package notify

import (
	"context"
	"errors"
	"net"
	"testing"
	"time"
)

func TestRetryConnectSucceedsAfterRetries(t *testing.T) {
	var attempts int
	wantErr := errors.New("dial failed")

	err := RetryConnect(context.Background(), &ConnectRetryOptions{
		MaxAttempts: 4,
		BaseDelay:   time.Millisecond,
		MaxDelay:    2 * time.Millisecond,
	}, func(context.Context) error {
		attempts++
		if attempts < 3 {
			return wantErr
		}
		return nil
	})
	if err != nil {
		t.Fatalf("RetryConnect failed: %v", err)
	}
	if got, want := attempts, 3; got != want {
		t.Fatalf("attempts mismatch: got %d want %d", got, want)
	}
}

func TestRetryConnectReturnsLastError(t *testing.T) {
	var attempts int
	wantErr := errors.New("connect failed")

	err := RetryConnect(context.Background(), &ConnectRetryOptions{
		MaxAttempts: 3,
		BaseDelay:   time.Millisecond,
		MaxDelay:    time.Millisecond,
	}, func(context.Context) error {
		attempts++
		return wantErr
	})
	if !errors.Is(err, wantErr) {
		t.Fatalf("RetryConnect error = %v, want %v", err, wantErr)
	}
	if got, want := attempts, 3; got != want {
		t.Fatalf("attempts mismatch: got %d want %d", got, want)
	}
}

func TestRetryConnectContextCanceled(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	var attempts int

	err := RetryConnect(ctx, &ConnectRetryOptions{
		MaxAttempts: 3,
		BaseDelay:   100 * time.Millisecond,
		MaxDelay:    100 * time.Millisecond,
	}, func(context.Context) error {
		attempts++
		cancel()
		return errors.New("fail")
	})
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("RetryConnect error = %v, want context canceled", err)
	}
	if got, want := attempts, 1; got != want {
		t.Fatalf("attempts mismatch: got %d want %d", got, want)
	}
}

func TestConnectRetryRejectsNilInputs(t *testing.T) {
	if err := RetryConnect(context.Background(), nil, nil); !errors.Is(err, errConnectRetryFnNil) {
		t.Fatalf("RetryConnect nil fn error = %v, want %v", err, errConnectRetryFnNil)
	}
	if err := ConnectClientWithRetry(context.Background(), nil, "tcp", "127.0.0.1:1", nil); !errors.Is(err, errConnectRetryClientNil) {
		t.Fatalf("ConnectClientWithRetry nil client error = %v, want %v", err, errConnectRetryClientNil)
	}
	if err := ConnectClientFactoryWithRetry(context.Background(), nil, nil, nil); !errors.Is(err, errConnectRetryClientNil) {
		t.Fatalf("ConnectClientFactoryWithRetry nil client error = %v, want %v", err, errConnectRetryClientNil)
	}
	if err := ConnectClientFactoryWithRetry(context.Background(), NewClient(), nil, nil); !errors.Is(err, errConnectRetryDialFnNil) {
		t.Fatalf("ConnectClientFactoryWithRetry nil dialFn error = %v, want %v", err, errConnectRetryDialFnNil)
	}
	if err := ListenServerWithRetry(context.Background(), nil, "tcp", "127.0.0.1:1", nil); !errors.Is(err, errConnectRetryServerNil) {
		t.Fatalf("ListenServerWithRetry nil server error = %v, want %v", err, errConnectRetryServerNil)
	}
}

func TestConnectRetryBackoffDelayCapped(t *testing.T) {
	cfg := normalizeConnectRetryOptions(&ConnectRetryOptions{
		MaxAttempts: 5,
		BaseDelay:   10 * time.Millisecond,
		MaxDelay:    30 * time.Millisecond,
	})
	if got, want := connectRetryBackoffDelay(cfg, 1), 10*time.Millisecond; got != want {
		t.Fatalf("delay attempt1 mismatch: got %v want %v", got, want)
	}
	if got, want := connectRetryBackoffDelay(cfg, 2), 20*time.Millisecond; got != want {
		t.Fatalf("delay attempt2 mismatch: got %v want %v", got, want)
	}
	if got, want := connectRetryBackoffDelay(cfg, 3), 30*time.Millisecond; got != want {
		t.Fatalf("delay attempt3 mismatch: got %v want %v", got, want)
	}
	if got, want := connectRetryBackoffDelay(cfg, 4), 30*time.Millisecond; got != want {
		t.Fatalf("delay attempt4 mismatch: got %v want %v", got, want)
	}
}

func TestRetryConnectShouldRetryCanStopEarly(t *testing.T) {
	var attempts int
	wantErr := errors.New("not retriable")

	err := RetryConnect(context.Background(), &ConnectRetryOptions{
		MaxAttempts: 5,
		BaseDelay:   time.Millisecond,
		MaxDelay:    2 * time.Millisecond,
		ShouldRetry: func(err error) bool {
			return !errors.Is(err, wantErr)
		},
	}, func(context.Context) error {
		attempts++
		return wantErr
	})
	if !errors.Is(err, wantErr) {
		t.Fatalf("RetryConnect error = %v, want %v", err, wantErr)
	}
	if got, want := attempts, 1; got != want {
		t.Fatalf("attempts mismatch: got %d want %d", got, want)
	}
}

func TestRetryConnectOnRetryHook(t *testing.T) {
	var events []ConnectRetryEvent
	wantErr := errors.New("dial failed")

	err := RetryConnect(context.Background(), &ConnectRetryOptions{
		MaxAttempts: 3,
		BaseDelay:   time.Millisecond,
		MaxDelay:    2 * time.Millisecond,
		OnRetry: func(event ConnectRetryEvent) {
			events = append(events, event)
		},
	}, func(context.Context) error {
		return wantErr
	})
	if !errors.Is(err, wantErr) {
		t.Fatalf("RetryConnect error = %v, want %v", err, wantErr)
	}
	if got, want := len(events), 2; got != want {
		t.Fatalf("retry events mismatch: got %d want %d", got, want)
	}
	if got, want := events[0].Attempt, 1; got != want {
		t.Fatalf("event[0] attempt mismatch: got %d want %d", got, want)
	}
	if got, want := events[0].MaxAttempts, 3; got != want {
		t.Fatalf("event[0] max attempts mismatch: got %d want %d", got, want)
	}
	if !errors.Is(events[0].Err, wantErr) {
		t.Fatalf("event[0] err mismatch: got %v want %v", events[0].Err, wantErr)
	}
	if got, want := events[0].NextDelay, time.Millisecond; got != want {
		t.Fatalf("event[0] next delay mismatch: got %v want %v", got, want)
	}
	if got, want := events[1].Attempt, 2; got != want {
		t.Fatalf("event[1] attempt mismatch: got %d want %d", got, want)
	}
	if got, want := events[1].NextDelay, 2*time.Millisecond; got != want {
		t.Fatalf("event[1] next delay mismatch: got %v want %v", got, want)
	}
}

func TestConnectClientFactoryWithRetryRecoversFromFailedStart(t *testing.T) {
	client := NewClient().(*ClientCommon)
	UseLegacySecurityClient(client)
	server := newRunningPeerAttachServerForTest(t, func(server *ServerCommon) {
		UseLegacySecurityServer(server)
	})

	wantErr := errors.New("key exchange failed on first attempt")
	keyExchangeAttempts := 0
	client.keyExchangeFn = func(Client) error {
		keyExchangeAttempts++
		if keyExchangeAttempts == 1 {
			return wantErr
		}
		return nil
	}

	dialAttempts := 0
	var peerConns []net.Conn
	dialFn := func(context.Context) (net.Conn, error) {
		dialAttempts++
		left, right := net.Pipe()
		peerConns = append(peerConns, right)
		bootstrapPeerAttachConnForTest(t, server, right)
		return left, nil
	}

	err := ConnectClientFactoryWithRetry(context.Background(), client, dialFn, &ConnectRetryOptions{
		MaxAttempts: 3,
		BaseDelay:   time.Millisecond,
		MaxDelay:    time.Millisecond,
	})
	if err != nil {
		t.Fatalf("ConnectClientFactoryWithRetry failed: %v", err)
	}
	if got, want := dialAttempts, 2; got != want {
		t.Fatalf("dial attempts mismatch: got %d want %d", got, want)
	}
	if got, want := keyExchangeAttempts, 2; got != want {
		t.Fatalf("key exchange attempts mismatch: got %d want %d", got, want)
	}
	if status := client.Status(); !status.Alive {
		t.Fatalf("client should be alive after retry success: %+v", status)
	}
	runtimeSnapshot, err := GetClientRuntimeSnapshot(client)
	if err != nil {
		t.Fatalf("GetClientRuntimeSnapshot failed: %v", err)
	}
	if got, want := runtimeSnapshot.Retry.RetryEventTotal, uint64(1); got != want {
		t.Fatalf("client retry events mismatch: got %d want %d", got, want)
	}
	if got, want := runtimeSnapshot.Retry.LastRetryAttempt, 1; got != want {
		t.Fatalf("client last retry attempt mismatch: got %d want %d", got, want)
	}
	if got, want := runtimeSnapshot.Retry.LastRetryError, wantErr.Error(); got != want {
		t.Fatalf("client last retry error mismatch: got %q want %q", got, want)
	}
	if runtimeSnapshot.Retry.LastRetryAt.IsZero() {
		t.Fatal("client last retry time should be recorded")
	}
	if runtimeSnapshot.Retry.LastResultError != "" {
		t.Fatalf("client last result error should be empty on success, got %q", runtimeSnapshot.Retry.LastResultError)
	}
	if runtimeSnapshot.Retry.LastResultAt.IsZero() {
		t.Fatal("client last result time should be recorded")
	}

	client.setByeFromServer(true)
	if err := client.Stop(); err != nil {
		t.Fatalf("client Stop failed: %v", err)
	}
	for _, conn := range peerConns {
		_ = conn.Close()
	}
}

func TestListenServerWithRetryRecoversFromFailedStart(t *testing.T) {
	server := NewServer().(*ServerCommon)
	var retryEvents []ConnectRetryEvent

	err := ListenServerWithRetry(context.Background(), server, "tcp", "127.0.0.1:0", &ConnectRetryOptions{
		MaxAttempts: 3,
		BaseDelay:   time.Millisecond,
		MaxDelay:    time.Millisecond,
		OnRetry: func(event ConnectRetryEvent) {
			retryEvents = append(retryEvents, event)
			if event.Attempt == 1 {
				UseLegacySecurityServer(server)
			}
		},
	})
	if err != nil {
		t.Fatalf("ListenServerWithRetry failed: %v", err)
	}
	if status := server.Status(); !status.Alive {
		t.Fatalf("server should be alive after retry success: %+v", status)
	}
	if got := len(retryEvents); got < 1 {
		t.Fatal("OnRetry should be called at least once")
	}
	if got, want := retryEvents[0].Attempt, 1; got != want {
		t.Fatalf("retry event attempt mismatch: got %d want %d", got, want)
	}
	if !errors.Is(retryEvents[0].Err, errModernPSKRequired) {
		t.Fatalf("retry event err mismatch: got %v want %v", retryEvents[0].Err, errModernPSKRequired)
	}
	runtimeSnapshot, err := GetServerRuntimeSnapshot(server)
	if err != nil {
		t.Fatalf("GetServerRuntimeSnapshot failed: %v", err)
	}
	if got, want := runtimeSnapshot.Retry.RetryEventTotal, uint64(1); got != want {
		t.Fatalf("server retry events mismatch: got %d want %d", got, want)
	}
	if got, want := runtimeSnapshot.Retry.LastRetryAttempt, 1; got != want {
		t.Fatalf("server last retry attempt mismatch: got %d want %d", got, want)
	}
	if got, want := runtimeSnapshot.Retry.LastRetryError, errModernPSKRequired.Error(); got != want {
		t.Fatalf("server last retry error mismatch: got %q want %q", got, want)
	}
	if runtimeSnapshot.Retry.LastRetryAt.IsZero() {
		t.Fatal("server last retry time should be recorded")
	}
	if runtimeSnapshot.Retry.LastResultError != "" {
		t.Fatalf("server last result error should be empty on success, got %q", runtimeSnapshot.Retry.LastResultError)
	}
	if runtimeSnapshot.Retry.LastResultAt.IsZero() {
		t.Fatal("server last result time should be recorded")
	}

	if err := server.Stop(); err != nil {
		t.Fatalf("server Stop failed: %v", err)
	}
}