use anyhow::Result;
use std::path::Path;

/// Last-known-published version per package, so re-runs don't re-flag a
/// version already handled. Deliberately just one file per package for
/// now — this is where a real review-queue persistence layer plugs in
/// later (see SPEC.md > Architecture > Reviewer queue).
pub fn load_last_version(state_dir: &Path, name: &str) -> Option<String> {
    std::fs::read_to_string(state_dir.join(format!("{name}.version")))
        .ok()
        .map(|s| s.trim().to_string())
}

pub fn save_last_version(state_dir: &Path, name: &str, version: &str) -> Result<()> {
    std::fs::create_dir_all(state_dir)?;
    std::fs::write(state_dir.join(format!("{name}.version")), version)?;
    Ok(())
}

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

    #[test]
    fn load_last_version_missing_file_returns_none() {
        let dir = tempfile::tempdir().unwrap();
        assert_eq!(load_last_version(dir.path(), "nonexistent"), None);
    }

    #[test]
    fn save_then_load_roundtrips() {
        let dir = tempfile::tempdir().unwrap();
        save_last_version(dir.path(), "uv", "0.12.15").unwrap();
        assert_eq!(
            load_last_version(dir.path(), "uv"),
            Some("0.12.15".to_string())
        );
    }

    #[test]
    fn load_last_version_trims_trailing_whitespace() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::write(dir.path().join("uv.version"), "0.12.15\n").unwrap();
        assert_eq!(
            load_last_version(dir.path(), "uv"),
            Some("0.12.15".to_string())
        );
    }

    #[test]
    fn save_last_version_creates_state_dir_if_missing() {
        let dir = tempfile::tempdir().unwrap();
        let nested = dir.path().join("nested/state");
        save_last_version(&nested, "uv", "0.12.15").unwrap();
        assert_eq!(
            load_last_version(&nested, "uv"),
            Some("0.12.15".to_string())
        );
    }
}