//
//  CreditCardView.swift
//  GME Remit
//
//  Created by InKwon James Kim on 2019/10/15.
//  Copyright © 2019 Gobal Money Express Co. Ltd. All rights reserved.
//

import UIKit

@IBDesignable
class CreditCardView: UIView {
  private enum PickerType: Int {
    case month = 0
    case year
  }
  private let xibName = "CreditCardView"
  
  @IBOutlet private weak var firstNumberTextField: UITextField!
  @IBOutlet private weak var secondNumberTextField: UITextField!
  @IBOutlet private weak var thirdNumberTextField: UITextField!
  @IBOutlet private weak var fourthNumberTextField: UITextField!
  
  @IBOutlet private weak var monthTextField: UITextField!
  @IBOutlet private weak var yearTextField: UITextField!
  
  @IBOutlet private weak var cardCompanyImageView: UIImageView!
  
  private var textFields: [UITextField]?
  
  private var months = ["01", "02", "03", "04", "05", "06", "07", "08", "09", "10" ,"11", "12"]
  private var years = [String]()
  
  override init(frame: CGRect) {
    super.init(frame: frame)
    commonInit()
  }
  
  required init?(coder: NSCoder) {
    super.init(coder: coder)
    commonInit()
  }
  
  private func commonInit() {
    guard let view = Bundle.main.loadNibNamed(
      xibName,
      owner: self,
      options: nil
    )?.first as? UIView else { return }
    
    view.frame = self.bounds
    
    view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    
    view.layer.cornerRadius = 10
    
    self.addSubview(view)
    
    textFields = [
      firstNumberTextField, secondNumberTextField, thirdNumberTextField, fourthNumberTextField,
      monthTextField, yearTextField
    ]
    
    textFields?.forEach {
      $0.addTarget(self, action: #selector(editingDidBegin(_:)), for: .editingDidBegin)
      $0.addTarget(self, action: #selector(editingChanged(_:)), for: .editingChanged)
    }
    
    let monthPickerView = UIPickerView()
    monthPickerView.tag = 0
    monthPickerView.delegate = self
    monthPickerView.dataSource = self
    monthTextField.inputView = monthPickerView
    
    let yearPickerView = UIPickerView()
    yearPickerView.tag = 1
    yearPickerView.delegate = self
    yearPickerView.dataSource = self
    yearTextField.inputView = yearPickerView
    
    let format = DateFormatter()
    format.dateFormat = "yy"
    
    let now = Date()
    let min = Int(format.string(from: now)) ?? 19
    let max = min + 5
    
    for year in min...max {
      years.append("\(year)")
    }
  }
  
  func focusFirstNumberField() {
    firstNumberTextField.becomeFirstResponder()
  }
  
  @objc private func editingChanged(_ textField: UITextField) {
    let limitCount: Int
    
    switch textField {
    case monthTextField, yearTextField:
      limitCount = 2
    default:
      limitCount = 4
    }

    if textField.text?.count == limitCount,
      let index = textFields?.firstIndex(of: textField)?.advanced(by: 1) {
      if index < textFields?.count ?? 6, textFields?[index].text?.count != limitCount {
        textFields?[index].becomeFirstResponder()
      } else {
        textField.resignFirstResponder()
        
        guard
          let first = firstNumberTextField.text,
          let second = secondNumberTextField.text,
          let third = thirdNumberTextField.text,
          let fourth = fourthNumberTextField.text,
          let month = monthTextField.text,
          let year = yearTextField.text else {
            return
        }
        
        let cardNumber = first + second + third + fourth
        cardCompanyImageView.image = CreditCardType.validate(cardNumber: cardNumber)?.image
      }
    }
  }
  
  @objc private func editingDidBegin(_ textField: UITextField) {
    textField.text = nil
  }
}

extension CreditCardView: UIPickerViewDataSource {
  func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
  }
  
  func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    guard let type = PickerType(rawValue: pickerView.tag) else { return 0 }
    
    switch type {
    case .month: return months.count
    case .year: return years.count
    }
  }
  
  func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    guard let type = PickerType(rawValue: pickerView.tag) else { return nil }
    
    switch type {
    case .month: return months[row]
    case .year: return years[row]
    }
  }
}

extension CreditCardView: UIPickerViewDelegate {
  func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    guard let type = PickerType(rawValue: pickerView.tag) else { return }
    
    switch type {
    case .month:
      monthTextField.text = months[row]
      monthTextField.sendActions(for: .editingChanged)
    case .year:
      yearTextField.text = years[row]
      yearTextField.sendActions(for: .editingChanged)
    }
  }
}