Add non-streaming completePrompt to all providers

src/api/providers/gemini.ts

@@ -1,11 +1,11 @@
 import { Anthropic } from "@anthropic-ai/sdk"
 import { GoogleGenerativeAI } from "@google/generative-ai"
-import { ApiHandler } from "../"
+import { ApiHandler, SingleCompletionHandler } from "../"
 import { ApiHandlerOptions, geminiDefaultModelId, GeminiModelId, geminiModels, ModelInfo } from "../../shared/api"
 import { convertAnthropicMessageToGemini } from "../transform/gemini-format"
 import { ApiStream } from "../transform/stream"
 
-export class GeminiHandler implements ApiHandler {
+export class GeminiHandler implements ApiHandler, SingleCompletionHandler {
 	private options: ApiHandlerOptions
 	private client: GoogleGenerativeAI
 
@@ -53,4 +53,26 @@ export class GeminiHandler implements ApiHandler {
 		}
 		return { id: geminiDefaultModelId, info: geminiModels[geminiDefaultModelId] }
 	}
+
+	async completePrompt(prompt: string): Promise<string> {
+		try {
+			const model = this.client.getGenerativeModel({
+				model: this.getModel().id,
+			})
+
+			const result = await model.generateContent({
+				contents: [{ role: "user", parts: [{ text: prompt }] }],
+				generationConfig: {
+					temperature: 0,
+				},
+			})
+
+			return result.response.text()
+		} catch (error) {
+			if (error instanceof Error) {
+				throw new Error(`Gemini completion error: ${error.message}`)
+			}
+			throw error
+		}
+	}
 }