vds_ios/VDS/Components/Buttons/Button/ButtonBase.swift

//
//  BaseButton.swift
//  VDS
//
//  Created by Matt Bruce on 11/22/22.
//

import Foundation
import UIKit
import VDSColorTokens
import VDSFormControlsTokens
import Combine

public protocol Buttonable: UIControl, Surfaceable, Disabling {
    var availableSizes: [ButtonSize] { get }
    var text: String? { get set }
    var intrinsicContentSize: CGSize { get }
}

@objc(VDSButtonBase)
open class ButtonBase: UIButton, Buttonable, Handlerable, ViewProtocol, Resettable {
    //--------------------------------------------------
    // MARK: - Configuration Properties
    //--------------------------------------------------
    private let hitAreaHeight = 44.0

    //--------------------------------------------------
    // MARK: - Combine Properties
    //--------------------------------------------------
    public var subject = PassthroughSubject<Void, Never>()
    public var subscribers = Set<AnyCancellable>()

    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var initialSetupPerformed = false

    //--------------------------------------------------
    // MARK: - Properties
    //--------------------------------------------------
    open var availableSizes: [ButtonSize] { [] }

    open var text: String? { didSet { didChange() } }
    
    open var attributes: [any LabelAttributeModel]? { nil }

    open var surface: Surface = .light { didSet { didChange() }}
    
    open var disabled: Bool = false { didSet { isEnabled = !disabled } }
    
    var isHighlightAnimating = false
    open override var isHighlighted: Bool {
        didSet {
            if isHighlightAnimating == false {
                isHighlightAnimating = true
                UIView.animate(withDuration: 0.1, animations: { [weak self] in
                    self?.updateView()
                }) { [weak self] _ in
                    //you update the view since this is typically a quick change
                    UIView.animate(withDuration: 0.1, animations: { [weak self] in
                        self?.updateView()
                        self?.isHighlightAnimating = false
                    })
                }
            }
        }
    }
  
    open var textStyle: TextStyle { .defaultStyle }
    
    open var textColor: UIColor { .black }

    open override var isEnabled: Bool {
        get { !disabled }
        set {
            if disabled != !newValue {
                disabled = !newValue
            }
            isUserInteractionEnabled = isEnabled
            didChange()
        }
    }

    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    required public init() {
        super.init(frame: .zero)
        initialSetup()
    }
    
    public override init(frame: CGRect) {
        super.init(frame: .zero)
        initialSetup()
    }
    
    public required init?(coder: NSCoder) {
        super.init(coder: coder)
        initialSetup()
    }
    
    //--------------------------------------------------
    // MARK: - Public Functions
    //--------------------------------------------------
    open func initialSetup() {
        if !initialSetupPerformed {
            backgroundColor = .clear
            translatesAutoresizingMaskIntoConstraints = false
            accessibilityCustomActions = []
            accessibilityTraits = .staticText
            setup()
            setupDidChangeEvent()
            updateView()
        }
    }
    
    open func setup() {
        
        translatesAutoresizingMaskIntoConstraints = false
        
        titleLabel?.adjustsFontSizeToFitWidth = false
        titleLabel?.lineBreakMode = .byTruncatingTail

    }

    open func reset() {
        surface = .light
        disabled = false
        text = nil
        accessibilityCustomActions = []
        accessibilityTraits = .button
    }
        
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    override open var intrinsicContentSize: CGSize {
        let intrinsicContentSize = super.intrinsicContentSize
        let adjustedWidth = intrinsicContentSize.width + titleEdgeInsets.left + titleEdgeInsets.right
        let adjustedHeight = intrinsicContentSize.height + titleEdgeInsets.top + titleEdgeInsets.bottom
        return CGSize(width: adjustedWidth, height: adjustedHeight)
    }
    
    open func updateView() {
        updateLabel()
    }

    //--------------------------------------------------
    // MARK: - PRIVATE
    //--------------------------------------------------
    private func updateLabel() {
        let font = textStyle.font
        
        //clear the arrays holding actions
        accessibilityCustomActions = []
        
        //create the primary string
        let startingAttributes = [NSAttributedString.Key.font: font, NSAttributedString.Key.foregroundColor: textColor]
        let mutableText = NSMutableAttributedString(string: text ?? "No Text", attributes: startingAttributes)
        
        //set the local lineHeight/lineSpacing attributes
        //get the range
        let entireRange = NSRange(location: 0, length: mutableText.length)
        
        //set letterSpacing
        if textStyle.letterSpacing > 0.0 {
            mutableText.addAttribute(.kern, value: textStyle.letterSpacing, range: entireRange)
        }
        
        let paragraph = NSMutableParagraphStyle().with {
            $0.alignment = titleLabel?.textAlignment ?? .center
            $0.lineBreakMode = titleLabel?.lineBreakMode ?? .byTruncatingTail
        }

        //set lineHeight
        if textStyle.lineHeight > 0.0 {
            let lineHeight = textStyle.lineHeight
            let adjustment = lineHeight > font.lineHeight ? 2.0 : 1.0
            let baselineOffset = (lineHeight - font.lineHeight) / 2.0 / adjustment
            paragraph.maximumLineHeight = lineHeight
            paragraph.minimumLineHeight = lineHeight
            mutableText.addAttribute(.baselineOffset, value: baselineOffset, range: entireRange)
            mutableText.addAttribute( .paragraphStyle, value: paragraph, range: entireRange)

        } else {
            mutableText.addAttribute( .paragraphStyle, value: paragraph, range: entireRange)
        }
        
        if let attributes = attributes {
            //loop through the models attributes
            for attribute in attributes {
                //add attribute on the string
                attribute.setAttribute(on: mutableText)
            }
        }
        
        //set the attributed text
        setAttributedTitle(mutableText, for: .normal)
        setAttributedTitle(mutableText, for: .highlighted)
    }
    
    open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        let size = intrinsicContentSize
        // Create a minimumHitArea variable with a value that represents the minimum size of the hit area you want to create for the button.
        let minimumHitArea = CGSize(width: size.width, height: hitAreaHeight)
        
        // Create a new hitFrame variable that is the same size as the minimumHitArea variable, but is centered on the button's frame.
        let hitFrame = CGRect(
            x: self.bounds.midX - minimumHitArea.width / 2,
            y: self.bounds.midY - minimumHitArea.height / 2,
            width: minimumHitArea.width,
            height: minimumHitArea.height
        )
        
        // If the point that was passed to the hitTest(_:with:) method is within the hitFrame, return the button itself. This will cause the button to handle the touch event.
        if hitFrame.contains(point) {
            return self
        }
        
        // If the point is not within the hitFrame, return nil. This will cause the touch event to be handled by another view.
        return nil
    }

}