refactor: simplify parseGhostResponse to return FillInAtCursorSuggestion directly

- Remove StreamingParseResult interface and related complexity
- parseGhostResponse now returns FillInAtCursorSuggestion with text, prefix, suffix
- Returns empty string for text when no completion found (instead of undefined)
- Update GhostInlineCompletionProvider to handle new return type
- Update all tests to work with simplified API
- Maintain backward compatibility by creating GhostSuggestionsState internally when needed

This change simplifies the API and reduces unnecessary abstraction layers while
maintaining all existing functionality.

Author: markijbema

src/services/ghost/__tests__/GhostServiceManager.spec.ts

@@ -108,7 +108,7 @@ describe("GhostServiceManager", () => {
 			const position = context.range?.start ?? context.document.positionAt(0)
 			const { prefix, suffix } = extractPrefixSuffix(context.document, position)
 			const result = parseGhostResponse("", prefix, suffix)
-			expect(result.suggestions.hasSuggestions()).toBe(false)
+			expect(result.text).toBe("")
 		})
 
 		it("should handle invalid COMPLETION format", async () => {
@@ -119,7 +119,7 @@ describe("GhostServiceManager", () => {
 			const position = context.range?.start ?? context.document.positionAt(0)
 			const { prefix, suffix } = extractPrefixSuffix(context.document, position)
 			const result = parseGhostResponse(invalidCOMPLETION, prefix, suffix)
-			expect(result.suggestions.hasSuggestions()).toBe(false)
+			expect(result.text).toBe("")
 		})
 
 		it("should handle file not found in context", async () => {
@@ -138,7 +138,7 @@ console.log('test');</COMPLETION>`
 			const position = context.range?.start ?? context.document.positionAt(0)
 			const { prefix, suffix } = extractPrefixSuffix(context.document, position)
 			const result = parseGhostResponse(completionResponse, prefix, suffix)
-			expect(result.suggestions.hasSuggestions()).toBe(true)
+			expect(result.text).toBe("// Added comment\nconsole.log('test');")
 		})
 	})
 

src/services/ghost/classic-auto-complete/GhostInlineCompletionProvider.ts

@@ -1,5 +1,5 @@
 import * as vscode from "vscode"
-import { FillInAtCursorSuggestion, GhostSuggestionsState } from "./GhostSuggestions"
+import { FillInAtCursorSuggestion } from "./GhostSuggestions"
 import { extractPrefixSuffix, GhostSuggestionContext, contextToAutocompleteInput } from "../types"
 import { parseGhostResponse } from "./GhostStreamingParser"
 import { AutoTriggerStrategy } from "./AutoTriggerStrategy"
@@ -62,7 +62,7 @@ export function findMatchingSuggestion(
 }
 
 export interface LLMRetrievalResult {
-	suggestions: GhostSuggestionsState
+	suggestion: FillInAtCursorSuggestion
 	cost: number
 	inputTokens: number
 	outputTokens: number
@@ -134,9 +134,9 @@ export class GhostInlineCompletionProvider implements vscode.InlineCompletionIte
 		// Check cache before making API call (includes both successful and failed lookups)
 		const cachedResult = findMatchingSuggestion(prefix, suffix, this.suggestionsHistory)
 		if (cachedResult !== null) {
-			// Return empty result if we have a cached entry (either success or failure)
+			// Return cached result (either success with text or failure with empty string)
 			return {
-				suggestions: new GhostSuggestionsState(),
+				suggestion: { text: cachedResult, prefix, suffix },
 				cost: 0,
 				inputTokens: 0,
 				outputTokens: 0,
@@ -154,7 +154,7 @@ export class GhostInlineCompletionProvider implements vscode.InlineCompletionIte
 
 		if (this.isRequestCancelled) {
 			return {
-				suggestions: new GhostSuggestionsState(),
+				suggestion: { text: "", prefix, suffix },
 				cost: 0,
 				inputTokens: 0,
 				outputTokens: 0,
@@ -183,7 +183,7 @@ export class GhostInlineCompletionProvider implements vscode.InlineCompletionIte
 
 		if (this.isRequestCancelled) {
 			return {
-				suggestions: new GhostSuggestionsState(),
+				suggestion: { text: "", prefix, suffix },
 				cost: usageInfo.cost,
 				inputTokens: usageInfo.inputTokens,
 				outputTokens: usageInfo.outputTokens,
@@ -193,14 +193,15 @@ export class GhostInlineCompletionProvider implements vscode.InlineCompletionIte
 		}
 
 		// Parse the response using the standalone function
-		const finalParseResult = parseGhostResponse(response, prefix, suffix)
+		const fillInAtCursorSuggestion = parseGhostResponse(response, prefix, suffix)
 
-		if (finalParseResult.suggestions.getFillInAtCursor()) {
-			console.info("Final suggestion:", finalParseResult.suggestions.getFillInAtCursor())
+		if (fillInAtCursorSuggestion.text) {
+			console.info("Final suggestion:", fillInAtCursorSuggestion)
 		}
 
+		// Always return a FillInAtCursorSuggestion, even if text is empty
 		return {
-			suggestions: finalParseResult.suggestions,
+			suggestion: fillInAtCursorSuggestion,
 			cost: usageInfo.cost,
 			inputTokens: usageInfo.inputTokens,
 			outputTokens: usageInfo.outputTokens,
@@ -281,19 +282,17 @@ export class GhostInlineCompletionProvider implements vscode.InlineCompletionIte
 					)
 				}
 
-				const fillInAtCursor = result.suggestions.getFillInAtCursor()
+				// Always update suggestions, even if text is empty (for caching)
+				this.updateSuggestions(result.suggestion)
 
-				if (fillInAtCursor) {
-					this.updateSuggestions(fillInAtCursor)
+				if (result.suggestion.text) {
 					const item: vscode.InlineCompletionItem = {
-						insertText: fillInAtCursor.text,
+						insertText: result.suggestion.text,
 						range: new vscode.Range(position, position),
 					}
 					return [item]
 				} else {
-					// Store empty suggestion to prevent re-requesting
-					this.updateSuggestions({ text: "", prefix, suffix })
-
+					// Empty text means no suggestion to show
 					return []
 				}
 			} catch (error) {

src/services/ghost/classic-auto-complete/GhostStreamingParser.ts

@@ -1,45 +1,26 @@
-import { GhostSuggestionsState } from "./GhostSuggestions"
-
-export interface StreamingParseResult {
-	suggestions: GhostSuggestionsState
-	isComplete: boolean
-	hasNewSuggestions: boolean
-}
+import { FillInAtCursorSuggestion } from "./GhostSuggestions"
 
 /**
  * Parse the response - only handles responses with <COMPLETION> tags
+ * Returns a FillInAtCursorSuggestion with the extracted text, or an empty string if nothing found
  */
-export function parseGhostResponse(fullResponse: string, prefix: string, suffix: string): StreamingParseResult {
-	const suggestions = new GhostSuggestionsState()
-	let hasNewSuggestions = false
-
+export function parseGhostResponse(fullResponse: string, prefix: string, suffix: string): FillInAtCursorSuggestion {
 	let fimText: string = ""
-	let isComplete: boolean = true
 
 	// Match content strictly between <COMPLETION> and </COMPLETION> tags
 	const completionMatch = fullResponse.match(/<COMPLETION>([\s\S]*?)<\/COMPLETION>/i)
 
 	if (completionMatch) {
 		// Extract the captured group (content between tags)
 		fimText = completionMatch[1] || ""
-		isComplete = true
 	}
 	// Remove any accidentally captured tag remnants
 	fimText = fimText.replace(/<\/?COMPLETION>/gi, "")
 
-	// Create suggestion if there's actual content
-	if (fimText.length > 0) {
-		suggestions.setFillInAtCursor({
-			text: fimText,
-			prefix,
-			suffix,
-		})
-		hasNewSuggestions = true
-	}
-
+	// Return FillInAtCursorSuggestion with the text (empty string if nothing found)
 	return {
-		suggestions,
-		isComplete,
-		hasNewSuggestions,
+		text: fimText,
+		prefix,
+		suffix,
 	}
 }

src/services/ghost/classic-auto-complete/GhostSuggestions.ts

@@ -3,25 +3,3 @@ export interface FillInAtCursorSuggestion {
 	prefix: string
 	suffix: string
 }
-
-export class GhostSuggestionsState {
-	private fillinAtCursorSuggestion: FillInAtCursorSuggestion | undefined = undefined
-
-	constructor() {}
-
-	public setFillInAtCursor(suggestion: FillInAtCursorSuggestion) {
-		this.fillinAtCursorSuggestion = suggestion
-	}
-
-	public getFillInAtCursor(): FillInAtCursorSuggestion | undefined {
-		return this.fillinAtCursorSuggestion
-	}
-
-	public hasSuggestions(): boolean {
-		return !!this.fillinAtCursorSuggestion
-	}
-
-	public clear(): void {
-		this.fillinAtCursorSuggestion = undefined
-	}
-}

src/services/ghost/classic-auto-complete/__tests__/GhostInlineCompletionProvider.test.ts

@@ -4,7 +4,7 @@ import {
 	findMatchingSuggestion,
 	CostTrackingCallback,
 } from "../GhostInlineCompletionProvider"
-import { GhostSuggestionsState, FillInAtCursorSuggestion } from "../GhostSuggestions"
+import { FillInAtCursorSuggestion } from "../GhostSuggestions"
 import { MockTextDocument } from "../../../mocking/MockTextDocument"
 import { GhostModel } from "../../GhostModel"
 import { GhostContext } from "../../GhostContext"