d-date · October 11, 2024 09:09 · Oct 11, 2024
diff --git a/CreditCardBrand.swift b/CreditCardBrand.swift
@@ -0,0 +1,67 @@
+enum CreditCardBrand: String {
+    enum Pattern {
+        static let visa = #"^4[0-9]{12}(?:[0-9]{3})?"#
+        static let master = #"^(?:5[1-5][0-9]{2}|222[1-9]|22[3-9][0-9]|2[3-6][0-9]{2}|27[01][0-9]|2720)[0-9]{12}$"#
+        static let amex = #"^3[47][0-9]{13}$"#
+        static let diners = #"^3(?:0[0-5]|[68][0-9])[0-9]{11,13}$"#
+        static let discover = #"^6(?:011|5[0-9]{2})[0-9]{12}$"#
+        static let jcb = #"^(?:2131|1800|35\d{3})\d{7}"#
+    }
+
+    case visa = "Visa"
+    case master = "Master"
+    case amex = "Amex"
+    case diners = "Diners"
+    case discover = "Discover"
+    case jcb = "JCB"
+
+    init?(cardBrand: CafeAPIClient.CreditCard.CardBrand) {
+        switch cardBrand {
+        case .americanExpress:
+            self = .amex
+
+        case .dinersClub:
+            self = .diners
+
+        case .discover:
+            self = .discover
+
+        case .jcb:
+            self = .jcb
+
+        case .masterCard:
+            self = .master
+
+        case .visa:
+            self = .visa
+
+        case .unknown:
+            return nil
+        }
+    }
+
+    init?(cardNumber: String) {
+        switch cardNumber {
+        case Regex(pattern: Pattern.visa):
+            self = .visa
+
+        case Regex(pattern: Pattern.master):
+            self = .master
+
+        case Regex(pattern: Pattern.amex):
+            self = .amex
+
+        case Regex(pattern: Pattern.diners):
+            self = .diners
+
+        case Regex(pattern: Pattern.discover):
+            self = .discover
+
+        case Regex(pattern: Pattern.jcb):
+            self = .jcb
+
+        default:
+            return nil
+        }
+    }
+}
diff --git a/Regex.swift b/Regex.swift
@@ -0,0 +1,38 @@
+import Foundation
+
+protocol RegularExpressionMatchable {
+    func match(regex: Regex) -> Bool
+}
+
+extension String: RegularExpressionMatchable {
+    func match(regex: Regex) -> Bool {
+        regex.match(string: self)
+    }
+}
+
+func ~= <T: RegularExpressionMatchable>(pattern: Regex, matchable: T) -> Bool {
+    matchable.match(regex: pattern)
+}
+
+struct Regex {
+    let pattern: String
+    let options: NSRegularExpression.Options
+
+    init(pattern: String, options: NSRegularExpression.Options = []) {
+        self.pattern = pattern
+        self.options = options
+    }
+
+    private var matcher: NSRegularExpression {
+        do {
+            return try NSRegularExpression(pattern: pattern, options: options)
+        } catch {
+            print(error)
+            fatalError()
+        }
+    }
+
+    func match(string: String, options: NSRegularExpression.MatchingOptions = []) -> Bool {
+        matcher.firstMatch(in: string, options: options, range: .init(location: 0, length: string.count)) != nil
+    }
+}