Simple square grid showing coloured circles depending on their type

BoulderBoard.swift

//
//  ContentView.swift
//  poc-bolderGrid
//
//  Created by Andreas Seeger on 10.11.2023.
//

import SwiftUI

struct ContentView: View {
  @State private var holdsModel = GridModel.mock

  var body: some View {
    if holdsModel.validGrid {
      Grid {
        ForEach(0..<holdsModel.length, id: \.self) { row in
          GridRow {
            ForEach(0..<holdsModel.length, id: \.self) { column in
              Button(
                action: {
                  // TODO: implement action here
                  holdsModel.grid[row][column].holdType =
                  holdsModel.grid[row][column].holdType == .regular ? .special : .regular
                }, label: {
                  Circle()
                    .foregroundStyle(holdsModel.grid[row][column].holdType.color)
                })
            }
          }
        }
      }
      .padding()
    } else {
      ContentUnavailableView("Invalid Grid", systemImage: "xmark")
    }
  }
}

#Preview {
    ContentView()
}

enum HoldType {
  case regular, special

  var color: Color {
    switch self {
    case .regular:
        .blue
    case .special:
        .red
    }
  }
}

struct Hold {
  let rowPosition: Int
  let columnPosition: Int
  var holdType: HoldType
}

struct GridModel {
  var grid: [[Hold]]
  var length: Int {
    grid.count
  }
  var validGrid: Bool {
    let rows = grid.count
    print("Rows:", rows)
    let columnsSum = grid.reduce(0, { partialResult, columns in
      let count = columns.count
      print("Column count:", count)
      return partialResult + count
    })
    print("Coulum sum:", columnsSum)
    let columnSquareRoot = Double(sqrt(Double(columnsSum)))
    print("Columns:", columnSquareRoot)
    let isValid = Double(rows) == columnSquareRoot
    print("Valid:", isValid)
    return isValid
  }
}

extension GridModel {
  static let mock = GridModel(
    grid: [
      [
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .special),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular)
      ],
      [
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .special),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular)
      ],
      [
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular)
      ],
      [
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .special),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular),
        Hold(rowPosition: 0, columnPosition: 0, holdType: .regular)
      ]
    ]
  )
}