// 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 LineSplitter, json, utf8;
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 at which the local benchmark server is served.
const int benchmarkServerPort = 9999;

/// The port at which Chrome listens for a debug connection.
const int chromeDebugPort = 10000;

/// The port at which the benchmark's app is being served.
const int benchmarksAppPort = 10001;

typedef WebBenchmarkOptions = ({
  bool useWasm,
  bool forceSingleThreadedSkwasm,
  bool useDdc,
  bool withHotReload,
  String buildMode,
});

/// Deletes a directory with retry logic to handle file locks on various platforms.
Future<void> deleteDirectoryWithRetry(
  io.Directory dir, {
  int maxAttempts = 10,
  Duration delay = const Duration(milliseconds: 500),
}) async {
  for (var attempt = 1; attempt <= maxAttempts; attempt++) {
    try {
      if (dir.existsSync()) {
        await dir.delete(recursive: true);
      }
      return;
    } on io.FileSystemException catch (e) {
      if (attempt == maxAttempts) {
        print('Warning: Failed to delete directory ${dir.path} after $maxAttempts attempts: $e');
      } else {
        await Future<void>.delayed(delay);
      }
    }
  }
}

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',
  );

  io.HttpServer? server;
  Chrome? chrome;
  Future<Chrome>? whenChromeIsReady;
  io.Process? flutterRunProcess;
  String? userDataDir;

  var isCleaningUp = false;
  final cleanupCompleter = Completer<void>();

  Future<void> performCleanup() async {
    if (isCleaningUp) {
      return cleanupCompleter.future;
    }
    isCleaningUp = true;
    try {
      // 1. Close Shelf server
      try {
        await server?.close(force: true);
      } catch (e) {
        print('Warning: Error closing server: $e');
      }

      // 2. Stop or disconnect Chrome (in DDC mode Chrome is managed by flutterRunProcess)
      void cleanChrome(Chrome c) {
        if (benchmarkOptions.useDdc) {
          c.disconnect();
        } else {
          c.stop();
        }
      }

      final currentChrome = chrome;
      final readyFuture = whenChromeIsReady;
      if (currentChrome != null) {
        try {
          cleanChrome(currentChrome);
        } catch (e) {
          final action = benchmarkOptions.useDdc ? 'disconnecting' : 'stopping';
          print('Warning: Error $action Chrome: $e');
        }
      } else if (readyFuture != null) {
        try {
          var cleanedUp = false;
          unawaited(
            readyFuture.then((Chrome readyChrome) {
              if (!cleanedUp) {
                cleanedUp = true;
                cleanChrome(readyChrome);
              }
            }, onError: (_) {}),
          );

          final Chrome readyChrome = await readyFuture.timeout(
            const Duration(seconds: 5),
            onTimeout: () => throw TimeoutException('Chrome ready timeout during cleanup'),
          );
          if (!cleanedUp) {
            cleanedUp = true;
            cleanChrome(readyChrome);
          }
        } catch (e) {
          final action = benchmarkOptions.useDdc ? 'disconnecting' : 'stopping';
          print('Warning: Error $action Chrome: $e');
        }
      }

      // 3. Stop flutter run process if present
      final process = flutterRunProcess;
      if (process != null) {
        try {
          process.stdin.write('q');
          await process.stdin.flush();
        } catch (_) {
          // Stdin pipe may already be closed if Chrome process was killed
        }
        await process.exitCode.timeout(
          const Duration(seconds: 2),
          onTimeout: () {
            process.kill();
            return 0;
          },
        );
      }

      // 4. Clean up temporary directory
      final dirPath = userDataDir;
      if (dirPath != null) {
        await deleteDirectoryWithRetry(io.Directory(dirPath));
      }
    } finally {
      cleanupCompleter.complete();
    }
  }

  StreamSubscription<io.ProcessSignal>? sigintSub;
  StreamSubscription<io.ProcessSignal>? sigtermSub;

  try {
    sigintSub = io.ProcessSignal.sigint.watch().listen((io.ProcessSignal signal) async {
      print('\nReceived SIGINT. Cleaning up benchmark processes and temporary directories...');
      await performCleanup();
      io.exit(130);
    });
  } catch (e) {
    print('Warning: Unable to watch SIGINT signal: $e');
  }

  if (!io.Platform.isWindows) {
    try {
      sigtermSub = io.ProcessSignal.sigterm.watch().listen((io.ProcessSignal signal) async {
        print('\nReceived SIGTERM. Cleaning up benchmark processes and temporary directories...');
        await performCleanup();
        io.exit(143);
      });
    } catch (e) {
      print('Warning: Unable to watch SIGTERM signal: $e');
    }
  }

  try {
    return await inDirectory(macrobenchmarksDirectory, () async {
      await flutter('clean');

      server = await io.HttpServer.bind('localhost', benchmarkServerPort);

      // DDC runs the benchmarks suite with 'flutter run', attaching to its
      // Chrome instance instead of starting a new one.
      if (benchmarkOptions.useDdc) {
        final ddcAppReady = Completer<void>();
        flutterRunProcess = await startFlutter(
          'run',
          options: <String>[
            '-d',
            'chrome',
            '--web-port',
            '$benchmarksAppPort',
            '--web-browser-debug-port',
            '$chromeDebugPort',
            '--web-launch-url',
            'http://localhost:$benchmarksAppPort/index.html',
            '--debug',
            '--web-run-headless',
            '--no-web-enable-expression-evaluation',
            '--web-browser-flag=--disable-popup-blocking',
            '--web-browser-flag=--bwsi',
            '--web-browser-flag=--no-first-run',
            '--web-browser-flag=--no-default-browser-check',
            '--web-browser-flag=--disable-default-apps',
            '--web-browser-flag=--disable-translate',
            '--web-browser-flag=--disable-background-timer-throttling',
            '--web-browser-flag=--disable-backgrounding-occluded-windows',
            '--web-browser-flag=--disable-renderer-backgrounding',
            '--web-browser-flag=--disable-background-networking',
            '--web-browser-flag=--disable-sync',
            '--web-browser-flag=--disable-client-side-phishing-detection',
            '--web-browser-flag=--disable-notifications',
            ...kGcmDisabledFlags.map((String flag) => '--web-browser-flag=$flag'),
            '--web-browser-flag=--headless=new',
            '--web-browser-flag=--no-sandbox',
            '--web-browser-flag=--password-store=basic',
            if (io.Platform.isMacOS) '--web-browser-flag=--use-mock-keychain',
            '--dart-define=FLUTTER_WEB_ENABLE_PROFILING=true',
            '--dart-define=BENCHMARK_SERVER_PORT=${server!.port}',
            if (!benchmarkOptions.withHotReload) '--no-web-experimental-hot-reload',
            '--no-web-resources-cdn',
            '-t',
            'lib/web_benchmarks.dart',
          ],
        );
        flutterRunProcess!.stdout.transform(utf8.decoder).transform(const LineSplitter()).listen((
          String line,
        ) {
          if (!ddcAppReady.isCompleted && line.startsWith('Debug service listening on')) {
            ddcAppReady.complete();
          }
          print('[CHROME STDOUT]: $line');
        });
        flutterRunProcess!.stderr.transform(utf8.decoder).transform(const LineSplitter()).listen((
          String line,
        ) {
          print('[CHROME STDERR]: $line');
        });
        // Wait for the app to load in DDC's Chrome instance before trying to
        // connect the debugger.
        await ddcAppReady.future;
      } else {
        await evalFlutter(
          'build',
          options: <String>[
            'web',
            '--no-tree-shake-icons', // local engine builds are frequently out of sync with the Dart Kernel version
            if (benchmarkOptions.useWasm) ...<String>['--wasm', '--no-strip-wasm'],
            '--dart-define=FLUTTER_WEB_ENABLE_PROFILING=true',
            '--${benchmarkOptions.buildMode}',
            '--no-web-resources-cdn',
            '-t',
            'lib/web_benchmarks.dart',
          ],
        );
      }
      final profileData = Completer<List<Map<String, dynamic>>>();
      final collectedProfiles = <Map<String, dynamic>>[];
      List<String>? benchmarks;
      late Iterator<String> benchmarkIterator;

      var cascade = Cascade();
      List<Map<String, dynamic>>? latestPerformanceTrace;
      final requestHeaders = <String, List<String>>{
        'Access-Control-Allow-Headers': <String>[
          'Accept',
          'Access-Control-Allow-Headers',
          'Access-Control-Allow-Methods',
          'Access-Control-Allow-Origin',
          'Content-Type',
          'Origin',
        ],
        'Access-Control-Allow-Methods': <String>['Post'],
        'Access-Control-Allow-Origin': <String>['http://localhost:$benchmarksAppPort'],
      };

      cascade = cascade.add((Request request) async {
        final String requestContents = await request.readAsString();
        try {
          chrome ??= await whenChromeIsReady;
          if (request.method == 'OPTIONS') {
            return Response.ok('', headers: requestHeaders);
          }
          if (request.requestedUri.path.endsWith('/profile-data')) {
            final profile = json.decode(requestContents) as Map<String, dynamic>;
            final benchmarkName = profile['name'] as String;
            if (benchmarkName != benchmarkIterator.current) {
              if (!profileData.isCompleted) {
                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', headers: requestHeaders);
          } else if (request.requestedUri.path.endsWith('/start-performance-tracing')) {
            latestPerformanceTrace = null;
            await chrome!.beginRecordingPerformance(request.requestedUri.queryParameters['label']!);
            return Response.ok('Started performance tracing', headers: requestHeaders);
          } else if (request.requestedUri.path.endsWith('/stop-performance-tracing')) {
            latestPerformanceTrace = await chrome!.endRecordingPerformance();
            return Response.ok('Stopped performance tracing', headers: requestHeaders);
          } else if (request.requestedUri.path.endsWith('/on-error')) {
            final errorDetails = json.decode(requestContents) as Map<String, dynamic>;
            unawaited(server!.close());
            // Keep the stack trace as a string. It's thrown in the browser, not this Dart VM.
            if (!profileData.isCompleted) {
              profileData.completeError('${errorDetails['error']}\n${errorDetails['stackTrace']}');
            }
            return Response.ok('', headers: requestHeaders);
          } else if (request.requestedUri.path.endsWith('/next-benchmark')) {
            if (benchmarks == null) {
              benchmarks = (json.decode(requestContents) as List<dynamic>).cast<String>();
              benchmarkIterator = benchmarks!.iterator;
            }
            if (benchmarkIterator.moveNext()) {
              final String nextBenchmark = benchmarkIterator.current;
              print('Launching benchmark "$nextBenchmark"');
              return Response.ok(nextBenchmark, headers: requestHeaders);
            } else {
              if (!profileData.isCompleted) {
                profileData.complete(collectedProfiles);
              }
              return Response.notFound('Finished running benchmarks.', headers: requestHeaders);
            }
          } else if (request.requestedUri.path.endsWith('/print-to-console')) {
            // A passthrough used by
            // `dev/benchmarks/macrobenchmarks/lib/web_benchmarks.dart`
            // to print information.
            final message = requestContents;
            print('[APP] $message');
            return Response.ok('Reported.', headers: requestHeaders);
          } else {
            return Response.notFound(
              'This request is not handled by the profile-data handler.',
              headers: requestHeaders,
            );
          }
        } catch (error, stackTrace) {
          if (!profileData.isCompleted) {
            profileData.completeError(error, stackTrace);
          }
          return Response.internalServerError(body: '$error', headers: requestHeaders);
        }
      });
      // Macrobenchmarks using 'flutter build' serve files from their local build directory alongside the orchestration logic.
      if (!benchmarkOptions.useDdc) {
        cascade = cascade.add(
          createBuildDirectoryHandler(path.join(macrobenchmarksDirectory, 'build', 'web')),
        );
      }

      shelf_io.serveRequests(server!, cascade.handler);

      final String dartToolDirectory = path.join(macrobenchmarksDirectory, '.dart_tool');
      final dartToolDir = io.Directory(dartToolDirectory);
      if (!dartToolDir.existsSync()) {
        dartToolDir.createSync(recursive: true);
      }
      userDataDir = dartToolDir.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 isUncalibratedSmokeTest = io.Platform.environment['CALIBRATED'] != 'true';
      // final bool isUncalibratedSmokeTest =
      //     io.Platform.environment['UNCALIBRATED_SMOKE_TEST'] == 'true';
      final urlParams = benchmarkOptions.forceSingleThreadedSkwasm ? '?force_st=true' : '';
      // DDC apps are served from a different port from the orchestration server.
      final int appServingPort = benchmarkOptions.useDdc ? benchmarksAppPort : benchmarkServerPort;
      final options = ChromeOptions(
        url: 'http://localhost:$appServingPort/index.html$urlParams',
        userDataDirectory: userDataDir,
        headless: isUncalibratedSmokeTest,
        debugPort: chromeDebugPort,
        enableWasmGC: benchmarkOptions.useWasm,
      );

      print('Launching Chrome.');

      if (benchmarkOptions.useDdc) {
        // DDC reuses the existing Chrome connection spawned via 'flutter run'.
        whenChromeIsReady = Chrome.connect(
          flutterRunProcess!,
          options,
          onError: (String error) {
            if (!profileData.isCompleted) {
              profileData.completeError(Exception(error));
            }
          },
          workingDirectory: cwd,
        );
      } else {
        whenChromeIsReady = Chrome.launch(
          options,
          onError: (String error) {
            if (!profileData.isCompleted) {
              profileData.completeError(Exception(error));
            }
          },
          workingDirectory: cwd,
        );
      }
      unawaited(whenChromeIsReady?.then((Chrome c) => chrome = c, onError: (_) {}));

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

      print('Received profile data');
      for (final profile in profiles) {
        final 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 namespace = '$benchmarkName.$webRendererName';
        final scoreKeys = List<String>.from(profile['scoreKeys'] as List<dynamic>);
        if (scoreKeys.isEmpty) {
          throw 'No score keys in benchmark "$benchmarkName"';
        }
        for (final scoreKey in scoreKeys) {
          if (scoreKey.isEmpty) {
            throw 'Score key is empty in benchmark "$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 {
    await sigintSub?.cancel();
    await sigtermSub?.cancel();
    await performCleanup();
  }
}

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;
    }
  };
}