// Copyright (c) 2022, 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:convert';

import 'package:analysis_server/lsp_protocol/protocol.dart';
import 'package:analysis_server/protocol/protocol_constants.dart';
import 'package:analysis_server/src/analytics/active_request_data.dart';
import 'package:analysis_server/src/analytics/context_structure.dart';
import 'package:analysis_server/src/analytics/notification_data.dart';
import 'package:analysis_server/src/analytics/plugin_data.dart';
import 'package:analysis_server/src/analytics/request_data.dart';
import 'package:analysis_server/src/analytics/session_data.dart';
import 'package:analysis_server/src/lsp/lsp_analysis_server.dart';
import 'package:analysis_server/src/plugin/plugin_manager.dart';
import 'package:analysis_server/src/protocol_server.dart';
import 'package:analysis_server/src/status/pages.dart';
import 'package:analyzer/dart/analysis/analysis_context.dart';
import 'package:analyzer/src/dart/analysis/driver_based_analysis_context.dart';
import 'package:collection/collection.dart';
import 'package:memory_usage/memory_usage.dart';
import 'package:meta/meta.dart';
import 'package:unified_analytics/unified_analytics.dart';

/// An interface for managing and reporting analytics.
///
/// Individual methods can either send an analytics event immediately or can
/// collect and even consolidate information to be reported later. Clients are
/// required to invoke the [shutdown] method before the server shuts down in
/// order to send any cached data.
class AnalyticsManager {
  /// A flag set during development to allow experimental data to be sent to a
  /// development-time analytics account.
  static const bool sendExperimentalData = false;

  static const addedKey = 'added';

  static const removedKey = 'removed';

  static const commandEnumKey = 'command';

  static const openWorkspacePathsKey = 'openWorkspacePaths';

  static const refactoringKindEnumKey = EDIT_REQUEST_GET_REFACTORING_KIND;

  static const includedKey = ANALYSIS_REQUEST_SET_ANALYSIS_ROOTS_INCLUDED;

  static const excludedKey = ANALYSIS_REQUEST_SET_ANALYSIS_ROOTS_EXCLUDED;

  static const filesKey = ANALYSIS_REQUEST_SET_PRIORITY_FILES_FILES;

  /// The object used to send analytics.
  final Analytics analytics;

  /// Data about the current session, or `null` if the [startUp] method has not
  /// been invoked.
  SessionData? _sessionData;

  final PluginData _pluginData = PluginData();

  /// The data about analysis, or `null` if no analysis has been performed.
  ContextStructure? _contextStructure;

  /// A map from the id of a request to data about the request.
  final Map<String, ActiveRequestData> _activeRequests = {};

  /// A map from the name of a request to data about all such requests that have
  /// been responded to.
  final Map<String, RequestData> _completedRequests = {};

  /// A map from the name of a notification to data about all such notifications
  /// that have been handled.
  final Map<String, NotificationData> _completedNotifications = {};

  /// A map from the name of a lint to the number of contexts in which the lint
  /// was enabled.
  final Map<String, int> _lintUsageCounts = {};

  /// A map from the name of a diagnostic to a map whose values are the number
  /// of times that the severity of the diagnostic was changed to the severity
  /// represented by the key.
  final Map<String, Map<String, int>> _severityAdjustments = {};

  /// A periodic timer used to send analytics data. This timer should be
  /// cancelled at shutdown.
  Timer? periodicTimer;

  /// Initialize a newly created analytics manager to report to the [analytics]
  /// service.
  AnalyticsManager(this.analytics) {
    if (analytics is! NoOpAnalytics) {
      periodicTimer = Timer.periodic(Duration(minutes: 30), (_) {
        _sendPeriodicData();
      });
    }
  }

  /// Record information about the number of files and the number of lines of
  /// code in those files, for both immediate files, transitive files, and the
  /// number of unique transitive files.
  void analysisComplete({
    required int numberOfContexts,
    required int contextsWithoutFiles,
    required int contextsFromPackagesFiles,
    required int contextsFromOptionsFiles,
    required int contextsFromBothFiles,
    required int immediateFileCount,
    required int immediateFileLineCount,
    required int transitiveFileCount,
    required int transitiveFileLineCount,
    required int transitiveFileUniqueCount,
    required int transitiveFileUniqueLineCount,
  }) {
    // This is currently keeping the first report of completed analysis, but we
    // might want to consider alternatives, such as keeping the "largest"
    // analysis or keeping all of the data and sending back percentile.
    _contextStructure ??= ContextStructure(
      numberOfContexts: numberOfContexts,
      contextsWithoutFiles: contextsWithoutFiles,
      contextsFromPackagesFiles: contextsFromPackagesFiles,
      contextsFromOptionsFiles: contextsFromOptionsFiles,
      contextsFromBothFiles: contextsFromBothFiles,
      immediateFileCount: immediateFileCount,
      immediateFileLineCount: immediateFileLineCount,
      transitiveFileCount: transitiveFileCount,
      transitiveFileLineCount: transitiveFileLineCount,
      transitiveFileUniqueCount: transitiveFileUniqueCount,
      transitiveFileUniqueLineCount: transitiveFileUniqueLineCount,
    );
  }

  /// Record that the set of plugins known to the [pluginManager] has changed.
  void changedPlugins(PluginManager pluginManager) {
    _pluginData.recordPlugins(pluginManager);
  }

  /// Record the number of [added] folders and [removed] folders.
  void changedWorkspaceFolders({
    required List<String> added,
    required List<String> removed,
  }) {
    var requestData = getRequestData(
      Method.workspace_didChangeWorkspaceFolders.toString(),
    );
    requestData.addValue(addedKey, added.length);
    requestData.addValue(removedKey, removed.length);
  }

  /// Record that the [contexts] have been created.
  void createdAnalysisContexts(List<AnalysisContext> contexts) {
    for (var context in contexts) {
      var allOptions =
          (context as DriverBasedAnalysisContext).allAnalysisOptions;
      for (var analysisOptions in allOptions) {
        for (var rule in analysisOptions.lintRules) {
          var name = rule.name;
          _lintUsageCounts[name] = (_lintUsageCounts[name] ?? 0) + 1;
        }

        for (var processor in analysisOptions.errorProcessors) {
          var severity = processor.severity?.name ?? 'ignore';
          var severityCounts = _severityAdjustments.putIfAbsent(
            processor.code,
            () => {},
          );
          severityCounts[severity] = (severityCounts[severity] ?? 0) + 1;
        }
      }
    }
  }

  /// Record that the given [command] was executed.
  void executedCommand(String command) {
    var requestData = getRequestData(
      Method.workspace_executeCommand.toString(),
    );
    requestData.addEnumValue(commandEnumKey, command);
  }

  /// Return the request data for requests that have the given [method].
  @visibleForTesting
  RequestData getRequestData(String method) {
    return _completedRequests.putIfAbsent(method, () => RequestData(method));
  }

  /// Record that the given [notification] was received and has been handled.
  void handledNotificationMessage({
    required NotificationMessage notification,
    required DateTime startTime,
    required DateTime endTime,
  }) {
    var method = notification.method.toString();
    var requestTime = notification.clientRequestTime;
    var start = startTime.millisecondsSinceEpoch;
    var end = endTime.millisecondsSinceEpoch;
    var data = _completedNotifications.putIfAbsent(
      method,
      () => NotificationData(method),
    );
    if (requestTime != null) {
      data.latencyTimes.addValue(start - requestTime);
    }
    data.handlingTimes.addValue(end - start);
  }

  /// Record the parameters passed on initialize.
  void initialize(InitializeParams params) {
    var options = LspInitializationOptions(params.initializationOptions);
    var paramNames = <String>[
      if (options.closingLabels) 'closingLabels',
      if (options.completionBudgetMilliseconds != null)
        'completionBudgetMilliseconds',
      if (options.flutterOutline) 'flutterOutline',
      if (options.onlyAnalyzeProjectsWithOpenFiles)
        'onlyAnalyzeProjectsWithOpenFiles',
      if (options.outline) 'outline',
      if (options.suggestFromUnimportedLibraries)
        'suggestFromUnimportedLibraries',
    ];
    _sessionData?.initializeParams = paramNames.join(',');
  }

  /// Record the number of [openWorkspacePaths].
  void initialized({required List<String> openWorkspacePaths}) {
    var requestData = getRequestData(Method.initialized.toString());
    requestData.addValue(openWorkspacePathsKey, openWorkspacePaths.length);
  }

  Future<void> sendMemoryUsage(MemoryUsageEvent event) async {
    var delta = event.delta;
    var seconds = event.period?.inSeconds;

    assert((event.delta == null) == (event.period == null));

    if (delta == null || seconds == null) {
      analytics.send(Event.memoryInfo(rss: event.rss));
      return;
    }

    if (seconds == 0) seconds = 1;

    analytics.send(
      Event.memoryInfo(
        rss: event.rss,
        periodSec: seconds,
        mbPerSec: delta / seconds,
      ),
    );
  }

  /// Record that the given [response] was sent to the client.
  void sentResponse({required Response response}) {
    var sendTime = DateTime.now();
    _recordResponseData(response.id, sendTime);
  }

  /// Record that the given [response] was sent to the client.
  void sentResponseMessage({required ResponseMessage response}) {
    var sendTime = DateTime.now();
    var id = response.id?.asLspIdString;
    if (id == null) {
      return;
    }
    _recordResponseData(id, sendTime);
  }

  /// The server is shutting down. Report any accumulated analytics data.
  Future<void> shutdown() async {
    var sessionData = _sessionData;
    if (sessionData == null) {
      return;
    }
    await _sendSessionData(sessionData);
    await _sendPeriodicData();
    await _sendAnalysisData();

    periodicTimer?.cancel();
    periodicTimer = null;
    await analytics.close();
  }

  /// Record data from the given [params].
  void startedGetRefactoring(EditGetRefactoringParams params) {
    var requestData = getRequestData(EDIT_REQUEST_GET_REFACTORING);
    requestData.addEnumValue(refactoringKindEnumKey, params.kind.name);
  }

  /// Record that the server started working on the give [request] at the given
  /// [startTime].
  void startedRequest({required Request request, required DateTime startTime}) {
    var method = request.method;
    _activeRequests[request.id] = ActiveRequestData(
      method,
      request.clientRequestTime,
      startTime,
    );
  }

  /// Record that the server started working on the give [request] at the given
  /// [startTime].
  void startedRequestMessage({
    required RequestMessage request,
    required DateTime startTime,
  }) {
    _activeRequests[request.id.asLspIdString] = ActiveRequestData(
      request.method.toString(),
      request.clientRequestTime,
      startTime,
    );
  }

  /// Record data from the given [params].
  void startedSetAnalysisRoots(AnalysisSetAnalysisRootsParams params) {
    var requestData = getRequestData(ANALYSIS_REQUEST_SET_ANALYSIS_ROOTS);
    requestData.addValue(includedKey, params.included.length);
    requestData.addValue(excludedKey, params.excluded.length);
  }

  /// Record data from the given [params].
  void startedSetPriorityFiles(AnalysisSetPriorityFilesParams params) {
    var requestData = getRequestData(ANALYSIS_REQUEST_SET_PRIORITY_FILES);
    requestData.addValue(
      ANALYSIS_REQUEST_SET_PRIORITY_FILES_FILES,
      params.files.length,
    );
  }

  /// Record that the server was started at the given [time], that it was passed
  /// the given command-line [arguments], that it was started by the client with
  /// the given [clientId] and [clientVersion].
  void startUp({
    required DateTime time,
    required List<String> arguments,
    required String clientId,
    required String? clientVersion,
  }) {
    _sessionData = SessionData(
      startTime: time,
      commandLineArguments: arguments.join(','),
      clientId: clientId,
      clientVersion: clientVersion ?? '',
    );
  }

  /// Return an HTML representation of the data that has been recorded.
  String? toHtml(StringBuffer buffer) {
    var sessionData = _sessionData;
    if (sessionData == null) {
      return null;
    }

    void h3(String title) {
      buffer.writeln('<h3>${escape(title)}</h3>');
    }

    void h4(String title) {
      buffer.writeln('<h4>${escape(title)}</h4>');
    }

    void h5(String title) {
      buffer.writeln('<h5>${escape(title)}</h5>');
    }

    void li(String item) {
      buffer.writeln('<li>${escape(item)}</li>');
    }

    List<MapEntry<String, V>> sorted<V>(
      Iterable<MapEntry<String, V>> entries,
    ) => entries.sortedBy((entry) => entry.key);

    buffer.writeln('<hr>');

    var endTime = DateTime.now().millisecondsSinceEpoch;
    var duration = endTime - sessionData.startTime.millisecondsSinceEpoch;
    h3('Session data');
    buffer.writeln('<ul>');
    li('clientId: ${sessionData.clientId}');
    li('clientVersion: ${sessionData.clientVersion}');
    li('duration: ${duration.toString()}');
    li('flags: ${sessionData.commandLineArguments}');
    li('parameters: ${sessionData.initializeParams}');
    li('plugins: ${_pluginData.usageCountData}');
    buffer.writeln('</ul>');

    if (_completedRequests.isNotEmpty) {
      h3('Server response times');
      var entries = sorted(_completedRequests.entries);
      for (var entry in entries) {
        var data = entry.value;
        h4(data.method);
        buffer.writeln('<ul>');
        li('latency: ${data.latencyTimes.toAnalyticsString()}');
        li('duration: ${data.responseTimes.toAnalyticsString()}');
        for (var field in data.additionalPercentiles.entries) {
          li('${field.key}: ${field.value.toAnalyticsString()}');
        }
        for (var field in data.additionalEnumCounts.entries) {
          li('${field.key}: ${json.encode(field.value)}');
        }
        buffer.writeln('</ul>');
      }
    }

    var responseTimes = PluginManager.pluginResponseTimes;
    if (responseTimes.isNotEmpty) {
      h3('Plugin response times');
      for (var pluginEntry in responseTimes.entries) {
        h4(pluginEntry.key.safePluginId);
        var entries = sorted(pluginEntry.value.entries);
        for (var responseEntry in entries) {
          h5(responseEntry.key);
          buffer.writeln('<ul>');
          li('duration: ${responseEntry.value.toAnalyticsString()}');
          buffer.writeln('</ul>');
        }
      }
    }

    if (_completedNotifications.isNotEmpty) {
      h3('Notification handling times');
      buffer.writeln('<ul>');
      var entries = sorted(_completedNotifications.entries);
      for (var entry in entries) {
        var data = entry.value;
        li('latency: ${data.latencyTimes.toAnalyticsString()}');
        li('method: ${data.method}');
        li('duration: ${data.handlingTimes.toAnalyticsString()}');
      }
      buffer.writeln('</ul>');
    }

    if (_lintUsageCounts.isNotEmpty) {
      h3('Lint usage counts');
      buffer.writeln('<ul>');
      li('usageCounts: ${json.encode(_lintUsageCounts)}');
      buffer.writeln('</ul>');
    }

    if (_severityAdjustments.isNotEmpty) {
      h3('Severity adjustments');
      buffer.writeln('<ul>');
      li('adjustmentCounts: ${json.encode(_severityAdjustments)}');
      buffer.writeln('</ul>');
    }

    var analysisData = _contextStructure;
    if (analysisData != null) {
      h3('Analysis data');
      buffer.writeln('<ul>');
      li('numberOfContexts: ${json.encode(analysisData.numberOfContexts)}');
      li(
        'contextsWithoutFiles: ${json.encode(analysisData.contextsWithoutFiles)}',
      );
      li(
        'contextsFromPackagesFiles: ${json.encode(analysisData.contextsFromPackagesFiles)}',
      );
      li(
        'contextsFromOptionsFiles: ${json.encode(analysisData.contextsFromOptionsFiles)}',
      );
      li(
        'contextsFromBothFiles: ${json.encode(analysisData.contextsFromBothFiles)}',
      );
      li('immediateFileCount: ${json.encode(analysisData.immediateFileCount)}');
      li(
        'immediateFileLineCount: ${json.encode(analysisData.immediateFileLineCount)}',
      );
      li(
        'transitiveFileCount: ${json.encode(analysisData.transitiveFileCount)}',
      );
      li(
        'transitiveFileLineCount: ${json.encode(analysisData.transitiveFileLineCount)}',
      );
      li(
        'transitiveFileUniqueCount: ${json.encode(analysisData.transitiveFileUniqueCount)}',
      );
      li(
        'transitiveFileUniqueLineCount: ${json.encode(analysisData.transitiveFileUniqueLineCount)}',
      );
      buffer.writeln('</ul>');
    }

    return buffer.toString();
  }

  /// Record that the request with the given [id] was responded to at the given
  /// [sendTime].
  void _recordResponseData(String id, DateTime sendTime) {
    var data = _activeRequests.remove(id);
    if (data == null) {
      return;
    }

    var method = data.method;
    var clientRequestTime = data.clientRequestTime;
    var startTime = data.startTime.millisecondsSinceEpoch;

    var requestData = getRequestData(method);

    if (clientRequestTime != null) {
      var latencyTime = startTime - clientRequestTime;
      requestData.latencyTimes.addValue(latencyTime);
    }

    var responseTime = sendTime.millisecondsSinceEpoch - startTime;
    requestData.responseTimes.addValue(responseTime);
  }

  /// Send information about the number of files and the number of lines of code
  /// in those files.
  Future<void> _sendAnalysisData() async {
    var contextStructure = _contextStructure;
    if (contextStructure != null) {
      analytics.send(
        Event.contextStructure(
          numberOfContexts: contextStructure.numberOfContexts,
          contextsWithoutFiles: contextStructure.contextsWithoutFiles,
          contextsFromPackagesFiles: contextStructure.contextsFromPackagesFiles,
          contextsFromOptionsFiles: contextStructure.contextsFromOptionsFiles,
          contextsFromBothFiles: contextStructure.contextsFromBothFiles,
          immediateFileCount: contextStructure.immediateFileCount,
          immediateFileLineCount: contextStructure.immediateFileLineCount,
          transitiveFileCount: contextStructure.transitiveFileCount,
          transitiveFileLineCount: contextStructure.transitiveFileLineCount,
          transitiveFileUniqueCount: contextStructure.transitiveFileUniqueCount,
          transitiveFileUniqueLineCount:
              contextStructure.transitiveFileUniqueLineCount,
        ),
      );
    }
  }

  /// Send information about the number of times each lint is enabled in an
  /// analysis options file.
  Future<void> _sendLintUsageCounts() async {
    if (_lintUsageCounts.isNotEmpty) {
      var entries = _lintUsageCounts.entries.toList();
      _lintUsageCounts.clear();
      for (var entry in entries) {
        analytics.send(
          Event.lintUsageCount(count: entry.value, name: entry.key),
        );
      }
    }
  }

  /// Send information about the notifications handled by the server.
  Future<void> _sendNotificationHandlingTimes() async {
    if (_completedNotifications.isNotEmpty) {
      var completedNotifications = _completedNotifications.values.toList();
      _completedNotifications.clear();
      for (var data in completedNotifications) {
        analytics.send(
          Event.clientNotification(
            latency: data.latencyTimes.toAnalyticsString(),
            method: data.method,
            duration: data.handlingTimes.toAnalyticsString(),
          ),
        );
      }
    }
  }

  /// Send the information that is sent periodically, which is everything other
  /// than the session data.
  Future<void> _sendPeriodicData() async {
    await _sendServerResponseTimes();
    await _sendPluginResponseTimes();
    await _sendNotificationHandlingTimes();
    await _sendLintUsageCounts();
    await _sendSeverityAdjustments();
  }

  /// Send information about the response times of plugins.
  Future<void> _sendPluginResponseTimes() async {
    var responseTimes = PluginManager.pluginResponseTimes;
    if (responseTimes.isNotEmpty) {
      var entries = responseTimes.entries.toList();
      responseTimes.clear();
      for (var pluginEntry in entries) {
        for (var responseEntry in pluginEntry.value.entries) {
          analytics.send(
            Event.pluginRequest(
              pluginId: pluginEntry.key.safePluginId,
              method: responseEntry.key,
              duration: responseEntry.value.toAnalyticsString(),
            ),
          );
        }
      }
    }
  }

  /// Send information about the response times of server.
  Future<void> _sendServerResponseTimes() async {
    if (_completedRequests.isNotEmpty) {
      var completedRequests = _completedRequests.values.toList();
      _completedRequests.clear();
      for (var data in completedRequests) {
        analytics.send(
          Event.clientRequest(
            latency: data.latencyTimes.toAnalyticsString(),
            method: data.method,
            duration: data.responseTimes.toAnalyticsString(),
            added: data.additionalPercentiles[addedKey]?.toAnalyticsString(),
            excluded:
                data.additionalPercentiles[excludedKey]?.toAnalyticsString(),
            files: data.additionalPercentiles[filesKey]?.toAnalyticsString(),
            included:
                data.additionalPercentiles[includedKey]?.toAnalyticsString(),
            openWorkspacePaths:
                data.additionalPercentiles[openWorkspacePathsKey]
                    ?.toAnalyticsString(),
            removed:
                data.additionalPercentiles[removedKey]?.toAnalyticsString(),
          ),
        );
        var commandMap = data.additionalEnumCounts[commandEnumKey];
        if (commandMap != null) {
          for (var entry in commandMap.entries) {
            analytics.send(
              Event.commandExecuted(count: entry.value, name: entry.key),
            );
          }
        }
        // TODO(brianwilkerson): We don't appear to have an event defined that we
        //  can use to send analytics about how often old-style refactorings are
        //  being invoked.
        // var refactoringMap = data.additionalEnumCounts[refactoringKindEnumKey];
      }
    }
  }

  /// Send information about the session.
  Future<void> _sendSessionData(SessionData sessionData) async {
    var endTime = DateTime.now().millisecondsSinceEpoch;
    var duration = endTime - sessionData.startTime.millisecondsSinceEpoch;
    analytics.send(
      Event.serverSession(
        flags: sessionData.commandLineArguments,
        parameters: sessionData.initializeParams,
        clientId: sessionData.clientId,
        clientVersion: sessionData.clientVersion,
        duration: duration,
      ),
    );
    for (var entry in _pluginData.usageCounts.entries) {
      analytics.send(
        Event.pluginUse(
          count: _pluginData.recordCount,
          enabled: entry.value.toAnalyticsString(),
          pluginId: entry.key,
        ),
      );
    }
  }

  /// Send information about the number of times that the severity of a
  /// diagnostic is changed in an analysis options file.
  Future<void> _sendSeverityAdjustments() async {
    if (_severityAdjustments.isNotEmpty) {
      var entries = _severityAdjustments.entries.toList();
      _severityAdjustments.clear();
      for (var entry in entries) {
        analytics.send(
          Event.severityAdjustment(
            adjustments: json.encode(entry.value),
            diagnostic: entry.key,
          ),
        );
      }
    }
  }
}

extension on Either2<int, String> {
  /// Returns a String ID for this LSP request ID.
  ///
  /// Prefixes with "LSP:" to avoid collisions with legacy IDs when both kinds
  /// of requests are being used (and may have independent/overlapping IDs).
  String get asLspIdString {
    var idString = map((value) => value.toString(), (value) => value);
    return 'LSP:$idString';
  }
}