flatland-client-lib 0.2.32

//! Client binary self-update against the public `latest.json` release manifest.

use std::collections::HashMap;
use std::fs::{self, File};
use std::io::{BufReader, Write};
use std::path::{Path, PathBuf};

use anyhow::{anyhow, bail, Context};
use flate2::read::GzDecoder;
use serde::{Deserialize, Serialize};
use sha2::{Digest, Sha256};
use tracing::{info, warn};

use crate::assets::DEFAULT_FIREBASE_BUCKET;

const DEFAULT_RELEASES_PREFIX: &str = "flatland3/client-releases";
const BINARIES: &[&str] = &["flatland3", "flatland3-gfx"];

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct UpdateManifest {
    pub version: String,
    #[serde(default)]
    pub published_at: Option<String>,
    pub artifacts: HashMap<String, Artifact>,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct Artifact {
    pub path: String,
    pub sha256: String,
    pub size: u64,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct UpdateAvailable {
    pub local_version: String,
    pub remote_version: String,
    pub platform: String,
    pub artifact: Artifact,
    pub archive_url: String,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct AppliedUpdate {
    pub version: String,
    pub install_dir: PathBuf,
}

/// Public HTTPS URL for `latest.json` (same construction as `install.sh`).
pub fn default_latest_url() -> String {
    if let Ok(url) = std::env::var("FLATLAND_UPDATE_URL") {
        if !url.trim().is_empty() {
            return url;
        }
    }
    let bucket = std::env::var("FLATLAND_ASSETS_BUCKET")
        .unwrap_or_else(|_| DEFAULT_FIREBASE_BUCKET.to_string());
    let prefix = std::env::var("FLATLAND_CLIENT_RELEASES_PREFIX")
        .unwrap_or_else(|_| DEFAULT_RELEASES_PREFIX.to_string());
    format!(
        "https://storage.googleapis.com/{}/{}/latest.json",
        bucket,
        prefix.trim_end_matches('/')
    )
}

pub fn local_version() -> &'static str {
    env!("CARGO_PKG_VERSION")
}

/// Mirror `detect_platform()` from `scripts/client-release/install.sh`.
pub fn platform_tag() -> Option<&'static str> {
    match (std::env::consts::OS, std::env::consts::ARCH) {
        ("macos", "aarch64") => Some("macos-aarch64"),
        ("macos", "x86_64") => Some("macos-x86_64"),
        ("linux", "x86_64") => Some("linux-x86_64"),
        ("windows", "x86_64") => Some("windows-x86_64"),
        _ => None,
    }
}

pub fn is_newer(local: &str, remote: &str) -> bool {
    match (parse_semver(local), parse_semver(remote)) {
        (Some(l), Some(r)) => r > l,
        _ => remote != local && !remote.is_empty(),
    }
}

fn parse_semver(raw: &str) -> Option<semver::Version> {
    let trimmed = raw.trim().trim_start_matches('v');
    semver::Version::parse(trimmed).ok()
}

/// Directory containing the running client binaries (`current_exe` parent).
pub fn update_dir() -> anyhow::Result<PathBuf> {
    let exe = std::env::current_exe().context("resolve current_exe")?;
    let dir = exe
        .parent()
        .ok_or_else(|| anyhow!("current_exe has no parent directory"))?
        .to_path_buf();
    Ok(dir)
}

pub async fn fetch_latest_manifest(
    client: &reqwest::Client,
    url: &str,
) -> anyhow::Result<UpdateManifest> {
    let resp = client
        .get(url)
        .header(
            reqwest::header::USER_AGENT,
            format!("flatland-client-lib/{}", local_version()),
        )
        .send()
        .await
        .with_context(|| format!("GET {url}"))?;
    let status = resp.status();
    if !status.is_success() {
        bail!("GET {url} returned HTTP {status}");
    }
    let manifest = resp
        .json::<UpdateManifest>()
        .await
        .context("parse latest.json")?;
    Ok(manifest)
}

pub async fn check_for_update(
    client: &reqwest::Client,
    local: &str,
    latest_url: Option<&str>,
) -> anyhow::Result<Option<UpdateAvailable>> {
    let url = latest_url
        .map(str::to_string)
        .unwrap_or_else(default_latest_url);
    let platform = platform_tag().ok_or_else(|| {
        anyhow!(
            "unsupported platform for self-update ({}-{})",
            std::env::consts::OS,
            std::env::consts::ARCH
        )
    })?;
    let manifest = fetch_latest_manifest(client, &url).await?;
    if !is_newer(local, &manifest.version) {
        return Ok(None);
    }
    let artifact = manifest
        .artifacts
        .get(platform)
        .cloned()
        .ok_or_else(|| anyhow!("latest.json missing artifact for {platform}"))?;
    let archive_url = archive_url_for(&url, &artifact.path);
    Ok(Some(UpdateAvailable {
        local_version: local.to_string(),
        remote_version: manifest.version,
        platform: platform.to_string(),
        artifact,
        archive_url,
    }))
}

fn archive_url_for(latest_url: &str, artifact_path: &str) -> String {
    if let Some(base) = latest_url.rsplit_once('/') {
        format!("{}/{}", base.0, artifact_path.trim_start_matches('/'))
    } else {
        artifact_path.to_string()
    }
}

/// Download, verify SHA-256, extract, and atomically swap both client binaries.
pub async fn apply_update(
    client: &reqwest::Client,
    offer: &UpdateAvailable,
) -> anyhow::Result<AppliedUpdate> {
    let install_dir = update_dir()?;
    let tmp = tempfile_dir(&install_dir)?;
    let archive_name = offer
        .artifact
        .path
        .rsplit('/')
        .next()
        .unwrap_or("client-archive");
    let archive_path = tmp.join(archive_name);

    download_file(client, &offer.archive_url, &archive_path).await?;
    verify_sha256(&archive_path, &offer.artifact.sha256)?;

    let extract_dir = tmp.join("extract");
    fs::create_dir_all(&extract_dir)?;
    extract_archive(&archive_path, &extract_dir, &offer.platform)?;

    for name in BINARIES {
        let src = find_binary(&extract_dir, name)?;
        swap_binary(&src, &install_dir.join(binary_filename(name)))?;
    }

    // Best-effort cleanup of the staging directory.
    let _ = fs::remove_dir_all(&tmp);

    info!(
        version = %offer.remote_version,
        dir = %install_dir.display(),
        "client self-update applied; restart required"
    );

    Ok(AppliedUpdate {
        version: offer.remote_version.clone(),
        install_dir,
    })
}

/// Remove `*.old` backups left by a previous successful apply (call on launch).
pub fn cleanup_old_binaries() {
    let Ok(dir) = update_dir() else {
        return;
    };
    for name in BINARIES {
        let old = dir.join(format!("{}.old", binary_filename(name)));
        if old.exists() {
            if let Err(err) = fs::remove_file(&old) {
                warn!(path = %old.display(), error = %err, "failed to remove old client binary");
            }
        }
    }
}

fn binary_filename(name: &str) -> String {
    if cfg!(windows) {
        format!("{name}.exe")
    } else {
        name.to_string()
    }
}

fn tempfile_dir(install_dir: &Path) -> anyhow::Result<PathBuf> {
    let stamp = std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_millis())
        .unwrap_or(0);
    let dir = install_dir.join(format!(".flatland-update-{stamp}"));
    fs::create_dir_all(&dir)?;
    Ok(dir)
}

async fn download_file(
    client: &reqwest::Client,
    url: &str,
    dest: &Path,
) -> anyhow::Result<()> {
    let mut resp = client
        .get(url)
        .header(
            reqwest::header::USER_AGENT,
            format!("flatland-client-lib/{}", local_version()),
        )
        .send()
        .await
        .with_context(|| format!("GET {url}"))?;
    let status = resp.status();
    if !status.is_success() {
        bail!("GET {url} returned HTTP {status}");
    }
    let mut file = File::create(dest).with_context(|| format!("create {}", dest.display()))?;
    while let Some(chunk) = resp.chunk().await.context("read download chunk")? {
        file.write_all(&chunk)?;
    }
    file.flush()?;
    Ok(())
}

fn verify_sha256(path: &Path, expected_hex: &str) -> anyhow::Result<()> {
    let mut file = File::open(path).with_context(|| format!("open {}", path.display()))?;
    let mut hasher = Sha256::new();
    std::io::copy(&mut file, &mut hasher)?;
    let got = hex::encode(hasher.finalize());
    let expected = expected_hex.trim().to_ascii_lowercase();
    if got != expected {
        bail!(
            "SHA-256 mismatch for {}: expected {expected}, got {got}",
            path.display()
        );
    }
    Ok(())
}

fn extract_archive(archive: &Path, dest: &Path, platform: &str) -> anyhow::Result<()> {
    if platform.starts_with("windows") || archive.extension().is_some_and(|e| e == "zip") {
        let file = File::open(archive)?;
        let mut zip = zip::ZipArchive::new(BufReader::new(file))
            .context("open zip archive")?;
        zip.extract(dest).context("extract zip archive")?;
    } else {
        let file = File::open(archive)?;
        let decoder = GzDecoder::new(BufReader::new(file));
        let mut tar = tar::Archive::new(decoder);
        tar.unpack(dest).context("extract tar.gz archive")?;
    }
    Ok(())
}

fn find_binary(extract_dir: &Path, name: &str) -> anyhow::Result<PathBuf> {
    let filename = binary_filename(name);
    let direct = extract_dir.join(&filename);
    if direct.is_file() {
        return Ok(direct);
    }
    for entry in walkdir_files(extract_dir)? {
        if entry
            .file_name()
            .and_then(|s| s.to_str())
            .is_some_and(|n| n == filename)
        {
            return Ok(entry);
        }
    }
    bail!("archive missing binary {filename}");
}

fn walkdir_files(root: &Path) -> anyhow::Result<Vec<PathBuf>> {
    let mut out = Vec::new();
    fn walk(dir: &Path, out: &mut Vec<PathBuf>) -> anyhow::Result<()> {
        for entry in fs::read_dir(dir)? {
            let entry = entry?;
            let path = entry.path();
            if path.is_dir() {
                walk(&path, out)?;
            } else if path.is_file() {
                out.push(path);
            }
        }
        Ok(())
    }
    walk(root, &mut out)?;
    Ok(out)
}

fn swap_binary(src: &Path, dest: &Path) -> anyhow::Result<()> {
    let dest_new = PathBuf::from(format!("{}.new", dest.display()));
    let dest_old = PathBuf::from(format!("{}.old", dest.display()));

    fs::copy(src, &dest_new).with_context(|| {
        format!(
            "copy {} → {}",
            src.display(),
            dest_new.display()
        )
    })?;
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        let mut perms = fs::metadata(&dest_new)?.permissions();
        perms.set_mode(0o755);
        fs::set_permissions(&dest_new, perms)?;
    }

    if dest.exists() {
        // Windows: renaming a running .exe is allowed; overwriting is not.
        // POSIX: rename over the running binary also works.
        let _ = fs::remove_file(&dest_old);
        fs::rename(dest, &dest_old).with_context(|| {
            format!(
                "rename running binary {} → {}",
                dest.display(),
                dest_old.display()
            )
        })?;
    }

    fs::rename(&dest_new, dest).with_context(|| {
        format!(
            "install new binary {} → {}",
            dest_new.display(),
            dest.display()
        )
    })?;
    Ok(())
}

/// Whether automatic update checks are enabled (default true).
pub fn check_updates_enabled(cfg: &crate::ClientConfig) -> bool {
    if let Ok(raw) = std::env::var("FLATLAND_CHECK_UPDATES") {
        let v = raw.trim().to_ascii_lowercase();
        if matches!(v.as_str(), "0" | "false" | "no" | "off") {
            return false;
        }
        if matches!(v.as_str(), "1" | "true" | "yes" | "on") {
            return true;
        }
    }
    cfg.check_updates.unwrap_or(true)
}

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

    #[test]
    fn is_newer_compares_semver() {
        assert!(is_newer("0.2.31", "0.2.32"));
        assert!(!is_newer("0.2.32", "0.2.32"));
        assert!(!is_newer("0.2.32", "0.2.31"));
        assert!(is_newer("0.2.9", "0.2.10"));
    }

    #[test]
    fn platform_tag_is_known_or_none() {
        if let Some(tag) = platform_tag() {
            assert!(
                matches!(
                    tag,
                    "macos-aarch64" | "macos-x86_64" | "linux-x86_64" | "windows-x86_64"
                ),
                "unexpected tag {tag}"
            );
        }
    }

    #[test]
    fn manifest_parses_assemble_latest_shape() {
        let json = r#"{
          "version": "0.2.32",
          "published_at": "2026-08-14T12:00:00Z",
          "artifacts": {
            "macos-aarch64": {
              "path": "v0.2.32/flatland3-client-0.2.32-macos-aarch64.tar.gz",
              "sha256": "abc",
              "size": 12
            }
          }
        }"#;
        let m: UpdateManifest = serde_json::from_str(json).unwrap();
        assert_eq!(m.version, "0.2.32");
        assert_eq!(
            m.artifacts["macos-aarch64"].path,
            "v0.2.32/flatland3-client-0.2.32-macos-aarch64.tar.gz"
        );
    }

    #[test]
    fn archive_url_joins_latest_base() {
        let url = archive_url_for(
            "https://storage.googleapis.com/bucket/flatland3/client-releases/latest.json",
            "v0.2.32/flatland3-client-0.2.32-macos-aarch64.tar.gz",
        );
        assert_eq!(
            url,
            "https://storage.googleapis.com/bucket/flatland3/client-releases/v0.2.32/flatland3-client-0.2.32-macos-aarch64.tar.gz"
        );
    }
}