import DesignSystem
import SwiftUI

@MainActor
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.replacing("AppIconAlternate", with: "")))!)!
      }
    }

    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, alt20, alt21
    case alt22, alt23, alt24, alt25
    case alt26, alt27, alt28
    case alt29, alt30, alt31, alt32
    case alt33
    case alt34, alt35
    case alt36
    case alt37
    case alt38, alt39
    case alt40, alt41, alt42
    case alt43, alt44, alt45, alt46, alt47

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

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

  struct IconSelector: Identifiable {
    var id = UUID()
    let title: String
    let icons: [Icon]

    static let items = [
      IconSelector(title: "settings.app.icon.official".localized, icons: [.primary, .alt1, .alt2, .alt3, .alt4, .alt5, .alt6, .alt7, .alt8,
                                                                          .alt9, .alt10, .alt11, .alt12, .alt13, .alt14,
                                                                          .alt15, .alt16, .alt17, .alt18, .alt19, .alt25, 
                                                                          .alt43, .alt44, .alt45, .alt46, .alt47]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) Albert Kinng", icons: [.alt20, .alt21, .alt22, .alt23, .alt24]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) Dan van Moll", icons: [.alt26, .alt27, .alt28]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) Chanhwi Joo (GitHub @te6-in)", icons: [.alt29, .alt34, .alt31, .alt35, .alt30, .alt32, .alt40]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) W. Kovács Ágnes (@wildgica)", icons: [.alt33]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) Duncan Horne", icons: [.alt36]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) BeAware@social.beaware.live", icons: [.alt37, .alt41, .alt42]),
      IconSelector(title: "\("settings.app.icon.designed-by".localized) Simone Margio", icons: [.alt38, .alt39]),
    ]
  }

  @Environment(Theme.self) private var 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) {
        ForEach(IconSelector.items) { item in
          Section {
            makeIconGridView(icons: item.icons)
          } header: {
            Text(item.title)
              .font(.scaledHeadline)
          }
        }
      }
      .padding(6)
      .navigationTitle("settings.app.icon.navigation-title")
    }
    .background(theme.primaryBackgroundColor)
  }

  private func makeIconGridView(icons: [Icon]) -> some View {
    LazyVGrid(columns: columns, spacing: 6) {
      ForEach(icons) { icon in
        Button {
          currentIcon = icon.appIconName
          if icon.rawValue == Icon.primary.rawValue {
            UIApplication.shared.setAlternateIconName(nil)
          } else {
            UIApplication.shared.setAlternateIconName(icon.appIconName) { err in
              guard let err else { return }
              assertionFailure("\(err.localizedDescription) - Icon name: \(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)
            }
          }
        }
      }
    }
  }
}

extension String {
  var localized: String {
    NSLocalizedString(self, comment: "")
  }
}