import Foundation
import WidgetKit

/// Snapshot of today's meals for the widget. Generic over meal types (2.0):
/// one entry per active meal type, in chronological order.
struct TodayMealData: Codable {
    struct Meal: Codable {
        let type: String   // MealType raw value (drives icon/color in widget)
        let label: String  // localized meal name
        let name: String?  // dish name, nil when the slot is empty
    }

    let meals: [Meal]
    let weekdayName: String
    let updatedAt: Date
}

enum WidgetDataStore {
    static let appGroupID = "group.com.alexandrevazquez.mealmood"
    private static let key = "mealmood.today_meals"

    static func update(plan: WeekPlan?, dishes: [Dish], settings: AppSettings) {
        let today = Date()
        let weekday = Calendar.current.component(.weekday, from: today)
        // weekday: 1=Sun,2=Mon..7=Sat → appDayOfWeek: 0=Mon..6=Sun
        let appDayOfWeek = (weekday + 5) % 7

        let meals: [TodayMealData.Meal] = settings.activeMealTypes.map { mealType in
            let dishId = plan?.slots.first {
                $0.dayOfWeek == appDayOfWeek && $0.mealType == mealType.rawValue
            }?.dishId
            let name = dishId.flatMap { id in dishes.first { $0.id == id }?.name }
            return TodayMealData.Meal(
                type: mealType.rawValue,
                label: String(localized: String.LocalizationValue(mealType.localizedKey)),
                name: name
            )
        }

        let locale = Locale(identifier: settings.languageEnum.resolved().localeIdentifier)
        let formatter = DateFormatter()
        formatter.locale = locale
        formatter.dateFormat = "EEEE"
        let weekdayName = formatter.string(from: today).capitalized(with: locale)

        let data = TodayMealData(
            meals: meals,
            weekdayName: weekdayName,
            updatedAt: today
        )

        guard let defaults = UserDefaults(suiteName: appGroupID),
              let encoded = try? JSONEncoder().encode(data) else { return }
        defaults.set(encoded, forKey: key)
        WidgetCenter.shared.reloadAllTimelines()
    }

    static func read() -> TodayMealData? {
        guard let defaults = UserDefaults(suiteName: appGroupID),
              let data = defaults.data(forKey: key) else { return nil }
        return try? JSONDecoder().decode(TodayMealData.self, from: data)
    }
}