A SwiftUI modifier to present a tip based on dynamic conditions.

PopoverTipModifier.swift

import SwiftUI
import TipKit

/// Encapsulate tip conditions with specified values.
protocol TipCondition {
    func evaluate() -> (Binding<Bool>, is: Bool)
}

/// Conform `Binding<Bool>` to `TipCondition` with a default value of `true`.
extension Binding: TipCondition where Value == Bool {
    func evaluate() -> (Binding<Bool>, is: Bool) {
        return (self, true)
    }
}

/// Conform tuples `(Binding<Bool>, Bool)` to `TipCondition`.
struct TupleCondition: TipCondition {
    let binding: Binding<Bool>
    let value: Bool

    func evaluate() -> (Binding<Bool>, is: Bool) {
        return (binding, value)
    }
}

/// A modifier to present a tip based on dynamic conditions.
struct PopoverTipModifier<Tip: TipKit.Tip>: ViewModifier {
    var tip: Tip
    var conditions: [TipCondition]

    @ViewBuilder
    func body(content: Content) -> some View {
        let shouldShowTip = conditions.allSatisfy { condition in
            let (binding, expectedValue) = condition.evaluate()
            return binding.wrappedValue == expectedValue
        }

        if shouldShowTip {
            content.popoverTip(tip)
        } else {
            content
        }
    }
}

extension View {
    /// Presents a tip when one or more conditions are met.
    /// - Parameters:
    ///   - tip: The tip to present.
    ///   - conditions: A variadic list of conditions that can be either `Binding<Bool>` or a tuple `(Binding<Bool>, Bool)`.
    /// - Returns: A view with the tip modifier applied.
    /// - Examples:
    ///   1. Use a single condition (defaults to `true`):
    ///      ```swift
    ///      .showPopoverTip(SheetMusicTip(), when: $presentTip)
    ///      ```
    ///   2. Use a single tuple condition:
    ///      ```swift
    ///      .showPopoverTip(SheetMusicTip(), when: ($someValue, is: false))
    ///      ```
    ///   3. Use multiple conditions, including tuples:
    ///      ```swift
    ///      .showPopoverTip(SheetMusicTip(),
    ///                     when: $presentTip,
    ///                           ($someOtherValue, is: false))
    ///      ```
    func showPopoverTip<Tip: TipKit.Tip>(_ tip: Tip, when conditions: Any...) -> some View {
        // Convert the variadic arguments into an array of `TipCondition`.
        let parsedConditions: [TipCondition] = conditions.map { condition in
            if let binding = condition as? Binding<Bool> {
                return binding
            } else if let tuple = condition as? (Binding<Bool>, Bool) {
                return TupleCondition(binding: tuple.0, value: tuple.1)
            } else {
                fatalError("Unsupported condition type.")
            }
        }

        return modifier(PopoverTipModifier(tip: tip, conditions: parsedConditions))
    }
}