Yattee v2 rewrite

Yattee/Services/Migration/LegacyDataMigrationService.swift

@@ -0,0 +1,220 @@
+//
+//  LegacyDataMigrationService.swift
+//  Yattee
+//
+//  Service for detecting, parsing, and importing v1 data during migration.
+//
+
+import Foundation
+
+/// Service that handles migration of v1 Yattee data to the v2 format.
+/// Detects legacy instances stored in UserDefaults and imports them into the new system.
+/// Credentials are not imported - users need to sign in again after import.
+@MainActor
+@Observable
+final class LegacyDataMigrationService {
+    // MARK: - Constants
+
+    /// UserDefaults key where v1 stored instances
+    private let legacyInstancesKey = "instances"
+
+    /// UserDefaults key where v1 stored accounts
+    private let legacyAccountsKey = "accounts"
+
+    // MARK: - Dependencies
+
+    private let instancesManager: InstancesManager
+    private let httpClient: HTTPClient
+
+    // MARK: - State
+
+    /// Whether an import is currently in progress
+    private(set) var isImporting = false
+
+    /// Progress of the current import (0.0 to 1.0)
+    private(set) var importProgress: Double = 0.0
+
+    // MARK: - Initialization
+
+    init(
+        instancesManager: InstancesManager,
+        httpClient: HTTPClient = HTTPClient()
+    ) {
+        self.instancesManager = instancesManager
+        self.httpClient = httpClient
+    }
+
+    // MARK: - Detection
+
+    /// Checks if there is legacy v1 data available for migration.
+    /// - Returns: true if v1 data exists and can be parsed
+    func hasLegacyData() -> Bool {
+        guard let items = parseLegacyData() else { return false }
+        return !items.isEmpty
+    }
+
+    /// Parses legacy v1 data from UserDefaults.
+    /// - Returns: Array of import items, or nil if data is corrupted or doesn't exist
+    func parseLegacyData() -> [LegacyImportItem]? {
+        let defaults = UserDefaults.standard
+
+        // Check if legacy data exists
+        guard defaults.object(forKey: legacyInstancesKey) != nil ||
+              defaults.object(forKey: legacyAccountsKey) != nil else {
+            return nil
+        }
+
+        // Parse instances only (credentials are not imported)
+        let legacyInstances = parseLegacyInstances(from: defaults)
+
+        // Build import items - one per unique instance
+        var items: [LegacyImportItem] = []
+
+        for instance in legacyInstances {
+            // Skip PeerTube (not supported in migration)
+            guard let instanceType = instance.instanceType,
+                  instanceType != .peertube else {
+                continue
+            }
+
+            guard let url = instance.url else { continue }
+
+            let item = LegacyImportItem(
+                id: UUID(),
+                legacyInstanceID: instance.id,
+                instanceType: instanceType,
+                url: url,
+                name: instance.name.isEmpty ? nil : instance.name
+            )
+            items.append(item)
+        }
+
+        // Return nil if no valid items were found (treat as no data)
+        return items.isEmpty ? nil : items
+    }
+
+    // MARK: - Parsing Helpers
+
+    private func parseLegacyInstances(from defaults: UserDefaults) -> [LegacyInstance] {
+        // v1 used Defaults library which stores arrays of dictionaries
+        guard let array = defaults.array(forKey: legacyInstancesKey) as? [[String: Any]] else {
+            return []
+        }
+
+        return array.compactMap { LegacyInstance.parse(from: $0) }
+    }
+
+    // MARK: - Reachability
+
+    /// Checks if an instance is reachable.
+    /// - Parameter item: The import item to check
+    /// - Returns: true if the instance responds, false otherwise
+    func checkReachability(for item: LegacyImportItem) async -> Bool {
+        // Build the appropriate health check endpoint based on instance type
+        let endpoint: GenericEndpoint
+        switch item.instanceType {
+        case .invidious:
+            endpoint = GenericEndpoint(path: "/api/v1/stats", timeout: 10)
+        case .piped:
+            endpoint = GenericEndpoint(path: "/healthcheck", timeout: 10)
+        default:
+            return false
+        }
+
+        do {
+            _ = try await httpClient.fetchData(endpoint, baseURL: item.url)
+            return true
+        } catch {
+            return false
+        }
+    }
+
+    // MARK: - Import
+
+    /// Imports the selected items into the v2 system.
+    /// - Parameter items: The items to import (only selected items will be processed)
+    /// - Returns: The result of the import operation
+    func importItems(_ items: [LegacyImportItem]) async -> MigrationResult {
+        isImporting = true
+        importProgress = 0.0
+
+        let selectedItems = items.filter(\.isSelected)
+        var succeeded: [LegacyImportItem] = []
+        var failed: [(item: LegacyImportItem, error: MigrationError)] = []
+        var skippedDuplicates: [LegacyImportItem] = []
+
+        let total = selectedItems.count
+
+        for (index, item) in selectedItems.enumerated() {
+            // Update progress
+            importProgress = Double(index) / Double(max(total, 1))
+
+            // Check for duplicates
+            if isDuplicate(item) {
+                skippedDuplicates.append(item)
+                continue
+            }
+
+            // Perform import
+            do {
+                try importItem(item)
+                succeeded.append(item)
+            } catch let error as MigrationError {
+                failed.append((item, error))
+            } catch {
+                failed.append((item, .unknown(error.localizedDescription)))
+            }
+        }
+
+        importProgress = 1.0
+        isImporting = false
+
+        return MigrationResult(
+            succeeded: succeeded,
+            failed: failed,
+            skippedDuplicates: skippedDuplicates
+        )
+    }
+
+    /// Imports a single item into the v2 system.
+    private func importItem(_ item: LegacyImportItem) throws {
+        // Create the new Instance (without credentials - user needs to sign in again)
+        let instance = Instance(
+            id: UUID(),
+            type: item.instanceType,
+            url: item.url,
+            name: item.name,
+            isEnabled: true
+        )
+
+        // Add to instances manager
+        instancesManager.add(instance)
+    }
+
+    /// Checks if an import item would be a duplicate of an existing instance.
+    private func isDuplicate(_ item: LegacyImportItem) -> Bool {
+        // Check if an instance with the same URL and type already exists
+        for existing in instancesManager.instances {
+            if existing.url.host == item.url.host && existing.type == item.instanceType {
+                return true
+            }
+        }
+        return false
+    }
+
+    // MARK: - Cleanup
+
+    /// Deletes the legacy v1 data from UserDefaults.
+    /// Call this after a successful import or when the user confirms they don't want to import.
+    func deleteLegacyData() {
+        let defaults = UserDefaults.standard
+
+        // Remove legacy keys
+        defaults.removeObject(forKey: legacyInstancesKey)
+        defaults.removeObject(forKey: legacyAccountsKey)
+
+        // Note: We don't delete the old Keychain items as they may be needed
+        // if the user reinstalls v1 or for debugging purposes.
+        // The old Keychain service name is different so there's no conflict.
+    }
+}