Yattee v2 rewrite

Yattee/Services/Subscriptions/SubscriptionProvider.swift

@@ -0,0 +1,79 @@
+//
+//  SubscriptionProvider.swift
+//  Yattee
+//
+//  Protocol defining subscription management operations.
+//  Implementations handle different subscription sources (local, Invidious, Piped).
+//
+
+import Foundation
+
+/// Protocol for subscription management providers.
+/// Each provider implementation handles a specific subscription source.
+@MainActor
+protocol SubscriptionProvider: Sendable {
+    /// The type of subscription account this provider handles.
+    var accountType: SubscriptionAccountType { get }
+
+    /// Fetches all subscriptions from the provider.
+    /// - Returns: Array of channels the user is subscribed to.
+    func fetchSubscriptions() async throws -> [Channel]
+
+    /// Subscribes to a channel.
+    /// - Parameter channel: The channel to subscribe to.
+    func subscribe(to channel: Channel) async throws
+
+    /// Unsubscribes from a channel.
+    /// - Parameter channelID: The channel ID to unsubscribe from.
+    func unsubscribe(from channelID: String) async throws
+
+    /// Checks if subscribed to a channel.
+    /// - Parameter channelID: The channel ID to check.
+    /// - Returns: `true` if subscribed, `false` otherwise.
+    func isSubscribed(to channelID: String) async -> Bool
+
+    /// Refreshes the local cache of subscriptions from the remote source.
+    /// For local provider, this is a no-op.
+    func refreshCache() async throws
+}
+
+// MARK: - Default Implementations
+
+extension SubscriptionProvider {
+    /// Default implementation for providers that don't need cache refresh.
+    func refreshCache() async throws {
+        // No-op by default
+    }
+}
+
+// MARK: - Subscription Provider Error
+
+/// Errors that can occur during subscription provider operations.
+enum SubscriptionProviderError: Error, LocalizedError, Equatable, Sendable {
+    case notAuthenticated
+    case networkError(String)
+    case channelNotFound
+    case alreadySubscribed
+    case notSubscribed
+    case instanceNotConfigured
+    case operationFailed(String)
+
+    var errorDescription: String? {
+        switch self {
+        case .notAuthenticated:
+            return String(localized: "subscription.error.notAuthenticated")
+        case .networkError(let message):
+            return String(localized: "subscription.error.network \(message)")
+        case .channelNotFound:
+            return String(localized: "subscription.error.channelNotFound")
+        case .alreadySubscribed:
+            return String(localized: "subscription.error.alreadySubscribed")
+        case .notSubscribed:
+            return String(localized: "subscription.error.notSubscribed")
+        case .instanceNotConfigured:
+            return String(localized: "subscription.error.instanceNotConfigured")
+        case .operationFailed(let message):
+            return String(localized: "subscription.error.operationFailed \(message)")
+        }
+    }
+}