import { Configuration, OpenAIApi } from 'openai';

const sanitizeMessage = (message: string) => message.trim().replace(/[\n\r]/g, '').replace(/(\w)\.$/, '$1');

const promptTemplate = 'Write an insightful but concise Git commit message in a complete sentence in present tense for the following diff without prefacing it with anything:';

export const generateCommitMessage = async (
	apiKey: string,
	diff: string,
	completions: number,
) => {
	const prompt = `${promptTemplate}\n${diff}`;

	// Accounting for GPT-3's input req of 4k tokens (approx 8k chars)
	if (prompt.length > 8000) {
		throw new Error('The diff is too large for the OpenAI API');
	}

	const openai = new OpenAIApi(new Configuration({ apiKey }));
	try {
		const completion = await openai.createCompletion({
			model: 'text-davinci-003',
			prompt,
			temperature: 0.7,
			top_p: 1,
			frequency_penalty: 0,
			presence_penalty: 0,
			max_tokens: 200,
			stream: false,
			n: completions,
		});

		return completion.data.choices
			.filter(choice => choice.text)
			.map(choice => sanitizeMessage(choice.text!));
	} catch (error) {
		const errorAsAny = error as any;
		errorAsAny.message = `OpenAI API Error: ${errorAsAny.message} - ${errorAsAny.response.statusText}`;
		throw errorAsAny;
	}
};