromString(_ string: String) -> CreditCardValidationType? {
    for type in types {
        let predicate = NSPredicate(format: "SELF MATCHES %@", type.regex)
        let numbersString = self.onlyNumbersFromString(string)
        if predicate.evaluate(with: numbersString) {
            return type
        }
    }
    return nil
}

/**
Validate card number

- parameter string: card number string

- returns: true or false
*/
open func validateString(_ string: String) -> Bool {
    let numbers = self.onlyNumbersFromString(string)
    if numbers.characters.count < 9 {
        return false
    }

    var reversedString = ""
    let range = Range<String.Index>(uncheckedBounds: (lower: numbers.startIndex, upper: numbers.endIndex))

    numbers.enumerateSubstrings(in: range, options: [NSString.EnumerationOptions.reverse, NSString.EnumerationOptions.byComposedCharacterSequences]) { (substring, substringRange, enclosingRange, stop) -> () in
        reversedString += substring!
    }

    var oddSum = 0, evenSum = 0
    let reversedArray = reversedString.characters
    var i = 0

    for s in reversedArray {

        let digit = Int(String(s))!

        if (i+1) % 2 == 0 {
            evenSum += digit
        } else {
            oddSum += digit / 5 + (2 * digit) % 10
        }
    }
    return (oddSum + evenSum) % 10 == 0
}

/**
Validate card number string for type

- parameter string: card number string
- parameter type:   CreditCardValidationType structure

- returns: true or false
*/
open func validateString(_ string: String, forType type: CreditCardValidationType) -> Bool {
    return typeFromString(string) == type
}

open func onlyNumbersFromString(_ string: String) -> String {
    let set = CharacterSet.decimalDigits.inverted
    let numbers = string.components(separatedBy: set)
    return numbers.joined(separator: "")
}

// MARK: - Loading data

fileprivate static let types = [
    [
        "name": "Amex",
        "regex": "^3[47][0-9]{5,}$"
    ], [
        "name": "Visa",
        "regex": "^4[0-9]{6,}$"
    ], [
        "name": "MasterCard",
        "regex": "^5[1-5][0-9]{5,}$"
    ], [
        "name": "Maestro",
        "regex": "^(?:5[0678]\\d\\d|6304|6390|67\\d\\d)\\d{8,15}$"
    ], [
        "name": "Diners Club",
        "regex": "^3(?:0[0-5]|[68][0-9])[0-9]{4,}$"
    ], [
        "name": "JCB",
        "regex": "^(?:2131|1800|35[0-9]{3})[0-9]{3,}$"
    ], [
        "name": "Discover",
        "regex": "^6(?:011|5[0-9]{2})[0-9]{3,}$"
    ], [
        "name": "UnionPay",
        "regex": "^62[0-5]\\d{13,16}$"
    ]
]