// 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.

import 'dart:async';
import 'dart:convert' show json;
import 'dart:io' as io;

import 'package:logging/logging.dart';
import 'package:path/path.dart' as path;
import 'package:shelf/shelf.dart';
import 'package:shelf/shelf_io.dart' as shelf_io;
import 'package:shelf_static/shelf_static.dart';

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

/// The port number used by the local benchmark server.
const int benchmarkServerPort = 9999;
const int chromeDebugPort = 10000;

typedef WebBenchmarkOptions = ({bool useWasm, bool forceSingleThreadedSkwasm});

Future<TaskResult> runWebBenchmark(WebBenchmarkOptions benchmarkOptions) async {
  // Reduce logging level. Otherwise, package:webkit_inspection_protocol is way too spammy.
  Logger.root.level = Level.INFO;
  final String macrobenchmarksDirectory = path.join(
    flutterDirectory.path,
    'dev',
    'benchmarks',
    'macrobenchmarks',
  );
  return inDirectory(macrobenchmarksDirectory, () async {
    await flutter('clean');
    await evalFlutter(
      'build',
      options: <String>[
        'web',
        '--no-tree-shake-icons', // local engine builds are frequently out of sync with the Dart Kernel version
        if (benchmarkOptions.useWasm) ...<String>['--wasm', '--no-strip-wasm'],
        '--dart-define=FLUTTER_WEB_ENABLE_PROFILING=true',
        '--profile',
        '--no-web-resources-cdn',
        '-t',
        'lib/web_benchmarks.dart',
      ],
    );
    final Completer<List<Map<String, dynamic>>> profileData =
        Completer<List<Map<String, dynamic>>>();
    final List<Map<String, dynamic>> collectedProfiles = <Map<String, dynamic>>[];
    List<String>? benchmarks;
    late Iterator<String> benchmarkIterator;

    // This future fixes a race condition between the web-page loading and
    // asking to run a benchmark, and us connecting to Chrome's DevTools port.
    // Sometime one wins. Other times, the other wins.
    Future<Chrome>? whenChromeIsReady;
    Chrome? chrome;
    late io.HttpServer server;
    Cascade cascade = Cascade();
    List<Map<String, dynamic>>? latestPerformanceTrace;
    cascade = cascade
        .add((Request request) async {
          try {
            chrome ??= await whenChromeIsReady;
            if (request.requestedUri.path.endsWith('/profile-data')) {
              final Map<String, dynamic> profile =
                  json.decode(await request.readAsString()) as Map<String, dynamic>;
              final String benchmarkName = profile['name'] as String;
              if (benchmarkName != benchmarkIterator.current) {
                profileData.completeError(
                  Exception(
                    'Browser returned benchmark results from a wrong benchmark.\n'
                    'Requested to run benchmark ${benchmarkIterator.current}, but '
                    'got results for $benchmarkName.',
                  ),
                );
                unawaited(server.close());
              }

              // Trace data is null when the benchmark is not frame-based, such as RawRecorder.
              if (latestPerformanceTrace != null) {
                final BlinkTraceSummary traceSummary =
                    BlinkTraceSummary.fromJson(latestPerformanceTrace!)!;
                profile['totalUiFrame.average'] =
                    traceSummary.averageTotalUIFrameTime.inMicroseconds;
                profile['scoreKeys'] ??= <dynamic>[]; // using dynamic for consistency with JSON
                (profile['scoreKeys'] as List<dynamic>).add('totalUiFrame.average');
                latestPerformanceTrace = null;
              }
              collectedProfiles.add(profile);
              return Response.ok('Profile received');
            } else if (request.requestedUri.path.endsWith('/start-performance-tracing')) {
              latestPerformanceTrace = null;
              await chrome!.beginRecordingPerformance(
                request.requestedUri.queryParameters['label']!,
              );
              return Response.ok('Started performance tracing');
            } else if (request.requestedUri.path.endsWith('/stop-performance-tracing')) {
              latestPerformanceTrace = await chrome!.endRecordingPerformance();
              return Response.ok('Stopped performance tracing');
            } else if (request.requestedUri.path.endsWith('/on-error')) {
              final Map<String, dynamic> errorDetails =
                  json.decode(await request.readAsString()) as Map<String, dynamic>;
              unawaited(server.close());
              // Keep the stack trace as a string. It's thrown in the browser, not this Dart VM.
              profileData.completeError('${errorDetails['error']}\n${errorDetails['stackTrace']}');
              return Response.ok('');
            } else if (request.requestedUri.path.endsWith('/next-benchmark')) {
              if (benchmarks == null) {
                benchmarks =
                    (json.decode(await request.readAsString()) as List<dynamic>).cast<String>();
                benchmarkIterator = benchmarks!.iterator;
              }
              if (benchmarkIterator.moveNext()) {
                final String nextBenchmark = benchmarkIterator.current;
                print('Launching benchmark "$nextBenchmark"');
                return Response.ok(nextBenchmark);
              } else {
                profileData.complete(collectedProfiles);
                return Response.notFound('Finished running benchmarks.');
              }
            } else if (request.requestedUri.path.endsWith('/print-to-console')) {
              // A passthrough used by
              // `dev/benchmarks/macrobenchmarks/lib/web_benchmarks.dart`
              // to print information.
              final String message = await request.readAsString();
              print('[APP] $message');
              return Response.ok('Reported.');
            } else {
              return Response.notFound('This request is not handled by the profile-data handler.');
            }
          } catch (error, stackTrace) {
            profileData.completeError(error, stackTrace);
            return Response.internalServerError(body: '$error');
          }
        })
        .add(createBuildDirectoryHandler(path.join(macrobenchmarksDirectory, 'build', 'web')));

    server = await io.HttpServer.bind('localhost', benchmarkServerPort);
    try {
      shelf_io.serveRequests(server, cascade.handler);

      final String dartToolDirectory = path.join('$macrobenchmarksDirectory/.dart_tool');
      final String userDataDir =
          io.Directory(dartToolDirectory).createTempSync('flutter_chrome_user_data.').path;

      // TODO(yjbanov): temporarily disables headful Chrome until we get
      //                devicelab hardware that is able to run it. Our current
      //                GCE VMs can only run in headless mode.
      //                See: https://github.com/flutter/flutter/issues/50164
      final bool isUncalibratedSmokeTest = io.Platform.environment['CALIBRATED'] != 'true';
      // final bool isUncalibratedSmokeTest =
      //     io.Platform.environment['UNCALIBRATED_SMOKE_TEST'] == 'true';
      final String urlParams = benchmarkOptions.forceSingleThreadedSkwasm ? '?force_st=true' : '';
      final ChromeOptions options = ChromeOptions(
        url: 'http://localhost:$benchmarkServerPort/index.html$urlParams',
        userDataDirectory: userDataDir,
        headless: isUncalibratedSmokeTest,
        debugPort: chromeDebugPort,
        enableWasmGC: benchmarkOptions.useWasm,
      );

      print('Launching Chrome.');
      whenChromeIsReady = Chrome.launch(
        options,
        onError: (String error) {
          profileData.completeError(Exception(error));
        },
        workingDirectory: cwd,
      );

      print('Waiting for the benchmark to report benchmark profile.');
      final Map<String, dynamic> taskResult = <String, dynamic>{};
      final List<String> benchmarkScoreKeys = <String>[];
      final List<Map<String, dynamic>> profiles = await profileData.future;

      print('Received profile data');
      for (final Map<String, dynamic> profile in profiles) {
        final String benchmarkName = profile['name'] as String;
        if (benchmarkName.isEmpty) {
          throw 'Benchmark name is empty';
        }

        final String webRendererName;
        if (benchmarkOptions.useWasm) {
          webRendererName = benchmarkOptions.forceSingleThreadedSkwasm ? 'skwasm_st' : 'skwasm';
        } else {
          webRendererName = 'canvaskit';
        }
        final String namespace = '$benchmarkName.$webRendererName';
        final List<String> scoreKeys = List<String>.from(profile['scoreKeys'] as List<dynamic>);
        if (scoreKeys.isEmpty) {
          throw 'No score keys in benchmark "$benchmarkName"';
        }
        for (final String scoreKey in scoreKeys) {
          if (scoreKey.isEmpty) {
            throw 'Score key is empty in benchmark "$benchmarkName". '
                'Received [${scoreKeys.join(', ')}]';
          }
          benchmarkScoreKeys.add('$namespace.$scoreKey');
        }

        for (final String key in profile.keys) {
          if (key == 'name' || key == 'scoreKeys') {
            continue;
          }
          taskResult['$namespace.$key'] = profile[key];
        }
      }
      return TaskResult.success(taskResult, benchmarkScoreKeys: benchmarkScoreKeys);
    } finally {
      unawaited(server.close());
      chrome?.stop();
    }
  });
}

Handler createBuildDirectoryHandler(String buildDirectoryPath) {
  final Handler childHandler = createStaticHandler(buildDirectoryPath);
  return (Request request) async {
    final Response response = await childHandler(request);
    final String? mimeType = response.mimeType;

    // Provide COOP/COEP headers so that the browser loads the page as
    // crossOriginIsolated. This will make sure that we get high-resolution
    // timers for our benchmark measurements.
    if (mimeType == 'text/html' || mimeType == 'text/javascript') {
      return response.change(
        headers: <String, String>{
          'Cross-Origin-Opener-Policy': 'same-origin',
          'Cross-Origin-Embedder-Policy': 'require-corp',
        },
      );
    } else {
      return response;
    }
  };
}