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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
import Foundation
/// Error types for summarization flows, mapping underlying model errors to user‑friendly cases.
/// The UI layer will rely on userMessage to display appropriate messages.
public enum SummarizerError: Error, LocalizedError, Sendable {
case tooLong
case rateLimited
case busy
case safetyBlocked
case unsupportedLanguage
case invalidResponse(statusCode: Int)
case unableToExtractContent
case invalidChunk
case cancelled
case noContent
case unknown(Error)
/// Returns a telemetry-safe string describing how the summarizer failed.
///
/// We need insights into failures while carefully limiting
/// what gets sent over to telemetry. Therefore:
/// - For known cases: plain tokens like `tooLong` or `rateLimited`.
/// - For invalid HTTP responses: we include the status code.
/// - For unknown errors:
/// - `NSError`: domain + code.
/// - Swift `Error`: the type name only.
/// This intentionally never uses `description`, `localizedDescription`,
/// or any raw serialization of the error
public var telemetryDescription: String {
switch self {
case .tooLong: return "tooLong"
case .rateLimited: return "rateLimited"
case .busy: return "busy"
case .safetyBlocked: return "safetyBlocked"
case .unsupportedLanguage: return "unsupportedLanguage"
case .invalidResponse(let statusCode): return "invalidResponse(statusCode: \(statusCode))"
case .unableToExtractContent: return "unableToExtractContent"
case .invalidChunk: return "invalidChunk"
case .cancelled: return "cancelled"
case .noContent: return "noContent"
case .unknown(let error):
if let nsError = error as NSError? {
return "unknown(domain: \(nsError.domain), code: \(nsError.code))"
}
return "unknown(type: \(String(describing: type(of: error))))"
}
}
// TODO(FXIOS-12934): Localize these strings
var userMessage: String {
switch self {
case .tooLong: return ""
case .rateLimited: return ""
case .busy: return ""
case .safetyBlocked: return ""
case .unsupportedLanguage: return ""
case .cancelled: return ""
case .invalidResponse: return ""
case .noContent: return ""
case .invalidChunk: return ""
case .unableToExtractContent: return ""
case .unknown: return ""
}
}
/// Maps from summarization checker reasons
init(reason: SummarizationReason?) {
switch reason {
case .contentTooLong: self = .tooLong
case .documentLanguageUnsupported: self = .unsupportedLanguage
case .documentNotReadable: self = .cancelled
case nil: self = .unableToExtractContent
}
}
}
/// We need these compile time checks so the app can be built with pre‑iOS 26 SDKs.
/// Once our BR workflow switches to 26, we can remove them,
/// as the runtime @available checks will be enough.
#if canImport(FoundationModels)
import FoundationModels
extension SummarizerError {
/// Initialize from `LanguageModelSession.GenerationError`.
@available(iOS 26, *)
init(_ error: LanguageModelSession.GenerationError) {
switch error {
case .exceededContextWindowSize: self = .tooLong
case .rateLimited: self = .rateLimited
case .concurrentRequests: self = .busy
case .guardrailViolation: self = .safetyBlocked
case .unsupportedLanguageOrLocale: self = .unsupportedLanguage
case .unsupportedGuide,
.decodingFailure,
.assetsUnavailable,
.refusal:
self = .unknown(error)
@unknown default:
self = .unknown(error)
}
}
}
#endif