import { lstat, mkdir, readFile, unlink, writeFile } from "node:fs/promises";
import { homedir } from "node:os";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";

const EXTENSION_ID = "omp-dashscope";
const EXTENSIONS_DIR = join(homedir(), ".omp", "agent", "extensions");
const EXTENSION_DIR = join(EXTENSIONS_DIR, EXTENSION_ID);
const PACKAGE_ROOT = dirname(fileURLToPath(import.meta.url));
const SOURCE_EXTENSION_FILE = join(PACKAGE_ROOT, "index.ts");
const TARGET_EXTENSION_FILE = join(EXTENSION_DIR, "index.ts");

async function ensureExtensionFiles(): Promise<void> {
	await mkdir(EXTENSIONS_DIR, { recursive: true });

	try {
		const stat = await lstat(EXTENSION_DIR);
		if (stat.isSymbolicLink()) {
			await unlink(EXTENSION_DIR);
		}
	} catch {
		// Extension directory does not exist yet.
	}

	await mkdir(EXTENSION_DIR, { recursive: true });

	const source = await readFile(SOURCE_EXTENSION_FILE, "utf8");
	let current = "";
	try {
		current = await readFile(TARGET_EXTENSION_FILE, "utf8");
	} catch {
		// File not present yet.
	}
	if (current !== source) {
		await writeFile(TARGET_EXTENSION_FILE, source, "utf8");
	}
}

export default async function () {
	try {
		await ensureExtensionFiles();
	} catch {
		// Ignore bootstrap errors: plugin should not block startup.
	}
	return [];
}