//
//  WalletTextInputView.swift
//  Malinka
//
//  Created by Nut.Tech on 27.07.2022.
//

import UIKit

protocol WalletTextInputViewDelegate: AnyObject {
    func walletUpdateTextOutput(wallet: WalletTextInputView, text: String?)
}

final class WalletTextInputView: UIStackView {
    
    private enum Constants {
        static let spacing: CGFloat = 4
        static let textCellCornerRadius: CGFloat = 3
        static let borderWidth: CGFloat = 1
        static let size: CGFloat = 20
        static let fontSize: CGFloat = 16
    }
    
    // MARK: - Properties
    
    private let length: Int
    private weak var delegate: WalletTextInputViewDelegate?
    private var lettersContainers: [UITextField]
    
    // MARK: - Init
    
    init(length: Int, delegate: WalletTextInputViewDelegate) {
        self.length = length
        self.lettersContainers = []
        super.init(frame: .zero)
        self.axis = .horizontal
        self.spacing = Constants.spacing
        self.alignment = .leading
        self.distribution = .fillEqually
        for i in 0..<length {
            let textfield = self.createTextCell()
            textfield.delegate = self
            textfield.tag = i
            self.lettersContainers.append(textfield)
            self.addArrangedSubview(textfield)
        }
        self.delegate = delegate
    }
    
    required init(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - Methods
    
    func hideKeyboard() {
        self.lettersContainers.forEach { 
            $0.resignFirstResponder()
        }
    }
    
    // MARK: - Private
    
    private func createTextCell() -> UITextField {
        let textField = UITextField()
        textField.layer.cornerRadius = Constants.textCellCornerRadius
        textField.clipsToBounds = true
        textField.layer.borderColor = Asset.deepWater.color.cgColor
        textField.layer.borderWidth = Constants.borderWidth
        textField.font = FontFamily.GolosUI.bold.font(size: Constants.fontSize)
        textField.textColor = Asset.dark.color
        textField.textAlignment = .center
        NSLayoutConstraint.activate([
            textField.heightAnchor.constraint(equalToConstant: Constants.size),
            textField.widthAnchor.constraint(equalToConstant: Constants.size)
        ])
        return textField
    }
    
    private func checkIfAllSymbolsEntered() {
        let string = self.lettersContainers
            .compactMap { $0.text }
            .reduce("", +)
        self.delegate?.walletUpdateTextOutput(wallet: self, text: string.count == self.length ? string : nil)
    }
}

// MARK: - UITextFieldDelegate

extension WalletTextInputView: UITextFieldDelegate {
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        
        guard string.matched(.accountName) || string.isEmpty else { return false }
        let newString = (textField.text ?? "").replacingCharacters(in: range, with: string).lowercased()
        if newString.count > 1 {
            let cutted = newString.dropLast()
            textField.text = String(cutted)
            if let field = self.lettersContainers[safe: textField.tag + 1] {
                field.text = string
                field.becomeFirstResponder()
            }
            return false
        }
        
        if string.isEmpty {
            textField.text = string
            if let field = self.lettersContainers[safe: textField.tag - 1] {
                field.becomeFirstResponder()
            }
            return false
        }
        
        return true
    }
    
    func textFieldDidEndEditing(_ textField: UITextField) {
        self.checkIfAllSymbolsEntered()
    }
}