// Copyright 2016-present the Material Components for iOS authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// swiftlint:disable function_body_length

import MaterialComponents.MaterialTextFields

final class TextFieldUnderlineSwiftExample: UIViewController {

  let scrollView = UIScrollView()

  let name: MDCTextField = {
    let name = MDCTextField()
    name.translatesAutoresizingMaskIntoConstraints = false
    name.autocapitalizationType = .words
    return name
  }()

  let address: MDCTextField = {
    let address = MDCTextField()
    address.translatesAutoresizingMaskIntoConstraints = false
    address.autocapitalizationType = .words
    return address
  }()

  let city: MDCTextField = {
    let city = MDCTextField()
    city.translatesAutoresizingMaskIntoConstraints = false
    city.autocapitalizationType = .words
    return city
  }()
  let cityController: MDCTextInputControllerUnderline

  let state: MDCTextField = {
    let state = MDCTextField()
    state.translatesAutoresizingMaskIntoConstraints = false
    state.autocapitalizationType = .allCharacters
    return state
  }()
  let stateController: MDCTextInputControllerUnderline

  let zip: MDCTextField = {
    let zip = MDCTextField()
    zip.translatesAutoresizingMaskIntoConstraints = false
    return zip
  }()
  let zipController: MDCTextInputControllerUnderline

  let phone: MDCTextField = {
    let phone = MDCTextField()
    phone.translatesAutoresizingMaskIntoConstraints = false
    return phone
  }()

  let message: MDCMultilineTextField = {
    let message = MDCMultilineTextField()
    message.translatesAutoresizingMaskIntoConstraints = false
    return message
  }()

  var allTextFieldControllers = [MDCTextInputControllerUnderline]()

  override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
    stateController = MDCTextInputControllerUnderline(textInput: state)
    cityController = MDCTextInputControllerUnderline(textInput: city)
    zipController = MDCTextInputControllerUnderline(textInput: zip)
    super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
  }

  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }

  deinit {
    NotificationCenter.default.removeObserver(self)
  }

  override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = UIColor(white:0.97, alpha: 1.0)

    title = "Material Text Fields"

    setupScrollView()
    setupTextFields()

    registerKeyboardNotifications()
    addGestureRecognizer()

    let styleButton = UIBarButtonItem(title: "Style",
                                      style: .plain,
                                      target: self,
                                      action: #selector(buttonDidTouch(sender: )))
    self.navigationItem.rightBarButtonItem = styleButton
  }

  func setupTextFields() {
    scrollView.addSubview(name)
    let nameController = MDCTextInputControllerUnderline(textInput: name)
    name.delegate = self
    name.text = "Grace Hopper"
    nameController.placeholderText = "Name"
    nameController.helperText = "First and Last"
    allTextFieldControllers.append(nameController)

    scrollView.addSubview(address)
    let addressController = MDCTextInputControllerUnderline(textInput: address)
    address.delegate = self
    addressController.placeholderText = "Address"
    allTextFieldControllers.append(addressController)

    scrollView.addSubview(city)
    city.delegate = self
    cityController.placeholderText = "City"
    allTextFieldControllers.append(cityController)

    // In iOS 9+, you could accomplish this with a UILayoutGuide.
    // TODO: (larche) add iOS version specific implementations
    let stateZip = UIView()
    stateZip.translatesAutoresizingMaskIntoConstraints = false
    scrollView.addSubview(stateZip)

    stateZip.addSubview(state)
    state.delegate = self
    stateController.placeholderText = "State"
    allTextFieldControllers.append(stateController)

    stateZip.addSubview(zip)
    zip.delegate = self
    zipController.placeholderText = "Zip Code"
    zipController.helperText = "XXXXX"
    allTextFieldControllers.append(zipController)

    scrollView.addSubview(phone)
    let phoneController = MDCTextInputControllerUnderline(textInput: phone)
    phone.delegate = self
    phoneController.placeholderText = "Phone Number"
    allTextFieldControllers.append(phoneController)

    scrollView.addSubview(message)
    let messageController = MDCTextInputControllerUnderline(textInput: message)
    message.textView?.delegate = self
    message.text = "This is where you could put a multi-line message like an email." + "\n\n" +
      "It can even handle new lines."
    message.multilineDelegate = self
    messageController.placeholderText = "Message"
    allTextFieldControllers.append(messageController)

    var tag = 0
    for controller in allTextFieldControllers {
      guard let textField = controller.textInput as? MDCTextField else { continue }
      textField.tag = tag
      tag += 1
    }

    let views = [ "name": name,
                  "address": address,
                  "city": city,
                  "stateZip": stateZip,
                  "phone": phone,
                  "message": message ]
    var constraints = NSLayoutConstraint.constraints(withVisualFormat:
      "V:[name]-[address]-[city]-[stateZip]-[phone]-[message]",
                                                     options: [.alignAllLeading, .alignAllTrailing],
                                                     metrics: nil,
                                                     views: views)

    constraints += [NSLayoutConstraint(item: name,
                                       attribute: .leading,
                                       relatedBy: .equal,
                                       toItem: view,
                                       attribute: .leadingMargin,
                                       multiplier: 1,
                                       constant: 0)]
    constraints += [NSLayoutConstraint(item: name,
                                       attribute: .trailing,
                                       relatedBy: .equal,
                                       toItem: view,
                                       attribute: .trailingMargin,
                                       multiplier: 1,
                                       constant: 0)]
    constraints += NSLayoutConstraint.constraints(withVisualFormat: "H:[name]|",
                                                  options: [],
                                                  metrics: nil,
                                                  views: views)

    if #available(iOS 11.0, *) {
      constraints += [NSLayoutConstraint(item: name,
                                         attribute: .top,
                                         relatedBy: .equal,
                                         toItem: scrollView.contentLayoutGuide,
                                         attribute: .top,
                                         multiplier: 1,
                                         constant: 20),
                      NSLayoutConstraint(item: message,
                                         attribute: .bottom,
                                         relatedBy: .equal,
                                         toItem: scrollView.contentLayoutGuide,
                                         attribute: .bottomMargin,
                                         multiplier: 1,
                                         constant: -20)]
    } else {
      constraints += [NSLayoutConstraint(item: name,
                                         attribute: .top,
                                         relatedBy: .equal,
                                         toItem: scrollView,
                                         attribute: .top,
                                         multiplier: 1,
                                         constant: 20),
                      NSLayoutConstraint(item: message,
                                         attribute: .bottom,
                                         relatedBy: .equal,
                                         toItem: scrollView,
                                         attribute: .bottomMargin,
                                         multiplier: 1,
                                         constant: -20)]
    }

    let stateZipViews = [ "state": state, "zip": zip ]
    constraints += NSLayoutConstraint.constraints(withVisualFormat: "H:|[state(80)]-[zip]|",
                                                  options: [.alignAllTop],
                                                  metrics: nil,
                                                  views: stateZipViews)
    constraints += NSLayoutConstraint.constraints(withVisualFormat: "V:|[state]|",
                                                  options: [],
                                                  metrics: nil,
                                                  views: stateZipViews)
    constraints += NSLayoutConstraint.constraints(withVisualFormat: "V:|[zip]|",
                                                  options: [],
                                                  metrics: nil,
                                                  views: stateZipViews)

    NSLayoutConstraint.activate(constraints)
  }

  func setupScrollView() {
    view.addSubview(scrollView)
    scrollView.translatesAutoresizingMaskIntoConstraints = false

    NSLayoutConstraint.activate(NSLayoutConstraint.constraints(
      withVisualFormat: "V:|[scrollView]|",
      options: [],
      metrics: nil,
      views: ["scrollView": scrollView]))
    NSLayoutConstraint.activate(NSLayoutConstraint.constraints(withVisualFormat: "H:|[scrollView]|",
                                                               options: [],
                                                               metrics: nil,
                                                               views: ["scrollView": scrollView]))
    let marginOffset: CGFloat = 16
    let margins = UIEdgeInsets(top: 0, left: marginOffset, bottom: 0, right: marginOffset)

    scrollView.layoutMargins = margins
  }

  func addGestureRecognizer() {
    let tapRecognizer = UITapGestureRecognizer(target: self,
                                               action: #selector(tapDidTouch(sender: )))
    self.scrollView.addGestureRecognizer(tapRecognizer)
  }

  // MARK: - Actions

  @objc func tapDidTouch(sender: Any) {
    self.view.endEditing(true)
  }

  @objc func buttonDidTouch(sender: Any) {
    let isFloatingEnabled = allTextFieldControllers.first?.isFloatingEnabled ?? false
    let alert = UIAlertController(title: "Floating Labels",
                                  message: nil,
                                  preferredStyle: .actionSheet)

    let defaultAction = UIAlertAction(title: "Default (Yes)" + (isFloatingEnabled ? " ✓" : ""),
                                      style: .default) { _ in
      self.allTextFieldControllers.forEach({ (controller) in
        controller.isFloatingEnabled = true
      })
    }
    alert.addAction(defaultAction)
    let floatingAction = UIAlertAction(title: "No" + (isFloatingEnabled ? "" : " ✓"),
                                       style: .default) { _ in
      self.allTextFieldControllers.forEach({ (controller) in
        controller.isFloatingEnabled = false
      })
    }
    alert.addAction(floatingAction)
    present(alert, animated: true, completion: nil)
  }
}

extension TextFieldUnderlineSwiftExample: UITextFieldDelegate {
  func textField(_ textField: UITextField,
                 shouldChangeCharactersIn range: NSRange,
                 replacementString string: String) -> Bool {
    guard let rawText = textField.text else {
      return true
    }

    let fullString = NSString(string: rawText).replacingCharacters(in: range, with: string)

    if textField == state {
      if let range = fullString.rangeOfCharacter(from: CharacterSet.letters.inverted),
        String(fullString[range]).characterCount > 0 {
        stateController.setErrorText("Error: State can only contain letters",
                                   errorAccessibilityValue: nil)
      } else {
        stateController.setErrorText(nil, errorAccessibilityValue: nil)
      }
    } else if textField == zip {
      if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
        String(fullString[range]).characterCount > 0 {
        zipController.setErrorText("Error: Zip can only contain numbers",
                                   errorAccessibilityValue: nil)
      } else if fullString.characterCount > 5 {
        zipController.setErrorText("Error: Zip can only contain five digits",
                                   errorAccessibilityValue: nil)
      } else {
        zipController.setErrorText(nil, errorAccessibilityValue: nil)
      }
    } else if textField == city {
      if let range = fullString.rangeOfCharacter(from: CharacterSet.decimalDigits),
        String(fullString[range]).characterCount > 0 {
        cityController.setErrorText("Error: City can only contain letters",
                                    errorAccessibilityValue: nil)
      } else {
        cityController.setErrorText(nil, errorAccessibilityValue: nil)
      }
    }
    return true
  }

  func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    let index = textField.tag
    if index + 1 < allTextFieldControllers.count,
      let nextField = allTextFieldControllers[index + 1].textInput {
      nextField.becomeFirstResponder()
    } else {
      textField.resignFirstResponder()
    }

    return false
  }
}

extension TextFieldUnderlineSwiftExample: UITextViewDelegate {
  func textViewDidEndEditing(_ textView: UITextView) {
    print(textView.text)
  }
}

extension TextFieldUnderlineSwiftExample: MDCMultilineTextInputDelegate {
  private func multilineTextFieldShouldClear(_ textField: UIView!) -> Bool {
    return true
  }
}

// MARK: - Keyboard Handling

extension TextFieldUnderlineSwiftExample {
  func registerKeyboardNotifications() {
    let notificationCenter = NotificationCenter.default
    notificationCenter.addObserver(
      self,
      selector: #selector(keyboardWillShow(notif:)),
      name: UIResponder.keyboardWillShowNotification,
      object: nil)
    notificationCenter.addObserver(
      self,
      selector: #selector(keyboardWillHide(notif:)),
      name: UIResponder.keyboardWillHideNotification,
      object: nil)
    notificationCenter.addObserver(
      self,
      selector: #selector(keyboardWillShow(notif:)),
      name: UIResponder.keyboardWillChangeFrameNotification,
      object: nil)
  }

  @objc func keyboardWillShow(notif: Notification) {
    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
      return
    }
    scrollView.contentInset = UIEdgeInsets(top: 0.0,
                                           left: 0.0,
                                           bottom: frame.height,
                                           right: 0.0)
  }

  @objc func keyboardWillHide(notif: Notification) {
    scrollView.contentInset = UIEdgeInsets()
  }
}

// MARK: - Status Bar Style

extension TextFieldUnderlineSwiftExample {
  override var preferredStatusBarStyle: UIStatusBarStyle {
    return .lightContent
  }
}

// MARK: - CatalogByConvention

extension TextFieldUnderlineSwiftExample {

  @objc class func catalogMetadata() -> [String: Any] {
    return [
      "breadcrumbs": ["Text Field", "Underline Style"],
      "description": "Text fields let users enter and edit text.",
      "primaryDemo": false,
      "presentable": false,
    ]
  }
}

internal extension String {
  var characterCount: Int {
    return self.count
  }
}