// Copyright 2020 The Flutter team. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:platform_channels/src/event_channel_demo.dart';

void main() {
  group('EventChannel Demo tests', () {
    final sensorValues = [1.3556, 2.3, -0.12];
    setUpAll(() {
      // By default EventChannel uses StandardMethodCodec to communicate with
      // platform.
      const standardMethod = StandardMethodCodec();

      // This function handles the incoming messages from the platform. It
      // calls the BinaryMessenger.setMessageHandler registered for the EventChannel
      // and add the incoming message to the StreamController used by the EventChannel
      // after decoding the message with codec used by the EventChannel.
      void emitValues(ByteData? event) {
        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
            .handlePlatformMessage('eventChannelDemo', event, (reply) {});
      }

      // Register a mock for EventChannel. EventChannel under the hood uses
      // MethodChannel to listen and cancel the created stream.

      TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
          .setMockMessageHandler('eventChannelDemo', (message) async {
            // Decode the message into MethodCallHandler.
            final methodCall = standardMethod.decodeMethodCall(message);

            if (methodCall.method == 'listen') {
              // Emit new sensor values.
              emitValues(
                standardMethod.encodeSuccessEnvelope(sensorValues),
              );
              emitValues(null);
              return standardMethod.encodeSuccessEnvelope(null);
            } else if (methodCall.method == 'cancel') {
              return standardMethod.encodeSuccessEnvelope(null);
            } else {
              fail('Expected listen or cancel');
            }
          });
    });

    testWidgets('EventChannel AccelerometerReadings Stream test', (
      tester,
    ) async {
      await tester.pumpWidget(const MaterialApp(home: EventChannelDemo()));

      await tester.pumpAndSettle();

      // Check the values of axis. The value is rounded to 3 decimal places.
      expect(
        find.text('x axis: ${sensorValues[0].toStringAsFixed(3)}'),
        findsOneWidget,
      );
      expect(
        find.text('y axis: ${sensorValues[1].toStringAsFixed(3)}'),
        findsOneWidget,
      );
      expect(
        find.text('z axis: ${sensorValues[2].toStringAsFixed(3)}'),
        findsOneWidget,
      );
    });
  });
}
