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.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

    static var officialIcons: [Icon] {
      [.primary, .alt1, .alt2, .alt3, .alt4, .alt5, .alt6, .alt7, .alt8,
       .alt9, .alt10, .alt11, .alt12, .alt13, .alt14,
       .alt15, .alt16, .alt17, .alt18, .alt19, .alt25]
    }

    static var albertKinngIcons: [Icon] {
      [.alt20, .alt21, .alt22, .alt23, .alt24]
    }

    static var danIcons: [Icon] {
      [.alt26, .alt27, .alt28]
    }

    static var tes6Icons: [Icon] {
      [.alt29, .alt30, .alt31, .alt32]
    }

    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) {
        Section {
          makeIconGridView(icons: Icon.officialIcons)
        } header: {
          Text("Official icons")
            .font(.scaledHeadline)
        }

        Section {
          makeIconGridView(icons: Icon.albertKinngIcons)
        } header: {
          Text("Icons by Albert Kinng")
            .font(.scaledHeadline)
        }

        Section {
          makeIconGridView(icons: Icon.danIcons)
        } header: {
          Text("Icons by Dan van Moll")
            .font(.scaledHeadline)
        }

        Section {
          makeIconGridView(icons: Icon.tes6Icons)
        } header: {
          Text("Icons by @te6-in (GitHub)")
            .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)
          }
        } 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)
            }
          }
        }
      }
    }
  }
}