// Copyright (c) 2013-2016 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.

package wire

import (
	"bytes"
	"io"
	"reflect"
	"testing"

	"github.com/daglabs/btcd/util/daghash"
	"github.com/davecgh/go-spew/spew"
)

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

	// Block 99500 hash.
	hashStr := "000000000002e7ad7b9eef9479e4aabc65cb831269cc20d2632c13684406dee0"
	startHash, err := daghash.NewHashFromStr(hashStr)
	if err != nil {
		t.Errorf("NewHashFromStr: %v", err)
	}

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

	// Ensure max payload is start hash (32 bytes) + stop 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)
	}
}

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

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

	// MsgGetHeaders message with no block locators or stop hash.
	noStartAndStopHash := NewMsgGetHeaders(&daghash.ZeroHash, &daghash.ZeroHash)
	noStartAndStopHashEncoded := []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, // Start 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, // Stop hash
	}

	// MsgGetHeaders message with multiple block locators and a stop hash.
	withStartAndStopHash := NewMsgGetHeaders(startHash, stopHash)
	withStartAndStopHashEncoded := []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, // Start 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, // Stop hash
	}

	tests := []struct {
		in   *MsgGetHeaders // Message to encode
		out  *MsgGetHeaders // Expected decoded message
		buf  []byte         // Wire encoding
		pver uint32         // Protocol version for wire encoding
	}{
		// Message with no start hash and stop hash.
		{
			noStartAndStopHash,
			noStartAndStopHash,
			noStartAndStopHashEncoded,
			ProtocolVersion,
		},

		// Message with start hash and stop hash.
		{
			withStartAndStopHash,
			withStartAndStopHash,
			withStartAndStopHashEncoded,
			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.BtcEncode(&buf, test.pver)
		if err != nil {
			t.Errorf("BtcEncode #%d error %v", i, err)
			continue
		}
		if !bytes.Equal(buf.Bytes(), test.buf) {
			t.Errorf("BtcEncode #%d\n got: %s want: %s", i,
				spew.Sdump(buf.Bytes()), spew.Sdump(test.buf))
			continue
		}

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

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

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

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

	// MsgGetHeaders message with multiple block locators and a stop hash.
	baseGetHeaders := NewMsgGetHeaders(startHash, stopHash)
	baseGetHeadersEncoded := []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, // Start 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, // Stop hash
	}

	tests := []struct {
		in       *MsgGetHeaders // 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 start hash.
		{baseGetHeaders, baseGetHeadersEncoded, pver, 0, io.ErrShortWrite, io.EOF},
		// Force error in stop hash.
		{baseGetHeaders, baseGetHeadersEncoded, 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.BtcEncode(w, test.pver)
		if reflect.TypeOf(err) != reflect.TypeOf(test.writeErr) {
			t.Errorf("BtcEncode #%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 _, ok := err.(*MessageError); !ok {
			if err != test.writeErr {
				t.Errorf("BtcEncode #%d wrong error got: %v, "+
					"want: %v", i, err, test.writeErr)
				continue
			}
		}

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