feat: Add basic directory walker functionality

Walk a directory recursively finding all *.mp3 and *.flac files, exclue
common hidden files and folders.

src/main.rs

@@ -1,3 +1,47 @@
-fn main() {
-    println!("Hello, world!");
+use ignore::types::TypesBuilder;
+use ignore::WalkBuilder;
+use std::{env, io, path::PathBuf};
+
+use clap::Parser;
+
+#[derive(Parser)]
+#[command(version, about, long_about = None)]
+struct Args {
+    #[arg(help = "Directory to scan for files")]
+    path: Option<PathBuf>,
+}
+
+fn walk_dir(path: &PathBuf) -> io::Result<()> {
+    let mut types_builder = TypesBuilder::new();
+    types_builder.add_defaults();
+
+    let accepted_filetypes = ["mp3", "flac"];
+
+    for filetype in accepted_filetypes {
+        let _ = types_builder.add("sound", format!("*.{}", filetype).as_str());
+    }
+
+    types_builder.select("sound");
+
+    let entries = WalkBuilder::new(path)
+        .types(types_builder.build().unwrap())
+        .build()
+        .filter_map(|entry| entry.ok())
+        .filter(|entry| !entry.path().is_dir());
+
+    for result in entries {
+        let path = result.path();
+
+        println!("{}", path.display());
+    }
+    Ok(())
+}
+
+fn main() {
+    let cli = Args::parse();
+    let path = cli
+        .path
+        .unwrap_or(env::current_dir().expect("Current directory is not available."));
+
+    walk_dir(&path).expect("error");
 }