// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.8

import 'dart:convert';
import 'dart:io';
import 'dart:math' as math;

import '../framework/devices.dart';
import '../framework/framework.dart';
import '../framework/task_result.dart';
import '../framework/utils.dart';

TaskFunction createGalleryTransitionTest({bool semanticsEnabled = false}) {
  return GalleryTransitionTest(semanticsEnabled: semanticsEnabled);
}

TaskFunction createGalleryTransitionE2ETest({bool semanticsEnabled = false}) {
  return GalleryTransitionTest(
    testFile: semanticsEnabled
        ? 'transitions_perf_e2e_with_semantics'
        : 'transitions_perf_e2e',
    needFullTimeline: false,
    timelineSummaryFile: 'e2e_perf_summary',
    transitionDurationFile: null,
    timelineTraceFile: null,
    driverFile: 'transitions_perf_e2e_test',
  );
}

TaskFunction createGalleryTransitionHybridTest({bool semanticsEnabled = false}) {
  return GalleryTransitionTest(
    semanticsEnabled: semanticsEnabled,
    driverFile: semanticsEnabled
        ? 'transitions_perf_hybrid_with_semantics_test'
        : 'transitions_perf_hybrid_test',
  );
}

class GalleryTransitionTest {

  GalleryTransitionTest({
    this.semanticsEnabled = false,
    this.testFile = 'transitions_perf',
    this.needFullTimeline = true,
    this.timelineSummaryFile = 'transitions.timeline_summary',
    this.timelineTraceFile = 'transitions.timeline',
    this.transitionDurationFile = 'transition_durations.timeline',
    this.driverFile,
  });

  final bool semanticsEnabled;
  final bool needFullTimeline;
  final String testFile;
  final String timelineSummaryFile;
  final String timelineTraceFile;
  final String transitionDurationFile;
  final String driverFile;

  Future<TaskResult> call() async {
    final Device device = await devices.workingDevice;
    await device.unlock();
    final String deviceId = device.deviceId;
    final Directory galleryDirectory = dir('${flutterDirectory.path}/dev/integration_tests/flutter_gallery');
    await inDirectory<void>(galleryDirectory, () async {
      String applicationBinaryPath;
      if (deviceOperatingSystem == DeviceOperatingSystem.android) {
        section('BUILDING APPLICATION');
        await flutter(
          'build',
          options: <String>[
            'apk',
            '--no-android-gradle-daemon',
            '--profile',
            '-t',
            'test_driver/$testFile.dart',
            '--target-platform',
            'android-arm,android-arm64',
          ],
        );
        applicationBinaryPath = 'build/app/outputs/flutter-apk/app-profile.apk';
      }

      final String testDriver = driverFile ?? (semanticsEnabled
          ? '${testFile}_with_semantics_test'
          : '${testFile}_test');
      section('DRIVE START');
      await flutter('drive', options: <String>[
        '--no-dds',
        '--profile',
        if (needFullTimeline)
          '--trace-startup',
        if (applicationBinaryPath != null)
          '--use-application-binary=$applicationBinaryPath'
        else
          ...<String>[
            '-t',
            'test_driver/$testFile.dart',
          ],
        '--driver',
        'test_driver/$testDriver.dart',
        '-d',
        deviceId,
      ]);
    });

    final String testOutputDirectory = Platform.environment['FLUTTER_TEST_OUTPUTS_DIR'] ?? '${galleryDirectory.path}/build';
    final Map<String, dynamic> summary = json.decode(
      file('$testOutputDirectory/$timelineSummaryFile.json').readAsStringSync(),
    ) as Map<String, dynamic>;

    if (transitionDurationFile != null) {
      final Map<String, dynamic> original = json.decode(
        file('$testOutputDirectory/$transitionDurationFile.json').readAsStringSync(),
      ) as Map<String, dynamic>;
      final Map<String, List<int>> transitions = <String, List<int>>{};
      for (final String key in original.keys) {
        transitions[key] = List<int>.from(original[key] as List<dynamic>);
      }
      summary['transitions'] = transitions;
      summary['missed_transition_count'] = _countMissedTransitions(transitions);
    }

    return TaskResult.success(summary,
      detailFiles: <String>[
        if (transitionDurationFile != null)
          '$testOutputDirectory/$transitionDurationFile.json',
        if (timelineTraceFile != null)
          '$testOutputDirectory/$timelineTraceFile.json'
      ],
      benchmarkScoreKeys: <String>[
        if (transitionDurationFile != null)
          'missed_transition_count',
        'average_frame_build_time_millis',
        'worst_frame_build_time_millis',
        '90th_percentile_frame_build_time_millis',
        '99th_percentile_frame_build_time_millis',
        'average_frame_rasterizer_time_millis',
        'worst_frame_rasterizer_time_millis',
        '90th_percentile_frame_rasterizer_time_millis',
        '99th_percentile_frame_rasterizer_time_millis',
      ],
    );
  }
}

int _countMissedTransitions(Map<String, List<int>> transitions) {
  const int _kTransitionBudget = 100000; // µs
  int count = 0;
  transitions.forEach((String demoName, List<int> durations) {
    final int longestDuration = durations.reduce(math.max);
    if (longestDuration > _kTransitionBudget) {
      print('$demoName missed transition time budget ($longestDuration µs > $_kTransitionBudget µs)');
      count++;
    }
  });
  return count;
}