Rust TypeScript type generator for images

main.rs

use std::env;
use std::fs::File;
use std::io::Write;
use std::time::Instant;
use walkdir::WalkDir;
use image::GenericImageView;
use rayon::prelude::*;

fn main() {
    // Read input and output file paths
    let args: Vec<String> = env::args().collect();
    if args.len() != 3 {
        eprintln!("Usage: program_name input_file_path output_file_path");
        return;
    }
    let input_file_path = &args[1];
    let output_file_path = &args[2];

    println!("Generating image TypeScript file...");
    let start = Instant::now();

    let entries =
        WalkDir::new(input_file_path)
            .into_iter()
            .filter_map(|e| e.ok())
            .collect::<Vec<_>>();

    let extensions = ["webp"];  // TODO(acorn1010): Maybe add png here, since it's a different size?
    let results: Vec<_> = entries
        .par_iter()
        .filter_map(|entry| {
            match entry.path().extension().and_then(|ext| ext.to_str()) {
                Some(extension) if extensions.contains(&extension) => {
                    if let Ok(image) = image::open(&entry.path()) {
                        let (width, height) = image.dimensions();
                        let filename = entry.path()
                            .with_extension("")
                            .strip_prefix(input_file_path)
                            .unwrap()
                            .display()
                            .to_string();
                        Some((filename, width, height))
                    } else {
                        None
                    }
                }
                _ => None,
            }
        })
        .collect();

    let mut sorted_results = results;
    sorted_results.par_sort_unstable_by(|a, b| a.0.cmp(&b.0));

    let mut file = File::create(output_file_path).unwrap();
    file.write_all(b"/** This file is auto-generated by scripts/rust/image_utils. */\n").unwrap();
    file.write_all(b"\n").unwrap();
    file.write_all(b"/**\n").unwrap();
    file.write_all(b" * Maps the base filepath (from Foony's domain) to an image path without the extension.\n").unwrap();
    file.write_all(b" * .webp and .avif extensions are supported for all files here.\n").unwrap();
    file.write_all(b" */\n").unwrap();
    file.write_all(b"export type SiteImages = {\n").unwrap();
    for (filename, width, height) in sorted_results {
        let line = format!("  '{}': {{width: {}, height: {}}},\n", filename, width, height);
        file.write_all(line.as_bytes()).unwrap();
    }
    file.write_all(b"};\n").unwrap();
    file.write_all(b"export type SiteImage = keyof SiteImages;\n").unwrap();

    println!("Elapsed time: {:?}", start.elapsed());
}