rustbridge-cli 0.9.0

//! Pack command - auto-detect plugin project and create a bundle.
//!
//! Reads name/version from `Cargo.toml`, detects the platform, finds built libraries,
//! and delegates to `bundle::create()`.

use anyhow::{Context, Result};
use rustbridge_bundle::Platform;
use serde::Deserialize;
use std::path::{Path, PathBuf};
use std::time::SystemTime;
use yansi::{Condition, Paint, Style};

/// Yellow bold style for warnings, active only when stderr is a terminal.
static WARN: Style = Style::new()
    .yellow()
    .bold()
    .whenever(Condition::STDERR_IS_TTY);

/// Minimal Cargo.toml representation for plugin detection.
#[derive(Deserialize)]
struct CargoToml {
    package: Option<PackageInfo>,
    lib: Option<LibInfo>,
}

#[derive(Deserialize)]
struct PackageInfo {
    name: Option<String>,
    version: Option<toml::Value>,
    metadata: Option<PackageMetadata>,
}

#[derive(Deserialize)]
struct PackageMetadata {
    rustbridge: Option<RustbridgeMetadata>,
}

#[derive(Deserialize, Default)]
struct RustbridgeMetadata {
    #[serde(rename = "schema-source")]
    schema_source: Option<String>,
    #[serde(rename = "header-source")]
    header_source: Option<String>,
}

#[derive(Deserialize)]
struct LibInfo {
    name: Option<String>,
    #[serde(rename = "crate-type")]
    crate_type: Option<Vec<String>>,
}

/// Minimal workspace Cargo.toml representation for version resolution.
#[derive(Deserialize)]
struct WorkspaceCargoToml {
    workspace: Option<WorkspaceInfo>,
}

#[derive(Deserialize)]
struct WorkspaceInfo {
    package: Option<WorkspacePackageInfo>,
}

#[derive(Deserialize)]
struct WorkspacePackageInfo {
    version: Option<String>,
}

/// Detected plugin project metadata.
#[derive(Debug)]
pub struct PluginProject {
    /// Package name from Cargo.toml
    pub name: String,
    /// Resolved version string
    pub version: String,
    /// Library base name (underscored, used for filename generation)
    pub lib_name: String,
    /// Schema source from `[package.metadata.rustbridge]` (e.g. `"src/lib.rs:schema.json"`)
    pub schema_source: Option<String>,
    /// Header source from `[package.metadata.rustbridge]` (e.g. `"src/lib.rs:messages.h"`)
    pub header_source: Option<String>,
}

impl PluginProject {
    /// Detect plugin project from a directory containing Cargo.toml.
    pub fn detect(project_dir: &Path) -> Result<Self> {
        let cargo_toml_path = project_dir.join("Cargo.toml");
        if !cargo_toml_path.exists() {
            anyhow::bail!(
                "No Cargo.toml found in {}. Run this command from a plugin project directory.",
                project_dir.display()
            );
        }

        let contents = std::fs::read_to_string(&cargo_toml_path)
            .with_context(|| format!("Failed to read {}", cargo_toml_path.display()))?;

        let cargo_toml: CargoToml =
            toml::from_str(&contents).context("Failed to parse Cargo.toml")?;

        // Validate crate-type includes cdylib
        let lib_info = cargo_toml.lib.as_ref();
        let has_cdylib = lib_info
            .and_then(|l| l.crate_type.as_ref())
            .is_some_and(|types| types.iter().any(|t| t == "cdylib"));

        if !has_cdylib {
            anyhow::bail!(
                "Expected [lib] crate-type to include \"cdylib\" in {}. \
                 This command only works with plugin projects.",
                cargo_toml_path.display()
            );
        }

        // Extract package name
        let package = cargo_toml
            .package
            .as_ref()
            .ok_or_else(|| anyhow::anyhow!("Missing [package] section in Cargo.toml"))?;

        let name = package
            .name
            .clone()
            .ok_or_else(|| anyhow::anyhow!("Missing package.name in Cargo.toml"))?;

        // Resolve version
        let version = resolve_version(package, project_dir)?;

        // Determine library base name: [lib] name or derive from package name
        let lib_name = lib_info
            .and_then(|l| l.name.clone())
            .unwrap_or_else(|| name.replace('-', "_"));

        // Extract [package.metadata.rustbridge] fields
        let rb_meta = package
            .metadata
            .as_ref()
            .and_then(|m| m.rustbridge.as_ref());
        let schema_source = rb_meta.and_then(|r| r.schema_source.clone());
        let header_source = rb_meta.and_then(|r| r.header_source.clone());

        Ok(Self {
            name,
            version,
            lib_name,
            schema_source,
            header_source,
        })
    }
}

/// Resolve version from package info, following workspace inheritance.
fn resolve_version(package: &PackageInfo, project_dir: &Path) -> Result<String> {
    let version_value = package
        .version
        .as_ref()
        .ok_or_else(|| anyhow::anyhow!("Missing package.version in Cargo.toml"))?;

    match version_value {
        toml::Value::String(v) => Ok(v.clone()),
        toml::Value::Table(t) => {
            if t.get("workspace").and_then(|v| v.as_bool()) == Some(true) {
                find_workspace_version(project_dir)
            } else {
                anyhow::bail!("Unsupported package.version format in Cargo.toml")
            }
        }
        _ => anyhow::bail!("Unsupported package.version format in Cargo.toml"),
    }
}

/// Walk up parent directories to find the workspace root Cargo.toml and read its version.
fn find_workspace_version(start_dir: &Path) -> Result<String> {
    let mut dir = start_dir.to_path_buf();

    loop {
        // Check parent directory
        if !dir.pop() {
            anyhow::bail!(
                "Could not find workspace root with [workspace.package] version. \
                 Searched from {}",
                start_dir.display()
            );
        }

        let candidate = dir.join("Cargo.toml");
        if !candidate.exists() {
            continue;
        }

        let contents = std::fs::read_to_string(&candidate)
            .with_context(|| format!("Failed to read {}", candidate.display()))?;

        let workspace_toml: WorkspaceCargoToml = match toml::from_str(&contents) {
            Ok(parsed) => parsed,
            Err(_) => continue,
        };

        if let Some(workspace) = workspace_toml.workspace
            && let Some(pkg) = workspace.package
            && let Some(version) = pkg.version
        {
            return Ok(version);
        }
    }
}

/// Return the default signing key path (`~/.rustbridge/signing.key`).
fn default_signing_key_path() -> Result<PathBuf> {
    let home = std::env::var("HOME")
        .or_else(|_| std::env::var("USERPROFILE"))
        .context("Could not determine home directory")?;
    Ok(PathBuf::from(home).join(".rustbridge").join("signing.key"))
}

/// Derive the output bundle path.
fn derive_pack_output(project_dir: &Path, name: &str, version: &str, dev: bool) -> PathBuf {
    let suffix = if dev { "-dev" } else { "" };
    project_dir
        .join("target")
        .join("bundle")
        .join(format!("{name}-{version}{suffix}.rbp"))
}

/// Find the cargo target directory by walking up to the workspace root.
///
/// Cargo puts build artifacts in the workspace root's `target/` directory,
/// not in the member crate's directory.
fn find_target_dir(project_dir: &Path) -> PathBuf {
    // Check if there's a workspace root above us
    let mut dir = project_dir.to_path_buf();
    loop {
        if !dir.pop() {
            // No workspace root found, use project_dir
            return project_dir.join("target");
        }

        let candidate = dir.join("Cargo.toml");
        if !candidate.exists() {
            continue;
        }

        // Check if it has a [workspace] section
        if let Ok(contents) = std::fs::read_to_string(&candidate)
            && let Ok(parsed) = toml::from_str::<WorkspaceCargoToml>(&contents)
            && parsed.workspace.is_some()
        {
            return dir.join("target");
        }
    }
}

/// Format a `SystemTime` as `YYYY-MM-DD HH:MM:SS UTC`.
fn format_system_time(time: SystemTime) -> String {
    let duration = time
        .duration_since(SystemTime::UNIX_EPOCH)
        .unwrap_or_default();
    let secs = duration.as_secs();

    // Convert epoch seconds to calendar date/time (UTC)
    let days = secs / 86400;
    let time_of_day = secs % 86400;
    let hours = time_of_day / 3600;
    let minutes = (time_of_day % 3600) / 60;
    let seconds = time_of_day % 60;

    // Days since 1970-01-01 to (year, month, day) using a standard algorithm
    let (year, month, day) = {
        // Algorithm from Howard Hinnant's date library (public domain)
        let z = days as i64 + 719468;
        let era = if z >= 0 { z } else { z - 146096 } / 146097;
        let doe = (z - era * 146097) as u64;
        let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
        let y = yoe as i64 + era * 400;
        let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
        let mp = (5 * doy + 2) / 153;
        let d = doy - (153 * mp + 2) / 5 + 1;
        let m = if mp < 10 { mp + 3 } else { mp - 9 };
        let y = if m <= 2 { y + 1 } else { y };
        (y, m as u32, d as u32)
    };

    format!("{year:04}-{month:02}-{day:02} {hours:02}:{minutes:02}:{seconds:02} UTC")
}

/// Check if a library file is older than source files, warning if stale.
///
/// Compares the modification time of `lib_path` against `Cargo.toml` and
/// all `.rs` files under `src/`. Prints a warning to stderr if any source
/// file is newer than the library.
fn check_library_staleness(project_dir: &Path, lib_path: &Path, variant_label: &str) {
    let lib_mtime = match lib_path.metadata().and_then(|m| m.modified()) {
        Ok(t) => t,
        Err(_) => return,
    };

    let mut newest_source: Option<(PathBuf, SystemTime)> = None;

    let mut consider = |path: PathBuf| {
        if let Ok(meta) = path.metadata()
            && let Ok(mtime) = meta.modified()
            && newest_source.as_ref().is_none_or(|(_, prev)| mtime > *prev)
        {
            newest_source = Some((path, mtime));
        }
    };

    // Check Cargo.toml
    let cargo_toml = project_dir.join("Cargo.toml");
    if cargo_toml.exists() {
        consider(cargo_toml);
    }

    // Check build.rs
    let build_rs = project_dir.join("build.rs");
    if build_rs.exists() {
        consider(build_rs);
    }

    // Check all .rs files under src/
    let src_dir = project_dir.join("src");
    if src_dir.is_dir() {
        for entry in walkdir::WalkDir::new(&src_dir)
            .into_iter()
            .filter_map(|e| e.ok())
        {
            let path = entry.into_path();
            if path.extension().is_some_and(|ext| ext == "rs") {
                consider(path);
            }
        }
    }

    if let Some((newest_path, newest_mtime)) = newest_source
        && newest_mtime > lib_mtime
    {
        let lib_display = lib_path.display();
        let src_display = newest_path
            .strip_prefix(project_dir)
            .unwrap_or(&newest_path)
            .display();
        let lib_time_str = format_system_time(lib_mtime);
        let newest_time_str = format_system_time(newest_mtime);

        let build_hint = if variant_label == "Release" {
            "cargo build --release"
        } else {
            "cargo build"
        };

        let header = format!("Warning: {variant_label} library appears out of date.");
        eprintln!();
        eprintln!("{}", header.paint(WARN));
        eprintln!("  Library:       {lib_display}  ({lib_time_str})");
        eprintln!("  Newest source: {src_display}  ({newest_time_str})");
        eprintln!("  Run: {build_hint}");
        eprintln!();
    }
}

/// Run the pack command.
#[allow(clippy::too_many_arguments)]
pub fn run_pack(
    dev: bool,
    sign_key: Option<String>,
    no_sign: bool,
    schema_source: Option<String>,
    header_source: Option<String>,
) -> Result<()> {
    // Validate flag combinations
    if sign_key.is_some() && no_sign {
        anyhow::bail!("Conflicting flags: --sign-key and --no-sign cannot be used together");
    }

    let cwd = std::env::current_dir().context("Failed to get current directory")?;
    let project = PluginProject::detect(&cwd)?;

    // Merge CLI flags with Cargo.toml metadata (CLI wins)
    let effective_schema = schema_source.or_else(|| {
        if let Some(ref s) = project.schema_source {
            println!("  Schema source (from Cargo.toml): {s}");
        }
        project.schema_source.clone()
    });
    let effective_header = header_source.or_else(|| {
        if let Some(ref h) = project.header_source {
            println!("  Header source (from Cargo.toml): {h}");
        }
        project.header_source.clone()
    });

    let platform = Platform::current().ok_or_else(|| {
        anyhow::anyhow!(
            "Unsupported platform: {}-{}",
            std::env::consts::OS,
            std::env::consts::ARCH
        )
    })?;
    let platform_str = platform.to_string();

    println!("Packing plugin: {} v{}", project.name, project.version);
    println!("  Platform: {platform_str}");
    println!(
        "  Library name: {}",
        platform.library_name(&project.lib_name)
    );

    let target_dir = find_target_dir(&cwd);
    let lib_filename = platform.library_name(&project.lib_name);

    // Build library list
    let mut libraries: Vec<(String, String, String)> = Vec::new();

    // Always include release library
    let release_lib = target_dir.join("release").join(&lib_filename);
    if !release_lib.exists() {
        anyhow::bail!(
            "Release library not found: {}\n\
             Run: cargo build --release",
            release_lib.display()
        );
    }
    check_library_staleness(&cwd, &release_lib, "Release");
    libraries.push((
        platform_str.clone(),
        "release".to_string(),
        release_lib.to_string_lossy().to_string(),
    ));
    println!("  Release library: {}", release_lib.display());

    // Include debug library if dev mode
    if dev {
        let debug_lib = target_dir.join("debug").join(&lib_filename);
        if !debug_lib.exists() {
            anyhow::bail!(
                "Debug library not found: {}\n\
                 Run: cargo build",
                debug_lib.display()
            );
        }
        check_library_staleness(&cwd, &debug_lib, "Debug");
        libraries.push((
            platform_str,
            "debug".to_string(),
            debug_lib.to_string_lossy().to_string(),
        ));
        println!("  Debug library: {}", debug_lib.display());
    }

    // Find SBOM files
    let mut sbom_files: Vec<(String, String)> = Vec::new();
    for sbom_name in &["sbom.cdx.json", "sbom.spdx.json"] {
        let sbom_path = cwd.join(sbom_name);
        if sbom_path.exists() {
            println!("  SBOM: {sbom_name}");
            sbom_files.push((
                sbom_path.to_string_lossy().to_string(),
                (*sbom_name).to_string(),
            ));
        }
    }

    // Find LICENSE file
    let license_path = find_license_file(&cwd);
    if let Some(ref lp) = license_path {
        println!("  License: {}", lp.display());
    }

    // Resolve signing key for release mode
    let resolved_sign_key = if dev || no_sign {
        None
    } else {
        match sign_key {
            Some(path) => Some(path),
            None => {
                let default_key = default_signing_key_path()?;
                if default_key.exists() {
                    println!("  Signing with: {}", default_key.display());
                    Some(default_key.to_string_lossy().to_string())
                } else {
                    eprintln!(
                        "{} No signing key found at {}. Bundle will not be signed. \
                         Use 'rustbridge keygen' to generate a key.",
                        "Warning:".paint(WARN),
                        default_key.display()
                    );
                    None
                }
            }
        }
    };

    // Create output directory
    let output = derive_pack_output(&cwd, &project.name, &project.version, dev);
    if let Some(parent) = output.parent() {
        std::fs::create_dir_all(parent)
            .with_context(|| format!("Failed to create directory: {}", parent.display()))?;
    }

    println!("  Output: {}", output.display());

    // Delegate to bundle::create
    crate::bundle::create(
        &project.name,
        &project.version,
        &libraries,
        Some(output.to_string_lossy().to_string()),
        &[], // schema_files (handled via generate flags)
        resolved_sign_key,
        effective_header, // generate_header
        effective_schema, // generate_schema
        None,             // notices
        license_path.map(|p| p.to_string_lossy().to_string()),
        false, // no_metadata
        &sbom_files,
        &[], // custom_metadata
    )?;

    Ok(())
}

/// Find a LICENSE file in the project directory.
fn find_license_file(project_dir: &Path) -> Option<PathBuf> {
    for name in &[
        "LICENSE",
        "LICENSE.md",
        "LICENSE.txt",
        "LICENSE-MIT",
        "LICENSE-APACHE",
    ] {
        let path = project_dir.join(name);
        if path.exists() {
            return Some(path);
        }
    }
    None
}

#[cfg(test)]
mod tests {
    #![allow(non_snake_case)]

    use super::*;
    use std::fs;
    use tempfile::TempDir;

    fn write_cargo_toml(dir: &Path, content: &str) {
        fs::write(dir.join("Cargo.toml"), content).unwrap();
    }

    #[test]
    fn detect___standalone_project___extracts_name_and_version() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-plugin"
version = "2.1.0"

[lib]
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(temp.path()).unwrap();

        assert_eq!(project.name, "my-plugin");
        assert_eq!(project.version, "2.1.0");
    }

    #[test]
    fn detect___custom_lib_name___uses_lib_name() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-plugin"
version = "1.0.0"

[lib]
name = "custom_name"
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(temp.path()).unwrap();

        assert_eq!(project.lib_name, "custom_name");
    }

    #[test]
    fn detect___workspace_version___resolves_from_workspace_root() {
        let temp = TempDir::new().unwrap();

        // Create workspace root
        write_cargo_toml(
            temp.path(),
            r#"
[workspace]
members = ["crates/my-plugin"]

[workspace.package]
version = "3.0.0"
"#,
        );

        // Create member directory
        let member_dir = temp.path().join("crates").join("my-plugin");
        fs::create_dir_all(&member_dir).unwrap();
        write_cargo_toml(
            &member_dir,
            r#"
[package]
name = "my-plugin"
version.workspace = true

[lib]
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(&member_dir).unwrap();

        assert_eq!(project.version, "3.0.0");
    }

    #[test]
    fn detect___no_cargo_toml___returns_error() {
        let temp = TempDir::new().unwrap();

        let result = PluginProject::detect(temp.path());

        assert!(result.is_err());
        let err = result.unwrap_err().to_string();
        assert!(err.contains("No Cargo.toml"), "Error was: {err}");
    }

    #[test]
    fn detect___no_cdylib_crate_type___returns_error() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-lib"
version = "1.0.0"

[lib]
crate-type = ["rlib"]
"#,
        );

        let result = PluginProject::detect(temp.path());

        assert!(result.is_err());
        let err = result.unwrap_err().to_string();
        assert!(err.contains("cdylib"), "Error was: {err}");
    }

    #[test]
    fn detect___hyphenated_name___converts_to_underscores() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-cool-plugin"
version = "1.0.0"

[lib]
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(temp.path()).unwrap();

        assert_eq!(project.lib_name, "my_cool_plugin");
    }

    #[test]
    fn output_path___release_mode___no_dev_suffix() {
        let dir = Path::new("/project");

        let path = derive_pack_output(dir, "my-plugin", "1.0.0", false);

        assert_eq!(
            path,
            PathBuf::from("/project/target/bundle/my-plugin-1.0.0.rbp")
        );
    }

    #[test]
    fn output_path___dev_mode___has_dev_suffix() {
        let dir = Path::new("/project");

        let path = derive_pack_output(dir, "my-plugin", "1.0.0", true);

        assert_eq!(
            path,
            PathBuf::from("/project/target/bundle/my-plugin-1.0.0-dev.rbp")
        );
    }

    #[test]
    fn detect___metadata_schema_source___extracts_value() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-plugin"
version = "1.0.0"

[package.metadata.rustbridge]
schema-source = "src/lib.rs:schema.json"

[lib]
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(temp.path()).unwrap();

        assert_eq!(
            project.schema_source.as_deref(),
            Some("src/lib.rs:schema.json")
        );
    }

    #[test]
    fn detect___metadata_header_source___extracts_value() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-plugin"
version = "1.0.0"

[package.metadata.rustbridge]
header-source = "src/binary_messages.rs:messages.h"

[lib]
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(temp.path()).unwrap();

        assert_eq!(
            project.header_source.as_deref(),
            Some("src/binary_messages.rs:messages.h")
        );
    }

    #[test]
    fn detect___no_metadata___fields_are_none() {
        let temp = TempDir::new().unwrap();
        write_cargo_toml(
            temp.path(),
            r#"
[package]
name = "my-plugin"
version = "1.0.0"

[lib]
crate-type = ["cdylib"]
"#,
        );

        let project = PluginProject::detect(temp.path()).unwrap();

        assert!(project.schema_source.is_none());
        assert!(project.header_source.is_none());
    }

    #[test]
    fn staleness___library_older_than_source___prints_warning() {
        use filetime::FileTime;

        let temp = TempDir::new().unwrap();

        // Create project structure
        fs::write(temp.path().join("Cargo.toml"), "[package]\nname = \"x\"\n").unwrap();
        let src_dir = temp.path().join("src");
        fs::create_dir_all(&src_dir).unwrap();
        fs::write(src_dir.join("lib.rs"), "// source").unwrap();

        // Create a fake library file
        let lib_path = temp.path().join("libx.so");
        fs::write(&lib_path, "fake lib").unwrap();

        // Set lib to be old (year 2020), source to be new (year 2025)
        let old_time = FileTime::from_unix_time(1_577_836_800, 0); // 2020-01-01
        let new_time = FileTime::from_unix_time(1_737_849_600, 0); // 2025-01-26

        filetime::set_file_mtime(&lib_path, old_time).unwrap();
        filetime::set_file_mtime(src_dir.join("lib.rs"), new_time).unwrap();

        // The function prints to stderr via eprintln!, so we verify
        // the staleness condition is detected by checking timestamps directly
        let lib_mtime = fs::metadata(&lib_path).unwrap().modified().unwrap();
        let src_mtime = fs::metadata(src_dir.join("lib.rs"))
            .unwrap()
            .modified()
            .unwrap();

        assert!(src_mtime > lib_mtime, "Source should be newer than library");

        // Call the function (warning goes to stderr; no panic = success)
        check_library_staleness(temp.path(), &lib_path, "Release");
    }

    #[test]
    fn staleness___library_newer_than_source___no_warning() {
        use filetime::FileTime;

        let temp = TempDir::new().unwrap();

        // Create project structure
        fs::write(temp.path().join("Cargo.toml"), "[package]\nname = \"x\"\n").unwrap();
        let src_dir = temp.path().join("src");
        fs::create_dir_all(&src_dir).unwrap();
        fs::write(src_dir.join("lib.rs"), "// source").unwrap();

        // Create a fake library file
        let lib_path = temp.path().join("libx.so");
        fs::write(&lib_path, "fake lib").unwrap();

        // Set source to be old, lib to be new
        let old_time = FileTime::from_unix_time(1_577_836_800, 0); // 2020-01-01
        let new_time = FileTime::from_unix_time(1_737_849_600, 0); // 2025-01-26

        filetime::set_file_mtime(src_dir.join("lib.rs"), old_time).unwrap();
        filetime::set_file_mtime(temp.path().join("Cargo.toml"), old_time).unwrap();
        filetime::set_file_mtime(&lib_path, new_time).unwrap();

        // Verify the condition: lib should be newer than all sources
        let lib_mtime = fs::metadata(&lib_path).unwrap().modified().unwrap();
        let src_mtime = fs::metadata(src_dir.join("lib.rs"))
            .unwrap()
            .modified()
            .unwrap();

        assert!(lib_mtime > src_mtime, "Library should be newer than source");

        // Call the function (no warning expected; no panic = success)
        check_library_staleness(temp.path(), &lib_path, "Release");
    }

    #[test]
    fn staleness___no_src_directory___no_warning() {
        use filetime::FileTime;

        let temp = TempDir::new().unwrap();

        // Create project with Cargo.toml but no src/ directory
        fs::write(temp.path().join("Cargo.toml"), "[package]\nname = \"x\"\n").unwrap();

        let lib_path = temp.path().join("libx.so");
        fs::write(&lib_path, "fake lib").unwrap();

        // Set lib to be old so Cargo.toml alone could trigger a warning,
        // but the point is the function should not panic without src/
        let old_time = FileTime::from_unix_time(1_577_836_800, 0);
        filetime::set_file_mtime(&lib_path, old_time).unwrap();

        // Call the function (should not panic even without src/ directory)
        check_library_staleness(temp.path(), &lib_path, "Release");
    }
}