//
//  XJLCardTextField.swift
//  DemoStrip
//
//  Created by Nicky Y M LIU_SP on 2020/11/9.
//  Copyright © 2020 Demo Project. All rights reserved.
//

import UIKit

enum XJLCardValidationState: Int {
    case valid = 0 ,inValid = 1, complete = 2
}

class XJLCardTextField: UITextField {
    // MARK: - override
    override func invalidateIntrinsicContentSize() {
        self.rawExpiration = self.text ?? ""
    }
    
    override var text: String? {
        didSet (newVale){
            self.rawExpiration =  self.text ?? ""
            let state = self.validationStateForField()
            self.validText = true;
            switch (state) {
            case .inValid:
                self.validText = false;
                break;
            case .complete:
                break;
            case .valid:
                break;
            }
            
            
            let attributed = NSAttributedString(string: self.rawExpiration, attributes: defaultTextAttributes)
            attributedText = attributed
        }
    }
    
    override var attributedText: NSAttributedString? {
        get {
            return super.attributedText
        }
        set(attributedText) {
            let modified = attributedText
            super.attributedText = modified
            
            sendActions(for: .valueChanged)
        }
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        self.delegate = self
        self.defaultColor = .black;
        self.errorColor = .red
        self.validText = true
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.defaultColor = .black;
        self.errorColor = .red
        self.validText = true
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    // MARK: - 属性
    var errorColor: UIColor? {
        didSet {
        
            self.updateColor()
        }
    }
    
    var defaultColor: UIColor? {
        didSet {
            self.updateColor()
        }
    }
    
    var validText: Bool? {
        didSet {
            self.updateColor()
        }
    }
    
    
    var rawExpiration: String {
        set {
            let sanitizedExpiration = self.unformattedString(for: newValue)
            expirationMonth = (sanitizedExpiration as NSString).substring(to: min(2, sanitizedExpiration.count))
            let temp = (sanitizedExpiration as NSString).substring(from: min(2, sanitizedExpiration.count))
            expirationYear = (temp as NSString).substring(to: min(2, temp.count))
            
        }
        
        get {
            var array: [String] = []
            if expirationMonth != nil && expirationMonth != "" {
                array.append(expirationMonth!)
            }

            if self.validationState(forExpirationMonth: expirationMonth ?? "") == .valid {
                array.append(expirationYear!)
            }
            return array.joined(separator: "/")
        }
    }
    
    var expirationMonth: String? {
        didSet {
            var sanitizedExpiration = self.unformattedString(for: ((expirationMonth ?? "") as NSString) as String)
                 if sanitizedExpiration.count == 1 && !(sanitizedExpiration == "0") && !(sanitizedExpiration == "1") {
                     sanitizedExpiration = "0" + sanitizedExpiration
                 }
            expirationMonth = (sanitizedExpiration as NSString).substring(to: min(2, sanitizedExpiration.count))
             }
    }
    
   var expirationYear: String? {
       didSet {
          let temp = (self.unformattedString(for: expirationYear ?? "")
            as NSString)
          expirationYear = temp.substring(to: min(2, temp.length))
       }
   }
    
    
  // MARK: - Define Method
  func validationState(forExpirationMonth expirationMonth: String) -> XJLCardValidationState {

    let sanitizedExpiration = self.unformattedString(for: expirationMonth)

    if !((sanitizedExpiration as NSString).rangeOfCharacter(from: CharacterSet(charactersIn: "0123456789").inverted).location == NSNotFound) {
            return .inValid
        }

        switch sanitizedExpiration.count {
            case 0:
                return .complete
            case 1:
                return (((sanitizedExpiration == "0") || (sanitizedExpiration == "1")) ? .complete : .valid)
            case 2:
                return ((0 < Int(sanitizedExpiration) ?? 0 && Int(sanitizedExpiration) ?? 0 <= 12) ? .valid : .inValid)
            default:
                return .inValid
        }
    }
    
    func validationStateForField()  -> XJLCardValidationState  {
        let monthState =  self.validationState(forExpirationMonth: expirationMonth ?? "")
        let yearState = self.validationState(forYear: expirationYear, inMonth: expirationMonth)
        if monthState == .valid && yearState == .valid {
            return .valid
        } else if monthState == .inValid || yearState == .inValid {
            return .inValid
        } else {
            return .complete
        }
    }
    
    func validationState (
        forYear expirationYear: String?,inMonth expirationMonth: String?) -> XJLCardValidationState {
        return self.validationState(
            forExpirationYear: expirationYear,
            inMonth: expirationMonth,
            inCurrentYear: self.currentYear(),
            currentMonth: self.currentMonth())
    }
    
    func currentYear() -> Int {
        let calendar = Calendar(identifier: .gregorian)
        let dateComponents = calendar.component(.year, from:  Date())
        return (dateComponents) % 100
    }

    func currentMonth() -> Int {
        let calendar = Calendar(identifier: .gregorian)
        let dateComponents = calendar.component(.month, from: Date())
        return dateComponents
    }
    
    func validationState(forExpirationYear expirationYear: String?, inMonth expirationMonth: String?, inCurrentYear currentYear: Int, currentMonth: Int) -> XJLCardValidationState {
        let moddedYear = currentYear % 100
        
        if !self.stringIsNumeric(expirationMonth) || !self.stringIsNumeric(expirationYear) {
            return .inValid
        }
        
        let sanitizedMonth = self.unformattedString(for: expirationMonth ?? "")
        let sanitizedYear = self.unformattedString(for: expirationYear ?? "")

        switch sanitizedYear.count {
        case 0, 1:
            return .complete
        case 2:
            if validationState(forExpirationMonth: sanitizedMonth) == .inValid {
                return .inValid
            } else {
                if Int(sanitizedYear) == moddedYear {
                    return (Int(sanitizedMonth) ?? 0) >= currentMonth ? .valid : .inValid
                } else {
                    return (Int(sanitizedYear) ?? 0) > moddedYear ? .valid : .inValid
                }
            }
        default:
            return .inValid
        }
    }


    func stringIsNumeric(_ string: String?) -> Bool {
        return (string as NSString?)?.rangeOfCharacter(from:  CharacterSet(charactersIn: "0123456789").inverted).location == NSNotFound
    }
    
    func updateColor() {
        textColor = validText ?? true ? defaultColor : errorColor
    }
}



extension XJLCardTextField: UITextFieldDelegate {
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let insertingIntoEmptyField = textField.text!.count == 0 && range.location == 0 && range.length == 0
        var hasTextContentType = false
            if #available(iOS 11.0, *) {
                // This property is available starting in 10.0, but didn't offer in-app suggestions till 11.0
                hasTextContentType = textField.textContentType != nil
            }

        if hasTextContentType && insertingIntoEmptyField && (string == " ") {
            return true
        }
        
        let deleting = range.location == textField.text!.count - 1 && range.length == 1 && (string == "")
        var inputText: String?
        if deleting {
            let sanitized = self.unformattedString(for: textField.text ?? "")
            inputText = (sanitized as NSString).substring(to: min(sanitized.count,sanitized.count - 1))
        } else {
            let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
            let sanitized = self.unformattedString(for: newString)
            inputText = sanitized
        }

        if textField.text == inputText {
            return false
        }

        textField.text = inputText
        
        return false
        
    }
    
    func unformattedString(for string: String) -> String {
        return self.stringByRemovingCharactersFromSet(string: string as NSString)
    }
    
    fileprivate func stringByRemovingCharactersFromSet(string: NSString, cs: CharacterSet = CharacterSet(charactersIn: "0123456789").inverted) -> String {
    

        var range: NSRange = string.rangeOfCharacter(from: cs)
        if (range.location != NSNotFound) {
            var newString = string.substring(with: NSMakeRange(0, range.location))
            var lastPosition: Int = NSMaxRange(range)
            while (lastPosition < string.length) {
                
                range = string.rangeOfCharacter(from: cs, options: NSString.CompareOptions.init(rawValue: 0), range:  NSMakeRange(lastPosition, string.length - lastPosition))
                if (range.location == NSNotFound) {
                    break;
                }
                if (range.location != lastPosition) {
                    newString.append(string.substring(with: NSMakeRange(lastPosition, range.location - lastPosition)))
                }
                lastPosition = NSMaxRange(range);
            }
            if (lastPosition != string.length) {
                newString.append(string.substring(with: NSMakeRange(lastPosition, string.length - lastPosition)))
            }
            return newString  as String
        } else {
            return string as String
        }
    }
}

看这份代码 加了注释

//
//  LYMCardDateTextField.swift
//  XJL
//
//  Created by Nicky Y M LIU_SP on 2020/11/13.
//  Copyright © 2020 Nicky Y M LIU_SP. All rights reserved.
//

import UIKit

enum LYMCardValidationState: Int {
    case valid = 0 ,inValid = 1, complete = 2
}

class LYMCardDateTextField: UITextField {

    override func awakeFromNib() {
        super.awakeFromNib()
        self.delegate = self
        self.defaultColor = .black;
        self.errorColor = .red
        self.validText = true
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.delegate = self
        self.defaultColor = .black;
        self.errorColor = .red
        self.validText = true
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    override var text: String? {
        didSet (newVale){
            self.rawExpiration =  self.text ?? ""
            let state = self.validationStateForField()
            self.validText = true;
            switch (state) {
                case .inValid:
                    self.validText = false; // 控制文字颜色
                    break
                default:
                    break
            }
            
            // 用富文本赋值不再触发代理方法 textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String)，如果使用text = rawExpiration就会死循环
            let attributed = NSAttributedString(string: self.rawExpiration, attributes: defaultTextAttributes)
            attributedText = attributed
        }
    }
    
    // MARK: - 属性
    var rawExpiration: String {
        set {
            let sanitizedExpiration = self.validateNumberStringReturnNewString(newValue)
            expirationMonth = (sanitizedExpiration as NSString).substringTo(index: 2)
            let temp = (sanitizedExpiration as NSString).substring(from: min(2, sanitizedExpiration.count))
            expirationYear = (temp as NSString).substringTo(index: 2)
            
        }
        
        get {
            var array: [String] = []
            if expirationMonth != nil && expirationMonth != "" {
                array.append(expirationMonth!)
            }

            if self.validationMonthState(expirationMonth: expirationMonth ?? "") == .valid {
                array.append(expirationYear!)
            }
            return array.joined(separator: "/")
        }
    }

    var expirationMonth: String? {  // 月份
        didSet {
            var sanitizedExpiration = self.validateNumberStringReturnNewString(((expirationMonth ?? "") as NSString) as String)
            if sanitizedExpiration.count == 1 && !(sanitizedExpiration == "0") && !(sanitizedExpiration == "1") {
                sanitizedExpiration = "0" + sanitizedExpiration
            }
            expirationMonth = (sanitizedExpiration as NSString).substring(to: min(2, sanitizedExpiration.count))
        }
    }
    
    var expirationYear: String? {   // 年份
        didSet {
            let temp = (self.validateNumberStringReturnNewString(expirationYear ?? "")
                as NSString)
            expirationYear = temp.substring(to: min(2, temp.length))
        }
    }
    
    var errorColor: UIColor? {
        didSet {
            self.updateColor()
        }
    }
    
    var defaultColor: UIColor? {
        didSet {
            self.updateColor()
        }
    }
    
    var validText: Bool? {
        didSet {
            self.updateColor()
        }
    }
}

extension LYMCardDateTextField {
    // MARK: - Define Method
    func updateColor() {
        textColor = validText ?? true ? defaultColor : errorColor
    }
    
    // 校验月份
    func validationMonthState(expirationMonth: String) -> LYMCardValidationState {
        
        let sanitizedExpiration = expirationMonth
        
        if !self.validateNumberString(expirationMonth) {
            return .inValid
        }
        
        switch sanitizedExpiration.count {
        case 0:
            return .complete
        case 1:
            return (((sanitizedExpiration == "0") || (sanitizedExpiration == "1")) ? .complete : .valid)
        case 2:
            return ((0 < Int(sanitizedExpiration) ?? 0 && Int(sanitizedExpiration) ?? 0 <= 12) ? .valid : .inValid)
        default:
            return .inValid
        }
    }

    // 检验输入框输入是否符合要求
    func validationStateForField()  -> LYMCardValidationState  {
        let monthState =  self.validationMonthState(expirationMonth: expirationMonth ?? "")
        let yearState = self.validationState(forYear: expirationYear, inMonth: expirationMonth)
        if monthState == .valid && yearState == .valid {
            return .valid
        } else if monthState == .inValid || yearState == .inValid {
            return .inValid
        } else {
            return .complete
        }
    }
    
    // 检验年月
    func validationState (
        forYear expirationYear: String?,inMonth expirationMonth: String?) -> LYMCardValidationState {
        return self.validationState(
            forExpirationYear: expirationYear,
            inMonth: expirationMonth,
            inCurrentYear: self.currentYear(),
            currentMonth: self.currentMonth())
    }
    
    func currentYear() -> Int {
        let calendar = Calendar(identifier: .gregorian)
        let dateComponents = calendar.component(.year, from:  Date())
        return (dateComponents) % 100
    }

    func currentMonth() -> Int {
        let calendar = Calendar(identifier: .gregorian)
        let dateComponents = calendar.component(.month, from: Date())
        return dateComponents
    }
    
    func validationState(forExpirationYear expirationYear: String?, inMonth expirationMonth: String?, inCurrentYear currentYear: Int, currentMonth: Int) -> LYMCardValidationState {
        let moddedYear = currentYear % 100
        
        if !self.validateNumberString(expirationMonth ?? "") || !self.validateNumberString(expirationYear ?? "") {
            return .inValid
        }
        
        let sanitizedMonth = self.validateNumberStringReturnNewString( expirationMonth ?? "")
        let sanitizedYear = self.validateNumberStringReturnNewString(expirationYear ?? "")

        switch sanitizedYear.count {
        case 0, 1:
            return .complete
        case 2:
            if validationMonthState(expirationMonth: sanitizedMonth) == .inValid {
                return .inValid
            } else {
                if Int(sanitizedYear) == moddedYear {
                    return (Int(sanitizedMonth) ?? 0) >= currentMonth ? .valid : .inValid
                } else {
                    return (Int(sanitizedYear) ?? 0) > moddedYear ? .valid : .inValid
                }
            }
        default:
            return .inValid
        }
    }

    // 是否是数字
    func validateNumberString(_ string: String) -> Bool {
        let dateRegEx = "^\\d{0,}$"
        let dateTest = NSPredicate(format: "SELF MATCHES %@", dateRegEx)
        return dateTest.evaluate(with: string)
    }
    
    //  是数字直接返回，不是返回""
    func validateNumberStringReturnNewString(_ string: String) -> String {
        if self.validateNumberString(string) {
            return string
        }else {
            return ""
        }
    }
}

extension LYMCardDateTextField: UITextFieldDelegate {
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        
        var inputText: String?
        var newString = ""
        let deleting = range.location == textField.text!.count - 1 && range.length == 1 && (string == "")
        if deleting { // 光标在最后且是按了删除键
            newString = (textField.text! as NSString).replacingOccurrences(of: "/", with: "")
            newString = (newString as NSString).substringTo(index: newString.count - 1)
        }else {
            newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
            newString = (newString as NSString).replacingOccurrences(of: "/", with: "")
        }
        // 前面需要先把"/"替换掉再去走下面的代码，因为下面校验只能是0～9的数字
        let result = self.validateNumberString(newString)
        if result { // true 使用新的字符串
            inputText = newString
        }else {     // false 保留的字符串
            inputText = textField.text
        }

        if textField.text == inputText {
            return false
        }

        // 赋值，需要重写系统的text方法
        textField.text = inputText
        return false
    }
}

extension NSString {
    func substringTo(index: Int) -> String {
        return self.substring(to: min(index, self.length))
    }
}