vds_ios/VDS/Components/InputStepper/InputStepper.swift

//
//  InputStepper.swift
//  VDS
//
//  Created by Kanamarlapudi, Vasavi on 24/06/24.
//

import Foundation
import UIKit
import VDSCoreTokens
import Combine

/// A stepper is a two-segment control that people use to increase or decrease an incremental value.
@objc(VDSInputStepper)
open class InputStepper: EntryFieldBase {
    
    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    required public init() {
        super.init(frame: .zero)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: .zero)
    }
    
    public required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    //--------------------------------------------------
    // MARK: - Enums
    //--------------------------------------------------
    /// Enum used to describe the size of Input Stepper.
    public enum Size: String, CaseIterable {
        case large, small
    }
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    open var controlWidth: String? {
        get {  _controlWidth }
        set {
            setControlWidth(newValue)
            setNeedsUpdate()
        }
    }

    /// Default value of the input stepper, defaults to '0'.
    open var defaultValue:Int = 0 { didSet { setNeedsUpdate() } }
    
    /// Maximum value of the input stepper, defaults to '99'.
    open var maxValue:  Int? {
        get { return _maxValue }
        set {
            if let newValue, newValue <= 99 && newValue > 0 {
                _maxValue = newValue
            } else {
                _maxValue = 99
            }
            setNeedsUpdate()
        }
    }
    
    /// Minimum value of the input stepper, defaults to '0'.
    open var minValue: Int? {
        get { return _minValue }
        set {
            if let newValue, newValue >= 0 && newValue < 99 {
                _minValue = newValue
            } else {
                _minValue = 0
            }
            setNeedsUpdate()
        }
    }
        
    /// The size of the input stepper. Defaults to 'large'.
    open var size: Size {
        get { return _size }
        set {
            _size = newValue
            updateSize()
        }
    }
    
    /// Accepts any text or character to appear next to input stepper value.
    open var trailingText: String? { didSet { setNeedsUpdate() } }

    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    internal var _controlWidth = "auto"
    internal var _maxValue: Int = 99
    internal var _minValue: Int = 0
    internal var _size: Size = .large
    
    private var largeMinWidth = 121
    private var smallMinWidth = 90
    
    let decrementButton = ButtonIcon().with {
        $0.kind = .ghost
        $0.iconName =  Icon.Name(name: "minus")
        $0.iconOffset = .init(x: -2, y: 0)
        $0.customContainerSize = 32
        $0.icon.customSize = 16
        $0.backgroundColor = .clear
    }
    
    let incrementButton = ButtonIcon().with {
        $0.kind = .ghost
        $0.iconName = Icon.Name(name: "plus")
        $0.iconOffset = .init(x: 2, y: 0)
        $0.customContainerSize = 32
        $0.icon.customSize = 16
        $0.backgroundColor = .clear
    }
    
    let textLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .boldBodyLarge
        $0.backgroundColor = .clear
    }
        
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
    open override func initialSetup() {
        super.initialSetup()
    }
    
    open override func setup() {
        super.setup()
        isAccessibilityElement = false
        accessibilityLabel = "Input Stepper"
        containerView.isEnabled = false
        
        decrementButton.onClick =  { _ in  self.decrementButtonClick() }
        incrementButton.onClick =  { _ in  self.incrementButtonClick() }
    }
    
    open override func getFieldContainer() -> UIView {
        // stackview for controls in EntryFieldBase.controlContainerView
        let controlStackView = UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.axis = .horizontal
            $0.spacing = VDSLayout.space3X
            $0.backgroundColor = .clear
        }
        
        controlStackView.addArrangedSubview(decrementButton)
        controlStackView.addArrangedSubview(textLabel)
        controlStackView.addArrangedSubview(incrementButton)
        return controlStackView
    }
    
    open override func updateView() {
        super.updateView()
        updateContainerView(flag: false)
        textLabel.text = String(defaultValue) + " " + (trailingText ?? "")
        decrementButton.surface = surface
        incrementButton.surface = surface
        textLabel.surface = surface
        updateButtonStates()
        statusIcon.isHidden = true
    }
    
    /// Resets to default settings.
    open override func reset() {
        super.reset()
        textLabel.reset()
        textLabel.textStyle = .boldBodyLarge
        textLabel.text = ""
        controlWidth = nil
        minValue = nil
        maxValue = nil
        trailingText = nil
        helperTextPlacement = .bottom
    }
    
    //--------------------------------------------------
    // MARK: - Private Methods
    //--------------------------------------------------
    
    internal func decrementButtonClick() {
        defaultValue = defaultValue - 1
        updateButtonStates()
    }
    
    internal func incrementButtonClick() {
        defaultValue = defaultValue + 1
        updateButtonStates()
    }
    
    internal func updateButtonStates() {
        if isReadOnly || !isEnabled {
            decrementButton.isEnabled = false
            incrementButton.isEnabled = false
        } else {
            decrementButton.isEnabled = defaultValue > _minValue ? true : false
            incrementButton.isEnabled = defaultValue < _maxValue ? true : false
        }
    }
    
    internal func updateSize() {
        let value = size == .large ? 6.0 : VDSLayout.space1X
        updateConstraintsToFieldStackView(value: value)
        
//        textLabel.textStyle = size == .large ? .boldBodyLarge : .boldBodySmall
//        textLabel.heightAnchor.constraint(equalToConstant: size == .large ? 44 : 32).activate()

//        decrementButton.customContainerSize = size == .large ? 32 : 24
//        incrementButton.customContainerSize = size == .large ? 32 : 24

    }
    
    internal func setControlWidth(_ text: String?) {
        if let text, text == "auto" {
            // Set fixed width relative to default value, trailing text label
        } else if let controlWidth = Int(text ?? "") {
            // Use provided new width either pixel or percentage
            width = CGFloat(controlWidth)
        } else {
            // Use EntryFieldBase width
        }
    }

}