vds_ios/VDS/Components/Table/Table.swift

//
//  Table.swift
//  VDS
//
//  Created by Nadigadda, Sumanth on 24/04/24.
//

import Foundation
import UIKit
import VDSCoreTokens

///Table is view composed of rows and columns, which takes any view into each cell and resizes based on the highest cell height.
@objc(VDSTable)
open class Table: View {
    
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    
    /// CollectionView to show the rows and columns
    private lazy var matrixView = SelfSizingCollectionView(frame: .zero, collectionViewLayout: flowLayout).with {
        $0.register(TableCellItem.self, forCellWithReuseIdentifier: TableCellItem.Identifier)
        $0.dataSource = self
        $0.delegate = self
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.allowsSelection = false
        $0.showsVerticalScrollIndicator = false
        $0.showsHorizontalScrollIndicator = false
        $0.backgroundColor = .clear
    }
    
    /// Custom flow layout to manage the height of the cells
    private lazy var flowLayout = MatrixFlowLayout().with {
        $0.delegate = self
        $0.scrollDirection = .horizontal
    }
    
    /// Array of ``TableItemModel`` by combining Header & Row items
    private var tableData: [TableRowModel] {
        return tableHeader + tableRows
    }

    //--------------------------------------------------
    // MARK: - Enums
    //--------------------------------------------------
    
    /// Enums used to define the padding for the cell edge spacing.
    public enum Padding: String, CaseIterable {
        case standard, compact
        
        func horizontalValue() -> CGFloat {
            switch self {
            case .standard, .compact:
                return UIDevice.isIPad ? VDSLayout.space4X : VDSLayout.space3X
            }
        }
        
        func verticalValue() -> CGFloat {
            switch self {
            case .standard:
                return UIDevice.isIPad ? VDSLayout.space8X : VDSLayout.space6X
            case .compact:
                return UIDevice.isIPad ? VDSLayout.space4X : VDSLayout.space3X
            }
        }
    }
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    
    /// Parameter to set striped status for the table
    open var striped: Bool = false { didSet { setNeedsUpdate() } }
    
    /// Parameter to set the padding for the cell
    open var padding: Padding = .standard { didSet { setNeedsUpdate() } }
    
    /// Parameter to show the table header row
    open var tableHeader: [TableRowModel] = [] { didSet { setNeedsUpdate() } }
    
    /// Parameter to show the all table rows
    open var tableRows: [TableRowModel] = [] { didSet { setNeedsUpdate() } }
    
    open var fillContainer: Bool = true { didSet { setNeedsUpdate() } }
    
    open var columnWidths: [CGFloat]? { didSet { setNeedsUpdate() } }
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    
    ///Called upon initializing the table view
    open override func setup() {
        super.setup()
        addSubview(matrixView)
        matrixView.pinToSuperView()
    }
    
    /// Will update the table view, when called becasue of any changes in component parameters
    open override func updateView() {
        super.updateView()
        if fillContainer == true || (fillContainer == false && columnWidths == nil) {
            columnWidths = calculateColumnWidths()
        }
        flowLayout.layoutPadding = padding
        matrixView.reloadData()
        matrixView.collectionViewLayout.invalidateLayout()
    }
    
    open override func setDefaults() {
        super.setDefaults()
        striped = false
        padding = .standard
        tableHeader = []
        tableRows = []
        fillContainer = true
        columnWidths = nil
    }

    func calculateColumnWidths() -> [CGFloat] {
        guard let noOfColumns = tableData.first?.columnsCount else { return [] }
        let itemWidth = floor(matrixView.safeAreaLayoutGuide.layoutFrame.width / CGFloat(noOfColumns))
        return Array(repeating: itemWidth, count: noOfColumns)
    }
    
}

extension Table: UICollectionViewDelegate, UICollectionViewDataSource, TableCollectionViewLayoutDataDelegate {
    
    //--------------------------------------------------
    // MARK: - UICollectionViewDelegate & UICollectionViewDataSource
    //--------------------------------------------------
    
    public func numberOfSections(in collectionView: UICollectionView) -> Int {
        return tableData.count
    }
    public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return tableData[section].columnsCount
    }
    
    public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: TableCellItem.Identifier, for: indexPath) as? TableCellItem else { return UICollectionViewCell() }
        let currentItem = tableData[indexPath.section].columns[indexPath.row]
        let shouldStrip = striped ? (indexPath.section % 2 != 0) : false
        let isHeader = tableData[indexPath.section].isHeader
        var edgePadding = UIEdgeInsets(top: padding.verticalValue(), left: 0, bottom: padding.verticalValue(), right: padding.horizontalValue())
        edgePadding.left = (indexPath.row == 0 && !striped) ? VDSLayout.space1X : padding.horizontalValue()
        cell.updateCell(content: currentItem, surface: surface, striped: shouldStrip, padding: edgePadding, isHeader: isHeader)
        setAccessibilityForCell(cell: cell, content: currentItem, path: indexPath)
        return cell
    }
    
    //--------------------------------------------------
    // MARK: - TableCollectionViewLayoutDataDelegate
    //--------------------------------------------------
    
    func collectionView(_ collectionView: UICollectionView, dataForItemAt indexPath: IndexPath) -> TableItemModel {
        return tableData[indexPath.section].columns[indexPath.row]
    }
    
    func collectionView(_ collectionView: UICollectionView, widthForItemAt indexPath: IndexPath) -> CGFloat {
        return columnWidths?[indexPath.row] ?? 0.0
    }
    
    //--------------------------------------------------
    // MARK: - Accessibility
    //--------------------------------------------------
    
    /// To set the accessibility label for the each cell based on the criteria. Table name along with total no of column & row information should be passed in the first cell's accessibility label.
    private func setAccessibilityForCell(cell: TableCellItem, content: TableItemModel, path: IndexPath) {
        
        var accLabel = content.component?.accessibilityLabel ?? "Empty"
            
        ///Set the type of header label
        if path.section == 0 {
            accLabel.append(", Column Header")
        } else if path.row == 0 {
            ///As per design team, inspite of column 0 may not look like a header, it should be read as header.
            accLabel.append(", Row Header")
        }

        ///Set the Row/Column number for each cell
        if path.row == 0 {
            accLabel.append(", Row \(path.section + 1), Column \(path.row + 1)")
        } else {
            accLabel.append(", Column \(path.row + 1)")
        }
        
        ///Set the Row header accessibilityLabel at the end of the non-header cells accessibilityLabel
        if path.section != 0,
           path.row != 0,
           let columnHeaderAccLabel = tableHeader.first?.columns[path.row].component?.accessibilityLabel {
            accLabel.append(", \(columnHeaderAccLabel)")
        }
        
        cell.accessibilityLabel = accLabel
    }
}