//
//  TileletGroup.swift
//  VDS
//
//  Created by Matt Bruce on 10/8/24.
//

import Foundation
import UIKit
import VDSCoreTokens
import Combine

open class TileletGroup: View {   
    
    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    required public init() {
        super.init(frame: .zero)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: .zero)
    }
    
    public required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
        
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    /// An object containing number of Button components per row for iPhones
    open var rowQuantityPhone: Int = 0 { didSet { setNeedsUpdate() } }
    
    /// An object containing number of Button components per row for iPads
    open var rowQuantityTablet: Int = 0 { didSet { setNeedsUpdate() } }
    
    /// An object containing number of Button components per row
    open var rowQuantity: Int { UIDevice.isIPad ? rowQuantityTablet : rowQuantityPhone }
    
    /// Array of Buttonable Views that are shown in the group.
    open var tilelets: [Tilelet] = [] { didSet { setNeedsUpdate() } }
        
    /// Whether this object is enabled or not
    override open var isEnabled: Bool {
        didSet {
            tilelets.forEach { $0.isEnabled = isEnabled }
        }
    }
    
    /// Current Surface and this is used to pass down to child objects that implement Surfacable
    override open var surface: Surface {
        didSet {
            tilelets.forEach { $0.surface = surface }
        }
    }
    
    open var contentSizePublisher: AnyPublisher<CGSize, Never> { collectionView.contentSizePublisher }
        
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    
    fileprivate lazy var positionLayout = TileletGroupPositionLayout().with {
        $0.delegate = self
    }
    
    /// CollectionView that renders the array of buttonBase obects.
    fileprivate lazy var collectionView: SelfSizingCollectionView = {
        
        return SelfSizingCollectionView(frame: .zero, collectionViewLayout: positionLayout).with {
            $0.backgroundColor = .clear
            $0.showsHorizontalScrollIndicator = false
            $0.showsVerticalScrollIndicator = false
            $0.isScrollEnabled = false
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.dataSource = self
            $0.delegate = self
            $0.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "collectionViewCell")
        }
    }()
    
    //--------------------------------------------------
    // MARK: - Public Methods
    //--------------------------------------------------
    /// Called once when a view is initialized and is used to Setup additional UI or other constants and configurations.
    open override func setup() {
        super.setup()
        addSubview(collectionView)
        collectionView.pinToSuperView()
    }
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    /// Used to make changes to the View based off a change events or from local properties.
    open override func updateView() {
        super.updateView()
        positionLayout.rowQuantity = rowQuantity
        
        var width: CGFloat?
        tilelets.forEach { tilelet in
            if let width {
                tilelet.width = width
            }
        }
        collectionView.reloadData()
    }
    
    open override func setDefaults() {
        super.setDefaults()
        rowQuantityPhone = 0
        rowQuantityTablet = 0
        tilelets = []
    }
    
    open override func reset() {
        tilelets.forEach { $0.reset() }
        super.reset()
    }

    open override func layoutSubviews() {
        super.layoutSubviews()
        // Accounts for any collection size changes
        DispatchQueue.main.async { [weak self] in
            guard let self else { return }
            self.collectionView.collectionViewLayout.invalidateLayout()
        }
    }
}

extension TileletGroup: UICollectionViewDataSource, UICollectionViewDelegate {
    public func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
    public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return tilelets.count
    }
    
    open func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let tilelet = tilelets[indexPath.row]
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionViewCell", for: indexPath)
        cell.contentView.subviews.forEach { $0.removeFromSuperview() }
        cell.contentView.addSubview(tilelet)
        tilelet.pinToSuperView()
        if hasDebugBorder {
            cell.addDebugBorder()
        } else {
            cell.removeDebugBorder()
        }
        return cell
    }
    
    public func collectionView(_ collectionView: UICollectionView, sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
        tilelets[indexPath.row].intrinsicContentSize
    }
}

extension TileletGroup : TileletGroupPositionLayoutDelegate {
    func collectionView(_ collectionView: UICollectionView, tileletAtIndexPath indexPath: IndexPath) -> Tilelet {
        tilelets[indexPath.row]
    }
}