bitcoin-private-ios-wallet/Bitcoin Private/View Controllers/Wallet Creation and Restoration/VerificationViewController.swift

//
//  RecoveryViewController.swift
//  BlockEQ
//
//  Created by Satraj Bambra on 2018-03-11.
//  Copyright © 2018 Satraj Bambra. All rights reserved.
//

import UIKit

class VerificationViewController: UIViewController {
    
    @IBOutlet var collectionView: UICollectionView!
    @IBOutlet var textView: UITextView!
    @IBOutlet var textViewHeightConstraint: NSLayoutConstraint!
    @IBOutlet var progressView: UIView!
    @IBOutlet var progressViewWidthConstraint: NSLayoutConstraint!
    @IBOutlet var quicktypeView: UIView!
    @IBOutlet var questionHolderView: UIView!
    @IBOutlet var questionTitleLabel: UILabel!
    @IBOutlet var questionSubtitleLabel: UILabel!
    @IBOutlet var questionViewHeightConstraint: NSLayoutConstraint!
    
    public enum VerificationType {
        case recovery
        case confirmation
        case questions
    }
    
    let defaultQuestionViewHeight: CGFloat = 88.0
    let defaultTextViewHeight: CGFloat = 150.0
    let questionTextViewHeight: CGFloat = 48.0
    let totalQuestionCount = 4
    var questionsAnswered = 0
    var progressWidth: CGFloat {
        return UIScreen.main.bounds.size.width / CGFloat(totalQuestionCount)
    }
    
    var type: VerificationType = .recovery
    var suggestions: [String] = []
    var questionWords: [String] = []
    var currentWord: String = ""
    var mnemonic: String = ""
    
    let wordList = ["bench", "hurt", "jump", "file", "august", "wise", "shallow", "faculty", "impulse", "spring", "exact", "slush", "thunder", "author", "capable", "act", "festival", "slice", "deposit", "sauce", "coconut", "afford", "frown", "better"]
 
    @IBAction func nextButtonSelected() {
        switch type {
        case .questions:
            validateAnswer()
        default:
            // TODO: uncomment to add verification back
            /*
            guard var mnemonicString = textView.text, !mnemonicString.isEmpty else {
                return
            }
            
            let lastCharater = mnemonicString.last
            if lastCharater == " " {
                mnemonicString = String(mnemonicString.dropLast())
            }
            setPin(mnemonic: mnemonicString)
            */
            
            //TODO remove this when verification above is added.
            setPin(mnemonic: mnemonic)
        }
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    init(type: VerificationType, mnemonic: String) {
        super.init(nibName: String(describing: VerificationViewController.self), bundle: nil)
        
        self.type = type
        self.mnemonic = mnemonic
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        setupView()
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        textView.becomeFirstResponder()
    }

    func setupView() {
        let collectionViewNib = UINib(nibName: WordSuggestionCell.cellIdentifier, bundle: nil)
        collectionView.register(collectionViewNib, forCellWithReuseIdentifier: WordSuggestionCell.cellIdentifier)
        
        switch type {
        case .confirmation:
            navigationItem.title = "Re-enter Your Phrase"
            
            questionViewHeightConstraint.constant = 0.0
            textViewHeightConstraint.constant = defaultTextViewHeight
        case .questions:
            questionViewHeightConstraint.constant = defaultQuestionViewHeight
            textViewHeightConstraint.constant = questionTextViewHeight
            
            setQuestion(animated: false)
        default:
            navigationItem.title = "Enter Recovery Phrase"
            
            questionViewHeightConstraint.constant = 0.0
            textViewHeightConstraint.constant = defaultTextViewHeight
            
            let image = UIImage(named:"close")
            let leftBarButtonItem = UIBarButtonItem(image: image, style: .plain, target: self, action: #selector(self.dismissView))
            navigationItem.leftBarButtonItem = leftBarButtonItem
        }

        textView.textContainerInset = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0);
        textView.inputAccessoryView = quicktypeView
        
        progressView.backgroundColor = Colors.secondaryDark
        textView.textColor = Colors.darkGray
        questionHolderView.backgroundColor = Colors.lightBackground
        questionTitleLabel.textColor = Colors.darkGray
        questionSubtitleLabel.textColor = Colors.darkGray
        view.backgroundColor = Colors.lightBackground
    }
    
    @objc func dismissView() {
        view.endEditing(true)
        
        dismiss(animated: true, completion: nil)
    }
    
    func getWords(string: String) -> [String] {
        let components = string.components(separatedBy: .whitespacesAndNewlines)
        
        return components.filter { !$0.isEmpty }
    }
    
    func clearSuggestions(reload: Bool) {
        suggestions.removeAll()
        
        if reload {
            collectionView.reloadData()
        }
    }
    
    func getAutocompleteSuggestions(userText: String) -> [String] {
         var possibleMatches: [String] = []
        for item in wordList {
            let myString:NSString! = item as NSString
            let substringRange :NSRange! = myString.range(of: userText)
            
            if (substringRange.location == 0) {
                possibleMatches.append(item)
            }
        }
        return possibleMatches.enumerated().flatMap{ $0.offset < 3 ? $0.element : nil }
    }
    
    func validateAnswer() {
        if textView.text == currentWord {
            if questionsAnswered == 4 {
                setPin(mnemonic: mnemonic)
            } else {
                textView.text = ""
                setQuestion(animated: true)
            }
        } else {
            textView.textColor = UIColor.red
            textView.shake()
            
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.8) {
                self.textView.text = ""
                self.textView.textColor = Colors.darkGray
            }
        }
    }
    
    func setQuestion(animated: Bool) {
        if questionWords.count == 0 {
            questionWords = mnemonic.components(separatedBy: " ")
        }
        
        let randomIndex = Int(arc4random_uniform(UInt32(questionWords.count)))
        currentWord = questionWords[randomIndex]
        
        if let indexOfWord = mnemonic.components(separatedBy: " ").index(of: currentWord) {
            questionTitleLabel.text = "What was the word \(String(describing: indexOfWord + 1))?"
            questionWords.remove(at: randomIndex)
            questionsAnswered += 1
            
            setProgress(animated: animated)
        }
    }
    
    func setProgress(animated: Bool) {
        progressViewWidthConstraint.constant += progressWidth
        
        navigationItem.title = "Question \(questionsAnswered) of \(totalQuestionCount)"
        
        if animated {
            UIView.animate(withDuration: 0.3) {
                self.view.layoutIfNeeded()
            }
        }
    }
    
    func setPin(mnemonic: String) {
        let pinViewController = PinViewController(pin: nil, mnemonic: mnemonic)
        
        navigationController?.pushViewController(pinViewController, animated: true)
    }
}

extension VerificationViewController: UITextViewDelegate {
    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        clearSuggestions(reload: false)
        
        let subString = (textView.text! as NSString).replacingCharacters(in: range, with: text)

        if let lastWord = getWords(string: String(subString)).last {
            suggestions.append(contentsOf: getAutocompleteSuggestions(userText: lastWord))
        }
        
        collectionView.reloadData()
        
        return true
    }
}

extension VerificationViewController: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return suggestions.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: WordSuggestionCell.cellIdentifier, for: indexPath) as! WordSuggestionCell
        cell.titleLabel.text = suggestions[indexPath.row]
        return cell
    }
}

extension VerificationViewController: UICollectionViewDelegate {
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let suggestion = suggestions[indexPath.row]
        var words = getWords(string: textView.text)
        if words.count > 0 {
            words.removeLast()
        }
        words.append(suggestion)
        
        textView.text = words.joined(separator: " ")
        
        if type != .questions {
            textView.text.append(" ")
        }
        
        clearSuggestions(reload: true)
    }
}

extension VerificationViewController: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: UIScreen.main.bounds.size.width / 3, height: collectionView.frame.size.height)
    }
}