import Adw

/// Converts `duration` to the whole seconds `adw_toast_set_timeout` expects.
///
/// A positive duration never rounds down to `0`, because `0` means "never
/// auto-dismiss" in libadwaita and silently turning a brief toast into a
/// permanent one would be worse than rounding up. `.zero` and negative
/// durations map to `0` deliberately.
///
/// - Parameter duration: The requested on-screen time.
/// - Returns: Whole seconds, clamped to at least `1` for any positive duration.
private func toastTimeoutSeconds(_ duration: Duration) -> UInt32 {
    let components = duration.components
    guard components.seconds > 0 || (components.seconds == 0 && components.attoseconds > 0)
    else { return 0 }
    let rounded = components.seconds + (components.attoseconds >= 500_000_000_000_000_000 ? 1 : 0)
    return UInt32(clamping: max(1, rounded))
}

extension Adw.Toast {
    /// Creates a fully configured toast in one expression.
    ///
    /// ```swift
    /// toasts.addToast(Toast(title: "File saved", buttonLabel: "Undo") { undo() })
    /// ```
    ///
    /// `onClick` has no default value, so the inherited `Toast(title:)`
    /// initializer stays reachable and unambiguous for the bare case.
    ///
    /// - Parameters:
    ///   - title: The toast text, interpreted as Pango markup unless `useMarkup`
    ///     is `false`.
    ///   - timeout: How long the toast stays on screen. `nil` keeps libadwaita's
    ///     default. `.zero` (or a negative duration) means the toast never
    ///     dismisses itself. `AdwToast` counts whole seconds, so the value is
    ///     rounded to the nearest second and any positive duration is clamped to
    ///     at least one second rather than collapsing to "never".
    ///   - priority: How the toast behaves when one is already displayed. `nil`
    ///     keeps libadwaita's default.
    ///   - buttonLabel: Label for the toast's action button. `nil` shows no button.
    ///   - useMarkup: Whether `title` is Pango markup. `nil` keeps libadwaita's
    ///     default.
    ///   - onClick: Runs when the action button is clicked. The
    ///     `::button-clicked` handler is owned by the toast and released with it,
    ///     so there is nothing to unregister - but avoid capturing the toast
    ///     itself, which would keep it alive forever.
    public convenience init(
        title: String,
        timeout: Duration? = nil,
        priority: ToastPriority? = nil,
        buttonLabel: String? = nil,
        useMarkup: Bool? = nil,
        _ onClick: @escaping () -> Void
    ) {
        self.init(title: title)
        if let timeout { setTimeout(timeout: toastTimeoutSeconds(timeout)) }
        if let priority { setPriority(priority: priority) }
        if let buttonLabel { setButtonLabel(buttonLabel: buttonLabel) }
        if let useMarkup { setUseMarkup(useMarkup: useMarkup) }
        _ = connectButtonClicked { _ in onClick() }
    }
}