// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package nat

import (
	"net"
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

// This test checks that autodisc doesn't hang and returns
// consistent results when multiple goroutines call its methods
// concurrently.
func TestAutoDiscRace(t *testing.T) {
	ad := startautodisc("thing", func() Interface {
		time.Sleep(500 * time.Millisecond)
		return ExtIP{33, 44, 55, 66}
	})

	// Spawn a few concurrent calls to ad.ExternalIP.
	type rval struct {
		ip  net.IP
		err error
	}
	results := make(chan rval, 50)
	for i := 0; i < cap(results); i++ {
		go func() {
			ip, err := ad.ExternalIP()
			results <- rval{ip, err}
		}()
	}

	// Check that they all return the correct result within the deadline.
	deadline := time.After(2 * time.Second)
	for i := 0; i < cap(results); i++ {
		select {
		case <-deadline:
			t.Fatal("deadline exceeded")
		case rval := <-results:
			if rval.err != nil {
				t.Errorf("result %d: unexpected error: %v", i, rval.err)
			}
			wantIP := net.IP{33, 44, 55, 66}
			if !rval.ip.Equal(wantIP) {
				t.Errorf("result %d: got IP %v, want %v", i, rval.ip, wantIP)
			}
		}
	}
}

// stun should work well
func TestParseStun(t *testing.T) {
	testcases := []struct {
		natStr string
		want   *stun
	}{
		{"stun", &stun{serverList: strings.Split(stunDefaultServers, "\n")}},
		{"stun:1.2.3.4:1234", &stun{serverList: []string{"1.2.3.4:1234"}}},
	}

	for _, tc := range testcases {
		nat, err := Parse(tc.natStr)
		if err != nil {
			t.Errorf("should no err, but get %v", err)
		}
		stun := nat.(*stun)
		assert.Equal(t, stun.serverList, tc.want.serverList)
	}
}

func TestExtIP_MarshalText(t *testing.T) {
	tests := []struct {
		name    string
		input   ExtIP
		want    []byte
		wantErr bool
	}{
		{
			name:  "valid ipv4",
			input: ExtIP{192, 168, 1, 1},
			want:  []byte("extip:192.168.1.1"),
		},
		{
			name:  "valid ipv6",
			input: ExtIP(net.ParseIP("2001:db8::68")), // Create ExtIP from net.IP
			want:  []byte("extip:2001:db8::68"),
		},
		{
			name:  "zero ip",
			input: ExtIP{0, 0, 0, 0},
			want:  []byte("extip:0.0.0.0"),
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := tt.input.MarshalText()
			if (err != nil) != tt.wantErr {
				t.Errorf("ExtIP.MarshalText() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if string(got) != string(tt.want) { // Compare as strings for better error messages with IPs
				t.Errorf("ExtIP.MarshalText() = %s, want %s", got, tt.want)
			}
		})
	}
}
