package link

import (
	"context"
	"crypto/ed25519"
	"encoding/json"
	"sort"
	"strings"
	"testing"
	"time"

	"github.com/nats-io/nats.go"

	"github.com/novox/mesh-controller/internal/broker"
	"github.com/novox/mesh-controller/internal/testbus"
)

// The move's ask and answer keep the engine's field names (mesh-host internal/link,
// TestTheMovesAskKeepsItsFieldNamesAndContext): the row's fields beside a hand-over's, under a context of its own.
func TestTheMovesAskAndAnswerKeepTheirFieldNames(t *testing.T) {
	keys := func(v any) string {
		raw, _ := json.Marshal(v)
		var m map[string]any
		_ = json.Unmarshal(raw, &m)
		var out []string
		for k := range m {
			out = append(out, k)
		}
		sort.Strings(out)
		return strings.Join(out, " ")
	}
	ask := MoveSecretAsk{Module: "m", Name: "n", Provider: "p", Provision: "q", Consumer: "c", ConsumerModule: "cm",
		Local: "l", Origin: "made", Generation: "g", MadeAt: time.Unix(1, 0).UTC(), Sealed: "s", SealedTo: "k"}
	if got := keys(ask); got != "consumer consumer_module generation local made_at module name origin provider "+
		"provision sealed sealed_to" {
		t.Fatalf("the ask's fields are %q", got)
	}
	answer := MoveSecretAnswer{Said: "s", Refused: "r", Secret: "own/a/b/c", Generation: 1, Unchanged: true}
	if got := keys(answer); got != "generation refused said secret unchanged" {
		t.Fatalf("the answer's fields are %q", got)
	}
	if broker.AskMoveSecretSubject("laptop") != "mesh.node.laptop.ask.move-secret" ||
		MoveSecretContext != "novox-mesh move-secret v1\n" {
		t.Fatalf("the subject %q, the context %q", broker.AskMoveSecretSubject("laptop"), MoveSecretContext)
	}
}

// A move is asked of the machine on its own subject, signed under its own context — never a hand-over's — naming
// no path and carrying the row beside the hand-over's fields; the engine's answer comes back whole.
func TestAMoveIsAskedOfTheMachineSignedUnderItsOwnContext(t *testing.T) {
	conn, err := nats.Connect(testbus.URL(t))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(conn.Close)
	signer, public := testSigner(t)
	var heard HandOverAsk
	var row MoveSecretAsk
	engine, err := conn.Subscribe(broker.AskMoveSecretSubject("laptop"), func(msg *nats.Msg) {
		var signed SignedHandOver
		_ = json.Unmarshal(msg.Data, &signed)
		if ed25519.Verify(public, append([]byte(HandOverContext), signed.Ask...), signed.Signature) ||
			!ed25519.Verify(public, append([]byte(MoveSecretContext), signed.Ask...), signed.Signature) {
			_ = msg.Respond([]byte(`{"refused":"not signed as a move"}`))
			return
		}
		_ = json.Unmarshal(signed.Ask, &heard)
		_ = json.Unmarshal(signed.Ask, &row)
		body, _ := json.Marshal(MoveSecretAnswer{Said: "moved", Secret: "own/laptop/" + row.Module + "/" + row.Name,
			Generation: 1})
		_ = msg.Respond(body)
	})
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = engine.Unsubscribe() })
	a, err := AskMoveSecret(context.Background(), conn, signer, "laptop", "the move",
		MoveSecretAsk{Module: "postgres", Name: "superuser-password", Origin: "made", Sealed: "c2Vh"}, 5*time.Second)
	if err != nil || a.Secret != "own/laptop/postgres/superuser-password" || a.Generation != 1 {
		t.Fatalf("answered %+v, %v", a, err)
	}
	if heard.Node != "laptop" || heard.Path != "" || heard.Nonce == "" || heard.Expires.IsZero() || heard.By != "the move" ||
		row.Sealed != "c2Vh" || row.Origin != "made" {
		t.Fatalf("the engine heard %+v %+v", heard, row)
	}
	if _, err := AskMoveSecret(context.Background(), conn, signer, "anchor", "the move", MoveSecretAsk{}, 2*time.Second); err == nil ||
		!strings.Contains(err.Error(), "nothing was moved") {
		t.Fatalf("a machine with no engine listening: %v", err)
	}
}