package dht

import (
	"net"
	"strings"
	"testing"
)

func nid(c string) [20]byte {
	var id [20]byte
	copy(id[:], strings.Repeat(c, 20))
	return id
}

func TestEncodeDecodeNodes(t *testing.T) {
	tests := []struct {
		name  string
		nodes []node
	}{
		{
			name:  "empty",
			nodes: []node{},
		},
		{
			name: "single",
			nodes: []node{
				{
					ID: nid("a"),
					Addr: &net.UDPAddr{
						IP:   net.IPv4(127, 0, 0, 1),
						Port: 6881,
					},
				},
			},
		},
		{
			name: "multiple",
			nodes: []node{
				{
					ID: nid("a"),
					Addr: &net.UDPAddr{
						IP:   net.IPv4(127, 0, 0, 1),
						Port: 6881,
					},
				},
				{
					ID: nid("a"),
					Addr: &net.UDPAddr{
						IP:   net.IPv4(192, 168, 1, 1),
						Port: 8080,
					},
				},
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			data := encodeNodes(tt.nodes)
			got := decodeNodes(data)
			data2 := encodeNodes(got)
			if data != data2 {
				t.Errorf("roundtrip mismatch: got %x, want %x", data2, data)
			}
		})
	}
}