// Copyright 2019 The NATS Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package server

import (
	"fmt"
	"net/url"
	"strings"
	"testing"
	"time"
)

type captureLeafNodeRandomIPLogger struct {
	DummyLogger
	ch  chan struct{}
	ips [3]int
}

func (c *captureLeafNodeRandomIPLogger) Debugf(format string, v ...interface{}) {
	msg := fmt.Sprintf(format, v...)
	if strings.Contains(msg, "hostname_to_resolve") {
		ippos := strings.Index(msg, "127.0.0.")
		if ippos != -1 {
			n := int(msg[ippos+8] - '1')
			c.ips[n]++
			for _, v := range c.ips {
				if v < 2 {
					return
				}
			}
			// All IPs got at least some hit, we are done.
			c.ch <- struct{}{}
		}
	}
}

func TestLeafNodeRandomIP(t *testing.T) {
	u, err := url.Parse("nats://hostname_to_resolve:1234")
	if err != nil {
		t.Fatalf("Error parsing: %v", err)
	}

	resolver := &myDummyDNSResolver{ips: []string{"127.0.0.1", "127.0.0.2", "127.0.0.3"}}

	o := DefaultOptions()
	o.Host = "127.0.0.1"
	o.Port = -1
	o.LeafNode.Port = 0
	o.LeafNode.Remotes = []*RemoteLeafOpts{&RemoteLeafOpts{URL: u}}
	o.LeafNode.ReconnectInterval = 50 * time.Millisecond
	o.LeafNode.resolver = resolver
	o.LeafNode.dialTimeout = 15 * time.Millisecond
	s := RunServer(o)
	defer s.Shutdown()

	l := &captureLeafNodeRandomIPLogger{ch: make(chan struct{})}
	s.SetLogger(l, true, true)

	select {
	case <-l.ch:
	case <-time.After(3 * time.Second):
		t.Fatalf("Does not seem to have used random IPs")
	}
}