feat: implement OpenAI API integration for generating meeting notes

notetaker/Services/NotesGenerator.swift

@@ -2,6 +2,7 @@
 // Handles AI-powered note generation using OpenAI
 
 import Foundation
+import OpenAI
 
 /// Generates meeting notes using OpenAI API
 class NotesGenerator {
@@ -21,30 +22,29 @@ class NotesGenerator {
                       userBlurb: String,
                       systemPrompt: String) async throws -> String {
         
-        // TODO: Implement OpenAI API integration
-        // For now, return a placeholder
+        guard let apiKey = KeychainHelper.shared.get(forKey: "openAIKey"), !apiKey.isEmpty else {
+            throw NSError(domain: "NotesGenerator", code: 1, userInfo: [NSLocalizedDescriptionKey: "OpenAI API key not configured"])
+        }
         
-        // Simulate API delay
-        try await Task.sleep(nanoseconds: 2_000_000_000)
+        let openAI = OpenAI(apiToken: apiKey)
         
-        // Placeholder response
-        return """
-        # Meeting Notes
+        // Compose system prompt with user blurb wrapped in XML tags for clarity
+        let systemContent = "\(systemPrompt)\n\n<user_blurb>\n\(userBlurb)\n</user_blurb>"
+        let systemMessage = ChatQuery.ChatCompletionMessageParam(role: .system, content: systemContent)!
         
-        ## Summary
-        This is a placeholder for AI-generated meeting notes.
+        // Provide the model with structured XML-tagged input variables for improved parsing
+        let userContent = "<task>Generate concise and well-structured meeting notes using the information below.</task>\n\n<transcript>\n\(transcript)\n</transcript>\n\n<user_notes>\n\(userNotes)\n</user_notes>"
+        let userMessage = ChatQuery.ChatCompletionMessageParam(role: .user, content: userContent)!
         
-        ## Key Points
-        - Transcript length: \(transcript.count) characters
-        - User notes provided: \(!userNotes.isEmpty)
+        let query = ChatQuery(messages: [systemMessage, userMessage], model: .gpt4_1_mini)
         
-        ## Action Items
-        - Implement OpenAI API integration
-        - Add proper prompt engineering
+        let result = try await openAI.chats(query: query)
         
-        ## Next Steps
-        Once OpenAI API is integrated, this will provide comprehensive meeting notes based on the transcript and any additional context provided.
-        """
+        guard let generatedNotes = result.choices.first?.message.content else {
+            throw NSError(domain: "NotesGenerator", code: 2, userInfo: [NSLocalizedDescriptionKey: "Failed to generate notes"])
+        }
+        
+        return generatedNotes
     }
     
     /// Validates if OpenAI API key is configured