swiftui-utils.swift

import SwiftUI

struct ConditionalContent<TrueContent: View, FalseContent: View>: View {
    let value: Bool
    let trueContent: () -> TrueContent
    let falseContent: () -> FalseContent

    var body: some View {
        if value {
            return AnyView(trueContent())
        } else {
            return AnyView(falseContent())
        }
    }
}

extension View {
    func conditionally<TrueContent: View>(
        _ value: Bool,
        content: @escaping (Self) -> TrueContent
    ) -> ConditionalContent<TrueContent, Self> {
        return ConditionalContent(
            value: value,
            trueContent: { content(self) },
            falseContent: { self }
        )
    }
}

struct HoverView<Content: View>: View {
    let content: (Bool) -> Content

    @State var isHovering: Bool = false

    var body: some View {
        return content(isHovering).onHover { hovering in
            self.isHovering = hovering
        }
    }
}

extension View {
    func hoverContent<TransformedContent>(
        _ content: @escaping (Self) -> TransformedContent
    ) -> HoverView<ConditionalContent<TransformedContent, Self>> {
        return HoverView { isHovering in
            self.conditionally(isHovering, content: content)
        }
    }
}

extension View {
    func cursor(_ cursor: NSCursor) -> some View {
        return self.onHover { isInside in
            if isInside {
                cursor.push()
            } else {
                NSCursor.pop()
            }
        }
    }
}