//! Builds one WASIp2 guest and runs each filesystem topic in an isolated instance.
use sausage_vfs::{
    adapter::{self, Adapter, View},
    *,
};
use std::sync::{Arc, OnceLock};
use wasmtime::{
    Engine, Store,
    component::{Component, Linker, ResourceTable},
};
use wasmtime_wasi::{WasiCtx, WasiCtxBuilder, WasiCtxView, WasiView};
struct State {
    wasi: WasiCtx,
    table: ResourceTable,
    fs: Adapter,
}
impl WasiView for State {
    fn ctx(&mut self) -> WasiCtxView<'_> {
        WasiCtxView {
            ctx: &mut self.wasi,
            table: &mut self.table,
        }
    }
}
fn guest() -> &'static (Engine, Component) {
    static GUEST: OnceLock<(Engine, Component)> = OnceLock::new();
    GUEST.get_or_init(|| {
        let manifest =
            std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/guests/files/Cargo.toml");
        let target = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("../target/vfs/guests");
        let status = std::process::Command::new("cargo")
            .args([
                "build",
                "--release",
                "--offline",
                "--target",
                "wasm32-wasip2",
                "--manifest-path",
            ])
            .arg(manifest)
            .env("CARGO_TARGET_DIR", &target)
            .status()
            .unwrap();
        assert!(status.success(), "guest build failed");
        let engine = Engine::default();
        let component = Component::from_file(
            &engine,
            target.join("wasm32-wasip2/release/vfs-files-guest.wasm"),
        )
        .unwrap();
        (engine, component)
    })
}
async fn run(topic: &str, shared: Arc<Memory>) {
    let (engine, component) = guest();
    let world = tempfile::tempdir().unwrap();
    std::fs::create_dir(world.path().join("tmp")).unwrap();
    let outside = tempfile::tempdir().unwrap();
    if topic == "review_links" {
        std::fs::create_dir(world.path().join("target")).unwrap();
        std::fs::write(world.path().join("target/keep"), b"keep").unwrap();
        std::fs::write(outside.path().join("secret"), b"secret").unwrap();
        std::os::unix::fs::symlink("target", world.path().join("link")).unwrap();
        std::os::unix::fs::symlink(outside.path(), world.path().join("outside-link")).unwrap();
    }
    let mut mounts = Mounts::default();
    mounts.mount(
        "/",
        Arc::new(Host::new(world.path(), Process::default()).unwrap()),
        false,
    );
    mounts.mount("/run", shared, false);
    mounts.mount("/self", Arc::new(Memory::default()), false);
    let mut generated = Generated::default();
    generated.insert("/value", || Ok(b"snapshot".to_vec()));
    mounts.mount("/proc", Arc::new(generated), true);
    let mut linker = Linker::new(engine);
    wasmtime_wasi::p2::add_to_linker_async(&mut linker).unwrap();
    adapter::add_to_linker(&mut linker, |s: &mut State| View {
        adapter: &mut s.fs,
        table: &mut s.table,
    })
    .unwrap();
    let mut wasi = WasiCtxBuilder::new();
    wasi.inherit_stdio().env("VFS_TOPIC", topic);
    if topic == "review_preopen" {
        wasi.preopened_dir(
            world.path(),
            "/native",
            wasmtime_wasi::filesystem::FsPerms::ReadWrite,
        )
        .unwrap();
    }
    let mut store = Store::new(
        engine,
        State {
            wasi: wasi.build(),
            table: ResourceTable::new(),
            fs: Adapter::new(mounts),
        },
    );
    let command =
        wasmtime_wasi::p2::bindings::Command::instantiate_async(&mut store, component, &linker)
            .await
            .unwrap();
    let result = command.wasi_cli_run().call_run(&mut store).await;
    assert!(
        matches!(result, Ok(Ok(()))),
        "guest topic {topic} failed: {result:?}"
    );
}
async fn isolated(topic: &str) {
    run(topic, Arc::new(Memory::default())).await;
}

/// Basic filesystem operations support relative paths and metadata.
#[tokio::test(flavor = "multi_thread")]
async fn basic_files() {
    isolated("basic").await;
}
/// Recursive operations and directory entries preserve nested trees.
#[tokio::test(flavor = "multi_thread")]
async fn nested_trees() {
    isolated("trees").await;
}
/// Open flags and error kinds match Rust's filesystem contract.
#[tokio::test(flavor = "multi_thread")]
async fn options_and_errors() {
    isolated("options").await;
}
/// Renames replace existing files and move complete folders.
#[tokio::test(flavor = "multi_thread")]
async fn renames() {
    isolated("rename").await;
}
/// Sparse writes return zeros for the gap beyond EOF.
#[tokio::test(flavor = "multi_thread")]
async fn sparse_writes() {
    isolated("sparse").await;
}
/// Streams transfer several MiB with a verified checksum.
#[tokio::test(flavor = "multi_thread")]
async fn large_streams() {
    isolated("streams").await;
}
/// Mount listings, root writes, and read-only errors follow the namespace.
#[tokio::test(flavor = "multi_thread")]
async fn mount_boundaries() {
    isolated("mounts").await;
}
/// Separate guest stores share the same memory layer.
#[tokio::test(flavor = "multi_thread")]
async fn shared_memory_between_guests() {
    let memory = Arc::new(Memory::default());
    run("shared_write", memory.clone()).await;
    run("shared_read", memory).await;
}
/// SQLite commits many rows and reads them after reopen.
#[tokio::test(flavor = "multi_thread")]
async fn sqlite_transactions() {
    isolated("sqlite").await;
}
/// Named temporary files persist through the filesystem adapter.
#[tokio::test(flavor = "multi_thread")]
async fn named_temporary_files() {
    isolated("tempfile").await;
}

/// Stream drop preserves writes and small reads observe later mutations.
#[tokio::test(flavor = "multi_thread")]
async fn review_streams() {
    isolated("review_streams").await;
}

/// Timestamp conversion reports overflow and accepts directories.
#[tokio::test(flavor = "multi_thread")]
async fn review_times() {
    isolated("review_times").await;
}

/// Path errors distinguish trailing slashes, busy roots, and ordinary files.
#[tokio::test(flavor = "multi_thread")]
async fn review_paths() {
    isolated("review_paths").await;
}

/// Symlink traversal does not delete targets or escape the host root.
#[tokio::test(flavor = "multi_thread")]
async fn review_links() {
    isolated("review_links").await;
}

/// The guest sees only the virtual root preopen.
#[tokio::test(flavor = "multi_thread")]
async fn review_preopen() {
    isolated("review_preopen").await;
}

/// Adding the adapter restores duplicate-import errors on the caller's linker.
#[test]
fn linker_shadowing_is_reset() {
    let engine = Engine::default();
    let mut linker = Linker::<State>::new(&engine);
    wasmtime_wasi::p2::add_to_linker_async(&mut linker).unwrap();
    adapter::add_to_linker(&mut linker, |s| View {
        adapter: &mut s.fs,
        table: &mut s.table,
    })
    .unwrap();
    assert!(wasmtime_wasi::p2::add_to_linker_async(&mut linker).is_err());
}