harn-cli 0.8.25

//! Self-update for the `harn` CLI.
//!
//! Mirrors the logic in `install.sh`: resolves a target release on
//! GitHub, downloads the matching tarball, verifies it against the
//! release's `SHA256SUMS` manifest, then atomically replaces the
//! currently running binary. macOS binaries are notarized at release
//! time, so Gatekeeper does the cryptographic identity check on first
//! launch after replacement.

use std::env;
use std::fs;
use std::io::Read;
use std::path::Path;
use std::time::Duration;

use sha2::{Digest, Sha256};

use crate::cli::UpgradeArgs;

const REPO: &str = "burin-labs/harn";
const RELEASES_BASE: &str = "https://github.com/burin-labs/harn/releases";
const USER_AGENT: &str = concat!("harn-cli/", env!("CARGO_PKG_VERSION"));
const REQUEST_TIMEOUT: Duration = Duration::from_secs(60);

/// `harn upgrade` lives on tokio's blocking pool so the synchronous
/// `reqwest::blocking` / `tar::Archive` / `fs::rename` calls below can
/// share a single straight-line implementation. The CLI dispatcher
/// runs inside a tokio multi-thread runtime, where dropping a nested
/// blocking client on the async thread itself panics.
pub(crate) async fn run(args: UpgradeArgs) -> Result<(), String> {
    tokio::task::spawn_blocking(move || run_blocking(args))
        .await
        .map_err(|error| format!("upgrade task failed: {error}"))?
}

fn run_blocking(args: UpgradeArgs) -> Result<(), String> {
    let triple = target_triple()?;
    let current = env!("CARGO_PKG_VERSION");

    let target = match args.version.as_deref() {
        Some(v) => normalize_version(v)?,
        None => fetch_latest_tag()?,
    };

    println!("Installed: v{current}");
    println!("Target:    {target}");

    if args.check {
        return Ok(());
    }

    if !args.force && target.trim_start_matches('v') == current {
        println!("Already on the latest release.");
        return Ok(());
    }

    let current_exe =
        env::current_exe().map_err(|error| format!("failed to resolve current exe: {error}"))?;
    let current_exe = current_exe
        .canonicalize()
        .unwrap_or_else(|_| current_exe.clone());
    let install_dir = current_exe
        .parent()
        .ok_or_else(|| format!("{} has no parent directory", current_exe.display()))?
        .to_path_buf();

    let archive_name = format!("harn-{triple}.tar.gz");
    let archive_url = format!("{RELEASES_BASE}/download/{target}/{archive_name}");
    let checksums_url = format!("{RELEASES_BASE}/download/{target}/SHA256SUMS");

    let staging = tempfile::tempdir()
        .map_err(|error| format!("failed to create staging directory: {error}"))?;
    let archive_path = staging.path().join(&archive_name);

    println!("Downloading {archive_name}");
    download(&archive_url, &archive_path)?;

    if args.no_verify {
        eprintln!("warning: SHA256 verification skipped (--no-verify)");
    } else {
        verify_checksum(&checksums_url, &archive_name, &archive_path)?;
    }

    println!("Extracting");
    extract_tarball(&archive_path, staging.path())?;

    let staged_binary = staging.path().join(harn_binary_name());
    if !staged_binary.exists() {
        return Err(format!(
            "archive did not contain {} — refusing to upgrade",
            harn_binary_name(),
        ));
    }

    install_binaries(staging.path(), &install_dir)?;

    println!("Upgraded harn to {target}. Re-run your last command to use the new binary.",);
    Ok(())
}

/// Compile-time host target triple for selecting the matching release
/// archive. Keep this list in sync with the targets produced by
/// `.github/workflows/build-release-binaries.yml`.
fn target_triple() -> Result<&'static str, String> {
    let triple = if cfg!(all(target_os = "macos", target_arch = "x86_64")) {
        "x86_64-apple-darwin"
    } else if cfg!(all(target_os = "macos", target_arch = "aarch64")) {
        "aarch64-apple-darwin"
    } else if cfg!(all(target_os = "linux", target_arch = "x86_64")) {
        "x86_64-unknown-linux-gnu"
    } else if cfg!(all(target_os = "linux", target_arch = "aarch64")) {
        "aarch64-unknown-linux-gnu"
    } else if cfg!(all(target_os = "windows", target_arch = "x86_64")) {
        return Err(
            "`harn upgrade` is not implemented for Windows yet; download the zip from \
                    https://github.com/burin-labs/harn/releases and replace harn.exe manually"
                .to_string(),
        );
    } else {
        return Err("self-update is not supported on this target".to_string());
    };
    Ok(triple)
}

fn harn_binary_name() -> &'static str {
    if cfg!(target_os = "windows") {
        "harn.exe"
    } else {
        "harn"
    }
}

fn extra_binary_names() -> &'static [&'static str] {
    if cfg!(target_os = "windows") {
        &["harn-dap.exe", "harn-lsp.exe"]
    } else {
        &["harn-dap", "harn-lsp"]
    }
}

fn normalize_version(input: &str) -> Result<String, String> {
    let trimmed = input.trim();
    if trimmed.is_empty() {
        return Err("--version cannot be empty".to_string());
    }
    let normalized = if trimmed.starts_with('v') {
        trimmed.to_string()
    } else {
        format!("v{trimmed}")
    };
    let rest = normalized.trim_start_matches('v');
    let parts: Vec<&str> = rest.split('.').collect();
    if parts.len() != 3
        || parts
            .iter()
            .any(|p| p.is_empty() || !p.chars().all(|c| c.is_ascii_digit()))
    {
        return Err(format!("invalid version: {input} (expected vX.Y.Z)"));
    }
    Ok(normalized)
}

fn http_client() -> Result<reqwest::blocking::Client, String> {
    reqwest::blocking::Client::builder()
        .user_agent(USER_AGENT)
        .timeout(REQUEST_TIMEOUT)
        .build()
        .map_err(|error| format!("failed to build HTTP client: {error}"))
}

fn fetch_latest_tag() -> Result<String, String> {
    let client = http_client()?;
    let response = client
        .get(format!(
            "https://api.github.com/repos/{REPO}/releases/latest"
        ))
        .header("Accept", "application/vnd.github+json")
        .send()
        .map_err(|error| format!("failed to query latest release: {error}"))?;
    if !response.status().is_success() {
        return Err(format!(
            "GitHub API returned status {} when resolving latest release",
            response.status()
        ));
    }
    let body: serde_json::Value = response
        .json()
        .map_err(|error| format!("failed to parse latest release response: {error}"))?;
    let tag = body
        .get("tag_name")
        .and_then(|v| v.as_str())
        .ok_or_else(|| "GitHub API response did not include a tag_name".to_string())?;
    Ok(tag.to_string())
}

fn download(url: &str, dest: &Path) -> Result<(), String> {
    let client = http_client()?;
    let mut response = client
        .get(url)
        .send()
        .map_err(|error| format!("failed to download {url}: {error}"))?;
    if !response.status().is_success() {
        return Err(format!(
            "download {url} returned status {}",
            response.status()
        ));
    }
    let mut file = fs::File::create(dest)
        .map_err(|error| format!("failed to create {}: {error}", dest.display()))?;
    response
        .copy_to(&mut file)
        .map_err(|error| format!("failed to write {}: {error}", dest.display()))?;
    Ok(())
}

fn verify_checksum(checksums_url: &str, asset: &str, path: &Path) -> Result<(), String> {
    let client = http_client()?;
    let response = client
        .get(checksums_url)
        .send()
        .map_err(|error| format!("failed to fetch SHA256SUMS: {error}"))?;
    if !response.status().is_success() {
        // Releases predating the SHA256SUMS workflow step won't have
        // this manifest. Match install.sh's behavior and warn-and-skip
        // rather than refusing — TLS to github.com is still in place.
        eprintln!(
            "warning: no SHA256SUMS published for this release (status {}); skipping verification",
            response.status()
        );
        return Ok(());
    }
    let manifest = response
        .text()
        .map_err(|error| format!("failed to read SHA256SUMS body: {error}"))?;

    let expected = find_expected_sha(&manifest, asset)
        .ok_or_else(|| format!("SHA256SUMS does not include an entry for {asset}"))?;

    let mut file = fs::File::open(path)
        .map_err(|error| format!("failed to open {}: {error}", path.display()))?;
    let mut hasher = Sha256::new();
    let mut buf = [0u8; 64 * 1024];
    loop {
        let n = file
            .read(&mut buf)
            .map_err(|error| format!("failed to read {}: {error}", path.display()))?;
        if n == 0 {
            break;
        }
        hasher.update(&buf[..n]);
    }
    let actual = hex_lower(&hasher.finalize());

    if actual != expected {
        return Err(format!(
            "SHA256 mismatch for {asset}: expected {expected}, got {actual}"
        ));
    }
    println!("Verified SHA256 ({asset})");
    Ok(())
}

/// Parse a coreutils-style SHA256SUMS manifest and return the digest
/// for `asset`. Tolerates the leading `*` binary-mode marker and any
/// directory prefix on the filename.
fn find_expected_sha(manifest: &str, asset: &str) -> Option<String> {
    for line in manifest.lines() {
        let line = line.trim();
        if line.is_empty() || line.starts_with('#') {
            continue;
        }
        let mut parts = line.splitn(2, char::is_whitespace);
        let digest = parts.next()?.trim();
        let name = parts.next()?.trim().trim_start_matches('*');
        let basename = Path::new(name)
            .file_name()
            .and_then(|s| s.to_str())
            .unwrap_or(name);
        if basename == asset {
            return Some(digest.to_ascii_lowercase());
        }
    }
    None
}

fn hex_lower(bytes: &[u8]) -> String {
    let mut s = String::with_capacity(bytes.len() * 2);
    for b in bytes {
        s.push_str(&format!("{b:02x}"));
    }
    s
}

fn extract_tarball(archive: &Path, dest: &Path) -> Result<(), String> {
    let file = fs::File::open(archive)
        .map_err(|error| format!("failed to open archive {}: {error}", archive.display()))?;
    let gz = flate2::read::GzDecoder::new(file);
    let mut tar = tar::Archive::new(gz);
    tar.unpack(dest)
        .map_err(|error| format!("failed to extract archive: {error}"))?;
    Ok(())
}

fn install_binaries(staging: &Path, install_dir: &Path) -> Result<(), String> {
    let mut names: Vec<&str> = vec![harn_binary_name()];
    names.extend_from_slice(extra_binary_names());
    for name in names {
        let src = staging.join(name);
        if !src.exists() {
            // Only the main `harn` binary is required; sibling tools
            // are best-effort.
            if name == harn_binary_name() {
                return Err(format!("staging directory missing {name}"));
            }
            continue;
        }
        let dest = install_dir.join(name);
        atomic_replace(&src, &dest)?;
    }
    Ok(())
}

fn atomic_replace(src: &Path, dest: &Path) -> Result<(), String> {
    // Stage a sibling temp file inside the destination directory so the
    // rename is intra-filesystem and therefore atomic on POSIX. Copying
    // from the (potentially tmpfs) staging dir into the same directory
    // as `dest` ensures the final rename stays inside one filesystem.
    let parent = dest
        .parent()
        .ok_or_else(|| format!("{} has no parent directory", dest.display()))?;
    let dest_basename = dest
        .file_name()
        .and_then(|s| s.to_str())
        .ok_or_else(|| format!("{} has no file name", dest.display()))?;
    let temp_in_dest = parent.join(format!(
        ".{dest_basename}.harn-upgrade-{pid}-{counter}",
        pid = std::process::id(),
        counter = next_upgrade_counter(),
    ));
    if let Err(error) = fs::copy(src, &temp_in_dest) {
        return Err(format!(
            "failed to stage {} -> {}: {error}",
            src.display(),
            temp_in_dest.display(),
        ));
    }
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        let perms = fs::Permissions::from_mode(0o755);
        if let Err(error) = fs::set_permissions(&temp_in_dest, perms) {
            let _ = fs::remove_file(&temp_in_dest);
            return Err(format!("failed to chmod staged binary: {error}"));
        }
    }
    if let Err(error) = fs::rename(&temp_in_dest, dest) {
        let _ = fs::remove_file(&temp_in_dest);
        return Err(format!("failed to replace {}: {error}", dest.display(),));
    }
    Ok(())
}

fn next_upgrade_counter() -> u64 {
    use std::sync::atomic::{AtomicU64, Ordering};
    static COUNTER: AtomicU64 = AtomicU64::new(0);
    COUNTER.fetch_add(1, Ordering::Relaxed)
}

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

    #[test]
    fn normalize_version_accepts_v_prefix() {
        assert_eq!(normalize_version("v0.8.19").unwrap(), "v0.8.19");
    }

    #[test]
    fn normalize_version_adds_v_prefix() {
        assert_eq!(normalize_version("0.8.19").unwrap(), "v0.8.19");
    }

    #[test]
    fn normalize_version_rejects_garbage() {
        assert!(normalize_version("not-a-version").is_err());
        assert!(normalize_version("v0.8").is_err());
        assert!(normalize_version("").is_err());
        assert!(normalize_version("v0.8.x").is_err());
    }

    #[test]
    fn find_expected_sha_parses_coreutils_format() {
        let manifest = "\
deadbeef00000000000000000000000000000000000000000000000000000000  harn-x86_64-apple-darwin.tar.gz
cafef00d00000000000000000000000000000000000000000000000000000000  harn-aarch64-apple-darwin.tar.gz
";
        assert_eq!(
            find_expected_sha(manifest, "harn-aarch64-apple-darwin.tar.gz").as_deref(),
            Some("cafef00d00000000000000000000000000000000000000000000000000000000"),
        );
    }

    #[test]
    fn find_expected_sha_tolerates_binary_mode_marker() {
        let manifest =
            "deadbeef00000000000000000000000000000000000000000000000000000000 *harn-x86_64-pc-windows-msvc.zip\n";
        assert_eq!(
            find_expected_sha(manifest, "harn-x86_64-pc-windows-msvc.zip").as_deref(),
            Some("deadbeef00000000000000000000000000000000000000000000000000000000"),
        );
    }

    #[test]
    fn find_expected_sha_misses_unknown_asset() {
        let manifest = "abc  some-other.tar.gz\n";
        assert!(find_expected_sha(manifest, "harn-x86_64-apple-darwin.tar.gz").is_none());
    }
}