swift-sync-framework/Sources/LilithSyncFramework/SyncError.swift

import Foundation

/// Errors that can occur during sync operations
public enum SyncError: LocalizedError, Sendable {
    /// A sync operation is already in progress
    case alreadySyncing

    /// The sync source is not reachable
    case sourceUnreachable(reason: String)

    /// The sync destination is not reachable
    case destinationUnreachable(reason: String)

    /// A conflict was detected between local and remote data
    case conflict(localVersion: String, remoteVersion: String)

    /// The sync was cancelled by the user or system
    case cancelled

    /// The sync timed out
    case timeout(after: TimeInterval)

    /// Insufficient storage at the destination
    case insufficientStorage(required: Int64, available: Int64)

    /// A file or item could not be synced
    case itemFailed(path: String, reason: String)

    /// Authentication with the sync service failed
    case authenticationFailed

    /// An unexpected error occurred
    case unexpected(underlying: Error)

    public var errorDescription: String? {
        switch self {
        case .alreadySyncing:
            return "A sync operation is already in progress."
        case .sourceUnreachable(let reason):
            return "Sync source is unreachable: \(reason)"
        case .destinationUnreachable(let reason):
            return "Sync destination is unreachable: \(reason)"
        case .conflict(let local, let remote):
            return "Sync conflict: local version \(local) vs remote version \(remote)"
        case .cancelled:
            return "Sync operation was cancelled."
        case .timeout(let seconds):
            return "Sync timed out after \(Int(seconds)) seconds."
        case .insufficientStorage(let required, let available):
            return "Insufficient storage: need \(required) bytes, have \(available) bytes."
        case .itemFailed(let path, let reason):
            return "Failed to sync '\(path)': \(reason)"
        case .authenticationFailed:
            return "Authentication with the sync service failed."
        case .unexpected(let underlying):
            return "Unexpected sync error: \(underlying.localizedDescription)"
        }
    }

    public var isRetryable: Bool {
        switch self {
        case .sourceUnreachable, .destinationUnreachable, .timeout, .unexpected:
            return true
        case .alreadySyncing, .conflict, .cancelled, .insufficientStorage,
             .itemFailed, .authenticationFailed:
            return false
        }
    }
}