use proxywarden_lib::component_catalog::{ComponentId, ComponentPackage, UpdateTrustPolicy};
use proxywarden_lib::component_packages::{
    ComponentPackageService, ComponentUpdateObservation, ComponentUpdatesState,
    GithubReleaseDigestProof, PackageCacheManifest, PackageSource, TrustedGithubReleaseObservation,
    COMPONENT_UPDATES_STATE_SCHEMA_VERSION, PACKAGE_CACHE_MANIFEST_FILENAME,
    PACKAGE_CACHE_MANIFEST_SCHEMA_VERSION,
};
use proxywarden_lib::safe_fs::{ensure_no_reparse_ancestors, protect_path_for_owner_admin_system};
use proxywarden_lib::storage::StoragePaths;
use sha2::{Digest, Sha256};
use std::fs;
use std::path::{Path, PathBuf};
#[cfg(windows)]
use std::process::Command;
use std::time::{SystemTime, UNIX_EPOCH};
use uuid::Uuid;

#[test]
fn offline_selection_uses_the_real_bundled_package_without_a_cache() {
    let packages = TestDirectory::new();
    let paths = StoragePaths::new(packages.path().join("missing-storage"));
    let service = ComponentPackageService::open(bundled_root(), &paths)
        .expect("open local component package service");

    let selected = service
        .select_verified(ComponentId::Proxifyre)
        .expect("select bundled package offline");

    assert_eq!(selected.source, PackageSource::Bundled);
    assert_eq!(selected.version, "2.4.0");
    assert_eq!(
        selected.asset_path,
        bundled_root()
            .join("proxifyre")
            .join("ProxiFyre-v2.4.0-x64-signed.zip")
    );
}

#[test]
fn verified_newer_cache_wins_with_numeric_version_ordering() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (expected, manifest) =
        write_verified_cache(&packages.packages_path(), &component, "1.100.0", |_| {});
    write_trusted_state(&packages.state_path(), &manifest);

    let selected = service
        .select_verified(ComponentId::SingBox)
        .expect("select newest verified cache");

    assert_eq!(selected.source, PackageSource::Cache);
    assert_eq!(selected.version, "1.100.0");
    assert_eq!(selected.package_root, expected);
}

#[test]
fn same_verified_cache_does_not_replace_the_bundle() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (_, manifest) =
        write_verified_cache(&packages.packages_path(), &component, "1.13.19", |_| {});
    write_trusted_state(&packages.state_path(), &manifest);

    assert_bundled(&service);
}

#[test]
fn older_verified_cache_does_not_replace_the_bundle() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (_, manifest) =
        write_verified_cache(&packages.packages_path(), &component, "1.13.18", |_| {});
    write_trusted_state(&packages.state_path(), &manifest);

    assert_bundled(&service);
}

#[test]
fn corrupt_cache_does_not_break_bundled_fallback() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (version_root, manifest) =
        write_verified_cache(&packages.packages_path(), &component, "1.14.0", |_| {});
    write_trusted_state(&packages.state_path(), &manifest);
    fs::write(
        version_root.join(PACKAGE_CACHE_MANIFEST_FILENAME),
        b"{not-json",
    )
    .expect("write corrupt manifest");

    assert_bundled(&service);
}

#[test]
fn cache_from_the_wrong_repository_is_rejected() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (_, manifest) = write_verified_cache(
        &packages.packages_path(),
        &component,
        "1.14.0",
        |manifest| {
            manifest.independent_proof.repository = "attacker/sing-box".to_string();
        },
    );
    write_trusted_state(&packages.state_path(), &manifest);

    assert_bundled(&service);
}

#[test]
fn handwritten_far_future_cache_without_trusted_state_is_rejected() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    write_verified_cache(&packages.packages_path(), &component, "999.0.0", |_| {});

    assert_bundled(&service);
}

#[test]
fn matching_manifest_and_state_with_inherited_acl_are_rejected() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (_, manifest) = write_cache(
        &packages.packages_path(),
        &component,
        "1.14.0",
        |_| {},
        false,
    );
    write_state(&packages.state_path(), &manifest, false);

    assert_bundled(&service);
}

#[test]
fn cache_with_an_extra_file_is_rejected() {
    let packages = TestDirectory::new();
    let service = open_service(&packages);
    let component = sing_box_component(&service);
    let (version_root, manifest) =
        write_verified_cache(&packages.packages_path(), &component, "1.14.0", |_| {});
    write_trusted_state(&packages.state_path(), &manifest);
    fs::write(version_root.join("unexpected.txt"), b"not part of package")
        .expect("write unexpected cache file");

    assert_bundled(&service);
}

#[cfg(windows)]
#[test]
fn reparse_point_cache_root_is_rejected() {
    let workspace = TestDirectory::new();
    let target = workspace.path().join("junction-target");
    fs::create_dir_all(&target).expect("create junction target");
    let storage_paths = workspace.storage_paths();
    let service = ComponentPackageService::open(bundled_root(), &storage_paths)
        .expect("open service before creating junction");
    let component = sing_box_component(&service);
    let (_, manifest) = write_verified_cache(&target, &component, "1.14.0", |_| {});
    write_trusted_state(&storage_paths.component_updates_file, &manifest);

    let junction = storage_paths.packages_dir.clone();
    let _junction_guard = create_junction(&junction, &target, workspace.path());

    assert_bundled(&service);
}

fn bundled_root() -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR"))
        .join("bundled")
        .join("components")
}

fn open_service(packages: &TestDirectory) -> ComponentPackageService {
    ComponentPackageService::open(bundled_root(), &packages.storage_paths())
        .expect("production bundle must open")
}

fn sing_box_component(service: &ComponentPackageService) -> ComponentPackage {
    service
        .catalog()
        .components
        .iter()
        .find(|component| component.id == ComponentId::SingBox)
        .expect("production sing-box component")
        .clone()
}

fn assert_bundled(service: &ComponentPackageService) {
    let selected = service
        .select_verified(ComponentId::SingBox)
        .expect("fall back to bundled package");
    assert_eq!(selected.source, PackageSource::Bundled);
    assert_eq!(selected.version, "1.13.19");
}

fn cache_version_root(packages_root: &Path, version: &str) -> PathBuf {
    packages_root
        .join(ComponentId::SingBox.as_str())
        .join(version)
}

fn write_verified_cache(
    packages_root: &Path,
    component: &ComponentPackage,
    version: &str,
    mutate: impl FnOnce(&mut PackageCacheManifest),
) -> (PathBuf, PackageCacheManifest) {
    write_cache(packages_root, component, version, mutate, true)
}

fn write_cache(
    packages_root: &Path,
    component: &ComponentPackage,
    version: &str,
    mutate: impl FnOnce(&mut PackageCacheManifest),
    protect: bool,
) -> (PathBuf, PackageCacheManifest) {
    let version_root = cache_version_root(packages_root, version);
    fs::create_dir_all(&version_root).expect("create cache version directory");

    let asset_name = format!("sing-box-{version}-windows-amd64.zip");
    let asset_bytes = format!("verified sing-box package {version}").into_bytes();
    let sha256 = format!("{:x}", Sha256::digest(&asset_bytes));
    let repository = match &component.update_trust_policy {
        UpdateTrustPolicy::GithubReleaseDigest {
            repository,
            authenticode_publishers,
            ..
        } => {
            assert!(
                authenticode_publishers.is_none(),
                "sing-box cache must not claim Authenticode evidence"
            );
            repository.clone()
        }
        _ => panic!("sing-box must use GitHub release digest trust"),
    };
    let mut manifest = PackageCacheManifest {
        schema_version: PACKAGE_CACHE_MANIFEST_SCHEMA_VERSION,
        component_id: component.id,
        version: version.to_string(),
        asset_name: asset_name.clone(),
        sha256: sha256.clone(),
        size: asset_bytes.len() as u64,
        independent_proof: GithubReleaseDigestProof {
            repository,
            release_id: 1,
            asset_id: 1,
            stable_tag: format!("v{version}"),
            asset_name: asset_name.clone(),
            size: asset_bytes.len() as u64,
            sha256_from_api: sha256,
            verified_signatures: Vec::new(),
        },
    };
    mutate(&mut manifest);

    let asset_path = version_root.join(&asset_name);
    fs::write(&asset_path, asset_bytes).expect("write cached package asset");
    let manifest_path = version_root.join(PACKAGE_CACHE_MANIFEST_FILENAME);
    fs::write(
        &manifest_path,
        serde_json::to_vec_pretty(&manifest).expect("serialize cache manifest"),
    )
    .expect("write cache manifest");
    if protect {
        let component_root = packages_root.join(component.id.as_str());
        for path in [
            packages_root,
            component_root.as_path(),
            version_root.as_path(),
            asset_path.as_path(),
            manifest_path.as_path(),
        ] {
            protect_path_for_owner_admin_system(path).expect("protect trusted cache path");
        }
    }
    (version_root, manifest)
}

fn write_trusted_state(state_path: &Path, manifest: &PackageCacheManifest) {
    write_state(state_path, manifest, true);
}

fn write_state(state_path: &Path, manifest: &PackageCacheManifest, protect: bool) {
    let proof = &manifest.independent_proof;
    let checked_at_unix = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .expect("system clock must be after Unix epoch")
        .as_secs();
    let state = ComponentUpdatesState {
        schema_version: COMPONENT_UPDATES_STATE_SCHEMA_VERSION,
        observations: vec![ComponentUpdateObservation {
            component_id: manifest.component_id,
            checked_at_unix,
            latest_known_version: manifest.version.clone(),
            trusted_releases: vec![TrustedGithubReleaseObservation {
                repository: proof.repository.clone(),
                release_id: proof.release_id,
                asset_id: proof.asset_id,
                stable_tag: proof.stable_tag.clone(),
                asset_name: proof.asset_name.clone(),
                size: proof.size,
                sha256_from_api: proof.sha256_from_api.clone(),
            }],
        }],
    };
    let state_parent = state_path.parent().expect("state path has parent");
    fs::create_dir_all(state_parent).expect("create state directory");
    fs::write(
        state_path,
        serde_json::to_vec_pretty(&state).expect("serialize trusted update state"),
    )
    .expect("write trusted update state");
    if protect {
        protect_path_for_owner_admin_system(state_parent).expect("protect state parent");
        protect_path_for_owner_admin_system(state_path).expect("protect trusted update state");
    }
}

struct TestDirectory {
    path: PathBuf,
    target_root: PathBuf,
}

impl TestDirectory {
    fn new() -> Self {
        let target_root = Path::new(env!("CARGO_MANIFEST_DIR")).join("target");
        fs::create_dir_all(&target_root).expect("create Cargo target directory");
        let target_root =
            fs::canonicalize(target_root).expect("canonicalize Cargo target directory");
        let path = target_root.join(format!("component-package-tests-{}", Uuid::new_v4()));
        fs::create_dir(&path).expect("create isolated component package test directory");
        Self { path, target_root }
    }

    fn path(&self) -> &Path {
        &self.path
    }

    fn storage_paths(&self) -> StoragePaths {
        StoragePaths::new(&self.path)
    }

    fn packages_path(&self) -> PathBuf {
        self.storage_paths().packages_dir
    }

    fn state_path(&self) -> PathBuf {
        self.storage_paths().component_updates_file
    }
}

impl Drop for TestDirectory {
    fn drop(&mut self) {
        let has_exact_parent = self.path.parent() == Some(self.target_root.as_path());
        let has_test_name = self
            .path
            .file_name()
            .and_then(|name| name.to_str())
            .is_some_and(|name| {
                name.strip_prefix("component-package-tests-")
                    .is_some_and(|id| Uuid::parse_str(id).is_ok())
            });
        if has_exact_parent
            && has_test_name
            && self.path.is_absolute()
            && ensure_no_reparse_ancestors(&self.path).is_ok()
        {
            let _ = fs::remove_dir_all(&self.path);
        }
    }
}

#[cfg(windows)]
struct JunctionGuard {
    path: PathBuf,
    expected_parent: PathBuf,
}

#[cfg(windows)]
impl Drop for JunctionGuard {
    fn drop(&mut self) {
        if self.path.parent() == Some(self.expected_parent.as_path())
            && self.path.file_name().is_some_and(|name| name == "packages")
        {
            let _ = fs::remove_dir(&self.path);
        }
    }
}

#[cfg(windows)]
fn create_junction(path: &Path, target: &Path, expected_parent: &Path) -> JunctionGuard {
    assert_eq!(path.parent(), Some(expected_parent));
    assert_eq!(
        path.file_name().and_then(|name| name.to_str()),
        Some("packages")
    );
    let output = Command::new("cmd")
        .args(["/d", "/c", "mklink", "/J"])
        .arg(path)
        .arg(target)
        .output()
        .expect("run mklink for reparse-point fixture");
    assert!(
        output.status.success(),
        "mklink failed: {}",
        String::from_utf8_lossy(&output.stderr)
    );
    JunctionGuard {
        path: path.to_path_buf(),
        expected_parent: expected_parent.to_path_buf(),
    }
}