You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: scss.rs
    path of file: ./repos/eww/crates/eww/src/config
    
    the code of the file until where you have to start completion: use std::path::Path;

use anyhow::{anyhow, Context};

use crate::{error_handling_ctx, util::replace_env_var_references};

/// read an (s)css file, replace all environment variable references within it and
/// then parse it into css.
/// Also adds the CSS to the [`crate::file_database::FileDatabase`]
pub fn parse_scss_from_config(path: &Path) -> anyhow::Result<(usize, String)> {
    let css_file = path.join("eww.css");
    let scss_file = path.join("eww.scss");
    if css_file.exists() && scss_file.exists() {
        return Err(anyhow!("
    
pub fn parse_scss_from_config(path: &Path) -> anyhow::Result<(usize, String)> {
    let css_file = path.join("eww.css");
    let scss_file = path.join("eww.scss");
    if css_file.exists() && scss_file.exists() {
        return Err(anyhow!("Encountered both an SCSS and CSS file. Only one of these may exist at a time"));
    }

    let (s_css_path, css) = if css_file.exists() {
        let css_file_content = std::fs::read_to_string(&css_file)
            .with_context(|| format!("Given CSS file doesn't exist: {}", css_file.display()))?;
        let css = replace_env_var_references(css_file_content);
        (css_file, css)
    } else {
        let scss_file_content =
            std::fs::read_to_string(&scss_file).with_context(|| format!("Given SCSS file doesn't exist! {}", path.display()))?;
        let file_content = replace_env_var_references(scss_file_content);
        let grass_config = grass::Options::default().load_path(path);
        let css = grass::from_string(file_content, &grass_config).map_err(|err| anyhow!("SCSS parsing error: {}", err))?;
        (scss_file, css)
    };

    let mut file_db = error_handling_ctx::FILE_DATABASE.write().unwrap();
    let file_id = file_db.insert_string(s_css_path.display().to_string(), css.clone())?;
    Ok((file_id, css))
}