main.rs

use async_std::{fs, path::Path, prelude::*};
use rand::{prelude::*, thread_rng};
use std::io::{Error, ErrorKind};
use wallpaper;

const WALLPAPER_DIR: &'static str = "/home/zack/Pictures/Wallpapers";
const ACCEPTED_EXTENSIONS: [&str; 3] = ["jpeg", "jpg", "png"];

async fn read_wallpapers() -> Result<Vec<String>, Error> {
    let base_path = Path::new(WALLPAPER_DIR);
    let mut files = Vec::new();
    let mut entries = fs::read_dir(WALLPAPER_DIR).await?;

    while let Some(entry) = entries.next().await {
        let entry = entry?;
        let file_name = entry.file_name().to_string_lossy().into_owned();

        if let Some(file_extension) = entry.path().extension() {
            for extension in ACCEPTED_EXTENSIONS {
                if !file_extension.eq(extension) {
                    continue;
                }
            }
        }

        files.push(base_path.join(file_name).to_string_lossy().into_owned());
    }

    Ok(files)
}

async fn get_random_wallpaper(wallpapers: &mut Vec<String>) -> Result<String, Error> {
    wallpapers.shuffle(&mut thread_rng());

    if let Some(entry) = wallpapers.first() {
        Ok(entry.clone())
    } else {
        Err(ErrorKind::NotFound.into())
    }
}

#[async_std::main]
async fn main() -> Result<(), Error> {
    let mut wallpapers = read_wallpapers().await?;
    let random_wallpaper = get_random_wallpaper(&mut wallpapers).await?;

    wallpaper::set_from_path(random_wallpaper.as_str())
        .map_err(|_| -> Error { ErrorKind::Other.into() })?;

    Ok(())
}