package btcwire

import (
	"bytes"
	"testing"

	"git.smesh.lol/nostrino/pkg/crypto/chainhash"
)

func TestTxRoundTrip(t *testing.T) {
	raw := []byte{
		0x01, 0x00, 0x00, 0x00, // version
		0x01, // input count
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0xff, 0xff, 0xff, 0xff, // sequence
	}
	want := &Tx{Raw: raw}
	payload, err := want.EncodePayload()
	if err != nil {
		t.Fatalf("EncodePayload: %v", err)
	}
	if !bytes.Equal(payload, raw) {
		t.Fatalf("payload = %x, want %x", payload, raw)
	}
	var got Tx
	if err := got.DecodePayload(payload); err != nil {
		t.Fatalf("DecodePayload: %v", err)
	}
	if !bytes.Equal(got.Raw, raw) {
		t.Fatalf("decoded = %x, want %x", got.Raw, raw)
	}
	wantID := chainhash.DoubleHashH(raw)
	if got.TxID() != wantID {
		t.Fatalf("TxID = %s, want %s", got.TxID(), wantID)
	}
	// Any change to the raw transaction changes the txid.
	mutated := &Tx{Raw: append([]byte(nil), raw...)}
	mutated.Raw[0] ^= 0x01
	if mutated.TxID() == wantID {
		t.Fatal("mutated transaction kept the same txid")
	}
}

func TestTxEmpty(t *testing.T) {
	var tx Tx
	payload, err := tx.EncodePayload()
	if err != nil {
		t.Fatalf("EncodePayload: %v", err)
	}
	if len(payload) != 0 {
		t.Fatalf("payload = %x, want empty", payload)
	}
	var got Tx
	if err := got.DecodePayload(nil); err != nil {
		t.Fatalf("DecodePayload: %v", err)
	}
	if len(got.Raw) != 0 {
		t.Fatalf("raw = %x, want empty", got.Raw)
	}
	if got.TxID() != chainhash.DoubleHashH(nil) {
		t.Fatal("empty transaction txid mismatch")
	}
}

func TestTxFrameRoundTrip(t *testing.T) {
	raw := bytes.Repeat([]byte{0x42}, 500)
	frame, err := EncodeMessagePayload(TestNet3, CmdTx, &Tx{Raw: raw})
	if err != nil {
		t.Fatalf("EncodeMessagePayload: %v", err)
	}
	msg, err := DecodeMessage(TestNet3, bytes.NewReader(frame))
	if err != nil {
		t.Fatalf("DecodeMessage: %v", err)
	}
	var got Tx
	if err := msg.Decode(&got); err != nil {
		t.Fatalf("Decode: %v", err)
	}
	if !bytes.Equal(got.Raw, raw) {
		t.Fatalf("raw = %x, want %x", got.Raw, raw)
	}
}