feat: implement copyFiles function

src/app.js

@@ -1 +1,68 @@
+/* eslint-disable no-console */
 'use strict';
+
+const fs = require('fs/promises');
+const path = require('node:path');
+
+async function copyFiles() {
+  const args = process.argv.slice(2);
+  const [src, dest] = args;
+
+  if (!src || !dest || args.length > 2) {
+    console.error('Two arguments are required');
+
+    return;
+  }
+
+  for (const arg of args) {
+    if (arg.startsWith('-')) {
+      console.error('Arguments should not start with a dash');
+
+      return;
+    }
+  }
+
+  if (path.resolve(src) === path.resolve(dest)) {
+    return;
+  }
+
+  let srcStat;
+
+  try {
+    srcStat = await fs.stat(src);
+  } catch {
+    console.error('Source file does not exist');
+
+    return;
+  }
+
+  if (!srcStat.isFile()) {
+    console.error('Source is not a file');
+
+    return;
+  }
+
+  try {
+    const destStat = await fs.stat(dest);
+
+    if (destStat.isDirectory()) {
+      console.error('Destination is a directory');
+
+      return;
+    }
+  } catch (err) {
+    if (err.code !== 'ENOENT') {
+      console.error('Error checking destination file');
+
+      return;
+    }
+  }
+
+  try {
+    await fs.copyFile(src, dest);
+  } catch (err) {
+    console.error('Error copying file:', err.message);
+  }
+}
+
+copyFiles();