UINavigationBar+Appearance.swift

//
//  CustomNavigationBar.swift
//  MullvadVPN
//
//  Created by pronebird on 22/05/2019.
//  Copyright © 2025 Mullvad VPN AB. All rights reserved.
//

import UIKit

extension UINavigationBar {
    /// Locates the navigation bar prompt label within the view hirarchy and overrides the text color.
    /// - Note: Navigation bar does not provide the appearance configuration for the prompt.
    func overridePromptColor() {
        let promptView = subviews.first { $0.description.contains("Prompt") }
        let promptLabel = promptView?.subviews.first { $0 is UILabel } as? UILabel

        promptLabel?.textColor = UIColor.NavigationBar.promptColor
    }

    func configureCustomAppeareance() {
        var directionalMargins = directionalLayoutMargins
        directionalMargins.leading = UIMetrics.contentLayoutMargins.leading
        directionalMargins.trailing = UIMetrics.contentLayoutMargins.trailing

        directionalLayoutMargins = directionalMargins
        tintColor = UIColor.NavigationBar.titleColor

        standardAppearance = makeNavigationBarAppearance(isTransparent: false)
        scrollEdgeAppearance = makeNavigationBarAppearance(isTransparent: true)
    }

    private func makeNavigationBarAppearance(isTransparent: Bool) -> UINavigationBarAppearance {
        let backIndicatorImage = UIImage.Buttons.back.withTintColor(
            UIColor.NavigationBar.buttonColor,
            renderingMode: .alwaysOriginal
        )
        let backIndicatorTransitionMask = UIImage.backTransitionMask

        let titleTextAttributes: [NSAttributedString.Key: Any] = [
            .foregroundColor: UIColor.NavigationBar.titleColor,
        ]
        let backButtonTitlePositionOffset = UIOffset(horizontal: 4, vertical: 0)
        let backButtonTitleTextAttributes: [NSAttributedString.Key: Any] = [
            .foregroundColor: UIColor.NavigationBar.backButtonTitleColor,
        ]

        let navigationBarAppearance = UINavigationBarAppearance()

        if isTransparent {
            navigationBarAppearance.configureWithTransparentBackground()
        } else {
            navigationBarAppearance.configureWithDefaultBackground()
            navigationBarAppearance.backgroundEffect = UIBlurEffect(style: .dark)
        }

        navigationBarAppearance.titleTextAttributes = titleTextAttributes
        navigationBarAppearance.largeTitleTextAttributes = titleTextAttributes

        let plainBarButtonAppearance = UIBarButtonItemAppearance(style: .plain)
        plainBarButtonAppearance.normal.titleTextAttributes = titleTextAttributes

        let doneBarButtonAppearance = UIBarButtonItemAppearance(style: .done)
        doneBarButtonAppearance.normal.titleTextAttributes = titleTextAttributes

        let backButtonAppearance = UIBarButtonItemAppearance(style: .plain)
        backButtonAppearance.normal.titlePositionAdjustment = backButtonTitlePositionOffset
        backButtonAppearance.normal.titleTextAttributes = backButtonTitleTextAttributes

        navigationBarAppearance.buttonAppearance = plainBarButtonAppearance
        navigationBarAppearance.doneButtonAppearance = doneBarButtonAppearance
        navigationBarAppearance.backButtonAppearance = backButtonAppearance

        navigationBarAppearance.setBackIndicatorImage(
            backIndicatorImage,
            transitionMaskImage: backIndicatorTransitionMask
        )

        return navigationBarAppearance
    }
}