// Copyright 2016 The Chromium 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 'package:usage/usage_io.dart';

import 'base/context.dart';
import 'base/os.dart';
import 'base/utils.dart';
import 'globals.dart';
import 'version.dart';

// TODO(devoncarew): We'll want to find a way to send (sanitized) command parameters.

const String _kFlutterUA = 'UA-67589403-6';

Usage get flutterUsage => Usage.instance;

class Usage {
  /// Create a new Usage instance; [versionOverride] is used for testing.
  Usage({ String settingsName: 'flutter', String versionOverride }) {
    final String version = versionOverride ?? FlutterVersion.getVersionString(whitelistBranchName: true);
    _analytics = new AnalyticsIO(_kFlutterUA, settingsName, version);

    // Report a more detailed OS version string than package:usage does by
    // default as custom dimension 1 (configured in our analytics account).
    _analytics.setSessionValue('dimension1', os.name);

    bool runningOnCI = false;

    // Many CI systems don't do a full git checkout.
    if (version.endsWith('/unknown'))
      runningOnCI = true;

    // Check for common CI systems.
    if (isRunningOnBot)
      runningOnCI = true;

    // If we think we're running on a CI system, default to not sending analytics.
    _analytics.analyticsOpt = runningOnCI ? AnalyticsOpt.optIn : AnalyticsOpt.optOut;
  }

  /// Returns [Usage] active in the current app context.
  static Usage get instance => context.putIfAbsent(Usage, () => new Usage());

  Analytics _analytics;

  bool _printedWelcome = false;
  bool _suppressAnalytics = false;

  bool get isFirstRun => _analytics.firstRun;

  bool get enabled => _analytics.enabled;

  bool get suppressAnalytics => _suppressAnalytics || _analytics.firstRun;

  /// Suppress analytics for this session.
  set suppressAnalytics(bool value) {
    _suppressAnalytics = value;
  }

  /// Enable or disable reporting analytics.
  set enabled(bool value) {
    _analytics.enabled = value;
  }

  /// A stable randomly generated UUID used to deduplicate multiple identical
  /// reports coming from the same computer.
  String get clientId => _analytics.clientId;

  void sendCommand(String command) {
    if (!suppressAnalytics)
      _analytics.sendScreenView(command);
  }

  void sendEvent(String category, String parameter) {
    if (!suppressAnalytics)
      _analytics.sendEvent(category, parameter);
  }

  void sendTiming(String category, String variableName, Duration duration) {
    _analytics.sendTiming(variableName, duration.inMilliseconds, category: category);
  }

  UsageTimer startTimer(String event) {
    if (suppressAnalytics)
      return new _MockUsageTimer();
    else
      return new UsageTimer._(event, _analytics.startTimer(event, category: 'flutter'));
  }

  void sendException(dynamic exception, StackTrace trace) {
    if (!suppressAnalytics)
      _analytics.sendException('${exception.runtimeType}\n${sanitizeStacktrace(trace)}');
  }

  /// Fires whenever analytics data is sent over the network; public for testing.
  Stream<Map<String, dynamic>> get onSend => _analytics.onSend;

  /// Returns when the last analytics event has been sent, or after a fixed
  /// (short) delay, whichever is less.
  Future<Null> ensureAnalyticsSent() async {
    // TODO(devoncarew): This may delay tool exit and could cause some analytics
    // events to not be reported. Perhaps we could send the analytics pings
    // out-of-process from flutter_tools?
    await _analytics.waitForLastPing(timeout: const Duration(milliseconds: 250));
  }

  void printWelcome() {
    // This gets called if it's the first run by the selected command, if any,
    // and on exit, in case there was no command.
    if (_printedWelcome)
      return;
    _printedWelcome = true;

    printStatus('');
    printStatus('''
  ╔════════════════════════════════════════════════════════════════════════════╗
  ║                 Welcome to Flutter! - https://flutter.io                   ║
  ║                                                                            ║
  ║ The Flutter tool anonymously reports feature usage statistics and crash    ║
  ║ reports to Google in order to help Google contribute improvements to       ║
  ║ Flutter over time.                                                         ║
  ║                                                                            ║
  ║ Read about data we send with crash reports:                                ║
  ║ https://github.com/flutter/flutter/wiki/Flutter-CLI-crash-reporting        ║
  ║                                                                            ║
  ║ See Google's privacy policy:                                               ║
  ║ https://www.google.com/intl/en/policies/privacy/                           ║
  ║                                                                            ║
  ║ Use "flutter config --no-analytics" to disable analytics and crash         ║
  ║ reporting.                                                                 ║
  ╚════════════════════════════════════════════════════════════════════════════╝
  ''', emphasis: true);
  }
}

class UsageTimer {
  UsageTimer._(this.event, this._timer);

  final String event;
  final AnalyticsTimer _timer;

  void finish() {
    _timer.finish();
  }
}

class _MockUsageTimer implements UsageTimer {
  @override
  String event;
  @override
  AnalyticsTimer _timer;

  @override
  void finish() { }
}