import Foundation
import Observation

@Observable
@MainActor
final class WatchCardStore {
    private static let defaultCardIDKey = "WatchDefaultCardID"

    private(set) var cards: [WatchCard] = []
    var defaultCardID: UUID? {
        didSet {
            persistDefaultID()
        }
    }

    init() {
        loadDefaultID()
        WatchDesign.debugLog("WatchCardStore: Initialized, waiting for cards from iPhone")
    }

    var defaultCard: WatchCard? {
        guard let defaultCardID else { return cards.first(where: { $0.isDefault }) ?? cards.first }
        return cards.first(where: { $0.id == defaultCardID }) ?? cards.first(where: { $0.isDefault }) ?? cards.first
    }
    
    /// Called by WatchConnectivityService when cards are received from iPhone
    func updateCards(_ newCards: [WatchCard]) {
        WatchDesign.debugLog("WatchCardStore: Received \(newCards.count) cards from iPhone")
        cards = newCards
        
        // Update default card ID if current selection is no longer valid
        if let currentDefault = defaultCardID, !cards.contains(where: { $0.id == currentDefault }) {
            defaultCardID = cards.first(where: { $0.isDefault })?.id ?? cards.first?.id
        } else if defaultCardID == nil {
            defaultCardID = cards.first(where: { $0.isDefault })?.id ?? cards.first?.id
        }
    }

    func setDefault(_ card: WatchCard) {
        defaultCardID = card.id
    }

    private func persistDefaultID() {
        UserDefaults.standard.set(defaultCardID?.uuidString ?? "", forKey: Self.defaultCardIDKey)
    }

    private func loadDefaultID() {
        let storedValue = UserDefaults.standard.string(forKey: Self.defaultCardIDKey) ?? ""
        if let id = UUID(uuidString: storedValue) {
            defaultCardID = id
        }
    }
}