feat: meeting data migration and backup

notetaker/Managers/DataMigrationManager.swift

@@ -0,0 +1,54 @@
+// DataMigrationManager.swift
+// Handles data migration between different app versions
+
+import Foundation
+
+/// Manages data migration between different app versions
+class DataMigrationManager {
+    static let shared = DataMigrationManager()
+    
+    private init() {}
+    
+    /// Migrates a meeting from an older version to the current version
+    /// - Parameter meeting: The meeting to migrate
+    /// - Returns: The migrated meeting, or nil if migration failed
+    func migrateMeeting(_ meeting: Meeting) -> Meeting? {
+        // No releases prior to version 1 – any older file is considered unsupported.
+        guard meeting.dataVersion >= 1 else {
+            print("🚫 Cannot migrate meeting \(meeting.id) – unsupported data version \(meeting.dataVersion)")
+            return nil
+        }
+
+        // Future migrations can be added here as `switch` cases.
+        if meeting.dataVersion < Meeting.currentDataVersion {
+            print("⚠️ No migration path for versions \(meeting.dataVersion + 1)...\(Meeting.currentDataVersion)")
+            return nil
+        }
+
+        return meeting
+    }
+    
+    // Future migrateXToVersionY helpers will go here as needed
+    
+    /// Performs a backup of the meetings directory before migration
+    /// - Returns: The backup directory URL, or nil if backup failed
+    func backupMeetingsDirectory() -> URL? {
+        let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
+        let meetingsDirectory = documentsDirectory.appendingPathComponent("Meetings")
+        
+        let formatter = DateFormatter()
+        formatter.dateFormat = "yyyy-MM-dd_HH-mm-ss"
+        let timestamp = formatter.string(from: Date())
+        
+        let backupDirectory = documentsDirectory.appendingPathComponent("Meetings_Backup_\(timestamp)")
+        
+        do {
+            try FileManager.default.copyItem(at: meetingsDirectory, to: backupDirectory)
+            print("✅ Created backup at: \(backupDirectory)")
+            return backupDirectory
+        } catch {
+            print("❌ Failed to create backup: \(error)")
+            return nil
+        }
+    }
+}