cartog 0.34.0

//! Stable-release version parsing and comparison.
//!
//! Shared by the background update check (`auto_check`) and the bin target's
//! `cartog self` / `cartog doctor` commands, which all read the same GitHub
//! releases payload and must agree on what counts as a stable release —
//! three of them previously carried byte-identical private copies.

/// Pull `tag_name` out of the GitHub release JSON, strip a leading `v`, and
/// return `None` for any prerelease-shaped tag.
///
/// SemVer prerelease metadata is delimited by `-`, so any hyphen in the
/// version (e.g. `0.15.0-rc.1`, `0.15.0-alpha`, `0.15.0-nightly.42`)
/// disqualifies the tag.
#[must_use]
pub fn parse_release_tag(json: &str) -> Option<String> {
    let parsed: serde_json::Value = serde_json::from_str(json).ok()?;
    let tag = parsed.get("tag_name")?.as_str()?;
    let trimmed = tag.strip_prefix('v').unwrap_or(tag);
    if trimmed.contains('-') {
        return None;
    }
    if !is_stable_semver(trimmed) {
        return None;
    }
    Some(trimmed.to_string())
}

/// Quick guard: accept exactly three dot-separated non-empty numeric parts.
#[must_use]
pub fn is_stable_semver(s: &str) -> bool {
    let parts: Vec<&str> = s.split('.').collect();
    parts.len() == 3
        && parts
            .iter()
            .all(|p| !p.is_empty() && p.bytes().all(|b| b.is_ascii_digit()))
}

/// Lexicographic compare on `(major, minor, patch)`.
///
/// Both inputs are expected to be stable `MAJOR.MINOR.PATCH` triples — any
/// non-numeric component is treated as `0`, so the function never panics on
/// weird input but degrades gracefully.
#[must_use]
pub fn compare_stable_versions(a: &str, b: &str) -> std::cmp::Ordering {
    let parse = |s: &str| -> [u64; 3] {
        let mut parts = s.split('.').map(|p| p.parse::<u64>().unwrap_or(0));
        [
            parts.next().unwrap_or(0),
            parts.next().unwrap_or(0),
            parts.next().unwrap_or(0),
        ]
    };
    parse(a).cmp(&parse(b))
}