fidius-host 0.2.1

// Copyright 2026 Colliery, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Host-side package integration: manifest loading, discovery, and building.

use std::path::{Path, PathBuf};

use ed25519_dalek::{Signature, Verifier, VerifyingKey};
use fidius_core::package::{PackageError, PackageManifest};
use serde::de::DeserializeOwned;

/// Load and validate a package manifest against a host-defined schema.
///
/// This is the primary entry point for host applications working with packages.
/// The type parameter `M` is the host's metadata schema — if the manifest's
/// `[metadata]` section doesn't deserialize into `M`, this returns an error.
///
/// # Example
///
/// ```ignore
/// #[derive(Deserialize)]
/// struct MySchema {
///     category: String,
///     min_host_version: String,
/// }
///
/// let manifest = load_package_manifest::<MySchema>(Path::new("./packages/blur/"))?;
/// assert_eq!(manifest.metadata.category, "image-processing");
/// ```
pub fn load_package_manifest<M: DeserializeOwned>(
    dir: &Path,
) -> Result<PackageManifest<M>, PackageError> {
    fidius_core::package::load_manifest(dir)
}

/// Discover packages in a directory.
///
/// Scans `dir` for subdirectories containing a `package.toml` file.
/// Returns the paths to each package directory found.
pub fn discover_packages(dir: &Path) -> Result<Vec<PathBuf>, PackageError> {
    let mut packages = Vec::new();

    if !dir.is_dir() {
        return Ok(packages);
    }

    let entries = std::fs::read_dir(dir).map_err(PackageError::Io)?;

    for entry in entries {
        let entry = entry.map_err(PackageError::Io)?;
        let path = entry.path();
        if path.is_dir() && path.join("package.toml").exists() {
            packages.push(path);
        }
    }

    packages.sort();
    Ok(packages)
}

/// Verify a source package's signature against trusted public keys.
///
/// Recomputes the package digest from files on disk and verifies the
/// `package.sig` signature against the provided trusted keys.
///
/// # Errors
///
/// - `PackageError::SignatureNotFound` — if `package.sig` doesn't exist
/// - `PackageError::SignatureInvalid` — if no trusted key verifies the signature
pub fn verify_package(dir: &Path, trusted_keys: &[VerifyingKey]) -> Result<(), PackageError> {
    let sig_path = dir.join("package.sig");
    if !sig_path.exists() {
        return Err(PackageError::SignatureNotFound {
            path: dir.display().to_string(),
        });
    }

    let sig_bytes: [u8; 64] =
        std::fs::read(&sig_path)?
            .try_into()
            .map_err(|_| PackageError::SignatureInvalid {
                path: dir.display().to_string(),
            })?;

    let signature = Signature::from_bytes(&sig_bytes);
    let digest = fidius_core::package::package_digest(dir)?;

    for key in trusted_keys {
        if key.verify(&digest, &signature).is_ok() {
            return Ok(());
        }
    }

    Err(PackageError::SignatureInvalid {
        path: dir.display().to_string(),
    })
}

/// Extract a `.fid` archive and validate its contents.
///
/// Delegates to [`fidius_core::package::unpack_package`], which applies strict
/// safety defaults: entries with `..` components, absolute paths, symlinks, or
/// hardlinks are rejected, and the cumulative decompressed size is capped to
/// guard against decompression bombs. Emits a `tracing::warn!` if the unpacked
/// package has no `package.sig`.
///
/// For archives that legitimately exceed the default caps, call
/// [`fidius_core::package::unpack_package_with_options`] directly.
///
/// # Example
///
/// ```ignore
/// let pkg_dir = unpack_fid(Path::new("blur-filter-1.0.0.fid"), Path::new("./plugins/"))?;
/// let manifest = load_package_manifest::<MySchema>(&pkg_dir)?;
/// ```
pub fn unpack_fid(archive: &Path, dest: &Path) -> Result<PathBuf, PackageError> {
    let pkg_dir = fidius_core::package::unpack_package(archive, dest)?;

    if !pkg_dir.join("package.sig").exists() {
        #[cfg(feature = "tracing")]
        tracing::warn!(
            package = %pkg_dir.display(),
            "unpacked package is unsigned (no package.sig found)"
        );
    }

    Ok(pkg_dir)
}

/// Build a package by running `cargo build` inside the package directory.
///
/// Returns the path to the compiled cdylib on success.
pub fn build_package(dir: &Path, release: bool) -> Result<PathBuf, PackageError> {
    let cargo_toml = dir.join("Cargo.toml");
    if !cargo_toml.exists() {
        return Err(PackageError::BuildFailed(format!(
            "Cargo.toml not found in {}",
            dir.display()
        )));
    }

    let mut cmd = std::process::Command::new("cargo");
    cmd.arg("build").arg("--manifest-path").arg(&cargo_toml);
    if release {
        cmd.arg("--release");
    }

    let output = cmd.output().map_err(PackageError::Io)?;

    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr);
        return Err(PackageError::BuildFailed(stderr.to_string()));
    }

    let profile = if release { "release" } else { "debug" };
    let target_dir = dir.join("target").join(profile);

    // Find the cdylib in the target directory
    let dylib_ext = if cfg!(target_os = "macos") {
        "dylib"
    } else if cfg!(target_os = "windows") {
        "dll"
    } else {
        "so"
    };

    // Look for any file with the right extension
    if let Ok(entries) = std::fs::read_dir(&target_dir) {
        for entry in entries.flatten() {
            let path = entry.path();
            if path.extension().and_then(|e| e.to_str()) == Some(dylib_ext) {
                return Ok(path);
            }
        }
    }

    Err(PackageError::BuildFailed(format!(
        "build succeeded but no .{} file found in {}",
        dylib_ext,
        target_dir.display()
    )))
}