import DesignSystem
import SwiftUI

struct IconSelectorView: View {
  enum Icon: Int, CaseIterable, Identifiable {
    var id: String {
      "\(rawValue)"
    }

    init(string: String) {
      if string == Icon.primary.appIconName {
        self = .primary
      } else {
        self = .init(rawValue: Int(String(string.last!))!)!
      }
    }

    case primary = 0
    case alt1, alt2, alt3, alt4, alt5, alt6, alt7, alt8
    case alt9, alt10, alt11, alt12, alt13, alt14
    case alt15, alt16, alt17, alt18, alt19

    var appIconName: String {
      switch self {
      case .primary:
        return "AppIcon"
      default:
        return "AppIconAlternate\(rawValue)"
      }
    }

    var iconName: String {
      "icon\(rawValue)"
    }
  }

  @EnvironmentObject private var theme: Theme
  @State private var currentIcon = UIApplication.shared.alternateIconName ?? Icon.primary.appIconName

  private let columns = [GridItem(.adaptive(minimum: 125, maximum: 1024))]

  var body: some View {
    ScrollView {
      VStack(alignment: .leading) {
        LazyVGrid(columns: columns, spacing: 6) {
          ForEach(Icon.allCases) { icon in
            Button {
              currentIcon = icon.appIconName
              if icon.rawValue == Icon.primary.rawValue {
                UIApplication.shared.setAlternateIconName(nil)
              } else {
                UIApplication.shared.setAlternateIconName(icon.appIconName)
              }
            } label: {
              ZStack(alignment: .bottomTrailing) {
                Image(uiImage: .init(named: icon.iconName) ?? .init())
                  .resizable()
                  .aspectRatio(contentMode: .fit)
                  .frame(minHeight: 125, maxHeight: 1024)
                  .cornerRadius(6)
                  .shadow(radius: 3)
                if icon.appIconName == currentIcon {
                  Image(systemName: "checkmark.seal.fill")
                    .padding(4)
                    .tint(.green)
                }
              }
            }
          }
        }
      }
      .padding(6)
      .navigationTitle("Icons")
    }
    .background(theme.primaryBackgroundColor)
  }
}