package bt

import (
	"bytes"
	"testing"
)

func TestMsg(t *testing.T) {
	tests := []struct {
		name string
		msg  *Msg
	}{
		{
			name: "choke",
			msg:  &Msg{Kind: Choke},
		},
		{
			name: "unchoke",
			msg:  &Msg{Kind: Unchoke},
		},
		{
			name: "interested",
			msg:  &Msg{Kind: Interested},
		},
		{
			name: "not interested",
			msg:  &Msg{Kind: NotInterested},
		},
		{
			name: "have",
			msg: &Msg{
				Kind:  Have,
				Index: 42,
			},
		},
		{
			name: "bitfield",
			msg: &Msg{
				Kind:     Bitfield,
				Bitfield: []byte{0b1111_1111, 0b0000_0000},
			},
		},
		{
			name: "request",
			msg: &Msg{
				Kind:   Request,
				Index:  1,
				Begin:  16384,
				Length: 16384,
			},
		},
		{
			name: "piece",
			msg: &Msg{
				Kind:  Piece,
				Index: 1,
				Begin: 0,
				Block: []byte("data"),
			},
		},
		{
			name: "cancel",
			msg: &Msg{
				Kind:   Cancel,
				Index:  1,
				Begin:  0,
				Length: 16384,
			},
		},
		{
			name: "keep-alive",
			msg:  nil,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var buf bytes.Buffer
			writeMsg(&buf, tt.msg)
			data := buf.Bytes()
			got, _, err := readMsg(bytes.NewReader(data))
			if err != nil {
				t.Fatalf("readMsg: %v", err)
			}
			var buf2 bytes.Buffer
			writeMsg(&buf2, got)
			if !bytes.Equal(buf2.Bytes(), data) {
				t.Errorf("roundtrip mismatch: got %x, want %x", buf2.Bytes(), data)
			}
		})
	}
}