import Foundation

class HistoryManager: ObservableObject {
  static let shared = HistoryManager()

  @Published var history: [Wallpaper] = []
  private let key = "wallpaperHistory"
  private let maxHistoryItems = 50

  init() {
    loadHistory()
  }

  func addToHistory(_ wallpaper: Wallpaper) {
    // Remove if existing to promote to top
    if let index = history.firstIndex(where: { $0.id == wallpaper.id }) {
      history.remove(at: index)
    }

    history.insert(wallpaper, at: 0)

    if history.count > maxHistoryItems {
      history = Array(history.prefix(maxHistoryItems))
    }

    saveHistory()
  }

  func clearHistory() {
    history = []
    saveHistory()
  }

  private func saveHistory() {
    if let data = try? JSONEncoder().encode(history) {
      UserDefaults.standard.set(data, forKey: key)
    }
  }

  private func loadHistory() {
    if let data = UserDefaults.standard.data(forKey: key),
      let decoded = try? JSONDecoder().decode([Wallpaper].self, from: data)
    {
      history = decoded
    }
  }
}