//
//  PaginationCollectionView.swift
//  VDS
//
//  Created by Bandaru, Krishna Kishore on 12/03/24.
//

import UIKit

///PaginationCollectionView is a container view that holds collectionview for displaying page indexes
final class PaginationCollectionView: View {
    
    //--------------------------------------------------
    // MARK: - Internal Properties
    //--------------------------------------------------
    ///Notifies when accessibility increment is happend when user swipes up
    var onAccessibilityIncrement: (() -> Void)?
    ///Notifies when accessibility decrement is happend when user swipes down
    var onAccessibilityDecrement: (() -> Void)?
    ///Collectionview to render pagination indexes
    lazy var collectionView: UICollectionView = {
        let collectionView = UICollectionView(frame: .zero, collectionViewLayout: flowLayout)
        collectionView.isScrollEnabled = false
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        collectionView.showsHorizontalScrollIndicator = false
        collectionView.showsVerticalScrollIndicator = false
        collectionView.isAccessibilityElement = true
        collectionView.register(PaginationCellItem.self, forCellWithReuseIdentifier: PaginationCellItem.identifier)
        collectionView.backgroundColor = .clear
        return collectionView
    }()

    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    ///Custom flow layout defined for the Pagination
    private let flowLayout = PaginationFlowLayout()

    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    ///Accessibilty traits for the Pagination view
    override var accessibilityTraits: UIAccessibilityTraits {
        get { [.adjustable] }
        set { }
    }
    
    ///Accessibilty increment
    override func accessibilityIncrement() {
        onAccessibilityIncrement?()
    }
    
    ///Accessibilty decrement
    override func accessibilityDecrement() {
        onAccessibilityDecrement?()
    }
    
    /// Executed on initialization for this View.
    override func setup() {
        super.setup()
        addSubview(collectionView)
        collectionView.pinToSuperView()
        isAccessibilityElement = true
        accessibilityElements = [collectionView]
    }
}