// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';

import 'package:dds/dds.dart';
import 'package:dds/vm_service_extensions.dart';
import 'package:test/test.dart';
import 'package:vm_service/vm_service.dart';
import 'package:vm_service/vm_service_io.dart';
import 'common/test_helper.dart';

void main() {
  late Process process;
  late DartDevelopmentService dds;

  setUp(() async {
    process = await spawnDartProcess(
      'get_cached_cpu_samples_script.dart',
    );
  });

  tearDown(() async {
    await dds.shutdown();
    process.kill();
  });

  test(
    'No UserTags to cache',
    () async {
      dds = await DartDevelopmentService.startDartDevelopmentService(
        remoteVmServiceUri,
      );
      expect(dds.isRunning, true);
      final service = await vmServiceConnectUri(dds.wsUri.toString());

      // We didn't provide `cachedUserTags` when starting DDS, so we shouldn't
      // be caching anything.
      final availableCaches = await service.getAvailableCachedCpuSamples();
      expect(availableCaches.cacheNames.length, 0);

      final isolate = (await service.getVM()).isolates!.first;

      try {
        await service.getCachedCpuSamples(isolate.id!, 'Fake');
        fail('Invalid userTag did not cause an exception');
      } on RPCError catch (e) {
        expect(
          e.message,
          'CPU sample caching is not enabled for tag: "Fake"',
        );
      }
    },
    timeout: Timeout.none,
  );

  test(
    'Cache CPU samples for provided UserTag name',
    () async {
      const kUserTag = 'Testing';
      dds = await DartDevelopmentService.startDartDevelopmentService(
        remoteVmServiceUri,
        cachedUserTags: [kUserTag],
      );
      expect(dds.isRunning, true);
      final service = await vmServiceConnectUri(dds.wsUri.toString());

      // Ensure we're caching results for samples under the 'Testing' UserTag.
      final availableCaches = await service.getAvailableCachedCpuSamples();
      expect(availableCaches.cacheNames.length, 1);
      expect(availableCaches.cacheNames.first, kUserTag);

      final isolate = (await service.getVM()).isolates!.first;

      final completer = Completer<void>();
      int i = 0;
      int count = 0;
      service.onProfilerEvent.listen((event) async {
        if (event.kind == EventKind.kCpuSamples &&
            event.isolate!.id! == isolate.id!) {
          // Pause so we don't evict another block of samples before we've
          // retrieved the cached samples after this event.
          await service.pause(isolate.id!);

          // Ensure the number of CPU samples in the CpuSample event is
          // is consistent with the number of samples in the cache.
          expect(event.cpuSamples, isNotNull);
          count += event.cpuSamples!.samples!
              .where((e) => e.userTag == kUserTag)
              .length;
          final cache = await service.getCachedCpuSamples(
            isolate.id!,
            availableCaches.cacheNames.first,
          );
          expect(cache.sampleCount, count);

          await service.resume(isolate.id!);
          i++;
          if (i == 3) {
            completer.complete();
          }
        }
      });
      await service.streamListen(EventStreams.kProfiler);
      await service.resume(isolate.id!);
      await completer.future;
    },
    timeout: Timeout.none,
  );
}