//! Persists two independent per-package facts as plain files: the last
//! published version, and any version currently pending human review.
//! The only module that touches the state directory (see `paths.rs`) on disk.

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 docs/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(())
}

/// Tag currently awaiting human review for a tier 4-6 package (see
/// docs/SPEC.md > Architecture > Reviewer queue), if any. Separate from
/// `load_last_version`/`save_last_version`: approving a review doesn't
/// mean future versions auto-publish, so the two must be tracked
/// independently.
pub fn load_pending_version(state_dir: &Path, name: &str) -> Option<String> {
    std::fs::read_to_string(state_dir.join(format!("{name}.pending")))
        .ok()
        .map(|s| s.trim().to_string())
}

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

/// Clears a pending review, e.g. once it's been approved and published.
/// Not an error if there was nothing pending.
pub fn clear_pending_version(state_dir: &Path, name: &str) -> Result<()> {
    match std::fs::remove_file(state_dir.join(format!("{name}.pending"))) {
        Ok(()) => Ok(()),
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
        Err(e) => Err(e.into()),
    }
}

#[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())
        );
    }

    #[test]
    fn load_pending_version_missing_file_returns_none() {
        let dir = tempfile::tempdir().unwrap();
        assert_eq!(load_pending_version(dir.path(), "scaleway-cli"), None);
    }

    #[test]
    fn save_then_load_pending_roundtrips() {
        let dir = tempfile::tempdir().unwrap();
        save_pending_version(dir.path(), "scaleway-cli", "v2.62.0").unwrap();
        assert_eq!(
            load_pending_version(dir.path(), "scaleway-cli"),
            Some("v2.62.0".to_string())
        );
    }

    #[test]
    fn clear_pending_version_removes_it() {
        let dir = tempfile::tempdir().unwrap();
        save_pending_version(dir.path(), "scaleway-cli", "v2.62.0").unwrap();
        clear_pending_version(dir.path(), "scaleway-cli").unwrap();
        assert_eq!(load_pending_version(dir.path(), "scaleway-cli"), None);
    }

    #[test]
    fn clear_pending_version_is_a_noop_when_nothing_pending() {
        let dir = tempfile::tempdir().unwrap();
        assert!(clear_pending_version(dir.path(), "scaleway-cli").is_ok());
    }

    #[test]
    fn pending_and_last_version_are_tracked_independently() {
        let dir = tempfile::tempdir().unwrap();
        save_last_version(dir.path(), "scaleway-cli", "v2.61.0").unwrap();
        save_pending_version(dir.path(), "scaleway-cli", "v2.62.0").unwrap();
        assert_eq!(
            load_last_version(dir.path(), "scaleway-cli"),
            Some("v2.61.0".to_string())
        );
        assert_eq!(
            load_pending_version(dir.path(), "scaleway-cli"),
            Some("v2.62.0".to_string())
        );
    }
}