import Foundation

/// Reads and writes WidgetData from the shared App Group UserDefaults container.
/// Compiled into both the main app and widget extension targets.
final class WidgetDataManager {
    static let shared = WidgetDataManager()

    private let suiteName = "group.com.frenocorp.kordant"
    private let dataKey = "com.frenocorp.kordant.widgetData"

    private init() {}

    /// Persist widget data to the shared container.
    func save(_ data: WidgetData) {
        guard let defaults = UserDefaults(suiteName: suiteName) else {
            assertionFailure("WidgetDataManager: Unable to access App Group UserDefaults")
            return
        }
        do {
            let encoded = try JSONEncoder().encode(data)
            defaults.set(encoded, forKey: dataKey)
        } catch {
            assertionFailure("WidgetDataManager: Failed to encode widget data: \(error)")
        }
    }

    /// Load widget data from the shared container.
    /// Returns `nil` if no data has been written yet.
    func load() -> WidgetData? {
        guard let defaults = UserDefaults(suiteName: suiteName),
              let data = defaults.data(forKey: dataKey) else {
            return nil
        }
        do {
            return try JSONDecoder().decode(WidgetData.self, from: data)
        } catch {
            assertionFailure("WidgetDataManager: Failed to decode widget data: \(error)")
            return nil
        }
    }

    /// Remove all stored widget data (e.g. on logout).
    func clear() {
        UserDefaults(suiteName: suiteName)?.removeObject(forKey: dataKey)
    }
}