LeadKit/TIUIElements/Sources/Views/StatefulButton/StatefulButton+Appearance.swift

//
//  Copyright (c) 2023 Touch Instinct
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import TIUIKitCore
import UIKit

extension StatefulButton {
    public typealias StateAppearance = UIButton.BaseAppearance<UIView.NoLayout, DefaultContentLayout>
    public typealias StateAppearances = [StateKey: StateAppearance]

    open class BaseAppearance<Layout: ViewLayout, ContentLayout: BaseContentLayout & ViewLayout>:
        UIView.BaseAppearance<Layout> {

        public static var defaultStateAppearances: StateAppearances {
            [
                .normal: UIButton.DefaultStateAppearance.defaultAppearance,
                .highlighted: UIButton.DefaultStateAppearance.defaultAppearance,
                .selected: UIButton.DefaultStateAppearance.defaultAppearance,
                .disabled: UIButton.DefaultStateAppearance.defaultAppearance,
                .loading: UIButton.DefaultStateAppearance.defaultAppearance
            ]
        }

        public var stateAppearances: StateAppearances

        public init(layout: Layout = .defaultLayout,
                    background: UIViewBackground = UIViewColorBackground(color: .clear),
                    border: UIViewBorder = BaseUIViewBorder(),
                    shadow: UIViewShadow? = nil,
                    stateAppearances: StateAppearances = defaultStateAppearances) {

            self.stateAppearances = stateAppearances

            super.init(layout: layout,
                       background: background,
                       border: border,
                       shadow: shadow)
        }

        public func set(appearanceBuilder: (StateAppearance) -> Void, for states: [State]) {
            for state in states {
                stateAppearances[.init(controlState: state)] = DefaultStateAppearance.make(builder: appearanceBuilder)
            }
        }
    }

    open class BasePositionAppearance<Layout: ViewLayout, ContentLayout: BaseContentLayout & ViewLayout>:
        BaseAppearance<Layout, ContentLayout> {

        public var activityIndicatorPosition: ActivityIndicatorPosition

        public init(layout: Layout = .defaultLayout,
                    background: UIViewBackground = UIViewColorBackground(color: .clear),
                    border: UIViewBorder = BaseUIViewBorder(),
                    shadow: UIViewShadow? = nil,
                    stateAppearances: StateAppearances = defaultStateAppearances,
                    activityIndicatorPosition: ActivityIndicatorPosition = .center) {

            self.activityIndicatorPosition = activityIndicatorPosition

            super.init(layout: layout,
                       background: background,
                       border: border,
                       shadow: shadow,
                       stateAppearances: stateAppearances)
        }
    }

    public final class DefaultPositionAppearance: BasePositionAppearance<DefaultWrappedLayout, DefaultContentLayout>,
                                                  WrappedViewAppearance {
        public static var defaultAppearance: Self {
            Self()
        }
    }

    @available(iOS 15.0, *)
    open class BasePlacementAppearance<Layout: ViewLayout, ContentLayout: BaseContentLayout & ViewLayout>:
        BaseAppearance<Layout, ContentLayout> {

        public var activityIndicatorPlacement: ActivityIndicatorPlacement

        public init(layout: Layout = .defaultLayout,
                    background: UIViewBackground = UIViewColorBackground(color: .clear),
                    border: UIViewBorder = BaseUIViewBorder(),
                    shadow: UIViewShadow? = nil,
                    stateAppearances: StateAppearances = defaultStateAppearances,
                    activityIndicatorPlacement: ActivityIndicatorPlacement = .center) {

            self.activityIndicatorPlacement = activityIndicatorPlacement

            super.init(layout: layout,
                       background: background,
                       border: border,
                       shadow: shadow,
                       stateAppearances: stateAppearances)
        }
    }

    @available(iOS 15.0, *)
    public final class DefaultPlacementAppearance: BasePlacementAppearance<DefaultWrappedLayout, DefaultContentLayout>,
                                                   WrappedViewAppearance {
        public static var defaultAppearance: Self {
            Self()
        }
    }
}

extension StatefulButton {
    public func configureBaseStatefulButton(appearance: BaseAppearance<some ViewLayout, some BaseContentLayout>) {
        onStateChanged = { [weak self] in
            if let stateAppearance = appearance.stateAppearances[.init(controlState: $0)] {
                self?.configureUIButton(appearance: stateAppearance, for: $0)
            } else if $0 != .normal, let stateAppearance = appearance.stateAppearances[.normal] {
                self?.configureUIButton(appearance: stateAppearance, for: .normal)
            }
        }

        onStateChanged?(state)
    }

    public func configureStatefulButton(appearance: BasePositionAppearance<some ViewLayout, some BaseContentLayout>) {
        configureBaseStatefulButton(appearance: appearance)

        let baseOnStateChanged = onStateChanged

        onStateChanged = { [weak self] in
            baseOnStateChanged?($0)

            self?.configureStatefulButtonActivityIndicator(appearance: appearance)
        }

        onStateChanged?(state)
    }

    private func configureStatefulButtonActivityIndicator(appearance: BasePositionAppearance<some ViewLayout,
                                                          some BaseContentLayout>) {
        switch appearance.activityIndicatorPosition {
        case .beforeTitle:
            activityIndicatorShouldCenterInView = false

            let transparentImage = UIGraphicsImageRenderer(size: activityIndicatorSize)
                .image { _ in }

            super.setImage(transparentImage, for: .loading)

        case .center:
            activityIndicatorShouldCenterInView = true

            super.setImage(.init(), for: .loading)
        }

        if #available(iOS 15.0, *) {
            var config = configuration ?? .plain()

            if case let .beforeTitle(padding) = appearance.activityIndicatorPosition {
                config.imagePlacement = .leading
                config.imagePadding = padding
            }

            configuration = config
        } else {
            if case let .beforeTitle(padding) = appearance.activityIndicatorPosition {
                imageEdgeInsets.right += padding
            }
        }
    }

    @available(iOS 15.0, *)
    public func configureStatefulButton(appearance: BasePlacementAppearance<some ViewLayout, some BaseContentLayout>) {
        configureBaseStatefulButton(appearance: appearance)

        let baseOnStateChanged = onStateChanged

        onStateChanged = { [weak self] in
            baseOnStateChanged?($0)

            self?.configureActivityIndicator(appearance: appearance)
        }

        onStateChanged?(state)
    }

    @available(iOS 15.0, *)
    private func configureActivityIndicator(appearance: BasePlacementAppearance<some ViewLayout, some BaseContentLayout>) {
        var config = configuration ?? .plain()

        switch appearance.activityIndicatorPlacement {
        case let .placement(imagePlacement, padding):
            activityIndicatorShouldCenterInView = false

            let transparentImage = UIGraphicsImageRenderer(size: activityIndicatorSize)
                .image { _ in }

            super.setImage(transparentImage, for: .loading)

            config.imagePlacement = imagePlacement
            config.imagePadding = padding

        case .center:
            activityIndicatorShouldCenterInView = true

            super.setImage(.init(), for: .loading)
        }

        configuration = config
    }
}