//! Explicit data-directory isolation for portable use and native release QA.
//! Ordinary launches continue to use the operating system's app-data directory.
use std::{ffi::OsString, io, path::PathBuf};

pub fn resolve(default: PathBuf, override_path: Option<OsString>) -> io::Result<PathBuf> {
    let Some(value) = override_path else {
        return Ok(default);
    };
    let path = PathBuf::from(value);
    if !path.is_absolute() || path.as_os_str().len() > 32768 {
        return Err(io::Error::new(
            io::ErrorKind::InvalidInput,
            "SEARCHI_DATA_DIR must be an absolute bounded directory path",
        ));
    }
    Ok(path)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn explicit_directory_isolates_settings_and_index_without_changing_default() {
        let default = std::env::temp_dir().join("searchi-default");
        let isolated = std::env::temp_dir().join("searchi-isolated");
        assert_eq!(resolve(default.clone(), None).unwrap(), default);
        assert_eq!(
            resolve(default, Some(isolated.clone().into_os_string())).unwrap(),
            isolated
        );
    }

    #[test]
    fn invalid_override_is_rejected_without_falling_back_to_user_data() {
        let default = std::env::temp_dir().join("searchi-default");
        for value in [OsString::new(), OsString::from("relative/data")] {
            assert_eq!(
                resolve(default.clone(), Some(value)).unwrap_err().kind(),
                io::ErrorKind::InvalidInput
            );
        }
    }
}