import Foundation

// Locally persisted contacts saved from transfer receipts.
// Encrypted with AES-256-GCM via CacheEncryption, stored in UserDefaults.
struct SavedContactsStore {
    static let shared = SavedContactsStore()
    private let udKey = "thijooree_saved_contacts_v1"
    private init() {}

    func save(_ contact: BankContact) {
        var contacts = load()
        // Replace existing entry for the same account+source, then prepend (most-recent-first)
        contacts.removeAll { $0.benefAccount == contact.benefAccount && $0.source == contact.source }
        contacts.insert(contact, at: 0)
        if contacts.count > 100 { contacts = Array(contacts.prefix(100)) }
        persist(contacts)
    }

    func load() -> [BankContact] {
        guard let encrypted = UserDefaults.standard.string(forKey: udKey),
              let json = try? CacheEncryption.shared.decryptData(encrypted),
              let contacts = try? JSONDecoder().decode([BankContact].self, from: json) else { return [] }
        return contacts
    }

    func delete(id: String) {
        var contacts = load()
        contacts.removeAll { $0.id == id }
        persist(contacts)
    }

    func clear() {
        UserDefaults.standard.removeObject(forKey: udKey)
    }

    private func persist(_ contacts: [BankContact]) {
        guard let json = try? JSONEncoder().encode(contacts),
              let encrypted = try? CacheEncryption.shared.encryptData(json) else { return }
        UserDefaults.standard.set(encrypted, forKey: udKey)
    }
}