package lnwire

import (
	"bytes"
	"testing"

	"github.com/lightningnetwork/lnd/tlv"
	"github.com/stretchr/testify/require"
)

// TestChanAnn2EncodeDecode tests the encoding and decoding of the
// ChannelAnnouncement2 message using hardcoded byte slices.
func TestChanAnn2EncodeDecode(t *testing.T) {
	t.Parallel()

	// We'll create a raw byte stream that represents a valid
	// ChannelAnnouncement2 message with various known and unknown fields in
	// the signed TLV ranges along with the signature in the unsigned range.
	rawBytes := []byte{
		// ChainHash record (optional, not mainnet).
		0x00, // type.
		0x20, // length.
		0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1,
		0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1,
		0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1,

		// Features record.
		0x02,     // type.
		0x02,     // length.
		0x1, 0x2, // value.

		// ShortChannelID record.
		0x04,                                   // type.
		0x08,                                   // length.
		0x0, 0x0, 0x1, 0x0, 0x0, 0x2, 0x0, 0x3, // value.

		// Unknown TLV record.
		0x05,       // type.
		0x02,       // length.
		0xab, 0xcd, // value.

		// Capacity record.
		0x06,                                     // type.
		0x08,                                     // length.
		0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x86, 0xa0, // value: 100000.

		// NodeID1 record.
		0x08, // type.
		0x21, // length.
		0x2, 0x28, 0xf2, 0xaf, 0xa, 0xbe, 0x32, 0x24, 0x3, 0x48, 0xf,
		0xb3, 0xee, 0x17, 0x2f, 0x7f, 0x16, 0x1, 0xe6, 0x7d, 0x1d, 0xa6,
		0xca, 0xd4, 0xb, 0x54, 0xc4, 0x46, 0x8d, 0x48, 0x23, 0x6c, 0x39,

		// NodeID2 record.
		0x0a, // type.
		0x21, // length.
		0x3, 0x28, 0xf2, 0xaf, 0xa, 0xbe, 0x32, 0x24, 0x3, 0x48, 0xf,
		0xb3, 0xee, 0x17, 0x2f, 0x7f, 0x16, 0x1, 0xe6, 0x7d, 0x1d, 0xa6,
		0xca, 0xd4, 0xb, 0x54, 0xc4, 0x46, 0x8d, 0x48, 0x23, 0x6c, 0x39,

		// Outpoint record.
		0x12, // type (18).
		0x22, // length (34 bytes).
		// Hash (32 bytes).
		0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
		0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
		0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
		0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
		// Index (2 bytes).
		0x30, 0x39, // value: 12345.

		// Unknown TLV record.
		0x6f,       // type.
		0x2,        // length.
		0x79, 0x79, // value.

		// Signature.
		0xa0, // type.
		0x40, // length.
		0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, 0xb,
		0xc, 0xd, 0xe, 0xf, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
		0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
		0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a,
		0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34,
		0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e,
		0x3f, // value.
	}
	secondSignedRangeType := new(bytes.Buffer)
	var buf [8]byte
	err := tlv.WriteVarInt(
		secondSignedRangeType, pureTLVSignedSecondRangeStart+1, &buf,
	)
	require.NoError(t, err)
	rawBytes = append(rawBytes, secondSignedRangeType.Bytes()...) // type.
	rawBytes = append(rawBytes, []byte{
		0x02,       // length.
		0x79, 0x79, // value.
	}...)

	// Now, create a new empty message and decode the raw bytes into it.
	msg := &ChannelAnnouncement2{}
	r := bytes.NewReader(rawBytes)
	err = msg.Decode(r, 0)
	require.NoError(t, err)

	// Next, encode the message back into a new byte buffer.
	var b bytes.Buffer
	err = msg.Encode(&b, 0)
	require.NoError(t, err)

	// The re-encoded bytes should be exactly the same as the original raw
	// bytes.
	require.Equal(t, rawBytes, b.Bytes())
}