use std::path::Path;
use std::path::PathBuf;
use std::process::Command;
use std::process::Output;
use std::process::Stdio;
use std::time::Duration;

use codex_otel::CURATED_PLUGINS_STARTUP_SYNC_FINAL_METRIC;
use codex_otel::CURATED_PLUGINS_STARTUP_SYNC_METRIC;
use reqwest::Client;
use serde::Deserialize;
use tempfile::TempDir;
use tracing::warn;
use zip::ZipArchive;

use codex_login::default_client::build_reqwest_client;

const GITHUB_API_BASE_URL: &str = "https://api.github.com";
const GITHUB_API_ACCEPT_HEADER: &str = "application/vnd.github+json";
const GITHUB_API_VERSION_HEADER: &str = "2022-11-28";
const CURATED_PLUGINS_BACKUP_ARCHIVE_API_URL: &str =
    "https://chatgpt.com/backend-api/plugins/export/curated";
const OPENAI_PLUGINS_OWNER: &str = "openai";
const OPENAI_PLUGINS_REPO: &str = "plugins";
const CURATED_PLUGINS_RELATIVE_DIR: &str = ".tmp/plugins";
const CURATED_PLUGINS_SHA_FILE: &str = ".tmp/plugins.sha";
const CURATED_PLUGINS_BACKUP_ARCHIVE_FALLBACK_VERSION: &str = "export-backup";
const CURATED_PLUGINS_GIT_TIMEOUT: Duration = Duration::from_secs(30);
const CURATED_PLUGINS_HTTP_TIMEOUT: Duration = Duration::from_secs(30);
const CURATED_PLUGINS_BACKUP_ARCHIVE_TIMEOUT: Duration = Duration::from_secs(30);
// Keep this comfortably above a normal sync attempt so we do not race another Codex process.
const CURATED_PLUGINS_STALE_TEMP_DIR_MAX_AGE: Duration = Duration::from_secs(10 * 60);

#[derive(Debug, Deserialize)]
struct GitHubRepositorySummary {
    default_branch: String,
}

#[derive(Debug, Deserialize)]
struct GitHubGitRefSummary {
    object: GitHubGitRefObject,
}

#[derive(Debug, Deserialize)]
struct GitHubGitRefObject {
    sha: String,
}

#[derive(Debug, Deserialize)]
struct CuratedPluginsBackupArchiveResponse {
    download_url: String,
}

pub fn curated_plugins_repo_path(codex_home: &Path) -> PathBuf {
    codex_home.join(CURATED_PLUGINS_RELATIVE_DIR)
}

pub fn read_curated_plugins_sha(codex_home: &Path) -> Option<String> {
    read_sha_file(curated_plugins_sha_path(codex_home).as_path())
}

fn curated_plugins_sha_path(codex_home: &Path) -> PathBuf {
    codex_home.join(CURATED_PLUGINS_SHA_FILE)
}

pub fn sync_openai_plugins_repo(codex_home: &Path) -> Result<String, String> {
    sync_openai_plugins_repo_with_transport_overrides(
        codex_home,
        "git",
        GITHUB_API_BASE_URL,
        CURATED_PLUGINS_BACKUP_ARCHIVE_API_URL,
    )
}

fn sync_openai_plugins_repo_with_transport_overrides(
    codex_home: &Path,
    git_binary: &str,
    api_base_url: &str,
    backup_archive_api_url: &str,
) -> Result<String, String> {
    match sync_openai_plugins_repo_via_git(codex_home, git_binary) {
        Ok(remote_sha) => {
            emit_curated_plugins_startup_sync_metric("git", "success");
            emit_curated_plugins_startup_sync_final_metric("git", "success");
            Ok(remote_sha)
        }
        Err(err) => {
            emit_curated_plugins_startup_sync_metric("git", "failure");
            warn!(
                error = %err,
                git_binary,
                "git sync failed for curated plugin sync; falling back to GitHub HTTP"
            );
            match sync_openai_plugins_repo_via_http(codex_home, api_base_url) {
                Ok(remote_sha) => {
                    emit_curated_plugins_startup_sync_metric("http", "success");
                    emit_curated_plugins_startup_sync_final_metric("http", "success");
                    Ok(remote_sha)
                }
                Err(http_err) => {
                    emit_curated_plugins_startup_sync_metric("http", "failure");
                    if has_local_curated_plugins_snapshot(codex_home) {
                        emit_curated_plugins_startup_sync_final_metric("http", "failure");
                        warn!(
                            error = %http_err,
                            "GitHub HTTP sync failed for curated plugin sync; skipping export archive fallback because a local curated plugins snapshot already exists"
                        );
                        Err(format!(
                            "git sync failed for curated plugin sync: {err}; GitHub HTTP sync failed for curated plugin sync: {http_err}; export archive fallback skipped because a local curated plugins snapshot already exists"
                        ))
                    } else {
                        // The export archive is a lagging backup path. Only use it to bootstrap a
                        // missing local curated snapshot, never to refresh an existing one.
                        warn!(
                            error = %http_err,
                            backup_archive_api_url,
                            "GitHub HTTP sync failed for curated plugin sync; falling back to export archive"
                        );
                        let result = sync_openai_plugins_repo_via_backup_archive(
                            codex_home,
                            backup_archive_api_url,
                        );
                        let status = if result.is_ok() { "success" } else { "failure" };
                        emit_curated_plugins_startup_sync_metric("export_archive", status);
                        emit_curated_plugins_startup_sync_final_metric("export_archive", status);
                        result.map_err(|export_err| {
                            format!(
                                "git sync failed for curated plugin sync: {err}; GitHub HTTP sync failed for curated plugin sync: {http_err}; export archive sync failed for curated plugin sync: {export_err}"
                            )
                        })
                    }
                }
            }
        }
    }
}

fn sync_openai_plugins_repo_via_git(codex_home: &Path, git_binary: &str) -> Result<String, String> {
    let repo_path = curated_plugins_repo_path(codex_home);
    let sha_path = codex_home.join(CURATED_PLUGINS_SHA_FILE);
    let remote_sha = git_ls_remote_head_sha(git_binary)?;
    let local_sha = read_local_git_or_sha_file(&repo_path, &sha_path, git_binary);

    if local_sha.as_deref() == Some(remote_sha.as_str()) && repo_path.join(".git").is_dir() {
        return Ok(remote_sha);
    }

    let staged_repo_dir = prepare_curated_repo_parent_and_temp_dir(&repo_path)?;
    let clone_output = run_git_command_with_timeout(
        Command::new(git_binary)
            .env("GIT_OPTIONAL_LOCKS", "0")
            .arg("clone")
            .arg("--depth")
            .arg("1")
            .arg("https://github.com/openai/plugins.git")
            .arg(staged_repo_dir.path()),
        "git clone curated plugins repo",
        CURATED_PLUGINS_GIT_TIMEOUT,
    )?;
    ensure_git_success(&clone_output, "git clone curated plugins repo")?;

    let cloned_sha = git_head_sha(staged_repo_dir.path(), git_binary)?;
    if cloned_sha != remote_sha {
        return Err(format!(
            "curated plugins clone HEAD mismatch: expected {remote_sha}, got {cloned_sha}"
        ));
    }

    ensure_marketplace_manifest_exists(staged_repo_dir.path())?;
    activate_curated_repo(&repo_path, staged_repo_dir)?;
    write_curated_plugins_sha(&sha_path, &remote_sha)?;
    Ok(remote_sha)
}

fn sync_openai_plugins_repo_via_http(
    codex_home: &Path,
    api_base_url: &str,
) -> Result<String, String> {
    let repo_path = curated_plugins_repo_path(codex_home);
    let sha_path = codex_home.join(CURATED_PLUGINS_SHA_FILE);
    let runtime = tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()
        .map_err(|err| format!("failed to create curated plugins sync runtime: {err}"))?;
    let remote_sha = runtime.block_on(fetch_curated_repo_remote_sha(api_base_url))?;
    let local_sha = read_sha_file(&sha_path);

    if local_sha.as_deref() == Some(remote_sha.as_str()) && repo_path.is_dir() {
        return Ok(remote_sha);
    }

    let staged_repo_dir = prepare_curated_repo_parent_and_temp_dir(&repo_path)?;
    let zipball_bytes = runtime.block_on(fetch_curated_repo_zipball(api_base_url, &remote_sha))?;
    extract_zipball_to_dir(&zipball_bytes, staged_repo_dir.path())?;
    ensure_marketplace_manifest_exists(staged_repo_dir.path())?;
    activate_curated_repo(&repo_path, staged_repo_dir)?;
    write_curated_plugins_sha(&sha_path, &remote_sha)?;
    Ok(remote_sha)
}

fn sync_openai_plugins_repo_via_backup_archive(
    codex_home: &Path,
    backup_archive_api_url: &str,
) -> Result<String, String> {
    let repo_path = curated_plugins_repo_path(codex_home);
    let sha_path = curated_plugins_sha_path(codex_home);
    let runtime = tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()
        .map_err(|err| format!("failed to create curated plugins sync runtime: {err}"))?;
    let staged_repo_dir = prepare_curated_repo_parent_and_temp_dir(&repo_path)?;
    let zipball_bytes = runtime.block_on(fetch_curated_repo_backup_archive_zip(
        backup_archive_api_url,
    ))?;
    extract_zipball_to_dir(&zipball_bytes, staged_repo_dir.path())?;
    ensure_marketplace_manifest_exists(staged_repo_dir.path())?;
    let export_version = read_extracted_backup_archive_git_sha(staged_repo_dir.path())?
        .unwrap_or_else(|| CURATED_PLUGINS_BACKUP_ARCHIVE_FALLBACK_VERSION.to_string());
    activate_curated_repo(&repo_path, staged_repo_dir)?;
    write_curated_plugins_sha(&sha_path, &export_version)?;
    Ok(export_version)
}

pub fn has_local_curated_plugins_snapshot(codex_home: &Path) -> bool {
    curated_plugins_repo_path(codex_home)
        .join(".agents/plugins/marketplace.json")
        .is_file()
        && codex_home.join(CURATED_PLUGINS_SHA_FILE).is_file()
}

fn prepare_curated_repo_parent_and_temp_dir(repo_path: &Path) -> Result<TempDir, String> {
    let Some(parent) = repo_path.parent() else {
        return Err(format!(
            "failed to determine curated plugins parent directory for {}",
            repo_path.display()
        ));
    };
    std::fs::create_dir_all(parent).map_err(|err| {
        format!(
            "failed to create curated plugins parent directory {}: {err}",
            parent.display()
        )
    })?;
    remove_stale_curated_repo_temp_dirs(parent, CURATED_PLUGINS_STALE_TEMP_DIR_MAX_AGE);

    let clone_dir = tempfile::Builder::new()
        .prefix("plugins-clone-")
        .tempdir_in(parent)
        .map_err(|err| {
            format!(
                "failed to create temporary curated plugins directory in {}: {err}",
                parent.display()
            )
        })?;
    Ok(clone_dir)
}

fn remove_stale_curated_repo_temp_dirs(parent: &Path, max_age: Duration) {
    let entries = match std::fs::read_dir(parent) {
        Ok(entries) => entries,
        Err(err) => {
            warn!(
                error = %err,
                parent = %parent.display(),
                "failed to list curated plugins temp directory parent for stale cleanup"
            );
            return;
        }
    };

    for entry in entries.flatten() {
        let file_type = match entry.file_type() {
            Ok(file_type) => file_type,
            Err(err) => {
                warn!(
                    error = %err,
                    path = %entry.path().display(),
                    "failed to inspect curated plugins temp directory entry"
                );
                continue;
            }
        };
        if !file_type.is_dir() {
            continue;
        }

        let path = entry.path();
        let is_plugins_clone_dir = path
            .file_name()
            .and_then(|name| name.to_str())
            .is_some_and(|name| name.starts_with("plugins-clone-"));
        if !is_plugins_clone_dir {
            continue;
        }

        let metadata = match entry.metadata() {
            Ok(metadata) => metadata,
            Err(err) => {
                warn!(
                    error = %err,
                    path = %path.display(),
                    "failed to read curated plugins temp directory metadata"
                );
                continue;
            }
        };
        let modified = match metadata.modified() {
            Ok(modified) => modified,
            Err(err) => {
                warn!(
                    error = %err,
                    path = %path.display(),
                    "failed to read curated plugins temp directory modification time"
                );
                continue;
            }
        };
        let age = match modified.elapsed() {
            Ok(age) => age,
            Err(err) => {
                warn!(
                    error = %err,
                    path = %path.display(),
                    "failed to compute curated plugins temp directory age"
                );
                continue;
            }
        };
        if age < max_age {
            continue;
        }

        if let Err(err) = std::fs::remove_dir_all(&path) {
            warn!(
                error = %err,
                path = %path.display(),
                "failed to remove stale curated plugins temp directory"
            );
        }
    }
}

fn emit_curated_plugins_startup_sync_metric(transport: &'static str, status: &'static str) {
    emit_curated_plugins_startup_sync_counter(
        CURATED_PLUGINS_STARTUP_SYNC_METRIC,
        transport,
        status,
    );
}

fn emit_curated_plugins_startup_sync_final_metric(transport: &'static str, status: &'static str) {
    emit_curated_plugins_startup_sync_counter(
        CURATED_PLUGINS_STARTUP_SYNC_FINAL_METRIC,
        transport,
        status,
    );
}

fn emit_curated_plugins_startup_sync_counter(
    metric_name: &str,
    transport: &'static str,
    status: &'static str,
) {
    let Some(metrics) = codex_otel::global() else {
        return;
    };
    let tags = [("transport", transport), ("status", status)];
    let _ = metrics.counter(metric_name, /*inc*/ 1, &tags);
}

fn ensure_marketplace_manifest_exists(repo_path: &Path) -> Result<(), String> {
    if repo_path.join(".agents/plugins/marketplace.json").is_file() {
        return Ok(());
    }
    Err(format!(
        "curated plugins archive missing marketplace manifest at {}",
        repo_path.join(".agents/plugins/marketplace.json").display()
    ))
}

fn activate_curated_repo(repo_path: &Path, staged_repo_dir: TempDir) -> Result<(), String> {
    let staged_repo_path = staged_repo_dir.path();
    if repo_path.exists() {
        let parent = repo_path.parent().ok_or_else(|| {
            format!(
                "failed to determine curated plugins parent directory for {}",
                repo_path.display()
            )
        })?;
        let backup_dir = tempfile::Builder::new()
            .prefix("plugins-backup-")
            .tempdir_in(parent)
            .map_err(|err| {
                format!(
                    "failed to create curated plugins backup directory in {}: {err}",
                    parent.display()
                )
            })?;
        let backup_repo_path = backup_dir.path().join("repo");

        std::fs::rename(repo_path, &backup_repo_path).map_err(|err| {
            format!(
                "failed to move previous curated plugins repo out of the way at {}: {err}",
                repo_path.display()
            )
        })?;

        if let Err(err) = std::fs::rename(staged_repo_path, repo_path) {
            let rollback_result = std::fs::rename(&backup_repo_path, repo_path);
            return match rollback_result {
                Ok(()) => Err(format!(
                    "failed to activate new curated plugins repo at {}: {err}",
                    repo_path.display()
                )),
                Err(rollback_err) => {
                    let backup_path = backup_dir.keep().join("repo");
                    Err(format!(
                        "failed to activate new curated plugins repo at {}: {err}; failed to restore previous repo (left at {}): {rollback_err}",
                        repo_path.display(),
                        backup_path.display()
                    ))
                }
            };
        }
    } else {
        std::fs::rename(staged_repo_path, repo_path).map_err(|err| {
            format!(
                "failed to activate curated plugins repo at {}: {err}",
                repo_path.display()
            )
        })?;
    }

    Ok(())
}

fn write_curated_plugins_sha(sha_path: &Path, remote_sha: &str) -> Result<(), String> {
    if let Some(parent) = sha_path.parent() {
        std::fs::create_dir_all(parent).map_err(|err| {
            format!(
                "failed to create curated plugins sha directory {}: {err}",
                parent.display()
            )
        })?;
    }
    std::fs::write(sha_path, format!("{remote_sha}\n")).map_err(|err| {
        format!(
            "failed to write curated plugins sha file {}: {err}",
            sha_path.display()
        )
    })
}

fn read_local_git_or_sha_file(
    repo_path: &Path,
    sha_path: &Path,
    git_binary: &str,
) -> Option<String> {
    if repo_path.join(".git").is_dir()
        && let Ok(sha) = git_head_sha(repo_path, git_binary)
    {
        return Some(sha);
    }

    read_sha_file(sha_path)
}

fn git_ls_remote_head_sha(git_binary: &str) -> Result<String, String> {
    let output = run_git_command_with_timeout(
        Command::new(git_binary)
            .env("GIT_OPTIONAL_LOCKS", "0")
            .arg("ls-remote")
            .arg("https://github.com/openai/plugins.git")
            .arg("HEAD"),
        "git ls-remote curated plugins repo",
        CURATED_PLUGINS_GIT_TIMEOUT,
    )?;
    ensure_git_success(&output, "git ls-remote curated plugins repo")?;

    let stdout = String::from_utf8_lossy(&output.stdout);
    let Some(first_line) = stdout.lines().next() else {
        return Err("git ls-remote returned empty output for curated plugins repo".to_string());
    };
    let Some((sha, _)) = first_line.split_once('\t') else {
        return Err(format!(
            "unexpected git ls-remote output for curated plugins repo: {first_line}"
        ));
    };
    if sha.is_empty() {
        return Err("git ls-remote returned empty sha for curated plugins repo".to_string());
    }
    Ok(sha.to_string())
}

fn git_head_sha(repo_path: &Path, git_binary: &str) -> Result<String, String> {
    let output = Command::new(git_binary)
        .env("GIT_OPTIONAL_LOCKS", "0")
        .arg("-C")
        .arg(repo_path)
        .arg("rev-parse")
        .arg("HEAD")
        .output()
        .map_err(|err| {
            format!(
                "failed to run git rev-parse HEAD in {}: {err}",
                repo_path.display()
            )
        })?;
    ensure_git_success(&output, "git rev-parse HEAD")?;

    let sha = String::from_utf8_lossy(&output.stdout).trim().to_string();
    if sha.is_empty() {
        return Err(format!(
            "git rev-parse HEAD returned empty output in {}",
            repo_path.display()
        ));
    }
    Ok(sha)
}

fn run_git_command_with_timeout(
    command: &mut Command,
    context: &str,
    timeout: Duration,
) -> Result<Output, String> {
    let mut child = command
        .stdin(Stdio::null())
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .spawn()
        .map_err(|err| format!("failed to run {context}: {err}"))?;

    let start = std::time::Instant::now();
    loop {
        match child.try_wait() {
            Ok(Some(_)) => {
                return child
                    .wait_with_output()
                    .map_err(|err| format!("failed to wait for {context}: {err}"));
            }
            Ok(None) => {}
            Err(err) => return Err(format!("failed to poll {context}: {err}")),
        }

        if start.elapsed() >= timeout {
            match child.try_wait() {
                Ok(Some(_)) => {
                    return child
                        .wait_with_output()
                        .map_err(|err| format!("failed to wait for {context}: {err}"));
                }
                Ok(None) => {}
                Err(err) => return Err(format!("failed to poll {context}: {err}")),
            }

            let _ = child.kill();
            let output = child
                .wait_with_output()
                .map_err(|err| format!("failed to wait for {context} after timeout: {err}"))?;
            let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
            return if stderr.is_empty() {
                Err(format!("{context} timed out after {}s", timeout.as_secs()))
            } else {
                Err(format!(
                    "{context} timed out after {}s: {stderr}",
                    timeout.as_secs()
                ))
            };
        }

        std::thread::sleep(Duration::from_millis(100));
    }
}

fn ensure_git_success(output: &Output, context: &str) -> Result<(), String> {
    if output.status.success() {
        return Ok(());
    }
    let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
    if stderr.is_empty() {
        Err(format!("{context} failed with status {}", output.status))
    } else {
        Err(format!(
            "{context} failed with status {}: {stderr}",
            output.status
        ))
    }
}

async fn fetch_curated_repo_remote_sha(api_base_url: &str) -> Result<String, String> {
    let api_base_url = api_base_url.trim_end_matches('/');
    let repo_url = format!("{api_base_url}/repos/{OPENAI_PLUGINS_OWNER}/{OPENAI_PLUGINS_REPO}");
    let client = build_reqwest_client();
    let repo_body = fetch_github_text(&client, &repo_url, "get curated plugins repository").await?;
    let repo_summary: GitHubRepositorySummary =
        serde_json::from_str(&repo_body).map_err(|err| {
            format!("failed to parse curated plugins repository response from {repo_url}: {err}")
        })?;
    if repo_summary.default_branch.is_empty() {
        return Err(format!(
            "curated plugins repository response from {repo_url} did not include a default branch"
        ));
    }

    let git_ref_url = format!("{repo_url}/git/ref/heads/{}", repo_summary.default_branch);
    let git_ref_body =
        fetch_github_text(&client, &git_ref_url, "get curated plugins HEAD ref").await?;
    let git_ref: GitHubGitRefSummary = serde_json::from_str(&git_ref_body).map_err(|err| {
        format!("failed to parse curated plugins ref response from {git_ref_url}: {err}")
    })?;
    if git_ref.object.sha.is_empty() {
        return Err(format!(
            "curated plugins ref response from {git_ref_url} did not include a HEAD sha"
        ));
    }

    Ok(git_ref.object.sha)
}

async fn fetch_curated_repo_zipball(
    api_base_url: &str,
    remote_sha: &str,
) -> Result<Vec<u8>, String> {
    let api_base_url = api_base_url.trim_end_matches('/');
    let repo_url = format!("{api_base_url}/repos/{OPENAI_PLUGINS_OWNER}/{OPENAI_PLUGINS_REPO}");
    let zipball_url = format!("{repo_url}/zipball/{remote_sha}");
    let client = build_reqwest_client();
    fetch_github_bytes(&client, &zipball_url, "download curated plugins archive").await
}

async fn fetch_curated_repo_backup_archive_zip(
    backup_archive_api_url: &str,
) -> Result<Vec<u8>, String> {
    let client = build_reqwest_client();
    let export_body = fetch_public_text(
        &client,
        backup_archive_api_url,
        "get curated plugins export archive metadata",
    )
    .await?;
    let export_response: CuratedPluginsBackupArchiveResponse = serde_json::from_str(&export_body)
        .map_err(|err| {
            format!(
                "failed to parse curated plugins backup archive response from {backup_archive_api_url}: {err}"
            )
        })?;
    if export_response.download_url.is_empty() {
        return Err(format!(
            "curated plugins backup archive response from {backup_archive_api_url} did not include a download URL"
        ));
    }

    fetch_public_bytes(
        &client,
        &export_response.download_url,
        "download curated plugins export archive",
    )
    .await
}

fn read_extracted_backup_archive_git_sha(repo_path: &Path) -> Result<Option<String>, String> {
    let git_dir = repo_path.join(".git");
    if !git_dir.is_dir() {
        return Ok(None);
    }

    let head_path = git_dir.join("HEAD");
    let head = std::fs::read_to_string(&head_path).map_err(|err| {
        format!(
            "failed to read curated plugins backup archive git HEAD {}: {err}",
            head_path.display()
        )
    })?;
    let head = head.trim();
    if head.is_empty() {
        return Err(format!(
            "curated plugins backup archive git HEAD is empty at {}",
            head_path.display()
        ));
    }

    if let Some(reference) = head.strip_prefix("ref: ") {
        let reference = validate_backup_archive_git_ref(reference.trim())?;
        return read_git_ref_sha(&git_dir, reference).map(Some);
    }

    Ok(Some(head.to_string()))
}

fn validate_backup_archive_git_ref(reference: &str) -> Result<&str, String> {
    if !reference.starts_with("refs/") {
        return Err(format!(
            "curated plugins backup archive git ref must stay under refs/: {reference}"
        ));
    }

    let path = Path::new(reference);
    if path.is_absolute() {
        return Err(format!(
            "curated plugins backup archive git ref must be relative: {reference}"
        ));
    }

    for component in path.components() {
        match component {
            std::path::Component::Normal(_) => {}
            _ => {
                return Err(format!(
                    "curated plugins backup archive git ref contains invalid path components: {reference}"
                ));
            }
        }
    }

    Ok(reference)
}

fn read_git_ref_sha(git_dir: &Path, reference: &str) -> Result<String, String> {
    let ref_path = git_dir.join(reference);
    if let Ok(sha) = std::fs::read_to_string(&ref_path) {
        let sha = sha.trim();
        if sha.is_empty() {
            return Err(format!(
                "curated plugins backup archive git ref {reference} is empty at {}",
                ref_path.display()
            ));
        }
        return Ok(sha.to_string());
    }

    let packed_refs_path = git_dir.join("packed-refs");
    if let Ok(packed_refs) = std::fs::read_to_string(&packed_refs_path)
        && let Some(sha) = packed_refs.lines().find_map(|line| {
            let trimmed = line.trim();
            if trimmed.is_empty() || trimmed.starts_with('#') || trimmed.starts_with('^') {
                return None;
            }
            let (sha, candidate_ref) = trimmed.split_once(' ')?;
            (candidate_ref == reference).then_some(sha.to_string())
        })
    {
        return Ok(sha);
    }

    Err(format!(
        "failed to resolve curated plugins backup archive git ref {reference} from {}",
        git_dir.display()
    ))
}

async fn fetch_github_text(client: &Client, url: &str, context: &str) -> Result<String, String> {
    let response = github_request(client, url)
        .send()
        .await
        .map_err(|err| format!("failed to {context} from {url}: {err}"))?;
    let status = response.status();
    let body = response.text().await.unwrap_or_default();
    if !status.is_success() {
        return Err(format!(
            "{context} from {url} failed with status {status}: {body}"
        ));
    }
    Ok(body)
}

async fn fetch_github_bytes(client: &Client, url: &str, context: &str) -> Result<Vec<u8>, String> {
    let response = github_request(client, url)
        .send()
        .await
        .map_err(|err| format!("failed to {context} from {url}: {err}"))?;
    let status = response.status();
    let body = response
        .bytes()
        .await
        .map_err(|err| format!("failed to read {context} response from {url}: {err}"))?;
    if !status.is_success() {
        let body_text = String::from_utf8_lossy(&body);
        return Err(format!(
            "{context} from {url} failed with status {status}: {body_text}"
        ));
    }
    Ok(body.to_vec())
}

async fn fetch_public_text(client: &Client, url: &str, context: &str) -> Result<String, String> {
    let response = client
        .get(url)
        .timeout(CURATED_PLUGINS_BACKUP_ARCHIVE_TIMEOUT)
        .send()
        .await
        .map_err(|err| format!("failed to {context} from {url}: {err}"))?;
    let status = response.status();
    let body = response.text().await.unwrap_or_default();
    if !status.is_success() {
        return Err(format!(
            "{context} from {url} failed with status {status}: {body}"
        ));
    }
    Ok(body)
}

async fn fetch_public_bytes(client: &Client, url: &str, context: &str) -> Result<Vec<u8>, String> {
    let response = client
        .get(url)
        .timeout(CURATED_PLUGINS_BACKUP_ARCHIVE_TIMEOUT)
        .send()
        .await
        .map_err(|err| format!("failed to {context} from {url}: {err}"))?;
    let status = response.status();
    let body = response
        .bytes()
        .await
        .map_err(|err| format!("failed to read {context} response from {url}: {err}"))?;
    if !status.is_success() {
        let body_text = String::from_utf8_lossy(&body);
        return Err(format!(
            "{context} from {url} failed with status {status}: {body_text}"
        ));
    }
    Ok(body.to_vec())
}

fn github_request(client: &Client, url: &str) -> reqwest::RequestBuilder {
    client
        .get(url)
        .timeout(CURATED_PLUGINS_HTTP_TIMEOUT)
        .header("accept", GITHUB_API_ACCEPT_HEADER)
        .header("x-github-api-version", GITHUB_API_VERSION_HEADER)
}

fn read_sha_file(sha_path: &Path) -> Option<String> {
    std::fs::read_to_string(sha_path)
        .ok()
        .map(|sha| sha.trim().to_string())
        .filter(|sha| !sha.is_empty())
}

fn extract_zipball_to_dir(bytes: &[u8], destination: &Path) -> Result<(), String> {
    std::fs::create_dir_all(destination).map_err(|err| {
        format!(
            "failed to create curated plugins extraction directory {}: {err}",
            destination.display()
        )
    })?;

    let cursor = std::io::Cursor::new(bytes);
    let mut archive = ZipArchive::new(cursor)
        .map_err(|err| format!("failed to open curated plugins zip archive: {err}"))?;

    for index in 0..archive.len() {
        let mut entry = archive
            .by_index(index)
            .map_err(|err| format!("failed to read curated plugins zip entry: {err}"))?;
        let Some(relative_path) = entry.enclosed_name() else {
            return Err(format!(
                "curated plugins zip entry `{}` escapes extraction root",
                entry.name()
            ));
        };

        let mut components = relative_path.components();
        let Some(std::path::Component::Normal(_)) = components.next() else {
            continue;
        };

        let output_relative = components.fold(PathBuf::new(), |mut path, component| {
            if let std::path::Component::Normal(segment) = component {
                path.push(segment);
            }
            path
        });
        if output_relative.as_os_str().is_empty() {
            continue;
        }

        let output_path = destination.join(&output_relative);
        if entry.is_dir() {
            std::fs::create_dir_all(&output_path).map_err(|err| {
                format!(
                    "failed to create curated plugins directory {}: {err}",
                    output_path.display()
                )
            })?;
            continue;
        }

        if let Some(parent) = output_path.parent() {
            std::fs::create_dir_all(parent).map_err(|err| {
                format!(
                    "failed to create curated plugins directory {}: {err}",
                    parent.display()
                )
            })?;
        }
        let mut output = std::fs::File::create(&output_path).map_err(|err| {
            format!(
                "failed to create curated plugins file {}: {err}",
                output_path.display()
            )
        })?;
        std::io::copy(&mut entry, &mut output).map_err(|err| {
            format!(
                "failed to write curated plugins file {}: {err}",
                output_path.display()
            )
        })?;
        apply_zip_permissions(&entry, &output_path)?;
    }

    Ok(())
}

#[cfg(unix)]
fn apply_zip_permissions(entry: &zip::read::ZipFile<'_>, output_path: &Path) -> Result<(), String> {
    use std::os::unix::fs::PermissionsExt;

    let Some(mode) = entry.unix_mode() else {
        return Ok(());
    };
    std::fs::set_permissions(output_path, std::fs::Permissions::from_mode(mode)).map_err(|err| {
        format!(
            "failed to set permissions on curated plugins file {}: {err}",
            output_path.display()
        )
    })
}

#[cfg(not(unix))]
fn apply_zip_permissions(
    _entry: &zip::read::ZipFile<'_>,
    _output_path: &Path,
) -> Result<(), String> {
    Ok(())
}

#[cfg(test)]
#[path = "startup_sync_tests.rs"]
mod tests;