vds_ios/VDS/Components/Buttons/ButtonBase.swift

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

import Foundation
import UIKit
import VDSColorTokens
import VDSFormControlsTokens
import Combine

/// Base class used for UIButton type classes.
@objc(VDSButtonBase)
open class ButtonBase: UIButton, ViewProtocol, UserInfoable, Clickable {
    
    //--------------------------------------------------
    // 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: - Combine Properties
    //--------------------------------------------------
    /// Set of Subscribers for any Publishers for this Control.
    open var subscribers = Set<AnyCancellable>()
    
    open var onClickSubscriber: AnyCancellable? {
        willSet {
            if let onClickSubscriber {
                onClickSubscriber.cancel()
            }
        }
    }

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

    //--------------------------------------------------
    // MARK: - Properties
    //--------------------------------------------------
    /// Key of whether or not updateView() is called in setNeedsUpdate()
    open var shouldUpdateView: Bool = true 
    
    open var surface: Surface = .light { didSet { setNeedsUpdate() } }

    /// Text that will be used in the titleLabel.
    open var text: String? { didSet { setNeedsUpdate() } }
    
    /// Array of LabelAttributeModel objects used in rendering the text. 
    open var textAttributes: [any LabelAttributeModel]? { nil }
    
    /// TextStyle used on the titleLabel.
    open var textStyle: TextStyle { .defaultStyle }
    
    /// UIColor used on the titleLabel text.
    open var textColor: UIColor { .black }

    /// Will determine if a scaled font should be used for the titleLabel font.
    open var useScaledFont: Bool = false { didSet { setNeedsUpdate() } }
        
    open var userInfo = [String: Primitive]()
    
    /// State of animating isHighlight.
    public var isHighlighting = false
    
    /// Whether the Button should handle the isHighlighted state.
    open var shouldHighlight: Bool { isHighlighting == false }
    
    /// Whether the Control is highlighted or not.
    open override var isHighlighted: Bool {
        didSet {
            if shouldHighlight {
                isHighlighting = true
                setNeedsUpdate()
                isHighlighting = false
            }
        }
    }
    
    /// Whether the Control is enabled or not.
    open override var isEnabled: Bool { didSet { setNeedsUpdate() } }
    
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
    open func initialSetup() {
        if !initialSetupPerformed {
            initialSetupPerformed = true 
            backgroundColor = .clear
            translatesAutoresizingMaskIntoConstraints = false
            accessibilityCustomActions = []
            setup()
            setNeedsUpdate()
        }
    }
    
    
    open func setup() {
        translatesAutoresizingMaskIntoConstraints = false
        
        titleLabel?.adjustsFontSizeToFitWidth = false
        titleLabel?.lineBreakMode = .byTruncatingTail
        titleLabel?.numberOfLines = 1
    }
    
    open func updateView() {
        restyleText()
    }
    
    open func updateAccessibility() {
        if isEnabled {
            accessibilityTraits.remove(.notEnabled)
        } else {
            accessibilityTraits.insert(.notEnabled)
        }
    }

    open func reset() {
        shouldUpdateView = false
        surface = .light
        isEnabled = true 
        text = nil
        accessibilityCustomActions = []
        shouldUpdateView = true
        setNeedsUpdate()
    }
        
    //--------------------------------------------------
    // 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)
    }
    
    private enum TextSetMode {
        case text
        case attributedText
    }

    private var textSetMode: TextSetMode = .text

    /// :nodoc:
    override public func setTitle(_ title: String?, for state: UIControl.State) {
        // When text is set, we may need to re-style it as attributedText
        // with the correct paragraph style to achieve the desired line height.
        textSetMode = .text
        styleText(title, for: state)
    }

    /// :nodoc:
    override public func setAttributedTitle(_ title: NSAttributedString?, for state: UIControl.State) {
        // When text is set, we may need to re-style it as attributedText
        // with the correct paragraph style to achieve the desired line height.
        textSetMode = .attributedText
        styleAttributedText(title, for: state)
    }
    
    /// Gets or sets the text alignment of the button's title label.
    /// Default value = `.natural`
    public var textAlignment: NSTextAlignment = .natural {
        didSet {
            if textAlignment != oldValue {
                // Text alignment can be part of our paragraph style, so we may need to
                // re-style when changed
                restyleText()
            }
        }
    }

    /// Gets or sets the line break mode of the button's title label.
    /// Default value = `.byTruncatingTail`
    public var lineBreakMode: NSLineBreakMode = .byTruncatingTail {
        didSet {
            if lineBreakMode != oldValue {
                // Line break mode can be part of our paragraph style, so we may need to
                // re-style when changed
                restyleText()
            }
        }
    }

    //--------------------------------------------------
    // MARK: - Private Methods
    //--------------------------------------------------

    private func restyleText() {
        if textSetMode == .text {
            styleText(text, for: state)
        } else {
            styleAttributedText(currentAttributedTitle, for: state)
        }
    }

    private func styleText(_ newValue: String!, for state: UIControl.State) {
        defer { invalidateIntrinsicContentSize() }
        guard let newValue else {
            // We don't need to use attributed text
            super.setAttributedTitle(nil, for: state)
            super.setTitle(newValue, for: state)
            return
        }

        accessibilityCustomActions = []

        //create the primary string
        let mutableText = NSMutableAttributedString.mutableText(for: newValue,
                                                                textStyle: textStyle,
                                                                useScaledFont: useScaledFont,
                                                                textColor: textColor,
                                                                alignment: titleLabel?.textAlignment ?? .center,
                                                                lineBreakMode: titleLabel?.lineBreakMode ?? .byTruncatingTail)

        //apply any attributes
        if let attributes = textAttributes {
            mutableText.apply(attributes: attributes)
        }

        // Set attributed text to match typography
        super.setAttributedTitle(mutableText, for: state)

    }

    private func styleAttributedText(_ newValue: NSAttributedString?, for state: UIControl.State) {
        defer { invalidateIntrinsicContentSize() }
        guard let newValue = newValue else {
            // We don't need any additional styling
            super.setAttributedTitle(newValue, for: state)
            return
        }
        
        //clear the arrays holding actions
        accessibilityCustomActions = []

        let mutableText = NSMutableAttributedString(attributedString: newValue)

        //apply any attributes
        if let attributes = textAttributes {
            mutableText.apply(attributes: attributes)
        }

        // Modify attributed text to match typography
        super.setAttributedTitle(mutableText, for: state)
    }

    
}

// MARK: AppleGuidelinesTouchable
extension ButtonBase: AppleGuidelinesTouchable {
    /// Overrides to ensure that the touch point meets a minimum of the minimumTappableArea.
    override open func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        Self.acceptablyOutsideBounds(point: point, bounds: bounds)
    }

}