import (
    "bytes"
    _ "embed"
    "log"
    "os"

    "github.com/bytecodealliance/wasmtime-go/v11"
    "github.com/guregu/hammertime"
)

//go:embed hello.wasm
var wasmModule []byte // Protip: stuff your modules into your binary with embed

func main() {
    // Standard boilerplate
    engine := wasmtime.NewEngine()
    store := wasmtime.NewStore(engine)
    module, err := wasmtime.NewModule(engine, wasmModule)
    if err != nil {
        panic(err)
    }
    linker := wasmtime.NewLinker(engine)

    // Prepare our input and output
    input := "alice\nbob\n"
    stdin := strings.NewReader(input)
    stdout := new(bytes.Buffer)

    // Set up our custom WASI
    wasi := hammertime.NewWASI(
        WithArgs([]string{"hello.wasm"}),
        WithStdin(stdin),             // Stdin can be any io.Reader
        WithStdout(stdout),           // Capture stdout to a *bytes.Buffer!
        WithFS(os.DirFS("testdata")), // Works with Go's fs.FS! (kind of)
    )
    // Link our WASI
    if err := wasi.Link(store, linker); err != nil {
        panic(err)
    }

    // Use wasmtime as normal
    instance, err := linker.Instantiate(store, module)
    if err != nil {
        panic(err)
    }
    start := instance.GetFunc(store, "_start")
    _, err = start.Call(store)
    if err != nil {
        panic(err)
    }

    // Grab captured stdout data
    output := stdout.String()
    fmt.Println(output)
    // Prints: hello alice
    // hello bob
}