//
//  UIView+Accessibility.swift
//  VDS
//
//  Created by Matt Bruce on 8/4/23.
//

import Foundation
import UIKit

extension UIView {
    /// AccessibilityLabel helper for joining the accessibilityLabel property of all views passed in.
    /// - Parameters:
    ///   - views: Array of Views that you want to join the accessibilityLabel.
    ///   - separator: Separator used between the accessibilityLabel for each UIView.
    /// - Returns: Joined String.
    public func combineAccessibilityLabel(for views: [AnyObject], separator: String = ", ") -> String? {
        let labels: [String] = views.map({($0.accessibilityLabel?.isEmpty ?? true) ? nil : $0.accessibilityLabel}).compactMap({$0})
        return labels.joined(separator: separator)
    }
    
    /// AccessibilityLabel helper for joining the accessibilityLabel property of all views passed in.
    /// - Parameter views: Array of Views that you want to join the accessibilityLabel.
    public func setAccessibilityLabel(for views: [AnyObject]) {
        accessibilityLabel = combineAccessibilityLabel(for: views)
    }
    
    /// Will tell if the view is actually visibile on screen, also it will check the hierarchy above this view.
    public var isVisibleOnScreen: Bool {
        // Ensure the view has a window, meaning it's part of the view hierarchy
        guard let window = self.window, !self.isHidden, self.alpha > 0 else {
            return false
        }

        // Check if the view's frame intersects with the window's bounds
        let viewFrameInWindow = self.convert(self.bounds, to: window)
        var isIntersecting = viewFrameInWindow.intersects(window.bounds)

        // Check parent views for visibility
        var currentView: UIView? = self
        while let view = currentView, isIntersecting {
            // If any parent has a constraint making it effectively invisible, set isIntersecting to false
            if view.bounds.size.width == 0 || view.bounds.size.height == 0 {
                isIntersecting = false
                break
            }
            currentView = view.superview
        }

        return isIntersecting
    }

    public func gatherAccessibilityElements(from view: AnyObject) -> [AnyObject] {
        var elements: [AnyObject] = []
       
        for subview in view.subviews {
            if subview.isAccessibilityElement && subview.isVisibleOnScreen {
                elements.append(subview)
            } else {
                elements.append(contentsOf: gatherAccessibilityElements(from: subview))
            }
        }
       
        return elements
    }
}