//
//  HomeViewController.swift
//  Test
//
//  Created by yunhao on 2022/12/3.
//

import UIKit

// MARK: - Home View Controller

class HomeViewController: UICollectionViewController {
    
    init() {
        let configuration = UICollectionLayoutListConfiguration(appearance: .insetGrouped)
        let collectionViewLayout = UICollectionViewCompositionalLayout.list(using: configuration)
        super.init(collectionViewLayout: collectionViewLayout)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        collectionView.register(TextLabelCell.self, forCellWithReuseIdentifier: "\(TextLabelCell.self)")
        collectionView.register(ConfigurationTextLabelCell.self, forCellWithReuseIdentifier: "\(ConfigurationTextLabelCell.self)")
    }
    
    override func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 2
    }
    
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 1
    }
    
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if indexPath.section == 0 {
            // Configure the cell in transitional way.
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "\(TextLabelCell.self)", for: indexPath) as! TextLabelCell
            cell.textLabel.text = "\(indexPath)"
            return cell
        } else {
            // Configure the cell with new content configuration api.
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "\(ConfigurationTextLabelCell.self)", for: indexPath) as! ConfigurationTextLabelCell
            var content = cell.defaltTextLabelContent()
            content.text = "\(indexPath)"
            cell.contentConfiguration = content
            cell.setNeedsUpdateConfiguration()
            return cell
        }
    }
}

// MARK: - Tranditional Cell

class TextLabelCell: UICollectionViewListCell {
    
    let hStackView = UIStackView()
        
    let textLabel = UILabel()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        contentView.addSubview(hStackView)
        hStackView.addArrangedSubview(textLabel)
        
        hStackView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            hStackView.leadingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.leadingAnchor),
            hStackView.trailingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.trailingAnchor),
            hStackView.topAnchor.constraint(equalTo: contentView.layoutMarginsGuide.topAnchor),
            hStackView.bottomAnchor.constraint(equalTo: contentView.layoutMarginsGuide.bottomAnchor),
        ])
        
        hStackView.axis = .horizontal
        
        // FIXME: When alignment is set to `.center`, the stack view can't calculate it's height correctly. It's height is a little larger than it's content.
        hStackView.alignment = .center
        
        // The default `.fill` alignment is fine.
//        hStackView.alignment = .fill
        
        hStackView.strokeLine(width: 1, color: .blue)
        textLabel.strokeLine(width: 2, color: .red)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

// MARK: - Content Configuration Cell

class ConfigurationTextLabelCell: UICollectionViewListCell {
    
    func defaltTextLabelContent() -> TextLabelContentView.Configuration {
        return TextLabelContentView.Configuration()
    }
}

class TextLabelContentView: UIView, UIContentView {
    
    struct Configuration: UIContentConfiguration {
        
        var text: String? = "AAA"
        
        func makeContentView() -> UIView & UIContentView {
            return TextLabelContentView(configuration: self)
        }
        
        func updated(for state: UIConfigurationState) -> TextLabelContentView.Configuration {
            return self
        }
    }
    
    let hStackView = UIStackView()
    
    let textLabel = UILabel()
    
    var configuration: UIContentConfiguration {
        didSet { textLabel.text = (configuration as? Configuration)?.text }
    }
    
    func supports(_ configuration: UIContentConfiguration) -> Bool {
        return true
    }
    
    init(configuration: UIContentConfiguration) {
        self.configuration = configuration
        super.init(frame: .zero)
        
        addSubview(hStackView)
        hStackView.addArrangedSubview(textLabel)
        
        hStackView.translatesAutoresizingMaskIntoConstraints = false
        directionalLayoutMargins = NSDirectionalEdgeInsets(top: 8, leading: 20, bottom: 8, trailing: 20)
        NSLayoutConstraint.activate([
            hStackView.leadingAnchor.constraint(equalTo: layoutMarginsGuide.leadingAnchor),
            hStackView.trailingAnchor.constraint(equalTo: layoutMarginsGuide.trailingAnchor),
            hStackView.topAnchor.constraint(equalTo: layoutMarginsGuide.topAnchor),
            hStackView.bottomAnchor.constraint(equalTo: layoutMarginsGuide.bottomAnchor),
        ])
        
        hStackView.axis = .horizontal
        
        
        enum StackViewLayout {
            case alignmentFill
            case alignmentCenterWithOneSubview
            case alignmentCenterWithTwoSubview
        }
        
        // Change this value to see different behaviors.
        let layout: StackViewLayout = .alignmentCenterWithOneSubview
        
        switch layout {
        case .alignmentFill:
            hStackView.alignment = .fill
            
        case .alignmentCenterWithOneSubview:
            // FIXME: When the stack view's alignment is `.center` and it has only one arranged subview, This line will cause a crash:
            // *** Assertion failure in void _UIContentViewAssertValidFittingSize(UIView * _Nonnull __strong, CGSize, UILayoutPriority, UILayoutPriority)(), _UIContentViewShared.h:66
            // Thread 1: "Content view returned an invalid size {353, 1.7976931348623157e+308} from -systemLayoutSizeFittingSize:withHorizontalFittingPriority:verticalFittingPriority: which is not allowed. If you have implemented a custom content view, you need to add constraints inside it so that its size is not ambiguous, or you need to manually compute and return a valid size. Content view: ; layer = >"
            hStackView.alignment = .center
            
        case .alignmentCenterWithTwoSubview:
            // When the stack view's alignment is `.center` and it has more than one arranged subviews, it works fine.
            hStackView.alignment = .center
            hStackView.addArrangedSubview(UIView())
        }
        
        hStackView.strokeLine(width: 1, color: .blue)
        textLabel.strokeLine(width: 2, color: .red)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

// MARK: - Debug Helper

extension UIView {
    
    func strokeLine(width: CGFloat, color: UIColor) {
        layer.borderColor = color.cgColor
        layer.borderWidth = width
    }
}