Add OpenAI provider

src/api/index.ts

@@ -7,6 +7,7 @@ import { VertexHandler } from "./vertex"
 import { OpenAiHandler } from "./openai"
 import { OllamaHandler } from "./ollama"
 import { GeminiHandler } from "./gemini"
+import { OpenAiNativeHandler } from "./openai-native"
 
 export interface ApiHandlerMessageResponse {
 	message: Anthropic.Messages.Message
@@ -40,6 +41,8 @@ export function buildApiHandler(configuration: ApiConfiguration): ApiHandler {
 			return new OllamaHandler(options)
 		case "gemini":
 			return new GeminiHandler(options)
+		case "openai-native":
+			return new OpenAiNativeHandler(options)
 		default:
 			return new AnthropicHandler(options)
 	}

src/api/openai-native.ts

@@ -0,0 +1,65 @@
+import { Anthropic } from "@anthropic-ai/sdk"
+import OpenAI from "openai"
+import { ApiHandler, ApiHandlerMessageResponse } from "."
+import {
+	ApiHandlerOptions,
+	ModelInfo,
+	openAiNativeDefaultModelId,
+	OpenAiNativeModelId,
+	openAiNativeModels,
+} from "../shared/api"
+import { convertToAnthropicMessage, convertToOpenAiMessages } from "../utils/openai-format"
+
+export class OpenAiNativeHandler implements ApiHandler {
+	private options: ApiHandlerOptions
+	private client: OpenAI
+
+	constructor(options: ApiHandlerOptions) {
+		this.options = options
+		this.client = new OpenAI({
+			apiKey: this.options.openAiNativeApiKey,
+		})
+	}
+
+	async createMessage(
+		systemPrompt: string,
+		messages: Anthropic.Messages.MessageParam[],
+		tools: Anthropic.Messages.Tool[]
+	): Promise<ApiHandlerMessageResponse> {
+		const openAiMessages: OpenAI.Chat.ChatCompletionMessageParam[] = [
+			{ role: "system", content: systemPrompt },
+			...convertToOpenAiMessages(messages),
+		]
+		const openAiTools: OpenAI.Chat.ChatCompletionTool[] = tools.map((tool) => ({
+			type: "function",
+			function: {
+				name: tool.name,
+				description: tool.description,
+				parameters: tool.input_schema,
+			},
+		}))
+		const createParams: OpenAI.Chat.Completions.ChatCompletionCreateParamsNonStreaming = {
+			model: this.getModel().id,
+			max_tokens: this.getModel().info.maxTokens,
+			messages: openAiMessages,
+			tools: openAiTools,
+			tool_choice: "auto",
+		}
+		const completion = await this.client.chat.completions.create(createParams)
+		const errorMessage = (completion as any).error?.message
+		if (errorMessage) {
+			throw new Error(errorMessage)
+		}
+		const anthropicMessage = convertToAnthropicMessage(completion)
+		return { message: anthropicMessage }
+	}
+
+	getModel(): { id: OpenAiNativeModelId; info: ModelInfo } {
+		const modelId = this.options.apiModelId
+		if (modelId && modelId in openAiNativeModels) {
+			const id = modelId as OpenAiNativeModelId
+			return { id, info: openAiNativeModels[id] }
+		}
+		return { id: openAiNativeDefaultModelId, info: openAiNativeModels[openAiNativeDefaultModelId] }
+	}
+}