package token

import (
	"crypto/ed25519"
	"encoding/json"
	"strings"
	"testing"
)

func complete(t *testing.T) Token {
	t.Helper()
	public, _, err := ed25519.GenerateKey(nil)
	if err != nil {
		t.Fatal(err)
	}
	return Token{
		Broker:      "192.0.2.10:5671",
		Fingerprint: "sha256:" + strings.Repeat("ab", 32),
		Signer:      public,
		Secret:      "a-one-time-secret",
	}
}

func TestATokenSurvivesBeingCarried(t *testing.T) {
	// It is copied by hand out of a terminal and into a machine. Whatever comes back must be
	// exactly what went in, including the key — a signing key that changed in transit is a node
	// that refuses every declaration it is later sent.
	original := complete(t)
	encoded, err := original.Encode()
	if err != nil {
		t.Fatal(err)
	}
	if strings.ContainsAny(encoded, " \n\t") {
		t.Error("the encoded token contains whitespace; it is copied by hand as one line")
	}

	back, err := Decode(encoded)
	if err != nil {
		t.Fatal(err)
	}
	if back.Broker != original.Broker || back.Fingerprint != original.Fingerprint ||
		back.Secret != original.Secret || string(back.Signer) != string(original.Signer) {
		t.Errorf("the token changed in transit:\n  sent %+v\n  got  %+v", original, back)
	}
}

func TestSurroundingWhitespaceIsTolerated(t *testing.T) {
	// It arrives pasted. A trailing newline is not a corrupted token, and refusing one would
	// send somebody hunting for a fault that is not there.
	encoded, err := complete(t).Encode()
	if err != nil {
		t.Fatal(err)
	}
	if _, err := Decode("  " + encoded + "\n"); err != nil {
		t.Errorf("a pasted token was refused: %v", err)
	}
}

func TestGarbageIsRefusedAsNotBeingAToken(t *testing.T) {
	for _, bad := range []string{"", "not-base64-!!!", "aGVsbG8"} {
		if _, err := Decode(bad); err == nil {
			t.Errorf("%q was accepted as a token", bad)
		}
	}
}

func TestATokenFromAnotherVersionIsRefusedClearly(t *testing.T) {
	// The host must tell "this is not from the mesh I joined" apart from "this is malformed"
	// (novox/hq ADR 0004). A version it does not understand is the first case.
	future := complete(t)
	encoded, err := future.Encode()
	if err != nil {
		t.Fatal(err)
	}
	// Re-encode by hand at a version this build does not know.
	raw := strings.Replace(string(mustDecodeBase64(t, encoded)), `"v":1`, `"v":99`, 1)
	if _, err := Decode(encodeBase64(raw)); err == nil {
		t.Fatal("a token from an unknown version was accepted")
	}
}

func TestEveryMissingPartIsNamed(t *testing.T) {
	// "This token cannot be used" is not something anybody can act on. "It has no broker
	// address" is. And all of them at once, not the first: fixing one at a time turns a single
	// decision into four.
	empty := Token{}
	missing := empty.Missing()
	if len(missing) != 4 {
		t.Fatalf("an empty token named %d missing parts, expected 4: %v", len(missing), missing)
	}
	if empty.Complete() {
		t.Error("an empty token reported itself complete")
	}
}

func TestAShortSigningKeyIsNotASigningKey(t *testing.T) {
	// The one that would pass a nil check and fail at the moment a declaration is verified —
	// which is on a node, in production, long after this.
	t1 := complete(t)
	t1.Signer = []byte("too short")
	if t1.Complete() {
		t.Error("a truncated signing key was accepted as present")
	}
}

func TestACompleteTokenIsComplete(t *testing.T) {
	if got := complete(t); !got.Complete() {
		t.Errorf("a token with all four parts reported missing: %v", got.Missing())
	}
}

func mustDecodeBase64(t *testing.T, s string) []byte {
	t.Helper()
	raw, err := base64Decode(s)
	if err != nil {
		t.Fatal(err)
	}
	return raw
}

func TestTheWireFormatIsExactlyTheseFieldNames(t *testing.T) {
	// The contract with the host, which defines this format separately because it requires
	// nothing present and does not import this (novox/hq ADR 0005). There is a matching test on
	// that side. Rename a field on either and both fail — the alternative is a rename that only
	// shows up at enrolment, on a real machine.
	raw, err := json.Marshal(complete(t))
	if err != nil {
		t.Fatal(err)
	}
	var fields map[string]any
	if err := json.Unmarshal(raw, &fields); err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{"v", "broker", "fingerprint", "signer", "secret"} {
		if _, ok := fields[want]; !ok {
			t.Errorf("the token has no %q field; the host reads that name", want)
		}
	}
	if len(fields) != 5 {
		t.Errorf("the token has %d fields, expected 5: %v", len(fields), fields)
	}
}