package main

// Issue 755's proof on a real bus (novox/hq ADR 0349 §16): a core credential the vault sealed to this machine crosses
// the bus inside the declaration, which the controller carries and cannot open, and this engine opens it with its
// sealing key and writes the value. A listener on every subject keeps every byte that crossed; the value is never
// among them. Run against the throwaway bus merge-check.sh starts (MESH_TEST_NATS).

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

	"git.novox.be/novox/mesh-sdk/go/seal"
	"github.com/nats-io/nats.go"

	"git.novox.be/novox/mesh-sdk/go/declaration"
	"github.com/novox/mesh-host/internal/apply"
	"github.com/novox/mesh-host/internal/identity"
	"github.com/novox/mesh-host/internal/link"
	"github.com/novox/mesh-host/internal/store"
	"github.com/novox/mesh-host/internal/system"
)

const coreCredential = "the-provisioner-clients-bus-password-2025"

func TestNatsTheEngineFillsACoreCredentialFromTheVaultsBoxWithNoValueInTheClear(t *testing.T) {
	url := os.Getenv("MESH_TEST_NATS")
	if url == "" {
		t.Skip("MESH_TEST_NATS unset")
	}
	// This machine's sealing key, where the engine reads it.
	state := filepath.Join(t.TempDir(), "state.json")
	key, err := identity.GenerateSealingKey()
	if err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(identity.SealingKeyPath(state), []byte(key.Private), 0o600); err != nil {
		t.Fatal(err)
	}

	// Every byte that crosses.
	tap, err := nats.Connect(url)
	if err != nil {
		t.Fatal(err)
	}
	defer tap.Close()
	var mu sync.Mutex
	var crossed []string
	if _, err := tap.Subscribe(">", func(m *nats.Msg) {
		mu.Lock()
		crossed = append(crossed, m.Subject+" "+string(m.Data))
		mu.Unlock()
	}); err != nil {
		t.Fatal(err)
	}
	_ = tap.Flush()

	// The engine hears its declaration on its own subject.
	const node = "vaultbox"
	engine, err := nats.Connect(url)
	if err != nil {
		t.Fatal(err)
	}
	defer engine.Close()
	heard, err := engine.SubscribeSync(link.DeclareSubject(node))
	if err != nil {
		t.Fatal(err)
	}
	_ = engine.Flush()

	// The vault's answer to the controller: the value in the ADR 0206 box, sealed to this machine's key. The
	// controller carries it in the declaration as it is.
	pub, err := key.PublicPEM()
	if err != nil {
		t.Fatal(err)
	}
	box, err := seal.Seal(coreCredential, pub)
	if err != nil {
		t.Fatal(err)
	}
	path := filepath.Join(t.TempDir(), "broker")
	body, _ := json.Marshal(map[string]any{"declaration": 1, "resources": []map[string]any{
		{"id": "need-provisioner-broker", "type": "file", "path": path, "vault-sealed": box}}})
	controller, err := nats.Connect(url)
	if err != nil {
		t.Fatal(err)
	}
	defer controller.Close()
	if err := controller.Publish(link.DeclareSubject(node), body); err != nil {
		t.Fatal(err)
	}
	_ = controller.Flush()

	msg, err := heard.NextMsg(5 * time.Second)
	if err != nil {
		t.Fatalf("the declaration did not reach the engine: %v", err)
	}
	d, err := declaration.Parse(msg.Data)
	if err != nil {
		t.Fatal(err)
	}
	sys, err := system.For("arch")
	if err != nil {
		t.Fatal(err)
	}
	if _, _, err := apply.Apply(context.Background(), sys, d, store.State{}, store.OriginCarried,
		func(context.Context, string, ...string) (string, error) { return "", nil }, nil, sealOpener(state)); err != nil {
		t.Fatal(err)
	}
	on, err := os.ReadFile(path)
	if err != nil || string(on) != coreCredential {
		t.Fatalf("the engine wrote %q, %v", on, err)
	}

	_ = tap.Flush()
	time.Sleep(100 * time.Millisecond)
	mu.Lock()
	all := strings.Join(crossed, "\n")
	mu.Unlock()
	if !strings.Contains(all, link.DeclareSubject(node)) || !strings.Contains(all, "vault-sealed") {
		t.Fatalf("the listener heard nothing of the declaration:\n%s", all)
	}
	for _, form := range []string{coreCredential, base64.StdEncoding.EncodeToString([]byte(coreCredential))} {
		if strings.Contains(all, form) {
			t.Fatal("the core credential crossed the bus in the clear")
		}
	}
}

// The engine opens a value the controller sealed (the NaCl box) as before, and the vault's box, with one key.
func TestTheEnginesOpenerOpensBothBoxes(t *testing.T) {
	state := filepath.Join(t.TempDir(), "state.json")
	key, _ := identity.GenerateSealingKey()
	if err := os.WriteFile(identity.SealingKeyPath(state), []byte(key.Private), 0o600); err != nil {
		t.Fatal(err)
	}
	open := sealOpener(state)
	nacl, _ := identity.Seal(key.Public, []byte("old"))
	if got, err := open(nacl); err != nil || string(got) != "old" {
		t.Errorf("the controller's box opened to %q, %v", got, err)
	}
	pub, _ := key.PublicPEM()
	box, _ := seal.Seal("new", pub)
	raw, _ := json.Marshal(box)
	if got, err := open(string(raw)); err != nil || string(got) != "new" {
		t.Errorf("the vault's box opened to %q, %v", got, err)
	}
}