import Foundation
import RastrilloNative

/// The words the kit's sync views say. `.kit` reads the package's own
/// catalog, in the same twelve languages as the apps; an app overrides any
/// of them, for example to count cells instead of documents, by changing a
/// copy.
public struct NativeSyncStrings: Sendable {
  public var saving: String
  public var retrying: String
  /// "Offline · N pending".
  public var offline: @Sendable (Int) -> String
  /// "Sign in to send N pending".
  public var needsSignIn: @Sendable (Int) -> String
  public var signIn: String
  /// A held entry's words are the app's; this is the fallback.
  public var failed: @Sendable (SyncFailure) -> String
  /// The banner while the path or server is down and edits are not durable.
  public var offlineWaiting: String
  /// The banner once edits are kept on this device.
  public var offlineDurable: String
  /// Reported once after a lost key or corrupt entry removed unsent changes.
  public var unsentLost: String

  public init(saving: String, retrying: String, offline: @escaping @Sendable (Int) -> String,
              needsSignIn: @escaping @Sendable (Int) -> String, signIn: String,
              failed: @escaping @Sendable (SyncFailure) -> String, offlineWaiting: String,
              offlineDurable: String, unsentLost: String) {
    self.saving = saving; self.retrying = retrying; self.offline = offline; self.needsSignIn = needsSignIn
    self.signIn = signIn; self.failed = failed; self.offlineWaiting = offlineWaiting
    self.offlineDurable = offlineDurable; self.unsentLost = unsentLost
  }

  public static var kit: NativeSyncStrings { kit(localization: Bundle.module.preferredLocalizations.first ?? "en") }
  public static func kit(localization: String) -> NativeSyncStrings {
    let path = Bundle.module.path(forResource: localization, ofType: "lproj")
      ?? Bundle.module.path(forResource: "en", ofType: "lproj")!
    let bundle = Bundle(path: path)!
    @Sendable func text(_ key: String) -> String { bundle.localizedString(forKey: key, value: nil, table: nil) }
    @Sendable func plural(_ key: String, _ count: Int) -> String {
      String(format: text(key), locale: Locale(identifier: localization), arguments: [count])
    }
    return NativeSyncStrings(saving: text("sync.saving"), retrying: text("sync.retrying"),
      offline: { plural("sync.offline", $0) }, needsSignIn: { plural("sync.needsSignIn", $0) }, signIn: text("sync.signIn"),
      failed: { reason in
        switch reason {
        case .cannotSaveOnDevice: return text("sync.failed.cannotSave")
        case .tooManyUnsent: return text("sync.failed.tooManyUnsent")
        case .held: return text("sync.failed.held")
        }
      }, offlineWaiting: text("offline.waiting"), offlineDurable: text("offline.durable"), unsentLost: text("sync.unsentLost"))
  }
  public func text(for status: SyncStatus) -> String? {
    switch status {
    case .saved: return nil
    case .saving: return saving
    case .retrying: return retrying
    case .offline(let count): return offline(count)
    case .needsSignIn(let count): return needsSignIn(count)
    case .failed(_, let reason): return failed(reason)
    }
  }
}