//
//  SettingSliderTableViewCell.swift
//  Earthquake Network
//
//  Created by Busi Andrea on 25/08/2020.
//  Copyright © 2020 Earthquake Network. All rights reserved.
//

import UIKit

class SettingSliderTableViewCell: UITableViewCell {

    @objc static let Identifier = "SliderCell"
    
    @objc var isDisabled: Bool = false {
        didSet {
            updateUI()
        }
    }
    @objc var valueChanged: ((EQNGenericValue) -> Void)?
    @objc var dragEnded: (() -> Void)?
    private var items = [EQNGenericValue]()
    
    
    // MARK: - Properties
    
    @objc lazy var titleLabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        label.font = UIFont.preferredFont(forTextStyle: .body)
        label.textColor = AppTheme.shared.textColor
        return label
    }()
    
    @objc lazy var valueLabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        label.font = UIFont.preferredFont(forTextStyle: .subheadline)
        label.textColor = AppTheme.shared.valueColor
        return label
    }()
    
    @objc lazy var slider: UISlider = {
        let slider = UISlider()
        slider.isContinuous = true
        slider.addTarget(self, action: #selector(sliderChanged(_:)), for: .valueChanged)
        slider.addTarget(self, action: #selector(sliderEnded(_:)), for: .touchUpInside)
        return slider
    }()
    
    // MARK: - Init
    
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setupUI()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setupUI()
    }

    // MARK: - Private
    
    private func setupUI() {
        selectionStyle = .none

        let stackView = UIStackView()
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.axis = .vertical
        stackView.distribution = .equalSpacing
        stackView.spacing = 8
        
        stackView.addArrangedSubview(titleLabel)
        stackView.addArrangedSubview(valueLabel)
        stackView.addArrangedSubview(slider)
        
        contentView.addSubview(stackView)
        
        stackView.topAnchor.constraint(equalTo: contentView.layoutMarginsGuide.topAnchor).isActive = true
        stackView.trailingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.trailingAnchor).isActive = true
        stackView.leadingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.leadingAnchor).isActive = true
        stackView.bottomAnchor.constraint(equalTo: contentView.layoutMarginsGuide.bottomAnchor).isActive = true
    }
        
    private func updateUI() {
        let theme = AppTheme.shared
        titleLabel.textColor = isDisabled ? theme.textDisabledColor : theme.textColor
        valueLabel.textColor = isDisabled ? theme.textDisabledColor : theme.valueColor
        slider.isEnabled = !isDisabled
    }
    
    // MARK: - Actions
    
    @objc private func sliderChanged(_ sender: UISlider) {
        let index = Int(sender.value)
        let item = items[index]
        
        // make slider with step values
        let step: Float = 1
        let roundedValue = round(sender.value / step) * step
        sender.value = roundedValue
        
        // update value
        valueLabel.text = item.display
        valueChanged?(item)
    }
    
    @objc private func sliderEnded(_ sender: UISlider) {
        dragEnded?()
    }
    
    // MARK: - Public
    
    @objc func configureSlider(with items: [EQNGenericValue], current: EQNGenericValue) {
        self.items = items
        
        slider.minimumValue = 0
        slider.maximumValue = Float(items.count - 1)
        if let index = items.firstIndex(of: current) {
            slider.value = Float(index)
            valueLabel.text = current.display
        } else {
            slider.value = 0
            valueLabel.text = ""
        }
    }
}