#!/usr/bin/env node

import { execSync } from 'child_process';
import chalk from 'chalk';
import inquirer from 'inquirer';
import fetch from 'node-fetch';

const OPENAI_KEY = process.env.OPENAI_KEY ?? process.env.OPENAI_API_KEY;

export async function main() {
	console.log(chalk.white('▲ ') + chalk.green('Welcome to AICommits!'));

	if (!OPENAI_KEY) {
		console.error(
			`${chalk.white('▲ ')
         }Please save your OpenAI API key as an env variable by doing 'export OPENAI_KEY=YOUR_API_KEY'`,
		);
		process.exit(1);
	}
	try {
		execSync('git rev-parse --is-inside-work-tree', {
			encoding: 'utf8',
			stdio: 'ignore',
		});
	} catch {
		console.error(`${chalk.white('▲ ')}This is not a git repository`);
		process.exit(1);
	}

	const diff = execSync(
		'git diff --cached . ":(exclude)package-lock.json" ":(exclude)yarn.lock" ":(exclude)pnpm-lock.yaml"',
		{
			encoding: 'utf8',
		},
	);

	if (!diff) {
		console.log(
			`${chalk.white('▲ ')
         }No staged changes found. Make sure there are changes and run \`git add .\``,
		);
		process.exit(1);
	}

	// Accounting for GPT-3's input req of 4k tokens (approx 8k chars)
	if (diff.length > 8000) {
		console.log(
			`${chalk.white('▲ ')}The diff is too large to write a commit message.`,
		);
		process.exit(1);
	}

	const prompt = `I want you to act like a git commit message writer. I will input a git diff and your job is to convert it into a useful commit message. Do not preface the commit with anything, use the present tense, return a complete sentence, and do not repeat yourself: ${diff}`;

	console.log(
		chalk.white('▲ ') + chalk.gray('Generating your AI commit message...\n'),
	);

	try {
		const aiCommitMessage = await generateCommitMessage(prompt);
		console.log(
			`${chalk.white('▲ ') + chalk.bold('Commit message: ') + aiCommitMessage
		}\n`,
		);

		const confirmationMessage = await inquirer.prompt([
			{
				name: 'useCommitMessage',
				message: 'Would you like to use this commit message? (Y / n)',
				choices: ['Y', 'y', 'n'],
				default: 'y',
			},
		]);

		if (confirmationMessage.useCommitMessage === 'n') {
			console.log(`${chalk.white('▲ ')}Commit message has not been commited.`);
			process.exit(1);
		}

		execSync(`git commit -m "${aiCommitMessage}"`, {
			stdio: 'inherit',
			encoding: 'utf8',
		});
	} catch (error) {
		console.error(chalk.white('▲ ') + chalk.red(error.message));
		process.exit(1);
	}
}

async function generateCommitMessage(prompt: string) {
	const payload = {
		model: 'text-davinci-003',
		prompt,
		temperature: 0.7,
		top_p: 1,
		frequency_penalty: 0,
		presence_penalty: 0,
		max_tokens: 200,
		stream: false,
		n: 1,
	};
	const response = await fetch('https://api.openai.com/v1/completions', {
		headers: {
			'Content-Type': 'application/json',
			Authorization: `Bearer ${OPENAI_KEY ?? ''}`,
		},
		method: 'POST',
		body: JSON.stringify(payload),
	});
	if (response.status !== 200) {
		const errorJson: any = await response.json();
		throw new Error(
      `OpenAI API failed while processing the request '${errorJson?.error?.message}'`,
		);
	}

	const json: any = await response.json();
	const aiCommit = json.choices[0].text;

	return aiCommit.replace(/(\r\n|\n|\r)/g, '');
}