import Foundation

final class AppStateService {
    static let shared = AppStateService()

    private let configKey = "bugger.config"
    private let seenBugsKey = "bugger.seenBugs"

    private(set) var config: AppConfig? {
        didSet { persistConfig() }
    }

    private(set) var persistedSeenBugs: Set<String> = [] {
        didSet { persistSeenBugs() }
    }

    private init() {
        if let data = UserDefaults.standard.data(forKey: configKey),
           let config = try? JSONDecoder().decode(AppConfig.self, from: data) {
            self.config = config
        }
        if let data = UserDefaults.standard.data(forKey: seenBugsKey),
           let ids = try? JSONDecoder().decode(Set<String>.self, from: data) {
            self.persistedSeenBugs = ids
        }
    }

    func saveConfig(_ config: AppConfig) {
        self.config = config
    }

    func updateSeenBugs(_ ids: Set<String>) {
        persistedSeenBugs = ids
    }

    private func persistConfig() {
        guard let config,
              let data = try? JSONEncoder().encode(config) else {
            return
        }
        UserDefaults.standard.set(data, forKey: configKey)
    }

    private func persistSeenBugs() {
        guard let data = try? JSONEncoder().encode(persistedSeenBugs) else {
            return
        }
        UserDefaults.standard.set(data, forKey: seenBugsKey)
    }
}