// Copyright 2018-2025 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"
	"strings"
	"testing"
	"time"

	"github.com/nats-io/nats.go"
)

func checkClosedConns(t *testing.T, s *Server, num int, wait time.Duration) {
	t.Helper()
	checkFor(t, wait, 5*time.Millisecond, func() error {
		if nc := s.numClosedConns(); nc != num {
			return fmt.Errorf("Closed conns expected to be %v, got %v", num, nc)
		}
		return nil
	})
}

func checkTotalClosedConns(t *testing.T, s *Server, num uint64, wait time.Duration) {
	t.Helper()
	checkFor(t, wait, 5*time.Millisecond, func() error {
		if nc := s.totalClosedConns(); nc != num {
			return fmt.Errorf("Total closed conns expected to be %v, got %v", num, nc)
		}
		return nil
	})
}

func TestClosedConnsAccounting(t *testing.T) {
	opts := DefaultOptions()
	opts.MaxClosedClients = 10
	opts.NoSystemAccount = true

	s := RunServer(opts)
	defer s.Shutdown()

	wait := time.Second

	nc, err := nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	id, _ := nc.GetClientID()
	nc.Close()

	checkClosedConns(t, s, 1, wait)

	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	if conns[0].Cid != id {
		t.Fatalf("Expected CID to be %d, got %d\n", id, conns[0].Cid)
	}

	// Now create 21 more
	for i := 0; i < 21; i++ {
		nc, err = nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port))
		if err != nil {
			t.Fatalf("Error on connect: %v", err)
		}
		nc.Close()
		checkTotalClosedConns(t, s, uint64(i+2), wait)
	}

	checkClosedConns(t, s, opts.MaxClosedClients, wait)
	checkTotalClosedConns(t, s, 22, wait)

	conns = s.closedClients()
	if lc := len(conns); lc != opts.MaxClosedClients {
		t.Fatalf("len(conns) expected to be %d, got %d\n",
			opts.MaxClosedClients, lc)
	}

	// Set it to the start after overflow.
	cid := uint64(22 - opts.MaxClosedClients)
	for _, ci := range conns {
		cid++
		if ci.Cid != cid {
			t.Fatalf("Expected cid of %d, got %d\n", cid, ci.Cid)
		}
	}
}

func TestClosedConnsSubsAccounting(t *testing.T) {
	opts := DefaultOptions()
	s := RunServer(opts)
	defer s.Shutdown()

	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)

	nc, err := nats.Connect(url)
	if err != nil {
		t.Fatalf("Error on subscribe: %v", err)
	}
	defer nc.Close()

	// Now create some subscriptions
	numSubs := 10
	for i := 0; i < numSubs; i++ {
		subj := fmt.Sprintf("foo.%d", i)
		nc.Subscribe(subj, func(m *nats.Msg) {})
	}
	nc.Flush()
	nc.Close()

	checkClosedConns(t, s, 1, 20*time.Millisecond)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be 1, got %d\n", lc)
	}
	ci := conns[0]

	if len(ci.subs) != numSubs {
		t.Fatalf("Expected number of Subs to be %d, got %d\n", numSubs, len(ci.subs))
	}
}

func checkReason(t *testing.T, reason string, expected ClosedState) {
	if !strings.Contains(reason, expected.String()) {
		t.Fatalf("Expected closed connection with `%s` state, got `%s`\n",
			expected, reason)
	}
}

func TestClosedAuthorizationTimeout(t *testing.T) {
	serverOptions := DefaultOptions()
	serverOptions.Authorization = "my_token"
	serverOptions.AuthTimeout = 0.4
	s := RunServer(serverOptions)
	defer s.Shutdown()

	conn, err := net.Dial("tcp", net.JoinHostPort(serverOptions.Host, fmt.Sprintf("%d", serverOptions.Port)))
	if err != nil {
		t.Fatalf("Error dialing server: %v\n", err)
	}
	defer conn.Close()

	checkClosedConns(t, s, 1, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	checkReason(t, conns[0].Reason, AuthenticationTimeout)
}

func TestClosedAuthorizationViolation(t *testing.T) {
	serverOptions := DefaultOptions()
	serverOptions.Authorization = "my_token"
	s := RunServer(serverOptions)
	defer s.Shutdown()

	opts := s.getOpts()
	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)

	nc, err := nats.Connect(url)
	if err == nil {
		nc.Close()
		t.Fatal("Expected failure for connection")
	}

	checkClosedConns(t, s, 1, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	checkReason(t, conns[0].Reason, AuthenticationViolation)
}

func TestClosedUPAuthorizationViolation(t *testing.T) {
	serverOptions := DefaultOptions()
	serverOptions.Username = "my_user"
	serverOptions.Password = "my_secret"
	s := RunServer(serverOptions)
	defer s.Shutdown()

	opts := s.getOpts()
	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)

	nc, err := nats.Connect(url)
	if err == nil {
		nc.Close()
		t.Fatal("Expected failure for connection")
	}

	url2 := fmt.Sprintf("nats://my_user:wrong_pass@%s:%d", opts.Host, opts.Port)
	nc, err = nats.Connect(url2)
	if err == nil {
		nc.Close()
		t.Fatal("Expected failure for connection")
	}

	checkClosedConns(t, s, 2, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 2 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 2, lc)
	}
	checkReason(t, conns[0].Reason, AuthenticationViolation)
	checkReason(t, conns[1].Reason, AuthenticationViolation)
}

func TestClosedMaxPayload(t *testing.T) {
	serverOptions := DefaultOptions()
	serverOptions.MaxPayload = 100

	s := RunServer(serverOptions)
	defer s.Shutdown()

	opts := s.getOpts()
	endpoint := net.JoinHostPort(opts.Host, fmt.Sprintf("%d", opts.Port))

	conn, err := net.DialTimeout("tcp", endpoint, time.Second)
	if err != nil {
		t.Fatalf("Could not make a raw connection to the server: %v", err)
	}
	defer conn.Close()

	// This should trigger it.
	pub := "PUB foo.bar 1024\r\n"
	conn.Write([]byte(pub))

	checkClosedConns(t, s, 1, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	checkReason(t, conns[0].Reason, MaxPayloadExceeded)
}

func TestClosedTLSHandshake(t *testing.T) {
	opts, err := ProcessConfigFile("./configs/tls.conf")
	if err != nil {
		t.Fatalf("Error processing config file: %v", err)
	}
	opts.TLSVerify = true
	opts.NoLog = true
	opts.NoSigs = true
	s := RunServer(opts)
	defer s.Shutdown()

	nc, err := nats.Connect(fmt.Sprintf("tls://%s:%d", opts.Host, opts.Port))
	if err == nil {
		nc.Close()
		t.Fatal("Expected failure for connection")
	}

	checkClosedConns(t, s, 1, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	checkReason(t, conns[0].Reason, TLSHandshakeError)
}
