package hostevidence

import (
	"crypto/ed25519"
	"crypto/rand"
	"testing"
)

func TestReceiptSignatureBindsProducerKeyAndExactBytes(t *testing.T) {
	pub, private, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		t.Fatal(err)
	}
	key := "control/hosts/x.example/evidence/op/box/receipt.json"
	body := []byte(`{"evidence_at":"2026-10-07T00:00:00Z"}`)
	wire, err := message(key, body)
	if err != nil {
		t.Fatal(err)
	}
	signature := ed25519.Sign(private, wire)
	if err = Verify(pub, key, body, signature); err != nil {
		t.Fatal(err)
	}
	other, _, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		t.Fatal(err)
	}
	for _, test := range []struct {
		pub  ed25519.PublicKey
		key  string
		body []byte
	}{
		{other, key, body}, {pub, key + "changed", body}, {pub, key, []byte(`{"evidence_at":"2026-10-08T00:00:00Z"}`)},
	} {
		if Verify(test.pub, test.key, test.body, signature) == nil {
			t.Fatal("accepted forged receipt")
		}
	}
}

func TestReceiptSignatureSeparatesServingAndOperationEvidence(t *testing.T) {
	pub, private, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		t.Fatal(err)
	}
	body := []byte(`{"region":"ie","claim_etag":"etag","observed_boot_id":"boot","request_limit_ns":120000000000}`)
	keys := []string{
		"control/hosts/x.example/serving-evidence/box/receipt.json",
		"control/hosts/x.example/evidence/op/box/receipt.json",
	}
	for _, key := range keys {
		wire, err := message(key, body)
		if err != nil {
			t.Fatal(err)
		}
		sig := ed25519.Sign(private, wire)
		if err := Verify(pub, key, body, sig); err != nil {
			t.Fatal(err)
		}
		for _, other := range keys {
			if other != key && Verify(pub, other, body, sig) == nil {
				t.Fatal("receipt signature crossed evidence namespaces")
			}
		}
	}
	for _, key := range []string{
		"control/hosts/x.example/serving-evidence/op/box/receipt.json",
		"control/hosts/x.example/evidence/box/receipt.json",
		"control/hosts/x.example/serving-evidence/../receipt.json",
		"control/hosts/x.example/serving-evidence//receipt.json",
		"control/hosts/x.example/serving-evidence/box/receipt.json.sig",
	} {
		if _, err := message(key, body); err == nil {
			t.Fatalf("accepted invalid evidence key %q", key)
		}
	}
}