package wire

import (
	"bytes"
	"github.com/pkg/errors"
	"io"
	"reflect"
	"testing"

	"github.com/davecgh/go-spew/spew"
	"github.com/kaspanet/kaspad/util/daghash"
)

// TestGetBlockLocator tests the MsgGetBlockLocator API.
func TestGetBlockLocator(t *testing.T) {
	pver := ProtocolVersion

	hashStr := "000000000002e7ad7b9eef9479e4aabc65cb831269cc20d2632c13684406dee0"
	highHash, err := daghash.NewHashFromStr(hashStr)
	if err != nil {
		t.Errorf("NewHashFromStr: %v", err)
	}

	// Ensure the command is expected value.
	wantCmd := "getlocator"
	msg := NewMsgGetBlockLocator(highHash, &daghash.ZeroHash)
	if cmd := msg.Command(); cmd != wantCmd {
		t.Errorf("NewMsgGetBlockLocator: wrong command - got %v want %v",
			cmd, wantCmd)
	}

	// Ensure max payload is low hash (32 bytes) + high hash (32 bytes)..
	wantPayload := uint32(64)
	maxPayload := msg.MaxPayloadLength(pver)
	if maxPayload != wantPayload {
		t.Errorf("MaxPayloadLength: wrong max payload length for "+
			"protocol version %d - got %v, want %v", pver,
			maxPayload, wantPayload)
	}
}

// TestGetBlockLocatorWire tests the MsgGetBlockLocator wire encode and decode.
func TestGetBlockLocatorWire(t *testing.T) {
	hashStr := "2710f40c87ec93d010a6fd95f42c59a2cbacc60b18cf6b7957535"
	highHash, err := daghash.NewHashFromStr(hashStr)
	if err != nil {
		t.Errorf("NewHashFromStr: %v", err)
	}

	hashStr = "3ba27aa200b1cecaad478d2b00432346c3f1f3986da1afd33e506"
	lowHash, err := daghash.NewHashFromStr(hashStr)
	if err != nil {
		t.Errorf("NewHashFromStr: %v", err)
	}

	// MsgGetBlockLocator message with no block locators or high hash.
	noLowAndHighHash := NewMsgGetBlockLocator(&daghash.ZeroHash, &daghash.ZeroHash)
	noLowAndHighHashEncoded := []byte{
		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, // High hash
		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, // Low hash
	}

	// MsgGetBlockLocator message with multiple block locators and a high hash.
	withLowAndHighHash := NewMsgGetBlockLocator(highHash, lowHash)
	withLowAndHighHashEncoded := []byte{
		0x35, 0x75, 0x95, 0xb7, 0xf6, 0x8c, 0xb1, 0x60,
		0xcc, 0xba, 0x2c, 0x9a, 0xc5, 0x42, 0x5f, 0xd9,
		0x6f, 0x0a, 0x01, 0x3d, 0xc9, 0x7e, 0xc8, 0x40,
		0x0f, 0x71, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, // High hash
		0x06, 0xe5, 0x33, 0xfd, 0x1a, 0xda, 0x86, 0x39,
		0x1f, 0x3f, 0x6c, 0x34, 0x32, 0x04, 0xb0, 0xd2,
		0x78, 0xd4, 0xaa, 0xec, 0x1c, 0x0b, 0x20, 0xaa,
		0x27, 0xba, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, // Low hash
	}

	tests := []struct {
		in   *MsgGetBlockLocator // Message to encode
		out  *MsgGetBlockLocator // Expected decoded message
		buf  []byte              // Wire encoding
		pver uint32              // Protocol version for wire encoding
	}{
		// Message with no low hash and high hash.
		{
			noLowAndHighHash,
			noLowAndHighHash,
			noLowAndHighHashEncoded,
			ProtocolVersion,
		},

		// Message with low hash and high hash.
		{
			withLowAndHighHash,
			withLowAndHighHash,
			withLowAndHighHashEncoded,
			ProtocolVersion,
		},
	}

	t.Logf("Running %d tests", len(tests))
	for i, test := range tests {
		// Encode the message to wire format.
		var buf bytes.Buffer
		err := test.in.KaspaEncode(&buf, test.pver)
		if err != nil {
			t.Errorf("KaspaEncode #%d error %v", i, err)
			continue
		}
		if !bytes.Equal(buf.Bytes(), test.buf) {
			t.Errorf("KaspaEncode #%d\n got: %s want: %s", i,
				spew.Sdump(buf.Bytes()), spew.Sdump(test.buf))
			continue
		}

		// Decode the message from wire format.
		var msg MsgGetBlockLocator
		rbuf := bytes.NewReader(test.buf)
		err = msg.KaspaDecode(rbuf, test.pver)
		if err != nil {
			t.Errorf("KaspaDecode #%d error %v", i, err)
			continue
		}
		if !reflect.DeepEqual(&msg, test.out) {
			t.Errorf("KaspaDecode #%d\n got: %s want: %s", i,
				spew.Sdump(&msg), spew.Sdump(test.out))
			continue
		}
	}
}

// TestGetBlockLocatorWireErrors performs negative tests against wire encode and
// decode of MsgGetBlockLocator to confirm error paths work correctly.
func TestGetBlockLocatorWireErrors(t *testing.T) {
	// Set protocol inside getlocator message.
	pver := ProtocolVersion

	hashStr := "2710f40c87ec93d010a6fd95f42c59a2cbacc60b18cf6b7957535"
	highHash, err := daghash.NewHashFromStr(hashStr)
	if err != nil {
		t.Errorf("NewHashFromStr: %v", err)
	}

	hashStr = "3ba27aa200b1cecaad478d2b00432346c3f1f3986da1afd33e506"
	lowHash, err := daghash.NewHashFromStr(hashStr)
	if err != nil {
		t.Errorf("NewHashFromStr: %v", err)
	}

	// MsgGetBlockLocator message with multiple block locators and a high hash.
	baseGetBlockLocator := NewMsgGetBlockLocator(highHash, lowHash)
	baseGetBlockLocatorEncoded := []byte{
		0x35, 0x75, 0x95, 0xb7, 0xf6, 0x8c, 0xb1, 0x60,
		0xcc, 0xba, 0x2c, 0x9a, 0xc5, 0x42, 0x5f, 0xd9,
		0x6f, 0x0a, 0x01, 0x3d, 0xc9, 0x7e, 0xc8, 0x40,
		0x0f, 0x71, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, // High hash
		0x06, 0xe5, 0x33, 0xfd, 0x1a, 0xda, 0x86, 0x39,
		0x1f, 0x3f, 0x6c, 0x34, 0x32, 0x04, 0xb0, 0xd2,
		0x78, 0xd4, 0xaa, 0xec, 0x1c, 0x0b, 0x20, 0xaa,
		0x27, 0xba, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, // Low hash
	}

	tests := []struct {
		in       *MsgGetBlockLocator // Value to encode
		buf      []byte              // Wire encoding
		pver     uint32              // Protocol version for wire encoding
		max      int                 // Max size of fixed buffer to induce errors
		writeErr error               // Expected write error
		readErr  error               // Expected read error
	}{
		// Force error in low hash.
		{baseGetBlockLocator, baseGetBlockLocatorEncoded, pver, 0, io.ErrShortWrite, io.EOF},
		// Force error in high hash.
		{baseGetBlockLocator, baseGetBlockLocatorEncoded, pver, 32, io.ErrShortWrite, io.EOF},
	}

	t.Logf("Running %d tests", len(tests))
	for i, test := range tests {
		// Encode to wire format.
		w := newFixedWriter(test.max)
		err := test.in.KaspaEncode(w, test.pver)
		if reflect.TypeOf(err) != reflect.TypeOf(test.writeErr) {
			t.Errorf("KaspaEncode #%d wrong error got: %v, want: %v",
				i, err, test.writeErr)
			continue
		}

		// For errors which are not of type MessageError, check them for
		// equality. If the error is a MessageError, check only if it's
		// the expected type.
		if msgErr := &(MessageError{}); !errors.As(err, &msgErr) {
			if err != test.writeErr {
				t.Errorf("KaspaEncode #%d wrong error got: %v, "+
					"want: %v", i, err, test.writeErr)
				continue
			}
		}

		// Decode from wire format.
		var msg MsgGetBlockLocator
		r := newFixedReader(test.max, test.buf)
		err = msg.KaspaDecode(r, test.pver)
		if reflect.TypeOf(err) != reflect.TypeOf(test.readErr) {
			t.Errorf("KaspaDecode #%d wrong error got: %v, want: %v",
				i, err, test.readErr)
			continue
		}

		// For errors which are not of type MessageError, check them for
		// equality. If the error is a MessageError, check only if it's
		// the expected type.
		if msgErr := &(MessageError{}); !errors.As(err, &msgErr) {
			if err != test.readErr {
				t.Errorf("KaspaDecode #%d wrong error got: %v, "+
					"want: %v", i, err, test.readErr)
				continue
			}
		}
	}
}