/**
 * Shared filesystem helpers.
 */

import { lstatSync, readdirSync, statSync } from 'node:fs'
import { join } from 'node:path'

/**
 * Recursively collect files matching an extension filter.
 * Single sort at the end — no intermediate sorting during recursion.
 */
export function walkDir(dir: string, extensions: string[]): string[] {
	const results: string[] = []
	collect(dir, extensions, results)
	return results.sort()
}

function collect(dir: string, extensions: string[], out: string[]) {
	let entries
	try {
		entries = readdirSync(dir, { withFileTypes: true })
	} catch {
		return
	}
	for (const entry of entries) {
		const full = join(dir, entry.name)
		if (entry.isDirectory()) {
			collect(full, extensions, out)
		} else if (extensions.some((ext) => entry.name.endsWith(ext))) {
			out.push(full)
		}
	}
}

/** Check if path is a directory — single syscall, no throw. */
export function isDir(path: string): boolean {
	try {
		return statSync(path).isDirectory()
	} catch {
		return false
	}
}

/** Check if path is a file — single syscall, no throw. */
export function isFile(path: string): boolean {
	try {
		return statSync(path).isFile()
	} catch {
		return false
	}
}

/** Check if path is a symbolic link — uses lstat, no throw. */
export function isSymlink(path: string): boolean {
	try {
		return lstatSync(path).isSymbolicLink()
	} catch {
		return false
	}
}